The diagnosis of autoimmune bullous disorders (AIBDs) relies on several different diagnostic methods. These include histopathology, direct immunofluorescence (DIF), indirect immunofluorescence (IIF), enzyme-linked immunosorbent assay (ELISA) and immunoblotting. When faced with a presumptive AIBD, the most widely employed method for diagnosis by dermatologists is a combination of histopathology and DIF. While DIF is still the diagnostic method of choice for linear IgA bullous disease and IgA pemphigus, ELISA is a more accurate, cost-effective and less invasive method of diagnosis for several AIBDs including pemphigus vulgaris and foliaceus, based on currently available evidence [1-3].
The purpose of this article is to review and compare the evidence supporting the use of these diagnostic methods, both traditional and recent, which are available to practitioners. This comparison should provide a practical reference for the evidence-based diagnostic method or combined methods of choice for each AIBD. The techniques and basic science underlying widely available methods are briefly explained. Additionally, newer methods with limited availability but which may become diagnostically relevant in the near future, such as mosaic IIF, are also reviewed.
Overview of methods for the detection of autoantibodies in AIBDs
DIF is the most commonly used technique in practice to diagnose AIBDs. In DIF, the target antigen is the patient’s autoantibody. Skin 5 mm from the site of a blister is obtained and placed in a transport medium such as Michel’s buffer. Frozen sections of this perilesional skin are prepared, and each section is incubated with a single primary antibody, such as anti-IgG, anti-IgM, or anti-C3. These primary antibodies are linked to fluorescein isothiocyanate (FITC), a fluorophore which is visualized by a pathologist using a fluorescent microscope. The presence or absence of epifluorescence is then reported and can be relatively and subjectively quantified .
In IIF, the target antigen is present in a known and readily available substrate. This substrate is incubated with the patient’s dilute serum which contains the primary antibody. Secondary antibodies labeled with FITC are then added and bind to the primary antibodies. Epifluorescence is visualized with a fluorescent microscope and can be quantified by successive titration of the patient’s serum .
In an ELISA, the target antigen of interest (such as the NC16a domain of BP180) is immobilized by physical adsorption or by antibody capture. When antibody capture is utilized, this is referred to as “sandwich ELISA” because the target antigen is bound between the immobilizing antibody and the primary antibody. Primary antibodies are present in the patient’s serum. Enzyme-linked secondary antibodies are then added which bind the Fc region of primary antibodies. Substrate is added and converted by the enzyme into a signal. A resulting color change, fluorescence, or electrochemical signal is quantitatively measured and reported .
Western blot is synonymous with immunoblot. For this method, cells which express the target antigen or antigens of interest are cultured and then lysed to release proteins. These proteins are denatured and then separated by gel electrophoresis on the basis of their molecular weights, measured in kilodaltons (kDa). Electroblotting then transfers these proteins to a membranous medium. After non-specific sites on the membrane are blocked, it is incubated with the primary antibodies (patient’s serum). A secondary antibody linked with a reporter enzyme, frequently horseradish peroxidase, binds to the primary antibody. The enzymatic reaction produces a luminescent signal which is captured by a camera and then quantified . Immunoprecipitation is a variant of immunoblot that can be used to identify, isolate, and concentrate multiple (potential) target antigens. A lysate solution is incubated with a patient’s serum, and complexes are formed between target antigens and primary autoantibodies. These antigen-antibody complexes are then immobilized on beads, precipitated out of solution, and then analyzed by standard immunoblotting technique .
The pemphigus group includes pemphigus vulgaris (PV), pemphigus foliaceus (PF), drug-induced pemphigus (DIP) and paraneoplastic pemphigus (PNP), mediated primarily by IgG autoantibodies directed against desmosomal cadherin proteins involved in intercellular adhesion. Pemphigus vulgaris typically presents in the fifth and sixth decades of life and is characterized by thin-walled, flaccid bullae, which rupture easily to form painful erosions and crusted lesions. PV typically affects mucosal surfaces in addition to keratinized skin, with the majority of cases first presenting in the mouth. Autoantibodies are most often directed against desmoglein 3 (Dsg3), with molecular weight 130 kDa, but may also target desmoglein 1 (Dsg1) in mucocutaneous disease. However, diagnosis is made when anti-Dsg3 autoantibodies are present, regardless of presence or absence of anti-Dsg1. Pemphigus foliaceus is characterized by superficial, flaccid bullae that easily rupture and lead to shallow erosions with adherent scale crust, described as resembling corn flakes (Figure 1). Unlike PV, PF rarely affects mucosal surfaces. Antibodies in PF target desmoglein 1 (Dsg1), with molecular weight 160 kDa .
ELISA is the most accurate diagnostic tool for the diagnosis of PV and PF. In a 2012 meta-analysis of 13 studies with a sample size of 1058 patients, ELISA for anti-Dsg3 IgG had a pooled sensitivity of 97% and specificity of 98% . ELISA for anti-Dsg IgG in patients with PF has a sensitivity and specificity of 96% and 99%, respectively [2,3]. One limitation of ELISA is observed at very high antibody titers (equivalent to that of IIF assay titers of 320 or greater), at which readings plateau. In contrast, IIF remains quantitative at high titers .
Histology provides important clues, but cannot by itself distinguish between PV and PF given variability in the level of clefting. Generally, acantholysis is suprabasilar in PV and subcorneal or intragranular in PF. However, a 2014 study by Ohata et al. found significant histologic overlap in the location of acantholysis between these two diseases with a quarter of all pemphigus cases showing diffuse acantholysis. Additionally, while acantholytic dyskeratotic cells are commonly reported in PV, they were identified in over 60% of casees of both PV and PF. Neutrophils were found as the predominant cell type in the epidermis over eosinophils more often in PF than PV (70.8% versus 54.8%) .
DIF approaches 100% sensitivity, but cannot distinguish PF from PV as both show a similar fluorescence pattern with typical uniform intercellular IgG and complement staining (“swiss cheese” or “chicken wire” pattern) [10-13]. IIF is less sensitive than ELISA and DIF, but can helpful to establish antibody titers. Similar to DIF, IIF cannot distinguish between PV and PF and will demonstrate intercellular staining in both. Sensitivity ranges between 81-95% [13-15]. Of note, the choice of substrate affects the results of IIF. Several studies have compared these monkey and human esophagus. In one study monkey esophagus was superior or equal in sensitivity for antibody detection in either pemphigus subtype while another study found monkey esophagus superior for PV diagnosis and human esophagus superior for PF diagnosis [15,16]. Although not commonly used, immunoblotting differentiates between the different clinical phenotypes of PV (mucocutaneous, purely mucosal or purely cutaneous) with 100% specificity. However, it is only 89% sensitive for the diagnosis of PV and more expensive. For PF, immunoblotting has a sensitivity of 100% and specificity of 95% .
In monitoring patient response to therapy, ELISA index values correlate better with disease activity compared to IIF titers [3,18]. In particular, anti-Dsg1 ELISA values correlate with skin lesion severity in both PV and PF, while anti-Dsg3 values do not follow mucosal lesion severity in PV . ELISA is also better than DIF in evaluating immunologic remission of PV. Negative predictive value in one study was 100%, which is important when discontinuing treatment, in order to minimize false negatives .
In mucosal PV, the combination of ELISA and Tzanck smear has the best overall sensitivity and specificity, 82% and 98.7% respectively, compared to either test alone or other diagnostic methods . Histologic evaluation alone of affected mucosa can be misleading given frequently nonspecific findings or subtle acantholysis. In a series of 12 cases, two identified initially as mucous membrane pemphigoid (MMP) based on histology alone were ultimately diagnosed as PV .
If drug-induced pemphigus (DIP) is suspected, the most specific test is immunohistochemical staining with 32-2B, a monoclonal antibody against Dsg1 and Dsg3. Immunoperoxidase for 32-2B is 84% specific and 70% sensitive for DIP. Normal skin and DIP both show net-like deposits along cytoplasmic membranes in contrast to idiopathic pemphigus, which shows coarse pericytoplasmic granules . Unfortunately, this immunostain is routinely or widely available, and most pathologists are not familiar with its interpretation. Histology, DIF, IIF, ELISA and immunoblotting cannot distinguish DIP from idiopathic pemphigus. Thus, distinction between DIP and idiopathic pemphigus most often depends on clinical correlation.
PNP has a wide range of clinical manifestations. Mucosal lesions may resemble Stevens-Johnson syndrome with hemorrhagic crusting of the lips and widespread mucosal erosions. Cutaneous lesions may appear lichen planus-like, erythema multiforme-like, bullous pemphigoid-like or with erosions typical of pemphigus. The implicated target antigens are also more varied and include desmoplakin 1 (250 kDa), envoplakin (210 kDa), periplakin (190 kDa) and bullous pemphigoid antigen-1 (BPAg1, 230 kDa), in addition to Dsg1 and Dsg3. Recently, alpha-2-macroglobulin-like protein 1 (A2ML1) has also been characterized as a target in PNP .
Immunoblotting for envoplakin and/or periplakin approaches 100% sensitivity and is considered the gold standard diagnostic method. However, specificity is lowered by false positives to 82-91% [24-26]. IIF on rat bladder is the best confirmatory test; although sensitivity ranges from 67-95%, specificity is close to 100% [24,26,27]. The histology of PNP is nonspecific and is lichenoid as often as it is acantholytic (Figure 2); both reaction patterns may be observed together in up to 60% of cases. Of note, keratinocyte necrosis is associated with a poorer prognosis. DIF is considered diagnostic (specificity up to 97%) when staining for IgG and/or C3 is observed both within intercellular spaces as well at the dermoepidermal junction (DEJ). However, less than half of PNP cases show both intercellular and junctional immunofluorescence, making this unique finding insensitive [24,26,28]. DIF is 100% sensitive when considering either intercellular or junctional staining, but only 40% specific .
Currently, ELISA is considered a complementary test only for PNP. A 2015 study by Ohzono et al. evaluated several ELISAs for PNP diagnosis. ELISA for anti-Dsg1 and anti-Dsg3 IgG was 86% sensitive, but these assays cannot distinguish PNP from PF or PV. ELISA for IgG against desmocollins (Dsc) 1, 2, and 3 demonstrated a combined sensitivity of 72%. ELISA for IgG against A2ML1 has a sensitivity of 60% . Separate studies have evaluated ELISA arrays for envoplakin, with variable sensitivity (30-100%) but high specificity (90-100%) [24,25,29]. A study by Huang et al. of 16 PNP cases found positive IgG autoantibodies against envoplakin and periplakin by ELISA in all 16 cases of PNP evaluated .
IgA pemphigus presents with flaccid vesicles or pustules in annular or circinate configuration with central crusting (Figure 3). The axilla and groin are most commonly involved, but it also found on the trunk and extremities. Two distinct subtypes of this disease have been identified. The target antigen in the subcorneal pustular dermatosis (SPD) type is Dsc1. The intraepidermal neutrophilic (IEN) type has an unknown target antigen .
DIF is the most sensitive and specific test for IgA pemphigus, demonstrating intercellular deposition of IgA in all cases. In the SPD type, IgA deposits are concentrated in the upper epidermis, while in the IEN type, IgA is observed throughout the entire epidermis [32,33]. DIF should be performed to distinguish cases of subcorneal pustular dermatosis (Sneddon-Wilkinson disease) from the SPD type of IgA pemphigus. Sneddon-Wilkinson disease demonstrates a negative DIF but is associated with monoclonal gammopathy, while the SPD type of IgA pemphigus demonstrates a positive DIF but is not associated with hematologic abnormalities . IIF has shown variable sensitivity for the diagnosis of IgA pemphigus, ranging from 50-100% and is often negative in the IEN type [33,35]. Histology is highly nonspecific with a broad differential diagnosis, and unlike classic pemphigus, acantholysis is typically absent. ELISA is approximately 20% sensitive for the diagnosis of IgA pemphigus based on detection of IgG or IgA against Dsg1 or Dsg3, but may be useful in excluding classic pemphigus [33,36].
Bullous pemphigoid (BP) is the most common AIBD and is characterized by the typical clinical presentation of pruritic urticarial lesions that evolve into tense blisters. Typical histologic features are generally nonspecific, and include eosinophil-rich or cell-poor subepidermal blisters. Urticarial lesions demonstrate numerous eosinophils at the DEJ (Figure 4). In BP, autoantibodies target two hemidesmosomal proteins at the DEJ: BP antigen 1 (BPAG1 or BP230), a 230-kDa intracellular plakin-family protein, and BP antigen 2 (BPAG2 or BP180), a 180-kDa transmembrane collagen-family protein comprised of a central domain separating two N- and C- terminal domains [37-39]. Due to the greater prevalence of BP180 autoimmunity and the ability of BP180-directed antibodies to reproduce disease in animal models, BP180 is thought to be the major antigenic target in BP. However, a small proportion of patients with BP only develop antibodies against BP230 [40-42].
DIF is the most sensitive test for the diagnosis of BP and serves as a reference to evaluate to sensitivities of other methods. DIF most commonly shows linear deposition of IgG and C3, although additional immunoreactants including IgM, IgA, and/or IgE may also be seen. Given its role as a reference test, it is difficult to assess the true sensitivity of DIF, but numbers ranging from 82-96% have been reported [43-45]. Given that DIF does not identify antigenic targets, this test does not differentiate between BP and other AIBDs with linear staining at the DEJ such as mucous membrane pemphigoid (MMP) or epidermolysis bullosa acquisita (EBA).
IIF on salt split skin (SSS) allows improved localization of the target antigen and may be used to confirm the diagnosis of BP. IIF demonstrates localization of autoantibodies to the epidermal side of the salt split, although some cases demonstrate immunofluorescence on the dermal side as well. Sensitivities are comparable to those of ELISA and slightly lower than those reported for DIF, ranging from 81-96%.(39, 41) IIF positivity has been found to correlate more strongly with ELISA for anti-BP230 compared to that for anti-BP180 [41,43,46]. This may explain why IIF titers do not correlate well with disease activity (see below) .
Commercial availability of ELISA for IgG autoantibodies against BP180 and BP230 has popularized the use of this assay for the diagnosis of BP and has allowed for a standardized comparison of sensitivities and specificities. ELISA for anti-BP180 evaluates for the presence of antibodies against the NC16a region of BP180. Reported sensitivity ranges from 79-100% with a specificity above 95% [1,39,41,46,47]. Of note, reported sensitivities may be inflated by the requirement of DIF positivity for inclusion in comparison studies. Studies including DIF-negative cases of BP have reported sensitivities near 72% . Additionally, the sensitivity of ELISA for anti-BP180 may be limited by exclusion of targets outside the NC16a domain of the target antigen. Fairley et al. found that 4 of 51 patients with BP had sera that reacted with areas of BP180 outside of the NC16a domain by immunoblot . However, immunoblot is not recommended for the diagnosis of BP given that it frequently detects nonpathogenic autoantibodies directed against antigens outside of the NC16a domain.(49) ELISA titers for anti-BP180 correlate with disease response [39,50-55]. and, when high initially, predict relapse following treatment cessation .
ELISA for IgG against BP230 demonstrates lower sensitivities for diagnosis, ranging from 57-61% [41,43,46]. When combined with ELISA for anti-BP180, it does offer a modest increase in sensitivity (8-10%) for the diagnosis of BP [41,42,46]. Due to a high rate of false negatives, ELISA for anti-BP230 is not preferred as an initial diagnostic screening test. However, following the use of ELISA for anti-BP180 as a diagnostic screen, ELISA for anti-BP230 may be evaluated in patients seronegative for antibodies against BP180. Additionally, ELISA for anti-BP230 may also be selected in patients with mucosal disease. Unlike ELISA titers for IgG against BP180, titers for IgG against BP230 do not correlate with disease course [39,50-55].
MMP (also referred to as cicatricial pemphigoid, CP) is an AIBD characterized by autoantibodies against BP230, BP180, laminin-332 (laminin 5), integrin β4, or type VII collagen (COL7). Clinical manifestations include mucosal erosions with scarring, with or without cutaneous lesions [57,58]. The oral and ocular mucosae are most commonly involved; other sites include the nasopharynx, oropharynx, larynx and anogenital regions [57,59,60]. Histology is non-specific, revealing a subepidermal blister with fibrosis, pauci-inflammatory or with chronic inflammation . Sera from patients with MMP may target one or several autoantigens [57,58]. The most commonly identified autoantigens are BP180 and laminin 5 [58,60].
Linear DIF for IgG, IgA, IgM, and/or C3 at the DEJ in the appropriate clinical context is the most sensitive method for diagnosis, but is not specific [57,58,61]. Examination at high power for the n-serration pattern can distinguish MMP from possible epidermolysis bullosa acquisita (EBA) or bullous systemic lupus erythematosus (BSLE) [59,62]. ELISA may be useful to identify the specific autoantigen(s), confirm the diagnosis, or subtype the disease. ELISA for identification of anti-laminin 5 MMP (antiepiligrin CP, AECP) is important due to the increased risk of visceral malignancy and has been demonstrated to be both sensitive and specific for this diagnosis [63-67]. Reactivity to the C-terminal domain of BP180 is more common in MMP than other AIBDs and may help distinguish MMP from BP [60,68-71]. Yasukochi et al. demonstrated that ELISA for IgG against the C-terminal of BP180 has a high specificity but low sensitivity: 39% positive in non-anti-laminin 5 MMP, 17% positive in BP, and 9% positive in anti-laminin 5 MMP .
IIF has minimal utility in diagnosing MMP as it is neither sensitive nor specific [57,58,67]. When positive, sera from patients with MMP may label the epidermal side, dermal side, or both sides of the salt split, reflecting the locations of the varied target antigens [57,58].
Gestational pemphigoid (GP) is similar in pathogenesis to BP, with autoantibodies against BP180, particularly the NC16a region. GP presents with pruritic urticarial plaques that evolve into subepidermal blisters [72,73]. GP occurs in the post-partum period or the second or third trimesters of pregnancy . Histopathology classically demonstrates a subepidermal blister with eosinophils, but these findings are highly nonspecific .
Several studies have supported the use of ELISA for IgG against BP180 (NC16a) as a sensitive and specific means to diagnose GP [76,77]. Powell et al. reported a sensitivity and specificity of 96% . In a small study comparing sensitivity of IIF and ELISA, 4 of 4 patients with GP tested positive by ELISA while only 2 of 4 were seropositive by IIF . Sitaru et al. also demonstrated a high sensitivity and specificity of this assay: 84% and 99%, respectively . Even with a higher threshold for seropositivity, Tani et al. reported a sensitivity of 92% . Given its accuracy, a benefit of ELISA is its ability to noninvasively differentiate GP from polymorphic eruption of pregnancy (PEP, previously known as pruritic urticarial plaques and papules of pregnancy), which are often considered in the same clinical differential diagnosis.
The target antigen in EBA is COL7, an important structural component of the sublamina densa . Clinical manifestations include skin fragility, blisters, erosions, scars, milia and nail loss. Two major clinical subtypes of EBA have been described, including a mechanobullous type which presents with skin fragility and scarring over extensor surfaces and sites of trauma (Figure 5), and an inflammatory type that presents with blisters over non-traumatized areas [80,81]. As the clinical presentation of the inflammatory subtype overlaps with a range of immunobullous disorders including BP, MMP, and LABD, immunofluorescence testing is necessary for accurate diagnosis .
DIF has been shown be highly sensitive and specific for EBA when evaluated for the pattern of immunodeposition. A characteristic u-serrated fluorescence pattern has been described that is both sensitive and specific for EBA and BSLE, both of which feature autoimmunity towards COL7A [62,83]. Using this technique, Vodegel et al. were able to detect 26 of 26 patients with EBA . These findings have been reproduced with a sensitivity of 89% and a specificity over 97% reported .
ELISA for anti-COL7 has been shown to be a highly specific (above 95%) but variably sensitive test for the diagnosis of EBA. Detection of autoantibodies by ELISA has been correlated with detection by IIF in several studies, with a reported sensitivity of over 80% in IIF-positive cases. However, in IIF-negative cases, ELISA was only positive in 23% of cases [85,86]. Other studies have provided corroborating evidence for the diagnostic utility of ELISA for anti-COL7, with sensitivities above 90% and strong correlation with disease course and severity [87-91]. Of note, low sensitivities, close to 20%, have also been reported . Immunoblot appears to be the gold standard for diagnosis, with sensitivity and specificity approaching 100% [86,92].
IIF is utilized to differentiate EBA from BP since DIF and histology are usually indistinguishable in these two entities. IIF localizes autoantibodies to the dermal side of SSS in EBA. However, up to 50% of cases are negative for autoantibodies by IIF . The sensitivities reported by most studies range from 50-100%[13,86,87,91,92].
IGA-mediated bullous dermatoses
Dermatitis herpetiformis (DH) presents with symmetric, small, clustered vesicles located on the elbows, knees and buttocks. Due to intense pruritus, intact vesicles are encoutered less often than small erosions and excoriations. As a cutaneous manifestation of a gluten-sensitive enteropathy, target antigens are epidermal transglutaminase (eTG) and tissue transglutaminase (tTG).
DIF and ELISA for anti-eTG IgA autoantibodies are the most accurate tests for diagnosis. Granular deposition of IgA in the dermal papillae as observed by DIF (Figure 6) is 92-100% sensitive for DH, but is less specific than ELISA for anti-eTG given the variability of immmunofluorescence patterns . Continuous granular IgA along the dermoepiermal junction has been identified as the predominant staining pattern in up to 60% of patients [94,95]. ELISA for anti-eTG is 90-100% sensitive and nears 100% specificity if the patient undergoing evaluation is consuming gluten . However, sensitivity drops to 50% if a patient’s diet is gluten-free. ELISA for anti-tTG is 79-100% sensitive, but not specific for DH given that patients with Celiac disease also produce this autoantibody . Similar to eTG, the sensitivity decreases, to approximately 20%, if a patient’s diet is gluten-free . A study of nine DH patients found a significant correlation between both anti-eTG and anti-tTG titers and the degree of enteropathy . IIF on monkey esophagus for circulating anti-endomysial antibodies is between 60-90% sensitive, but is not specific for DH given that these autoantibodies are also present in Celiac disease. IIF for IgA autoantibodies against basement mebrane zone antigens is always negative in DH [93,97]. Common histologic findings in DH are small subepidermal vesicles with neutrophilic infiltrate forming microabscesses within dermal papillae. Eosinophils may be rare or numerous. However, these classic findings are relatively insensitive given that 25-54% of cases demonstrate nonclassic findings such as predominantly perivascular lymphocytic infiltrates, minimal dermal papillary inflammation, and absence of neutrophils. Although H&E has poor sensitivity, the specificity of classic findings is 95% [95,100,101].
Linear IgA bullous disease (LABD) presents with tense blisters in a linearly or annular arrangement (“string of pearls,” Figure 7). There are two subgroups of LABD, lamina lucida-type and sublamina densa-type. The target antigens in the lamina lucida-type are the 97 kDA ectodomain of BP180 (LABD97) or the 120 kDa antigen termed LAD-1, also located on BP180 [102,103]. The target antigen of the sublamina densa-type has been reported to be COL7 by several small studies .
DIF is the best method for the diagnosis of LABD, showing linear IgA deposition at the DEJ in 100% of patients. Approximately 50% of cases will also demonstrate linear junctional staining for other reactants including IgG, IgM, C3 and fibrinogen . IIF in an insensitive (15-36%) diagnostic test [13,105]. Csorba et al. developed an ELISA for the detection of IgA autoantibodies against BP180. Among 30 patients with LABD, the study authors found a sensitivity of 83% and specificity of 100% with this assay . In a 2015 study Tsuchisaka, et al. developed an ELISA for IgA against COL7 and found that 8 of 12 sera from patients with sublamina-densa type of LABD reacted while all 16 control sera were negative .
Several new diagnostic modalities are now available allowing for efficient and accurate testing. These new immunoasssays include the Biochip mosaic-based IIF, automated DIF, and DNA microarray scanner. The Biochip mosaic-based IIF consolidates a multiple step diagnostic pathway into a single incubation, allowing for screening and testing of multiple target antigen-specific substrates of BP, PF and PV at once. Six test substrates (monkey esophagus, primate salt-split skin, antigen dots of tetrameric BP180, and BP230, Dsg1 and Dsg3-transfected HEK293 cells) are plated onto a glass slide. Following incubation with the patient serum and detection antibody, the case is ready for review in one hour. The sensitivity and specificity for the diagnosis of PV, PF, and BP are above 90% with this method. Sensitivity for individual IgG autoantibodies are 90% for anti-Dsg1, 99% for anti-Dsg3, 100% for anti-BP180 and 54% for anti-BP230 [107,108].
Automated DIF allows for quicker and less labor-intensive staining than conventional manual DIF. Compared to the standard manual procedure, automated DIF creates more intense IF signals and less background staining . Euroimmun, based in New Jersey, USA, manufactures the Biochip mosaic IIF and automated DIF tests.
A DNA microarray scanner can be used in place of standard epifluorescent microscopy as a digital fluorescence microscope to evaluate multiple antibodies at one time. It is more sensitive and efficient than standard fluorescence microscopy, but more expensive. Frozen sections of skin biopsies are incubated with cyanine-labeled antibodies and then scanned using a machine originally created to analyze gene expression, allowing for review of the entire specimen at once .
Conclusion and summary
Although DIF, in conjunction with routine histology, is most frequently used for the diagnosis of AIBDs, several more recently applied methods such as ELISA are useful and in some cases, more accurate. ELISA for anti-Dsg3 and anti-Dsg1 is the most accurate diagnostic method for PV and PF, and anti-Dsg1 titers correlate with the course of cutaneous disease [1-3]. For the diagnosis of mucosal-only PV, ELISA for anti-dsg3, in combination with Tzanck smear to identify acantholysis, is highly accurate and noninvasive . Distinction of DIP from idiopathic PV or PF most often requires clinical correlation; immunohistochemistry for 32-2B is useful but not widely available . The diagnostic methods of choice for PNP are immunoblot (western blot) for IgG against envoplakin and/or periplakin and IIF on rat bladder epithelium [24-26]. DIF is the most accurate method for the diagnosis of IgA pemphigus and allows distinction from Sneddon-Wilkinson disease [32-34].
For bullous pemphigoid, the most sensitive diagnostic test is still DIF [43-45]. However, ELISA for IgG against BP180 is cost-effective, noninvasive, and highly accurate, making it useful as a screening test [1,6,39,41,46,47]. If negative, ELISA for IgG against BP230 should be evaluated [41,42,46]. Additionally, ELISA for anti-BP180 is the best test for assessing disease course in BP [39,50-55]. For CP, DIF is the best test currently available for diagnosis, but is still highly nonspecific [57,58,61]. Clinicopathologic correlation is required for accurate diagnosis of CP, and ELISA for anti-laminin 5 should be evaluated to exclude the diagnosis of AECP [63-67]. Similar to BP, DIF and ELISA for anti-BP180 are the most accurate diagnostic tests for GP, and ELISA serves as a cost-effective and noninvasive screen in patients for whom the clinical differential diagnosis includes PEP [75-78]. Immunoblot for IgG against COL7 is the gold standard for EBA [86,92]; ELISA for anti-COL7 correlates well with disease activity but is variably sensitive for diagnosis [85-92]. While DIF alone is nonspecific, evaluation for the u-serration pattern is both sensitive and specific for EBA [62,83,84].
In DH, DIF and ELISA for IgA against eTG are the most accurate tests; if either or both of these tests are negative in a patient who consumes gluten, the diagnosis of DH can be confidently excluded [93,96]. For LABD, DIF is still the best diagnostic test .
Among newer methods, the Biochip mosaic IIF is a highly accurate method to screen for multiple AIBDs at once, is less expensive and quicker than ELISA, and is available to practitioners. Results can be confirmed by ELISA to complete a cost-effective and noninvasive multistep diagnostic algorithm [107,108].
- Tampoia M, Giavarina D, Di Giorgio C, Bizzaro N (2012) Diagnostic accuracy of enzyme-linked immunosorbent assays (ELISA) to detect anti-skin autoantibodies in autoimmune blistering skin diseases: a systematic review and meta-analysis. Autoimmun Rev 12: 121-126. [Crossref]
- Ishii K, Amagai M, Hall RP, Hashimoto T, Takayanagi A, et al. (1997) Characterization of autoantibodies in pemphigus using antigen-specific enzyme-linked immunosorbent assays with baculovirus-expressed recombinant desmogleins. Journal of immunology (Baltimore, Md : 1950). 159: 2010-2017. [Crossref]
- Schmidt E, Dahnrich C, Rosemann A, Probst C, Komorowski L, et al. (2010) Novel ELISA systems for antibodies to desmoglein 1 and 3: correlation of disease activity with serum autoantibody levels in individual pemphigus patients. Exp Dermatol 19: 458-463. [Crossref]
- Fritschy J-M, Härtig W (2001) Immunofluorescence. eLS: John Wiley & Sons, Ltd., USA.
- Lequin RM (2005) Enzyme immunoassay (EIA)/enzyme-linked immunosorbent assay (ELISA). Clin Chem 51: 2415-2418. [Crossref]
- Burnette WN (1981) "Western blotting": electrophoretic transfer of proteins from sodium dodecyl sulfate--polyacrylamide gels to unmodified nitrocellulose and radiographic detection with antibody and radioiodinated protein A. Anal Biochem 112: 195-203. [Crossref]
- Bonifacino JS, Dell'Angelica EC, Springer TA (2001) Immunoprecipitation. Curr Protoc Mol Biol Chapter 10: Unit 10. [Crossref]
- Kershenovich R, Hodak E, Mimouni D3 (2014) Diagnosis and classification of pemphigus and bullous pemphigoid. Autoimmun Rev 13: 477-481. [Crossref]
- Bystryn JC, Akman A, Jiao D (2002) Limitations in enzyme-linked immunosorbent assays for antibodies against desmogleins 1 and 3 in patients with pemphigus. Arch Dermatol 138: 1252-1253. [Crossref]
- Ohata C, Ishii N, Furumura M (2014) Locations of acantholysis in pemphigus vulgaris and pemphigus foliaceus. J Cutan Pathol 41: 880-889. [Crossref]
- Buch AC, Kumar H, Panicker N, Misal S, Sharma Y, et al. (2014) A Cross-sectional Study of Direct Immunofluorescence in the Diagnosis of Immunobullous Dermatoses. Indian J Dermatol 59: 364-368. [Crossref]
- Kumar S, Thappa DM, Sehgal S (1995) Immunofluorescence study of pemphigus from north India. J Dermatol 22: 571-575. [Crossref]
- Arbache ST, Nogueira TG, Delgado L, Miyamoto D, Aoki V (2014) Immunofluorescence testing in the diagnosis of autoimmune blistering diseases: overview of 10-year experience. An Bras Dermatol 89: 885-889.
- Zagorodniuk I, Weltfriend S, Shtruminger L, Sprecher E, Kogan O, et al. (2005) A comparison of anti-desmoglein antibodies and indirect immunofluorescence in the serodiagnosis of pemphigus vulgaris. Int J Dermatol 44: 541-544. [Crossref]
- Ng PP, Thng ST, Mohamed K, Tan SH (2005) Comparison of desmoglein ELISA and indirect immunofluorescence using two substrates (monkey oesophagus and normal human skin) in the diagnosis of pemphigus. Australas J Dermatol 46: 239-241. [Crossref]
- Harman KE, Gratian MJ, Bhogal BS, Challacombe SJ, Black MM (2000) The use of two substrates to improve the sensitivity of indirect immunofluorescence in the diagnosis of pemphigus. Br J Dermatol 142: 1135-1139. [Crossref]
- Khandpur S, Sharma VK, Sharma A, Pathria G, Satyam A (2010) Comparison of enzyme-linked immunosorbent assay test with immunoblot assay in the diagnosis of pemphigus in Indian patients. Indian J Dermatol Venereol Leprol 76: 27-32. [Crossref]
- Weiss D, Ristl R, Griss J, Bangert C, Foedinger D, et al. (2015) Autoantibody Levels and Clinical Disease Severity in Patients with Pemphigus: Comparison of Aggregated Anti-desmoglein ELISA Values and Indirect Immunofluorescence Titres. Acta derm venereol 95: 559-564. [Crossref]
- Abasq C, Mouquet H, Gilbert D, Tron F, Grassi V, et al. (2009) ELISA testing of anti-desmoglein 1 and 3 antibodies in the management of pemphigus. Arch Dermatol 145: 529-535. [Crossref]
- Daneshpazhooh M, Kamyab K, Kalantari MS, Balighi K, Naraghi ZS, et al. (2014) Comparison of desmoglein 1 and 3 enzyme-linked immunosorbent assay and direct immunofluorescence for evaluation of immunological remission in pemphigus vulgaris. Clin Exp Dermatol 39: 41-47. [Crossref]
- Zhou T, Fang S, Li C, Hua H (2016) Comparative study of indirect immunofluorescence, enzyme-linked immunosorbent assay, and the Tzanck smear test for the diagnosis of pemphigus. J Oral Pathol Med. [Crossref]
- Rameshkumar A, Varghese AK, Dineshkumar T, Ahmed S, Venkatramani J, Sugirtharaj G (2015) Oral mucocutaneous lesions - a comparative clinicopathological and immunofluorescence study. J Int Oral Health 7: 59-63. [Crossref]
- Maruani A, Machet MC, Carlotti A, Giraudeau B, Vaillant L, et al. (2008) Immunostaining with antibodies to desmoglein provides the diagnosis of drug-induced pemphigus and allows prediction of outcome. Am J Clin Pathol 130: 369-374. [Crossref]
- Joly P, Richard C, Gilbert D, Courville P, Chosidow O, et al. (2000) Sensitivity and specificity of clinical, histologic, and immunologic features in the diagnosis of paraneoplastic pemphigus. J Am Acad Dermatol 43: 619-626. [Crossref]
- Powell JG, Grover RK, Plunkett RW, Seiffert-Sinha K, Sinha AA (2015) Evaluation of a Newly Available ELISA for Envoplakin Autoantibodies for the Diagnosis of Paraneoplastic Pemphigus. J Drugs Dermatol 14: 1103-1106. [Crossref]
- Choi Y, Nam KH, Lee JB, Lee JY, Ihm CW, et al. (2012) Retrospective analysis of 12 Korean patients with paraneoplastic pemphigus. J Dermatol 39: 973-981. [Crossref]
- Ohzono A, Sogame R, Li X, Teye K, Tsuchisaka A, et al. (2015) Clinical and immunological findings in 104 cases of paraneoplastic pemphigus. Br J Dermatol 173: 1447-1452. [Crossref]
- Poot AM, Siland J, Jonkman MF, Pas HH, Diercks GF (2016) Direct and indirect immunofluorescence staining patterns in the diagnosis of paraneoplastic pemphigus. Br J Dermatol 174: 912-915. [Crossref]
- Probst C, Schlumberger W, Stocker W, Recke A, Schmidt E, et al. (2009) Development of ELISA for the specific determination of autoantibodies against envoplakin and periplakin in paraneoplastic pemphigus. Clin Chim Acta 410: 13-18. [Crossref]
- Huang Y, Li J, Zhu X (2009) Detection of anti-envoplakin and anti-periplakin autoantibodies by ELISA in patients with paraneoplastic pemphigus. Arch Dermatol Res 301: 703-709. [Crossref]
- Toosi S, Collins JW, Lohse CM, Wolz MM, Wieland CN, et al. (2016) Clinicopathologic features of IgG/IgA pemphigus in comparison with classic (IgG) and IgA pemphigus. Int J Dermatol 55: e184-190. [Crossref]
- Nishikawa T, Hashimoto T (2000) Dermatoses with intraepidermal IgA deposits. Clin Dermatol 18: 315-318. [Crossref]
- Hashimoto T, Komai A, Futei Y, Nishikawa T, Amagai M (2001) Detection of IgA autoantibodies to desmogleins by an enzyme-linked immunosorbent assay: the presence of new minor subtypes of IgA pemphigus. Arch Dermatol 137: 735-738. [Crossref]
- Lutz ME, Daoud MS, McEvoy MT, Gibson LE (1998) Subcorneal pustular dermatosis: a clinical study of ten patients. Cutis 61: 203-208. [Crossref]
- Porro AM, Caetano Lde V, Maehara Lde S, Enokihara MM (2014) Non-classical forms of pemphigus: pemphigus herpetiformis, IgA pemphigus, paraneoplastic pemphigus and IgG/IgA pemphigus. An Bras Dermatol 89: 96-106. [Crossref]
- Hashimoto T, Yasumoto S, Nagata Y, Okamoto T, Fujita S (2002) Clinical, histopathological and immunological distinction in two cases of IgA pemphigus. Clin Exp Dermatol 27: 636-640. [Crossref]
- Stanley JR, Hawley-Nelson P, Yuspa SH, Shevach EM, Katz SI (1981) Characterization of bullous pemphigoid antigen: a unique basement membrane protein of stratified squamous epithelia. Cell 24: 897-903. [Crossref]
- Ishiko A, Shimizu H, Kikuchi A, Ebihara T, Hashimoto T, et al. (1993) Human autoantibodies against the 230-kD bullous pemphigoid antigen (BPAG1) bind only to the intracellular domain of the hemidesmosome, whereas those against the 180-kD bullous pemphigoid antigen (BPAG2) bind along the plasma membrane of the hemidesmosome in normal human and swine skin. J Clin Invest 91: 1608-1615. [Crossref]
- Lee EH, Kim YH, Kim S, Kim SE, Kim SC (2012) Usefulness of Enzyme-linked Immunosorbent Assay Using Recombinant BP180 and BP230 for Serodiagnosis and Monitoring Disease Activity of Bullous Pemphigoid. Ann Dermatol 24: 45-55. [Crossref]
- Nishie W1 (2014) Update on the pathogenesis of bullous pemphigoid: an autoantibody-mediated blistering disease targeting collagen XVII. J Dermatol Sci 73: 179-186. [Crossref]
- Roussel A, Benichou J, Randriamanantany ZA, Gilbert D, Drenovska K, et al. (2011) Enzyme-linked immunosorbent assay for the combination of bullous pemphigoid antigens 1 and 2 in the diagnosis of bullous pemphigoid. Arch Dermatol 147: 293-298. [Crossref]
- Yoshida M, Hamada T, Amagai M, Hashimoto K, Uehara R, et al. (2006) Enzyme-linked immunosorbent assay using bacterial recombinant proteins of human BP230 as a diagnostic tool for bullous pemphigoid. J Dermatol Sci 41: 21-30. [Crossref]
- Sardy M, Kostaki D, Varga R, Peris K, Ruzicka T (2013) Comparative study of direct and indirect immunofluorescence and of bullous pemphigoid 180 and 230 enzyme-linked immunosorbent assays for diagnosis of bullous pemphigoid. J Am Acad Dermatol 69: 748-753. [Crossref]
- Mysorekar VV, Sumathy TK, Shyam Prasad AL2 (2015) Role of direct immunofluorescence in dermatological disorders. Indian Dermatol Online J 6: 172-180. [Crossref]
- Inchara YK, Rajalakshmi T (2007) Direct immunofluorescence in cutaneous vesiculobullous lesions. Indian J Pathol Microbiol 50: 730-732. [Crossref]
- Yang B, Wang C, Chen S, Chen X, Lu X, et al. (2012) Evaluation of the combination of BP180-NC16a enzyme-linked immunosorbent assay and BP230 enzyme-linked immunosorbent assay in the diagnosis of bullous pemphigoid. Indian J Dermatol Venereol Leprol 78: 722-727. [Crossref]
- Chan YC, Sun YJ, Ng PP, Tan SH (2003) Comparison of immunofluorescence microscopy, immunoblotting and enzyme-linked immunosorbent assay methods in the laboratory diagnosis of bullous pemphigoid. Clin Exp Dermatol 28: 651-656. [Crossref]
- Fairley JA, Bream M, Fullenkamp C, Syrbu S, Chen M, et al. (2013) Missing the target: characterization of bullous pemphigoid patients who are negative using the BP180 enzyme-linked immunosorbant assay. J Am Acad Dermatol 68: 395-403. [Crossref]
- Desai N, Allen J, Ali I, Venning V, Wojnarowska F (2008) Autoantibodies to basement membrane proteins BP180 and BP230 are commonly detected in normal subjects by immunoblotting. Australas J Dermatol 49: 137-141. [Crossref]
- Hofmann S, Thoma-Uszynski S, Hunziker T, Bernard P, Koebnick C, et al. (2002) Severity and phenotype of bullous pemphigoid relate to autoantibody profile against the NH2- and COOH-terminal regions of the BP180 ectodomain. J Invest Dermatol 119: 1065-1073. [Crossref]
- Schmidt E, Obe K, Bröcker EB, Zillikens D (2000) Serum levels of autoantibodies to BP180 correlate with disease activity in patients with bullous pemphigoid. Arch Dermatol 136: 174-178. [Crossref]
- Amo Y, Ohkawa T, Tatsuta M, Hamada Y, Fujimura T, et al. (2001) Clinical significance of enzyme-linked immunosorbent assay for the detection of circulating anti-BP180 autoantibodies in patients with bullous pemphigoid. J Dermatol Sci 26: 14-18. [Crossref]
- Haase C, Budinger L, Borradori L, Yee C, Merk HF, et al. (1998) Detection of IgG autoantibodies in the sera of patients with bullous and gestational pemphigoid: ELISA studies utilizing a baculovirus-encoded form of bullous pemphigoid antigen 2. J Invest Dermatol 110: 282-286. [Crossref]
- Tsuji-Abe Y, Akiyama M, Yamanaka Y, Kikuchi T, Sato-Matsumura KC, et al. (2005) Correlation of clinical severity and ELISA indices for the NC16A domain of BP180 measured using BP180 ELISA kit in bullous pemphigoid. J Dermatol Sci 37: 145-149. [Crossref]
- Feng S, Wu Q, Jin P, Lin L, Zhou W, et al. (2008) Serum levels of autoantibodies to BP180 correlate with disease activity in patients with bullous pemphigoid. Int J Dermatol 47: 225-228. [Crossref]
- Bernard P, Reguiai Z, Tancrède-Bohin E, Cordel N, Plantin P, et al. (2009) Risk factors for relapse in patients with bullous pemphigoid in clinical remission: a multicenter, prospective, cohort study. Arch Dermatol 145: 537-542. [Crossref]
- Chan LS, Ahmed AR, Anhalt GJ, Bernauer W, Cooper KD, et al. (2002) The first international consensus on mucous membrane pemphigoid: definition, diagnostic criteria, pathogenic factors, medical treatment, and prognostic indicators. Arch Dermatol 138: 370-379. [Crossref]
- Cozzani E, Di Zenzo G, Calabresi V, Carrozzo M, Burlando M, et al. (2015) Autoantibody Profile of a Cohort of 78 Italian Patients with Mucous Membrane Pemphigoid: Correlation Between Reactivity Profile and Clinical Involvement. Acta Derm Venereol. [Crossref]
- Terra JB, Pas HH, Hertl M, Dikkers FG, Kamminga N, et al. (2011) Immunofluorescence serration pattern analysis as a diagnostic criterion in antilaminin-332 mucous membrane pemphigoid: immunopathological findings and clinical experience in 10 Dutch patients. Br J Dermatol 165: 815-22. [Crossref]
- Yasukochi A, Teye K, Ishii N, Hashimoto T (2016) Clinical and Immunological Study of 332 Japanese Patients Tentatively Diagnosed with Anti-BP180-type Mucous Membrane Pemphigoid: A Novel BP180 C-terminal Domain Enzyme-linked Immunosorbent Assay. Acta Derm Venereol. [Crossref]
- Suresh L, Martinez Calixto LE, Radfar L (2006) Successful treatment of mucous membrane pemphigoid with tacrolimus. Spec Care Dentist 26: 66-70. [Crossref]
- Vodegel RM, Jonkman MF, Pas HH, de Jong MC (2004) U-serrated immunodeposition pattern differentiates type VII collagen targeting bullous diseases from other subepidermal bullous autoimmune diseases. Br J Dermatol 151: 112-1128. [Crossref]
- Domloge-Hultsch N, Anhalt GJ, Gammon WR, Lazarova Z, Briggaman R, et al. (1994) Antiepiligrin cicatricial pemphigoid. A subepithelial bullous disorder. Arch Dermatol 130: 1521-1529. [Crossref]
- Egan CA, Lazarova Z, Darling TN, Yee C, Yancey KB (2003) Anti-epiligrin cicatricial pemphigoid: clinical findings, immunopathogenesis, and significant associations. Medicine (Baltimore). 82: 177-1786. [Crossref]
- Lazarova Z, Salato VK, Lanschuetzer CM, Janson M, Fairley JA, et al. (2008) IgG anti-laminin-332 autoantibodies are present in a subset of patients with mucous membrane, but not bullous, pemphigoid. J Am Acad Dermatol 58: 951-958. [Crossref]
- Bekou V, Thoma-Uszynski S, Wendler O, Uter W, Schwietzke S, et al. (2005) Detection of laminin 5-specific auto-antibodies in mucous membrane and bullous pemphigoid sera by ELISA. J Invest Dermatol 124: 732-740. [Crossref]
- Bernard P, Antonicelli F, Bedane C, Joly P, Le Roux-Villet C, et al. (2013) Prevalence and clinical significance of anti-laminin 332 autoantibodies detected by a novel enzyme-linked immunosorbent assay in mucous membrane pemphigoid. JAMA Dermatol 149: 533-540. [Crossref]
- Lazarova Z, Hsu R, Yee C, Yancey KB (2000) Human anti-laminin 5 autoantibodies induce subepidermal blisters in an experimental human skin graft model. J Invest Dermatol 114: 1781-1784. [Crossref]
- Nakatani C, Muramatsu T, Shirai T (1998) Immunoreactivity of bullous pemphigoid (BP) autoantibodies against the NC16A and C-terminal domains of the 180 kDa BP antigen (BP180): immunoblot analysis and enzyme-linked immunosorbent assay using BP180 recombinant proteins. Br J Dermatol 139: 365-370. [Crossref]
- Nie Z, Hashimoto T (1999) IgA antibodies of cicatricial pemphigoid sera specifically react with C-terminus of BP180. J Invest Dermatol 112: 254-255. [Crossref]
- Balding SD, Prost C, Diaz LA, Bernard P, Bedane C, et al. (1996) Cicatricial pemphigoid autoantibodies react with multiple sites on the BP180 extracellular domain. J Invest Dermatol 106: 141-146. [Crossref]
- Aoyama Y, Asai K, Hioki K, Funato M, Kondo N, et al. (2007) Herpes gestationis in a mother and newborn: immunoclinical perspectives based on a weekly follow-up of the enzyme-linked immunosorbent assay index of a bullous pemphigoid antigen noncollagenous domain. Arch Dermatol 143: 1168-1172. [Crossref]
- Borrego L, Peterson EA, Diez LI, de Pablo Martin P, Wagner JM, et al. (1999) Polymorphic eruption of pregnancy and herpes gestationis: comparison of granulated cell proteins in tissue and serum. Clin Exp Dermatol 24: 213-225. [Crossref]
- Cobo MF, Santi CG, Maruta CW, Aoki V (2009) Pemphigoid gestationis: clinical and laboratory evaluation. Clinics (Sao Paulo) 64: 1043-1047. [Crossref]
- Tani N, Kimura Y, Koga H, Kawakami T, Ohata C, et al. (2015) Clinical and immunological profiles of 25 patients with pemphigoid gestationis. Br J Dermatol 172: 120-129. [Crossref]
- Barnadas MA, Rubiales MV, Gonzalez MJ, Puig L, Garcia P, et al. (2008) Enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence testing in a bullous pemphigoid and pemphigoid gestationis. Int J Dermatol 47: 1245-1249. [Crossref]
- Powell AM, Sakuma-Oyama Y, Oyama N, Albert S, Bhogal B, et al. (2005) Usefulness of BP180 NC16a enzyme-linked immunosorbent assay in the serodiagnosis of pemphigoid gestationis and in differentiating between pemphigoid gestationis and pruritic urticarial papules and plaques of pregnancy. Arch Dermatol. 141: 705-710. [Crossref]
- Sitaru C, Powell J, Messer G, Bröcker EB, Wojnarowska F, et al. (2004) Immunoblotting and enzyme-linked immunosorbent assay for the diagnosis of pemphigoid gestationis. Obstet Gynecol 103: 757-763. [Crossref]
- Woodley DT, Briggaman RA, O'Keefe EJ, Inman AO, Queen LL, et al. (1984) Identification of the skin basement-membrane autoantigen in epidermolysis bullosa acquisita. N Engl J Med. 310: 1007-1013. [Crossref]
- Gammon WR, Briggaman RA, Wheeler CE Jr (1982) Epidermolysis bullosa acquisita presenting as an inflammatory bullous disease. J Am Acad Dermatol 7: 382-387. [Crossref]
- Gupta R, Woodley DT, Chen M (2012) Epidermolysis bullosa acquisita. Clin Dermatol 30: 60-69.[Crossref]
- Kim JH, Kim YH, Kim SC (2011) Epidermolysis bullosa acquisita: a retrospective clinical analysis of 30 cases. Acta Derm Venereol 91: 307-312. [Crossref]
- Gammon WR, Woodley DT, Dole KC, Briggaman RA (1985) Evidence that anti-basement membrane zone antibodies in bullous eruption of systemic lupus erythematosus recognize epidermolysis bullosa acquisita autoantigen. J Invest Dermatol 84: 472-476. [Crossref]
- Terra JB, Meijer JM, Jonkman MF, Diercks GF (2013) The n- vs. u-serration is a learnable criterion to differentiate pemphigoid from epidermolysis bullosa acquisita in direct immunofluorescence serration pattern analysis. Br J Dermatol 169: 100-105. [Crossref]
- Terra JB, Jonkman MF, Diercks GF, Pas HH (2013) Low sensitivity of type VII collagen enzyme-linked immunosorbent assay in epidermolysis bullosa acquisita: serration pattern analysis on skin biopsy is required for diagnosis. Br J Dermatol 169: 164-167. [Crossref]
- Calabresi V, Sinistro A, Cozzani E, Cerasaro C, Lolicato F, et al. (2014) Sensitivity of different assays for the serological diagnosis of epidermolysis bullosa acquisita: analysis of a cohort of 24 Italian patients. J Eur Acad Dermatol Venereol 28: 483-490. [Crossref]
- Chen M, Chan LS, Cai X, O'Toole EA, Sample JC, et al. (1997) Development of an ELISA for rapid detection of anti-type VII collagen autoantibodies in epidermolysis bullosa acquisita. J Invest Dermatol 108: 68-72. [Crossref]
- Ito Y, Kasai H, Yoshida T, Saleh MA, Amagai M, et al. (2013) Anti-type VII collagen autoantibodies, detected by enzyme-linked immunosorbent assay, fluctuate in parallel with clinical severity in patients with epidermolysis bullosa acquisita. J Dermatol 40: 864-868. [Crossref]
- Kim JH, Kim YH, Kim S, Noh EB, Kim SE, et al. (2013) Serum levels of anti-type VII collagen antibodies detected by enzyme-linked immunosorbent assay in patients with epidermolysis bullosa acquisita are correlated with the severity of skin lesions. J Eur Acad Dermatol Venereol 27: e224-e230. [Crossref]
- Marzano AV, Cozzani E, Fanoni D, De Pita O, Vassallo C, et al. (2013) Diagnosis and disease severity assessment of epidermolysis bullosa acquisita by ELISA for anti-type VII collagen autoantibodies: an Italian multicentre study. Br J Dermatol. 168: 80-84. [Crossref]
- Saleh MA, Ishii K, Kim YJ, Murakami A, Ishii N, et al. (2011) Development of NC1 and NC2 domains of type VII collagen ELISA for the diagnosis and analysis of the time course of epidermolysis bullosa acquisita patients. J Dermatol Sci 62: 169-175. [Crossref]
- Barreiro-Capurro A, Mascaro-Galy JM, Iranzo P (2013) Retrospective study of the clinical, histologic, and immunologic features of epidermolysis bullosa acquisita in 9 patients. Actas Dermosifiliogr 104: 904-914. [Crossref]
- Alonso-Llamazares J, Gibson LE, Rogers RS 3rd (2007) Clinical, pathologic, and immunopathologic features of dermatitis herpetiformis: review of the Mayo Clinic experience. Int J Dermatol 46: 910-919. [Crossref]
- Rose C, Brocker EB, Zillikens D (2010) Clinical, histological and immunpathological findings in 32 patients with dermatitis herpetiformis Duhring. J Dtsch Dermatol Ges 8: 265-270. [Crossref]
- Fuertes I, Mascaro JM, Bombi JA, Iranzo P (2011) [A retrospective study of clinical, histological, and immunological characteristics in patients with dermatitis herpetiformis. The experience of Hospital Clinic de Barcelona, Spain, between 1995 and 2010 and a review of the literature]. Actas Dermosifiliogr 102: 699-705. [Crossref]
- Borroni G, Biagi F, Ciocca O, Vassallo C, Carugno A, et al. (2013) IgA anti-epidermal transglutaminase autoantibodies: a sensible and sensitive marker for diagnosis of dermatitis herpetiformis in adult patients. J Eur Acad Dermatol Venereol 27: 836-841. [Crossref]
- Antiga E, Verdelli A, Calabro A, Fabbri P, Caproni M (2013) Clinical and immunopathological features of 159 patients with dermatitis herpetiformis: an Italian experience. G Ital Dermatol Venereol 148: 163-169. [Crossref]
- Rose C, Armbruster FP, Ruppert J, Igl BW, Zillikens D, et al. (2009) Autoantibodies against epidermal transglutaminase are a sensitive diagnostic marker in patients with dermatitis herpetiformis on a normal or gluten-free diet. Journal of the American Academy of Dermatology 61: 39-43. [Crossref]
- Marietta EV, Camilleri MJ, Castro LA, Krause PK, Pittelkow MR, et al. (2008) Transglutaminase autoantibodies in dermatitis herpetiformis and celiac sprue. The J Invest Dermatol 128: 332-335. [Crossref]
- Warren SJ, Cockerell CJ (2002) Characterization of a subgroup of patients with dermatitis herpetiformis with nonclassical histologic features. Am J Dermatopathol 24: 305-308. [Crossref]
- Bresler SC, Granter SR (2015) Utility of direct immunofluorescence testing for IgA in patients with high and low clinical suspicion for dermatitis herpetiformis. Am J Clin Pathol 144: 880-884. [Crossref]
- Zone JJ, Taylor TB, Meyer LJ, Petersen MJ (1998) The 97 kDa linear IgA bullous disease antigen is identical to a portion of the extracellular domain of the 180 kDa bullous pemphigoid antigen, BPAg2. J Invest Dermatol 110: 207-210. [Crossref]
- Pas HH, Kloosterhuis GJ, Heeres K, van der Meer JB, Jonkman MF (1997) Bullous pemphigoid and linear IgA dermatosis sera recognize a similar 120-kDa keratinocyte collagenous glycoprotein with antigenic cross-reactivity to BP180. J Invest Dermatol 108: 423-429. [Crossref]
- Tsuchisaka A, Ohara K, Ishii N, Nguyen NT, Marinkovich MP, et al. (2015) Type VII collagen is the major autoantigen for sublamina densa-type linear IgA bullous dermatosis. J Invest Dermatol 135: 626-629. [Crossref]
- Sobjanek M, Sokolowska-Wojdylo M, Sztaba-Kania M, Baranska-Rybak W, Maciejewska A, et al. (2008) Clinical and immunopathological heterogeneity of 22 cases of linear IgA bullous dermatosis. J Eur Acad Dermatol Venereol 22: 1131. [Crossref]
- Csorba K, Schmidt S, Florea F, Ishii N, Hashimoto T, et al. (2011) Development of an ELISA for sensitive and specific detection of IgA autoantibodies against BP180 in pemphigoid diseases. Orphanet J Rare Dis 6: 31. [Crossref]
- Damoiseaux J, van Rijsingen M, Warnemunde N, Dahnrich C, Fechner K, et al. (2012) Autoantibody detection in bullous pemphigoid: clinical evaluation of the EUROPLUS Dermatology Mosaic. J Immunol Methods 382: 76-80. [Crossref]
- van Beek N, Rentzsch K, Probst C, Komorowski L, Kasperkiewicz M, et al. (2012) Serological diagnosis of autoimmune bullous skin diseases: prospective comparison of the BIOCHIP mosaic-based indirect immunofluorescence technique with the conventional multi-step single test strategy. Orphanet J Rare Dis 7: 49. [Crossref]
- Lemcke S, Sokolowski S, Rieckhoff N, Buschtez M, et al. (2016) Automated direct immunofluorescence analyses of skin biopsies. J Cutan Pathol 43: 227-235. [Crossref]
- Iwamoto S, Iwamoto AT, Cha J, Clark T, Lu M, et al. (2009) The utility of the DNA microarray scanner to simplify the immunofluorescence evaluation of autoimmune bullous diseases. Am J Dermatopathol 31: 218-222. [Crossref]