Use of 1M NaCl split skin in the indirect immunofluorescence of the linear IgA bullous dermatoses

We compared 1M NaCl split skin with intact skin as substrates for detection of circulating IgA anti-basement membrane (BMZ) antibodies in linear IgA dermatosis (LAD). The sera of 63 patients with LAD including 27 adults and 36 with chronic bullous dermatosis of childhood (CBDC) were examined. 62% of patients overall had circulating IgA anti-BMZ antibodies detectable on intact skin. 73% of patients had circulating antibodies detectable on lM NaCl split skin as an additional 7 sera were positive. This was a statistically significant increase (p<0.01). The sera were mostly positive at a higher titre on the split skin when compared with intact skin. On routine indirect immunofluorescence (IIF) all positive sera produced linear fluorescence on the epidermal side of the split. Twenty serum samples were incubated with split skin overnight; 4 of these specimens exhibited linear fluorescence on the epidermal and dermal sides of the split after this prolonged incubation. These findings suggest that 1M NaCl split skin is a more sensitive substrate for detection of circulating IgA anti-BMZ antibodies in LAD, that these antibodies are heterogeneous and that the target antigen has an epidermal component.     

盐裂间接免疫荧光技术在大疱性类天疱疮鉴别诊断中的应用研究

目的:探讨盐裂皮肤间接免疫荧光(IIF)技术在大疱性类天疱疮(BP)鉴别诊断中的作用.方法:应用盐裂IIF技术检测78例常规方法诊断为BP的患者血清.结果:43例血清IgG沉积于表皮侧,7例IgG沉积于双侧,11例IgG沉积于真皮侧,另有17例双侧均未见抗体沉积.结论:盐裂IIF仅能用于BP的初步鉴别诊断.     

Direct and indirect immunofluorescence for the diagnosis of bullous autoimmune diseases

DIF and IIF evaluates in vivo bound and circulating autoantibodies and are the preferred methods for diagnosing AIBDs. In pemphigus diseases and dermatitis herpetiformis, the titer of circulating autoantibodies reflects the disease activity. In patients with a classical clinical picture, the DIF confirms the diagnosis. Furthermore, this technique is essential in subtypes of AIBDs with atypical clinical manifestations (eg, no blisters or erosions) or clinically similar presenting manifestations, such as bullous pemphigoid, MMP, or EBA. A direct or indirect SSST is often crucial for the differential diagnosis between subtypes of these diseases, leading to proper treatment for severely affected patients.     

Heterogeneous bullous pemphigoid antibodies: detection and characterization by immunoblotting when absent by indirect immunofluorescence

We studied sera from 59 patients with bullous pemphigoid (BP) and 25 control subjects (normal volunteers, patients with pemphigus, psoriasis, eczema, or other dermatoses) by western blotting analysis on protein bands from normal human heat-separated epidermis. BP sera reacted with four protein bands that were not detected by control sera: two major bands at 220-240 and 165 kD and two faint bands at 190 and 95 kD. Three of these bands were significantly associated with BP: 220-240 kd (51% of the BP patients; p less than 0.001), 165 kD (49%; p less than 0.001) and 190 kD (20%; p less than 0.05). These results are consistent with a molecular heterogeneity of BP antibodies, because each individual BP serum showed a distinctive pattern of reactivity. Thirty out of the 59 BP sera contained anti-basement membrane zone antibodies demonstrable by indirect immunofluorescence (IIF). All these IIF positive BP sera reacted by immunoblotting with at least one protein band: 23 (77%) with the 220-240-kD band and 21 (70%) with the 165-kD band. Furthermore, 45% of the 29 IIF negative BP sera showed a reactivity with the 220-240-kD band and/or the 165-kD band. These results indicate that western immunoblotting might be a more sensitive method for the detection of circulating BP antibodies than IIF techniques, including IIF on salt split skin.     

Serological diagnosis of bullous pemphigoid (BP): comparison of the sensitivity of indirect immunofluorescence on salt-split to immunoblotting

Specialized immunological assays are required for the accurate diagnosis of bullous dermatoses such as bullous pemphigoid (BP), epidermolysis bullosa acquisita and bullous lupus erythematosus. The aim of this study was to analyse and compare the sensitivity of indirect immunofluorescence (IF) on salt-split skin and immunoblotting for the detection of circulating autoantibodies in BP. Of the BP patients selected for the study, 74/79 (94%) had circulating autoantibodies detected by at least one of the two methods. Both methods had comparable sensitivity and detected BP-specific autoantibodies in 82-85% of the patients. Because 20% of the patients were found to be positive by only one of the methods, both methods should be used in the diagnosis of BP. Indirect IF on salt-split skin is easier to perform and is preferable in routine analysis, but Western blotting may be used as a complementary assay with sera showing no reactivity on salt-split skin.     

盐裂皮肤间接免疫荧光技术在大疱性类天疱疮诊断中的价值评估

目的:评价盐裂皮肤间接免疫荧光（IIF-SSS）在大疱性类天疱疮（BP）诊断中的价值。方法:采用单中心临床回顾性研究。纳入2013年1月至2019年1月在中国医学科学院皮肤病医院就诊的初诊BP患者163例,对照组404例,包括天疱疮161例、湿疹67例、药疹26例、多形红斑23例、结节性痒疹18例等。于患者用药前采血,...     

Comparative study of indirect immunofluorescence and immunoblotting for the diagnosis of autoimmune pemphigus

The diagnosis of pemphigus relies on immunopathological criteria including the detection of circulating autoantibodies to desmosomal components. In the present work we compared the usefulness of immunoblotting (IB) and indirect immunofluorescence (IIF) in the diagnosis of pemphigus using monkey oesophagus (MO) and rabbit lip (RL) as epithelial substrates. Among 54 sera from patients with well-documented pemphigus (40 pemphigus vulgaris, PV, and 14 pemphigus foliaceus, PF), 46 (85%) proved positive by IFF (46 on MO and 41 on RL) as compared with 44 (81.5%) positive by IB. IIF and IB were equally sensitive (90%) for the diagnosis of PV whereas IIF (on RL) was more sensitive (71%) than IB (57%) for the detection of PF autoantibodies. However, when the two techniques were considered in combination, the sensitivity of the detection of pemphigus autoantibodies rose to 94.5%. An IB study would therefore be warranted in the presence of an (alleged) pemphigus serum that was IIF-negative since approximately 10% of these were found to be positive. Furthermore, the pattern of IB reactivity may assist in classification, since the 130- and the 160-kDa antigens seem specifically correlated with PV and PF, respectively.     

不同底物间接免疫荧光对自身免疫性表皮下水疱病诊断的评价

目的评价以正常人皮肤、猴食管及盐裂皮肤为底物的间接免疫荧光对自身免疫性表皮下水疱病的诊断价值。方法选取2015年1月至2016年12月在中国医学科学院皮肤病研究所诊断的自身免疫性表皮下水疱病56例,其中大疱性类天疱疮(BP)47例,获得性大疱性表皮松解症(EBA)6例,线状IgA大疱性皮病2例,P200类天疱疮1例。对照组为70例天疱疮、15例慢性湿疹和15例健康成人。分别以正常人皮肤、猴食管及盐裂皮肤为底物行间接免疫荧光,观察荧光沉积情况,比较不同表皮下水疱病间接免疫荧光检测的敏感性和特异性。采用SPSS 13.0软件,计数资料比较采用χ^2检验。结果BP患者血清以正常人皮肤、猴食管为底物间接免疫荧光可见到荧光物质沿基底膜带线性沉积,盐裂皮肤间接免疫荧光可见BP患者荧光线性沉积于表皮侧,EBA和P200类天疱疮线性沉积于真皮侧。以正常人皮肤、猴食管及盐裂皮肤为底物间接免疫荧光对表皮下水疱病诊断的敏感性分别为73.2%、60.7%、94.6%,差异有统计学意义(χ^2=18.2,P<0.05),特异性分别为98.0%、100%、97.1%,差异无统计学意义(P >0.05),以盐裂皮肤为底物时诊断的敏感性高于以正常人皮肤、猴食管为底物(χ^2值分别为8.0、16.7,均P<0.05)。结论对于自身免疫性表皮下水疱病的诊断,盐裂皮肤为底物行间接免疫荧光检查优于以猴食管和正常人皮肤为底物。     

Immunohistochemical examination of P-cadherin in bullous and acantholytic skin diseases

Autoimmune blistering diseases (pemphigus vulgaris, pemphigus foliaceus, bullous pemphigoid, dermatitis herpetiformis) and certain genodermatoses with acantholysis (Darier-disease, Hailey-Hailey disease) have different aetiological factors, but all result in bulla formation and/or in acantholysis. Cadherins are Ca++-dependent cell-cell adhesion molecules which play an important role in the cellular connection between normal cells. P-cadherin is involved in the selective adhesion of epidermal cells, and is expressed only on the surfaces of the two basal layers. We examined the expression of P-cadherin in some autoimmune bullous skin diseases and Darier's disease using immunohistochemistry and found P-cadherin to be strongly upregulated. We believe the upregulation is compensatory to the primary pathophysiological events in the various bullous dermatoses.     

Factors contributing to occasional failures in the laboratory diagnosis of bullous pemphigoid by indirect immunofluorescence

Summary.— The basement membrane antibodies in 3 sera of patients with bullous pemphigoid were studied by means of indirect immunofluorescent staining chessboard titrations on monkey, rabbit and guinea-pig lip tissue. Comparisons of the results of these studies with those obtained in previous studies of this type with 2 other sera, revealed wide variations in the spectra of specificities of the bullous pemphigoid antibodies. Monkey oral or oesophogeal mucosa appears to be the substrate of choice for routine tests for these antibodies, although this must be regarded as an approximation of the “ideal antigen”. The implication of these findings are discussed both from the practical and theoretical points of view.     

盐裂皮肤-间接免疫荧光方法优化及在大疱性类天疱疮抗体检测中的应用

目的:优化盐裂皮肤-间接免疫荧光方法（IIF-SSS）,评价其在大疱性类天疱疮（BP）抗体检测中的应用。方法:通过调整试验条件,利用正常人包皮或非包皮皮肤制备盐裂底物,分为3组：传统组在4 ℃旋转皮肤48~72 h;低温浸泡组在4 ℃浸泡皮肤48~72 h;室温浸泡组在室温25 ℃（23 ℃~27 ℃）浸泡皮肤24 h...     

The distribution of IgG subclass autoantibodies in bullous pemphigoid analysed by immunofluorescence and immunoblotting

Summary The distribution of IgG subclasses in bullous pemphigoid (BP) autoantibodies in 14 BP sera and four biopsies was analysed by immunofluorescence (IF) and immunoblotting (IB). Three clones of monoclonal antibodies (MoAbs) to each IgG subclass were used. All 14 sera showed linear fluorescence in the basement membrane zone with IF, and 240 kDa and/or 180 kDa protein bands in human epidermal extract were detected by IB using a polyclonal antibody to total IgG. BP antibody in IgG₄ subclass was found to be predominant, as it was detected most frequently and intensively in all positive sera and lesions studied by both techniques. In the IgG₁ to IgG₃ subclasses, a range of proportions of positive sera was obtained among MoAbs to the same IgG subclass in both techniques. However, one MoAb could detect IgG₁ subclass BP antibody with a high frequency in both techniques. No difference in IgG subclass distribution of BP antibodies was observed during the course of the disease. In each serum, any IgG subclass of BP antibody recognized the identical BP antigen(s). These results suggest the predominance of IgG₄ subclass and the possible presence of IgG₁ subclass in BP antibodies.     

Comparative study of autoantigens for various bullous skin diseases by immunoblotting using different dermo-epidermal separation techniques

We investigaged the reactivity of pemphigus vulgaris (PV), pemphigus vegetans, pemphigus foliaceus (Pf), Brazilian Pf, bullous pemphigoid (BP), and epidermolysis bullosa acquisita (EBA) sera with an immunoblot analysis using human epidermal and dermal extracts as a source of antigen. To obtain epidermal and dermal extracts three different dermo-epidermal separation methods were used: namely, ethylenediaminetetraacetic acid (EDTA) separation, heat separation, and dispase separation. All the 15PV and the seven pemphigus vegetans sera demonstrated a 130-kDa PV antigen in epidermal extracts obtained by all the three methods. Furthermore, three PV sera also showed a 160-kDa Pf antigen, desmoglein. Ten of 14 Pf sera and six of 15 Brazilian Pf sera reacted with desmoglein in the same pattern in all the three epidermal extracts. Fifteen of the 22 BP sera showed reactivity with 230-kDa BP antigen in the same pattern in all the three epidermal extracts, whereas 14 BP sera delected the 180-kDa BP antigen in extracts of EDTA-and heat-separated epidermis but not in dispase-separated epidermal extract. Dermal extracts were obtained by EDTA- and heat-separated dermis, and all six EBA sera labelled a 290-kDa EBA antigen in both samples. These results suggest that heat-separated skin is as useful as EDTA-separated skin for detecting various autoantigens, but heat separation is preferable because the preparation time is shorter.     

Autoimmune bullous skin diseases. Part 2: diagnosis and therapy

Autoimmune bullous skin diseases represent a heterogenous group of disorders of skin and mucosa which are commonly associated with IgG or IgA autoantibodies against distinct adhesion molecules of the skin. The antibodyinduced loss of adhesion between epidermis and dermis results in blister formation and extensive erosions. There is a great need for rapidly establishing the diagnosis of these disorders since they may run a severe and potentially life-threatening course. In addition, because of their rarity and heterogeneous symptoms, autoimmune bullous skin diseases often pose a major diagnostic challenge. While histopathological examinations provide evidence for the level of blister formation, immunofluorescence microscopy has been established to identify tissue-bound and circulating autoantibodies. Direct immunofluorescence microscopy represents the gold standard for detecting tissue-bound autoantibodies. Indirect immunofluorescence microscopy with defined tissue substrates is considered the first step in detecting circulating autoantibodies. Confirmatory tests such as ELISA, immunoblot or immunoprecipitation analyses are performed utilizing recombinant proteins or keratinocyte extracts. The later assays can be used for primary diagnosis as well as for immunoserological follow-up. Systemic immunosuppressive drugs usually represent the main therapeutic regimen. Initially, systemic corticosteroids are commonly administered in combination with steroid-sparing, immunosuppressive agents. Novel targeted treatments such as immunoadsorption, rituximab or high-dose intravenous immunoglobulins have proven to be highly effective in severe and refractory pemphigus. This review presents a state-of-the-art algorithm for making the diagnosis of autoimmune bullous disorders and provides an overview on currently available therapeutic options.     

Repeat direct immunofluorescence (DIF) test, using, 1 M NaCl treated skin, in the subepidermal autoimmune bullous diseases that contain IgG at the dermal epidermal junction

Knowledge of autoimmune bullous diseases has greatly increased with the recognition of new entities, and the use of the direct immunofluorescence (DIF) using 1 molar per liter of sodium chloride (1 M NaCl) treated skin has been proposed. To estimate the frequency with which the different DIF patterns are present, we performed a systematic study of the skin or oral mucosa samples in which linear deposits of IgG at the basement membrane zone were detected by routine DIF in the last 6 years. The DIF tests were done on 56 samples before and after splitting the epidermis from the dermis with 1M NaCl. In 40 biopsies (72%) IgG was found on either the epidermal side or on both sides after 1M NaCl split. These cases corresponded to bullous pemphigoid (n=33), herpes gestationis (n=5) and cicatricial pemphigoid (n=2). In 6 cases (10.7%), IgG deposits were observed only on the floor, five corresponding to bullous pemphigoid and one to bullous pemphigoid-like eruption induced by amoxicillin. Repeat direct immunofluorescence using 1M NaCl split skin indicates that at least 12% of patients who were initially diagnosed as bullous pemphigoid, may in fact suffer a different entity, requiring other techniques to achieve the right diagnosis. This test can be a useful routine screening for autoimmune bullous diseases.     

Comparison of immunofluorescence microscopy, immunoblotting and enzyme-linked immunosorbent assay methods in the laboratory diagnosis of bullous pemphigoid

This prospective study investigated patients with a clinical diagnosis of bullous pemphigoid (BP) who presented to a tertiary dermatology referral centre in Singapore. All patients had blood samples and skin biopsies taken for histology, immunofluorescence (IF) and immunoblot analysis prior to initiation of treatment. We analysed 23 new cases of BP during the 1-year study period. Seventeen of 22 biopsy specimens showed subepidermal blister formation, and 12 of the 17 (71%) had a predominance of eosinophils (>50%) in the blister cavity. The dermal inflammatory infiltrate of 22 biopsy specimens was predominantly lymphocytic in nine (41%) and eosinophilic in eight (36%). The histological picture was highly suggestive of BP in 15 of 22 patients (68%), suggestive in two (9%) and poorly suggestive in five (23%). Twenty-one of 23 (91%) patients had linear deposits of IgG and C3 along the dermo-epidermal junction. Serum indirect IF was positive in 22 of 23 (96%) patients, all showing antibody binding to the roof of the induced blister on salt-split skin. All of the 23 serum samples demonstrated positive immunoblot reactivity to BP180 and/or BP230 from epidermal extracts of normal human skin. Immunoblot reactivity with BP180 and BP230 was 78% (n=18) and 52% (n=12), respectively. The BP180 NC16A antibody could be detected in 22 of 23 (96%) sera using the enzyme-linked immunosorbent assay (ELISA) technique. The sensitivity of traditional diagnostic techniques, i.e. direct IF (91%) and indirect IF (96%), was comparable with that of the newer techniques, i.e. immunoblot analysis (100%) and ELISA (96%). ELISA in combination with routine indirect IF may be a useful diagnostic tool in patients with suspected BP who refuse a skin biopsy but consent to give a serum sample.     

Differentiating anti-lamina lucida and anti-sublamina densa anti-BMZ antibodies by indirect immunofluorescence on 1.0 M sodium chloride-separated skin

Sixty-one bullous disease sera containing IgG anti-BMZ antibodies were examined by indirect immunofluorescence on intact skin and skin separated through the lamina lucida by incubation in 1.0 M NaCl. All sera produced an indistinguishable pattern of linear immunofluorescence on intact skin at dilutions of 1:10 or higher. On separated skin, antibodies bound to either the epidermal (epidermal pattern), dermal (dermal pattern), or epidermal and dermal (combined pattern) sides of the separation. The binding patterns were consistent on separated skin from several donors and titers of anti-basement membrane zone antibodies on separated skin were comparable to those on intact skin. Sera from 3 patients with herpes gestationis (HG), 36 patients with bullous pemphigoid (BP), and 1 patient with clinical and histologic features of epidermolysis bullosa acquisita (EBA) showed an epidermal pattern. Sera from 9 patients with BP showed a combined pattern and sera from 6 patients with EBA and 6 patients with clinical and histologic features of BP showed a dermal pattern. Indirect immunoelectron microscopy of selected sera showed antibodies producing the epidermal and combined patterns were anti-lamina lucida antibodies and those producing the dermal pattern were anti-sublamina densa antibodies. These results show indirect immunofluorescence on separated skin is a dependable method for differentiating bullous disease anti-lamina lucida and anti-sublamina densa antibodies and that differentiating between the antibodies is essential for accurate diagnosis in some patients. The results also suggest BP anti-lamina lucida antibodies may have more than one antigenic specificity.     

盐裂皮肤间接免疫荧光及BP180 NC16a酶联免疫吸附测定在大疱性类天疱疮诊断中的意义

目的 探讨盐裂皮肤间接免疫荧光及大疱性类天疱疮（BP）180 NC16a-酶联免疫吸附测定（ELISA）检测在BP诊断中的意义。方法 收集2015年1月至2017年8月在中国医学科学院皮肤病医院用盐裂皮肤间接免疫荧光（IIF?SSS）和BP180 NC16a?ELISA检测BP患者174例和对照组129例血清。其中25例BP患者用直接免疫荧光（DIF）进行检测并与IIF?SSS和BP180 NC16a?ELISA敏感性进行比较。结果 IIF?SSS、BP180 NC16a?ELISA的敏感性分别为93.67%、96.55%;特异性分别为100%、96.12%。IIF?SSS与BP180 NC16a?ELISA相关系数0.147,为弱相关。其中25例BP患者血清学诊断方法（IIF?SSS,BP180 NC16a?ELISA）和DIF敏感性比较差异无统计学意义。结论 BP血清学诊断方法特异性强、敏感性高,值得临床推广应用。     

Bullous pemphigoid: correlation of mucosal involvement and mucosal expression of autoantigens studied by indirect immunofluorescence and immunoblotting

Twenty patients with bullous pemphigoid were studied prospectively: sequential sera, in different phases of the disease, were collected over a period of approximately 2 years. The sera were tested using standard immunofluorescence techniques with salt-split and intact human tissue from different sites of the body (thigh, breast, oral mucosa, vagina); an early serum of each patient was tested by Western blotting. The concentration of circulating antibodies detected by the intact skin and intact mucous membranes was similar; split tissue was more sensitive than intact tissue. For eight of 19 patients, split vagina and occasionally split oral mucosa (in the same patients) were much less sensitive than all other tissues. Furthermore, there was a correlation between autoantibody reactivity with split mucous membrane tissues and clinical mucosal involvement. These results strongly suggest heterogeneity of antigens or epitopes expressed between tissues. In both split skin and mucosa all sera consistently detected an antigen on the epidermal side of the split regardless of the stage of the disease. Immunoblotting studies showed no correlation between specific antigens and mucosal expression or skin involvement.