The detection of IgG and IgA autoantibodies to desmocollins 1-3 by enzyme-linked immunosorbent assays using baculovirus-expressed proteins, in atypical pemphigus but not in typical pemphigus

BACKGROUND: We have shown previously that human desmocollin (Dsc) 1 is recognized by IgA autoantibodies of subcorneal pustular dermatosis (SPD) type IgA pemphigus. However, the presence of IgG anti-Dsc autoantibodies is still controversial, and antibodies to Dsc2 and Dsc3 have not been clearly identified. OBJECTIVES: To investigate this by producing recombinant proteins consisting of the entire extracellular domains of human Dsc1, 2 and 3 in baculovirus, and to use them to establish an enzyme-linked immunosorbent assay (ELISA). METHODS: By this ELISA, we examined in total 165 cases of various types of autoimmune bullous diseases, as well as 23 normal controls. RESULTS: None of 45 sera of classical pemphigus showed either IgG or IgA antibodies to any Dsc. In contrast, one atypical pemphigus serum showed both IgG and IgA antibodies to Dsc1, which were adsorbed by incubation with Dsc1 baculoprotein. Furthermore, this ELISA detected both IgA and IgG anti-Dsc3 antibodies in one atypical case, and IgA antibodies to both Dsc2 and Dsc3 in another. This reactivity was confirmed by positive IgA immunofluorescence with Dsc2 and Dsc3 expressed on COS-7 cells. These results show that both IgG and IgA autoantibodies against all of Dsc1-3 are present in the sera of particular cases of nonclassical pemphigus, except for IgG antibodies to Dsc2, but that they are not detected in classical pemphigus. Unexpectedly, although IgA antibodies of all of eight SPD type IgA pemphigus sera reacted with Dsc1 expressed on COS-7 cells, only one serum was positive in Dsc1 ELISA for IgA. CONCLUSIONS: This result indicates either that Dscs expressed by baculovirus may not adopt the correct conformation or that Dscs may need association with other molecules to express all the epitopes for autoantibodies.     

A case of herpetiform pemphigus with anti-desmoglein 3 IgG autoantibodies

Herpetiform pemphigus (HP) is a rare variant of pemphigus characterized by a unique clinical phenotype of erythematous or urticarial plaques and vesicles that present in a herpetiform arrangement. Most HP cases have circulating anti-desmoglein 1 (Dsg1) IgG autoantibodies, but some HP cases have anti-desmoglein 3 (Dsg3) IgG. A 92-year-old Japanese woman presented with severely pruritic annular erythema and vesicles in a herpetiform arrangement on the trunk. No oral mucosal lesions were present. Histopathologically, these vesicles showed eosinophilic spongiosis as well as suprabasilar acantholysis. Direct immunofluorescence showed in vivo IgG deposition on keratinocyte cell surfaces, and indirect immunofluorescence showed circulating IgG autoantibodies against keratinocyte cell surfaces at a titer of 1:30. Enzyme-linked immunosorbent assay using recombinant Dsg1 and Dsg3 revealed the presence of anti-Dsg3 IgG but no anti-Dsg1 IgG autoantibodies. The lack of oral mucosal involvement and the unique clinical features favored the diagnosis of HP. It remains to be clarified why the anti-Dsg3 IgG autoantibodies in this patient induced this unique features of HP, rather than the mucosal dominant type of pemphigus vulgaris.     

Successful removal of pathogenic autoantibodies in pemphigus by immunoadsorption with a tryptophan-linked polyvinylalcohol adsorber

BACKGROUND: Autoantibodies against the glycoproteins desmogleins 1 and 3 which are components of the desmosomal adhesion complex have been shown to be responsible for the loss of epidermal adhesion characteristic of pemphigus. Elimination of these antibodies should clinically improve the pathology of this group of severe autoimmune blistering skin disorders. OBJECTIVES: To gather information about the efficacy of immunoadsorption in the reduction of pathogenic serum autoantibodies against desmogleins 1 and 3 and to evaluate the clinical benefit of immunoadsorption in the treatment of pemphigus. PATIENTS AND METHODS: Nine patients with pemphigus and detectable circulating desmoglein antibodies were included in this open trial. Two immunoadsorption treatments separated by a 48-h interval were performed per patient. Anti-desmoglein 1 and 3 antibodies in the patients' sera were monitored by enzyme-linked immunosorbent assay and indirect immunofluorescence before and following each immunoadsorption. In addition, the efficacy of the tryptophan-linked polyvinylalcohol adsorber in removing antidesmoglein antibodies was directly evaluated. RESULTS: IgG antibodies against desmogleins 1 and 3 were effectively eliminated from the patients' plasma upon passage through the adsorber and levels of serum autoantibodies were significantly reduced by immunoadsorption. A single immunoadsorption treatment led to a reduction of antidesmoglein autoantibodies of about 30%. Clinically, mucosal and cutaneous lesions improved allowing for a reduction of the systemic immunosuppressive treatment with glucocorticoids. CONCLUSIONS: Immunoadsorption with tryptophan-linked polyvinylalcohol adsorbers holds promise as a highly effective and safe adjuvant therapeutic regimen in pemphigus.     

The transition of pemphigus vulgaris into pemphigus foliaceus: a reflection of changing desmoglein 1 and 3 autoantibody levels in pemphigus vulgaris

The transition of pemphigus vulgaris (PV) into pemphigus foliaceus (PF) is rare and the immunological changes underlying this event are not well understood. We report a 44-year-old woman who presented with oral and cutaneous erosions typical of PV. Over a 9-year period, the clinical features evolved into those of PF. To examine whether quantitative changes in desmoglein (Dsg) antibodies were associated with this transition, Dsg1 and Dsg3 antibody levels were measured by enzyme-linked immunosorbent assay in 82 sequential serum samples collected over this period. At presentation, when the phenotype was PV with oral and cutaneous erosions, antibodies to both Dsg1 and Dsg3 were detected. The disappearance of oral involvement was associated with a decline in Dsg3 antibodies, which are now undetectable, while the development of more severe skin involvement was associated with rising Dsg1 antibody levels. These data strongly suggest that the change in clinical features is a reflection of qualitative and quantitative changes in antibody profile. It is not known whether the transition to PF is permanent or whether disease relapses in the future may be associated with the re-emergence of Dsg3 antibodies, oral ulceration and a PV phenotype.     

The clinical transition between pemphigus foliaceus and pemphigus vulgaris correlates well with the changes in autoantibody profile assessed by an enzyme-linked immunosorbent assay

BACKGROUND: There are a number of reports of pemphigus with clinical shifting between pemphigus foliaceus (PF) and pemphigus vulgaris (PV). On the other hand, a novel enzyme-linked immunosorbent assay (ELISA) against recombinant baculoproteins of desmoglein 1 (Dsg1) (PF antigen) and Dsg3 (PV antigen) has been established and found to be extremely sensitive and specific. OBJECTIVES: To characterize the change in the antibody profiles in a series of pemphigus cases with mixed features of PF and PV by various methods, including the novel ELISA. Patients/methods Sera were obtained from eight cases undergoing a shift between PF and PV and three cases of coexistent PF and PV. The autoantigens were analysed by ELISA, as well as by immunofluorescence using normal human skin sections and immunoblotting using normal human epidermal extracts. RESULTS: The results of the ELISA, immunofluorescence and immunoblotting studies showed that the transition between PF and PV correlates well with the changes of autoantibodies against either Dsg1 or Dsg3. CONCLUSIONS: The clinical phenotype at each stage is defined by the anti-Dsg antibody profile in the serum of these pemphigus patients showing mixed features of PF and PV. In addition, ELISA using recombinant baculoproteins was particularly useful in distinguishing PF and PV.     

IgG/IgA pemphigus with IgG and IgA antidesmoglein 1 antibodies detected by enzyme-linked immunosorbent assay

Pemphigus is an autoimmune mucocutaneous bullous disease characterized by autoantibodies against the cell surfaces of epidermal keratinocytes. Six cases with deposition of both IgG and IgA on keratinocyte cell surfaces have been reported in the recent literature. We provisionally termed these cases IgG/IgA pemphigus. We describe a 42-year-old Japanese woman with clinical and histopathological features resembling herpetiform pemphigus who demonstrated in vivo bound and circulating anticell surface autoantibodies of both IgG and IgA classes on immunofluorescence examination. Enzyme-linked immunosorbent assay using baculovirus-expressed recombinant desmoglein (Dsg) 1 and Dsg 3 showed that both IgG and IgA antibodies reacted with Dsg1. The reactivity was completely adsorbed with preincubation of serum with Dsg1 baculoprotein, further confirming the exclusive reactivity of both IgG and IgA antibodies with Dsg1. This is the second case of IgG/IgA pemphigus in which the human target antigens for both IgG and IgA antibodies have been unequivocally identified. This study provides further evidence that IgG/IgA pemphigus is a distinct disease entity.     

Neonatal pemphigus vulgaris with extensive mucocutaneous lesions from a mother with oral pemphigus vulgaris

The clinical phenotype of pemphigus is well explained by the combination of desmoglein (Dsg) 1 and Dsg3 distribution pattern and antiDsg autoantibody profile (Dsg compensation theory). It has been reported that neonatal skin has a similar Dsg distribution pattern to adult mucosal epithelia. We describe a newborn girl with mucocutaneous pemphigus vulgaris (PV) from a mother with mucosal dominant PV. The mother had had painful oral erosions for at least 7 months. Histopathological examination and direct and indirect immunofluorescence studies confirmed the diagnosis of PV and neonatal PV in the mother and daughter, respectively. The mother had a high titre of anti-Dsg3 IgG and a low titre of antiDsg1 IgG, while the neonate had only a high titre of anti-Dsg3 IgG, but no detectable antiDsg1 IgG. AntiDsg3 IgG, which caused the oral dominant phenotype in the mother, induced extensive oral as well as cutaneous lesions in the neonate. Our case provides clinical evidence for the Dsg compensation theory in neonatal PV.     

Evaluating efficacy of plasmapheresis for patients with pemphigus using desmoglein enzyme-linked immunosorbent assay

BACKGROUND: Pemphigus is an autoimmune bullous disease caused by circulating IgG autoantibodies against cell-cell adhesion molecules between keratinocytes: desmoglein (Dsg) 3 and Dsg1. Plasmapheresis is often used to treat severe cases of pemphigus. Enzyme-linked immunosorbent assays (ELISAs) against recombinant Dsg3 and Dsg1 have recently become available, allowing us to quantify IgG autoantibodies against Dsg3 and Dsg1. OBJECTIVES: Using ELISA against recombinant Dsg3 and Dsg1, to evaluate the efficacy of plasmapheresis in pemphigus. METHODS: Sera obtained from 10 patients with pemphigus vulgaris and one with pemphigus foliaceus following a total of 16 cycles of centrifugal plasmapheresis and 12 effluents from the plasmapheresis were subjected to ELISA against Dsgs. The percentage of IgG autoantibodies removed was calculated using two different formulae: one used serum titres before and immediately after plasmapheresis and the other used the absolute amounts of IgG autoantibodies in the effluents. The percentage fall of anti-Dsg antibody level was also calculated using the serum titres 1 day after plasmapheresis. RESULTS: Using serum titres immediately after plasmapheresis, there was a mean fall per treatment in anti-Dsg 3 antibody level of 43.0% (n = 12) and in anti-Dsg1 antibody level of 48.4% (n = 7). By contrast, calculated from the effluents, on average one treatment removed only 14.6% of anti-Dsg3 antibodies (n = 12) and 16.4% of anti-Dsg1 antibodies (n = 7). This should reflect the correct percentage as it is based on the absolute amounts of IgG autoantibodies removed. Using serum titres 1 day after plasmapheresis, there was a mean fall per treatment in anti-Dsg 3 antibody level of 12.9% (n = 2) and in anti-Dsg1 antibody level of 8.4% (n = 4). The percentage of IgG autoantibodies removed 1 day after plasmapheresis was lower than that found to be removed immediately after plasmapheresis (n = 6). CONCLUSIONS: One centrifugal plasmapheresis procedure eliminates about 15% of the IgG autoantibodies from the whole body. The percentage fall of anti-Dsg IgG antibody level differed depending on when the serum samples were obtained after plasmapheresis. The change in the percentage fall of anti-Dsg antibody level within 1 day after plasmapheresis is thought to be attributable to the passive diffusion of the IgG autoantibodies from the extravascular space to the intravascular space. Therefore, removal of IgG autoantibodies calculated using serum titres only should be evaluated carefully considering the equilibration of the IgG autoantibodies between the different body spaces.     

桥粒芯蛋白1酶联免疫吸附试验检测落叶型天疱疮血清抗体的评价

目的 探讨桥粒芯蛋白1（Dsg1）酶联免疫吸附试验（ELISA）检测落叶型天疱疮（PF）血清学抗体的意义。方法 将80例PF患者和132例对照人群的血清标本进行编盲,用ELISA法检测所有标本中抗Dsg1自身抗体,同时应用间接免疫荧光（IIF）法检测所有标本的抗体滴度,操作过程为随机检测,最后将两方法的结果进行比较。结果 75例PF患者和5例对照人群（包括1例不确定值,大疱性类天疱疮、SLE、皮肌炎、湿疹及健康者各1例）Dsg1 ELISA为阳性,71例PF患者和0例对照人群IIF为阳性。Dsg1 ELISA的敏感性为93.8%（95%可信区间0.85 ~ 0.98）,特异性为96.2%（95%可信区间0.91 ~ 0.99）。IIF的敏感性为88.8%（95%可信区间0.82 ~ 0.96）,特异性为100%（95%可信区间0.96 ~ 1.00）。两者相比,敏感性（P = 0.289）和特异性（P = 1.000）差异均无统计学意义。结论 Dsg1 ELISA是一种简便、敏感、特异的血清学检测方法,可作为诊断PF的一种辅助手段。     

天疱疮患者病情与抗桥粒芯蛋白抗体水平的相关性研究

目的:研究天疱疮患者血清中抗桥粒芯蛋白(desmoglein,Dsg)1和抗Dsg3抗体水平与其皮肤、口腔黏膜损害严重程度的相关性,同时对间接免疫荧光(IIF)检测的天疱疮抗体滴度与治疗中使用皮质类固醇控制剂量的相关性进行分析。方法:采用酶联免疫吸附试验(ELISA)试剂盒测定55例天疱疮患者血清中抗Dsg1和抗Dsg3抗体水平。结果:抗Dsg1抗体水平与患者皮肤损害严重程度有显著相关性(P<0.01),抗Dsg3抗体水平与口腔黏膜损害严重程度有显著相关性(P<0.01)。天疱疮患者血清IIF滴度与抗Dsg1抗体水平相关(P<0.01),寻常型天疱疮患者IIF滴度与抗Dsg1和抗Dsg3抗体水平均有相关性(P分别<0.01和<0.05)。寻常型天疱疮患者皮质类固醇控制剂量与抗Dsg1抗体水平和IIF滴度显著相关(P<0.05)。结论:ELISA方法检测天疱疮患者抗Dsg1和抗Dsg3抗体对天疱疮的临床诊断、分型、衡量口腔黏膜和皮肤损害严重程度具有一定意义。     

A study of desmoglein 1 autoantibodies in pemphigus vulgaris: racial differences in frequency and the association with a more severe phenotype

BACKGROUND: Pemphigus vulgaris (PV) is characterized by pathogenic autoantibodies to desmoglein (Dsg) 3, but additional antibodies to Dsg1, the pemphigus foliaceus antigen, are detectable in some cases. OBJECTIVES: To investigate the clinical significance of the presence of both Dsg 1 and 3 antibodies. METHODS: In 79 subjects with PV, enzyme-linked immunosorbent assays were used to detect IgG autoantibodies reactive with the ectodomain of Dsg1 and Dsg3. RESULTS: There was a clear association between the clinical phenotype and the Dsg antibody profile. All subjects had Dsg3 autoantibodies and 61% had coexisting Dsg1 antibodies (Dsg3+/Dsg1+). PV limited entirely to the mucosal surfaces was seen only in Dsg3+/Dsg1- patients, while additional Dsg1 antibodies (Dsg3+/Dsg1+) predicted cutaneous in addition to mucosal involvement. Although minor cutaneous involvement was observed in most Dsg3+/Dsg1- patients, severe cutaneous involvement was seen only in Dsg3+/Dsg1+ patients. Dsg1 antibodies were detectable early in the course of disease and their appearance did not relate to the use of systemic therapy. The proportion of Dsg1+ patients was higher in those of Indian origin compared with white northern Europeans (P < 0.05). CONCLUSIONS: These data suggest that the presence of Dsg1 antibodies is predictive of a potentially more severe disease and that genetic factors may determine the Dsg antibody profile.     

人皮肤和猴食道上皮用于间接免疫荧光检测天疱疮抗体的比较

目的 :　比较人皮肤 (HS)和猴食道上皮 (MO)用于检测天疱疮抗体的差异及不同底物检测的抗体滴度与疾病严重度的相关性。方法 :　采用HS和MO为底物分别检测天疱疮患者血清中抗体。结果 :以HS和MO为底物检测天疱疮患者血清抗体的阳性率分别为 73.5 %和 87.8% ,而联合两种底物检测的阳性率为 93.9%。两种底物检测PV抗体滴度与疾病严重度均有相关性 (P <0 .0 5 ) ,而PF仅以HS为底物时的抗体滴度与疾病严重度密切相关 (P <0 .0 0 1)。结论 :　MO适于检测PV ,HS适于检测PF ,两种底物联合可提高间接免疫荧光 (IIF)的敏感性。底物的选择对天疱疮病情严重度与抗体滴度的相关性有影响     

Monitoring disease activity in pemphigus with enzyme-linked immunosorbent assay using recombinant desmogleins 1 and 3

BACKGROUND: Pemphigus is an antidesmoglein (Dsg) autoimmune disease that is divided into two major subtypes: pemphigus foliaceus (PF) and pemphigus vulgaris (PV). We previously developed enzyme-linked immunosorbent assays (ELISAs) using recombinant Dsg1 and Dsg3 to detect IgG autoantibodies in patients with pemphigus. The protocol for the ELISAs was optimized for serological diagnosis, but under the conditions used, these assays were not particularly useful for monitoring disease activity in certain patients. That is, the sera from some patients with high-titre antibodies continued to show high index values in the ELISA after clinical improvement. OBJECTIVES: In the study reported here, we modified the ELISA protocol to obtain 'true' index values that exhibit a better correlation with disease activity. METHODS: We tested two cases of pemphigus foliaceus (PF) and four cases of pemphigus vulgaris (PV), each with ELISA index values greater than 150 for Dsg1 or Dsg3. We ran an ELISA with sera from these patients serially diluted from 1 : 100 to 1 : 12,800. We then performed ELISA with a series of PV No. 1 sera diluted to 1 : 800 and PV No. 2-4 and PF No. 1-2 sera diluted to 1 : 1600, after which we plotted the ELISA index values against the time course of disease activity. RESULTS: In each of these cases, there was no apparent decline, over the course of the disease activity, in the ELISA index values at a serum dilution of 1 : 100, probably because the antigen-antibody reaction was saturated at that dilution. After running an ELISA with sera serially diluted from 1 : 100 to 1 : 12,800 we found that a linear dose-dependency between the dilution value and the index value was only observed when sera were diluted to 1 : 800 or more in one case (PV No.1) and to 1 : 1600 or more in the other five cases (PV No. 2-4, PF No. 1-2). After performing ELISA with these series as outlined above we plotted the ELISA index values against the time course of disease activity and found that the index values obtained from these appropriately diluted sera fluctuated in parallel with disease activity, and declined with clinical improvement. CONCLUSIONS: These findings indicate that when appropriate dilutions are used in Dsg1 and Dsg3 ELISA, these assays can provide useful serological information for assessing disease activity in PF and PV.     

酶联免疫吸附试验检测血清天疱疮抗体的评价

目的评价酶联免疫吸附试验(ELISA)用于天疱疮血清学诊断的意义。方法用ELISA法检测49例天疱疮患者和36例非天疱疮对照者血清,同时以间接免疫荧光法(IIF)检测患者血清抗桥粒芯糖蛋白(Dsg)抗体滴度,比较两者的检测结果。结果27例寻常型天疱疮(PV)、14例落叶型天疱疮(PF)和6例非天疱疮大疱性疾病患者Dsg1ELISA呈阳性,27例PV、1例PF及1例非天疱疮大疱性疾病患者Dsg3ELISA呈阳性。Dsg1ELISA的敏感性和特异性分别是81.25%和88.89%,Dsg3ELISA的敏感性和特异性分别是81.82%和97.22%。与IIF相比,两者检测结果差异有显著性(χ2=4.31,P<0.05)。结论ELISA是一种简便、敏感和特异性高的天疱疮血清学诊断方法,并能辅助鉴别PV和PF。     

71例天疱疮的棘层松解位置分析

目的 探讨天疱疮的棘层松解位置,为天疱疮出现不同位置棘层松解的表现提供解释.方法 收集43例寻常型天疱疮和28例落叶型天疱疮患者的临床资料、组织病理、免疫病理、天疱疮抗体指标值进行分析.结果 寻常型天疱疮中有35例棘层松解的位置发生在基底层上方,8例发生在表皮中上部,落叶型天疱疮中有25例棘层松解的位置发生在颗粒层、棘层上方,3例发生在表皮中下部,落叶型天疱疮患者抗Dsg1抗体指标较寻常型天疱疮患者显著升高(P=0.047),寻常型天疱疮棘层松解的位置发生在表皮中上部的患者抗Dsg1、3抗体指标值与棘层松解发生在基底层上方的患者相比有差异,但无统计学意义.结论 寻常型天疱疮及落叶型天疱疮患者组织病理中,棘层松解的位置可发生于表皮中上部、表皮中下部.棘层松解的位置可能与抗Dsg1抗体和抗Dsg3抗体指标值等相关.     

A case of pemphigus vulgaris successfully treated with single filtration plasmapheresis: a correlation of clinical disease activity with serum antibody levels

We report a patient with pemphigus vulgaris (PV) successfully treated with single filtration plasmapheresis. A 40-year-old man with PV was started on therapy with prednisolone (PSL). Although the dosage of PSL was doubled, and both cyclosporin A (CyA) and pulse therapy were added, the disease was not controlled. After single filtration plasmapheresis began, most of the eroded lesions on the trunk reepithelialized. A switch to double filtration was followed by recurrence. Finally, additional treatments with single filtration plasmapheresis were required to obtain remission. To evaluate the efficacy of the treatment, circulating antibodies were measured by immunofluorescence (IIF) and enzyme-linked immunosorbent assays (ELISAs) using recombinant desmoglein (Dsg) 3. IIF titer and the ELISA scores correlated with the clinical disease activity. It is suggested that ELISA was more sensitive than IIF.     

Usefulness of enzyme-linked immunosorbent assay using recombinant desmogleins 1 and 3 for serodiagnosis of pemphigus

Pemphigus is an autoimmune blistering disease with two major subtypes, pemphigus vulgaris (PV) and pemphigus foliaceus (PF). Patients with pemphigus have circulating antidesmoglein (Dsg)1 and/or anti-Dsg3 IgG autoantibodies. We have previously developed enzyme-linked immunosorbent assays (ELISAs) using recombinant Dsg1 and Dsg3 expressed by baculovirus as a diagnostic tool for pemphigus. The purpose of this study was to evaluate the practical application of these ELISAs for clinical use with a large number of serum samples. We used 81 PV sera, 48 PF sera, 114 bullous pemphigoid (BP) sera, 124 collagen disease sera, nine sera of other non-pemphigus bullous diseases and 179 normal control sera. A cut-off value was determined by receiver-operating-characteristic plots. Forty-seven of 48 PF sera (97.9%) were positive in the Dsg1 ELISA and 79 of 81 PV sera (97.5%) were positive in the Dsg3 ELISA, while only two (1. 1%) and four (2.2%) of 179 normal sera were positive in Dsg1 and Dsg3 ELISAs, respectively. However, some disease control sera of BP and collagen diseases exceeded the cut-off value. Introduction of a grey zone helped to decrease the number of these false-positive sera. Furthermore, in three patients studied, the respective Dsg1 and Dsg3 ELISA scores showed parallel fluctuation with the disease activity along the time course. We conclude that Dsg1 and Dsg3 ELISAs provide a simple, sensitive and highly specific assay for the diagnosis of patients with PV and PF and that these ELISAs may be a valuable tool to monitor the disease activity. We also propose diagnostic criteria for pemphigus based on ELISA reactivity: if a serum is positive against Dsg3 it indicates a diagnosis of PV, regardless of reactivity against Dsg1; if a serum is negative for Dsg3 and positive for Dsg1, it indicates a diagnosis of PF.     

Subclass characteristics of IgG autoantibodies in bullous pemphigoid and pemphigus

Immunoglobulin (Ig) G subclasses in anti-basement membrane zone (BMZ) autoantibodies found in the sera of bullous pemphigoid (BP) and in anti-intercellular substance (ICS) autoantibodies of pemphigus were investigated using immunofluorescent (IF) staining. In BP, IgG4, IgG1, and IgG2 were detected in 13, 5 and 6 of 15 patients, respectively; IgG3 was not detected. In pemphigus, IgG4 was detected in all of 10 patients, IgG1 in 7, IgG2 in one, and IgG3 in one patient, respectively. In both BP and pemphigus, the most prominent subclass in intensity of IF staining was IgG4. Although one BP and one PV patient had only IgG4 autoantibodies, C3 deposition was detected. The quantification of IgG subclasses in the sera of the patients was performed by enzyme-linked immunosorbent assays (ELISA). Serum levels of IgG4 in both BP and pemphigus were elevated approximately 3-fold over those in normal controls; those of whole IgG and IgG1-3 were not significantly elevated. Using direct IF staining, the deposition of C3 at the BMZ and at the ICS was demonstrated in 9 of 10 BP and in 3 of 8 pemphigus patients, respectively. The prominent IgG subclasses of anti-BMZ and anti-ICS antibody were IgG4, a noncomplement-fixing antibody, suggesting that the deposition of C3 in the lesional skin occurred via the alternative pathway, or that small amounts of IgG1-3 subclass autoantibodies activated the classical pathway.     

The distribution of pemphigus vulgaris-IgG subclasses and their reactivity with desmoglein 3 and 1 in pemphigus patients and their first-degree relatives

BACKGROUND: Pemphigus vulgaris (PV) autoantibodies (PV-IgG) have been found in 40-70% of sera of first-degree relatives of pemphigus patients. OBJECTIVES: To determine the possible role of PV-IgG subclasses in the pathogenesis of the disease. PATIENTS AND METHODS: Study groups comprised 25 PV patients, 55 unaffected family members and 56 sera of healthy individuals. Indirect immunofluorescence (IIF) staining and Western immunoblotting (WB) techniques were used to determine total PV-IgG and PV-IgG subclasses and their reactivity to desmoglein (Dsg) 1 and 3. RESULTS: By IIF staining, circulating PV-IgG were found in 64% of the patients, in 15% of the relatives and in none of the controls (P < or = 0.001); by WB the results were 91%, 49% and 12%, respectively (P < or = 0.001). The distribution of PV-IgG subclasses 1-3 was similar among patients and their relatives. PV-IgG4 was found in 62% of the patients but in only one relative and was absent in the controls (P < or = 0.001). PV-IgG1, 2 and 4 were found to react mainly with Dsg3 and PV-IgG3 mainly with Dsg1 and 3. CONCLUSIONS: These results support the concept of a genetic predisposition in pemphigus. The non-complement-fixing PV-IgG4 and at least one complement-fixing PV-IgG subclass appear to be involved in the pathogenesis of the disease. The absence of PV-IgG4 among relatives who were PV-IgG carriers seems to be linked to the fact that they do not develop pemphigus. The exact nature of this linkage is still unclear.     

Nonclassical pemphigus with exclusively IgG anti-desmocollin 3-specific antibodies

We describe a patient with nonclassical clinical and histopathological features of pemphigus with exclusively IgG antibodies against desmocollin (Dsc) 3 detected by enzyme-linked immunosorbent assay of recombinant eukaryotic protein of Dsc1-Dsc3. The absence of antibodies against other known targets, such as desmogleins, reinforces the role of anti-Dsc antibodies in the pathophysiology of atypical pemphigus.