Coexistence of pemphigus foliaceus and bullous pemphigoid. Demonstration of autoantibodies that bind to both the pemphigus foliaceus antigen complex and the bullous pemphigoid antigen

Pemphigus and bullous pemphigoid are autoimmune blistering diseases of the skin characterized by circulating autoantibodies directed against the keratinocyte cell surface and the epidermal basement membrane zone, respectively. The coexistence of pemphigus and bullous pemphigoid is very uncommon. We describe a patient with pemphigus foliaceus who later developed bullous pemphigoid and show, by means of immunoprecipitation studies utilizing both cultured keratinocytes and suction blister epidermis, that our patient had circulating autoantibodies directed against both the pemphigus foliaceus antigen complex and the bullous pemphigoid antigen. This report is the first to demonstrate the coexistence of pemphigus foliaceus and bullous pemphigoid at the molecular level.     

Common human leukocyte antigen alleles in pemphigus vulgaris and pemphigus foliaceus Italian patients.

Pemphigus refers to a group of autoimmune blistering skin diseases, mainly identified as pemphigus vulgaris and pemphigus foliaceus, both characterized by the presence of autoantibodies against keratinocyte adhesion molecules, leading to loss of cell-cell adhesion with consequent blister formation. Pemphigus vulgaris is reported to be associated with human leukocyte antigen DR4 and/or DR6 whereas no data are available on pemphigus foliaceus, except for the endemic Brazilian form (fogo selvagem), which is reported to be associated with DR1 and DR4. We here report human leukocyte antigen molecular typing on a total of 87 patients, 61 with pemphigus vulgaris and 26 with pemphigus foliaceus, versus 128 healthy matched controls. Generic typing showed an increase of DRB1*04 and DRB1*14 and a decrease of DRB1*07 in both pemphigus vulgaris and pemphigus foliaceus patients. Molecular subtyping of DR4+ and DR14+ subjects showed a highly significant association between the DRB1*1401 and both pemphigus vulgaris (p < 0.0001) and pemphigus foliaceus patients (p < 0.0001) together with a significant increase of the linked DQB1*0503 (pemphigus vulgaris p < 0.0001; pemphigus foliaceus p < 0.0001). Moreover, whereas the association between DRB1*0402 and pemphigus vulgaris (p < 0.0001) has been confirmed, no significant association between a specific allele of the DR4 group and pemphigus foliaceus, has been found. Therefore, at least in Italian patients, pemphigus vulgaris and pemphigus foliaceus share DRB1*1401 and DQB1*0503, as susceptible human leukocyte antigen alleles, whereas DRB1*0402 is only found associated with pemphigus vulgaris. The observation that both diseases, pemphigus vulgaris and pemphigus foliaceus, carry the same susceptible human leukocyte antigen alleles has been interpreted as a common genetic background predisposing to pemphigus as, like in other autoimmune disorders, it is not sufficient to explain the onset of the disease on the basis of the sole aforementioned alleles. Other linked genes and/or environmental factors should play a facilitating role in the outbreak of pemphigus, either pemphigus vulgaris or pemphigus foliaceus.     

Non-pathogenic anti-desmoglein 3 IgG autoantibodies in Fogo Selvagem

The endemic form of pemphigus foliaceus, fogo selvagem, is caused by IgG autoantibodies directed against desmoglein 1 (Dsg1). Hilario-Vargas and his colleagues describe a high prevalence of IgG autoantibodies against Dsg3, the target antigen of pemphigus vulgaris, in a Brazilian population where fogo selvagem is endemic, although those patients do not develop any apparent clinical phenotype of pemphigus vulgaris.     

The anti-desmoglein 1 autoantibodies in pemphigus vulgaris sera are pathogenic

Pemphigus vulgaris and pemphigus foliaceus are two closely related, but clinically and histologically distinct, autoimmune skin diseases. The autoantigens for pemphigus vulgaris and pemphigus foliaceus are desmoglein 3 and desmoglein 1, respectively. The anti-desmoglein 1 antibodies in pemphigus foliaceus and anti-desmoglein 3 antibodies in pemphigus vulgaris are pathogenic as determined by immunoglobulin G passive transfer animal models. More than 50% of pemphigus vulgaris sera also contain anti-desmoglein 1 autoantibodies; however, the pathogenicity of the anti-desmoglein 1 autoantibodies in pemphigus vulgaris remains unknown. In this study, we used soluble recombinant extracellular domains of desmoglein 1 and desmoglein 3 to obtain affinity-purified anti-desmoglein 1 and anti-desmoglein 3 autoantibodies from pemphigus vulgaris sera and examined the pathogenicity of each fraction separately using the passive transfer mouse model. By immunoprecipitation, the purified anti-desmoglein 1 and anti-desmoglein 3 showed no cross-reactivity. The anti-desmoglein 1 autoantibodies in pemphigus vulgaris induced typical pemphigus foliaceus lesions in neonatal mice, whereas the anti-desmoglein 3 fraction induced pemphigus vulgaris-like lesions. In addition, the pathogenic anti-desmoglein 1 and anti-desmoglein 3 autoantibodies in pemphigus vulgaris had predominant IgG4 subclass specificity. These findings suggest that the anti-desmoglein 1 antibodies in pemphigus vulgaris are pathogenic.     

Autoantibodies against desmoglein 2 are not pathogenic in pemphigus

BackgroundAnti-desmoglein 1 and 3 autoantibodies justify acantholysis in pemphigus; however, the pathogenesis of anti-desmoglein 2 is hypothetical.ObjectiveTo compare the participation of desmogleins 1, 2 and 3 through the production of serum autoantibodies, and protein and gene expression in the skin/mucosa of patients with pemphigus foliaceus and pemphigus vulgaris.MethodsThe autoantibodies were titrated by ELISA in 202 samples of pemphigus foliaceus, 131 pemphigus vulgaris, 50 and 57 relatives of patients with pemphigus foliaceus and pemphigus vulgaris, respectively, and 114 controls. Protein and gene expressions were determined by immunohistochemistry and qPCR in the skin/mucosa of 3 patients with pemphigus foliaceus and 3 patients with pemphigus vulgaris.ResultsHigher titers of anti-desmoglein 2 (optical density) resulted in pemphigus foliaceus and pemphigus vulgaris, when compared to controls (0.166; 0.180; 0.102; respectively; p < 0.0001). There was a correlation between anti-desmoglein 2 and anti-desmoglein 1 titers in pemphigus foliaceus (r = 0.1680; p = 0.0206). There was no cross-reaction of anti-desmoglein 2 with desmoglein 1 and 3. Protein overexpression of desmoglein 2 was observed in intact and lesional skin of patients with pemphigus compared to the skin of controls. Internalization granules of desmoglein 1 and 3, but not of desmoglein 2, were observed in lesions of pemphigus foliaceus and pemphigus vulgaris, respectively. Gene overexpression of desmoglein 2 was observed in the mucosa.Study limitationsSmall sample size for the statistical analysis of protein and gene expression.ConclusionAutoantibodies against desmoglein 2 are not pathogenic in pemphigus; protein and gene overexpression of desmoglein 2 in the skin and mucosa may be involved in acantholysis repair.     

Induction of acantholysis in organ explant culture by penicillamine and captopril

Pemphigus is an autoimmune disease proved to be mediated by IgG autoantibodies. Skin lesions clinically and histologically identical to pemphigus may occur in patients receiving penicillamine and captopril, but some of these patients lack circulating or tissue-bound autoantibodies. Therefore, we examined the ability of these drugs to produce acantholysis directly in organ explant culture. Human skin explants were prepared from split-thickness graft skin from adults and from neonatal foreskins. Explants were cultured in media containing 0.1 to 200 mmol/L of penicillamine or captopril; parallel drug-free control cultures were also prepared. Acantholysis occurred in all split-thickness graft skin cultures incubated for 72 hours with at least 20 mmol/L of penicillamine and at 24 to 48 hours in those incubated with at least 10 mmol/L of captopril. Acantholysis occurred less frequently in foreskin cultures, being present in 1 (8%) of 12 of those exposed to at least 20 mmol/L of penicillamine and 3 (12%) of 25 of those exposed to at least 10 mmol/L of captopril. None of the parallel drug-free control cultures developed acantholysis. Subcorneal acantholysis, resembling that seen in pemphigus foliaceus, and suprabasilar acantholysis, resembling that seen in pemphigus vulgaris, were induced in vitro. Our results indicate that both drugs can act as ligands and produce acantholysis in organ explant culture in the absence of autoantibody. This ligand-induced acantholysis may also be responsible for induction of the disease in vivo in those patients who lack demonstrable autoantibodies.     

Diagnosis and clinical features of pemphigus vulgaris

Autoimmune bullous diseases are associated with autoimmunity against structural components that maintain cell-cell and cell-matrix adhesion in the skin and mucous membranes. They include those where the skin blisters at the basement membrane zone and those where the skin blisters within the epidermis (pemphigus vulgaris, pemphigus foliaceus, and other subtypes of pemphigus). The variants of pemphigus are determined according to the level of intraepidermal split formation. There are 5 main variants of pemphigus: pemphigus vulgaris, pemphigus foliaceus, pemphigus erythematosus, drug-induced pemphigus, and paraneoplastic pemphigus. This review focuses only on pemphigus vulgaris.     

Herpetiform pemphigus showing reactivity with pemphigus vulgaris antigen (desmoglein 3)

We report a patient with herpetiform pemphigus(HP)who showed reactivity only with pemphigus vulgaris(PV)antigen but not with pemphigus foliaceus(PF)antigen. Direct and indirect immuno- fluorescence revealed keratinocyte cell surface staining in the lower layers of the epidermis, where desmoglein 3 (Dsg3) is expressed. Immunoblot analysis, using ethylenediamine tetra-acetic acid- separated human epidermal extracts, revealed that the patient's serum recognized only a 130-kDa polypeptide which co-migrated with Dsg3. By antigen-specific immunoadsorption studies, using desmoglein 1 (Dsg1) and Dsg3 recombinant protein produced by baculovirus expression system, immunoreactivity of the patient's serum was completely adsorbed by Dsg3 alone, but not by Dsg1. These results indicate that this HP patient produced only anti-Dsg3 autoantibodies and no other autoantibodies against components of the keratinocyte cell surface. HP could be a variant of PV.in addition to PF, with unique clinical and histological features.     

Pemphigus

Pemphigus diseases comprise a group of autoimmune disorders which are characterized by intraepidermal blisters and autoantibodies to components of desmosomes. Desmosomes mediate adhesion between neighbouring keratinocytes. A common feature of pemphigus diseases are intercellular deposits of IgG or, less frequently, of IgA within the epidermis. The group of pemphigus diseases includes pemphigus vulgaris, pemphigus foliaceus, pemphigus vegetans, pemphigus herpetiformis, pemphigus erythematosus, paraneoplastic pemphigus, drug-induced pemphigus, and IgA pemphigus. Using molecular tools, some of the autoantigens in these diseases have been characterized. In pemphigus vulgaris, autoantibodies are directed to desmoglein 3 and in pemphigus foliaceus to desmoglein 1. Target antigens in IgA pemphigus are desmocollin 1 and desmoglein 3. In paraneoplastic pemphigus, autoantibodies react with a complex of various proteins, including desmoplakin 1 and 2, BP230, envoplakin, periplakin, plectin, desmoglein 3, and a yet uncharacterized 170 kD protein. This review summarizes new insights into the immunopathogenesis and diagnosis of pemphigus diseases.     

Serum plakophilin‐3 autoreactivity in paraneoplastic pemphigus

Summary Background Paraneoplastic pemphigus (PNP) is a malignancy‐associated autoimmune disease in which circulating autoantibodies recognize various polypeptides that constitute the desmosomes and hemidesmosomes of epithelial structures. Objectives To determine whether PNP is associated with autoreactivity against the armadillo‐repeat‐containing plakophilin‐3 (PKP3) protein. Methods HEK293 cells were transiently transfected with either a pEF6/myc‐His or a pEGFP‐N2 construct, both encoding human PKP3 (protein products of 85 kDa and 115 kDa, respectively). Protein lysates were made in Laemmli buffer. The proteins were separated by gel electrophoresis, transferred to filters and probed with five PNP sera, four pemphigus vulgaris sera, two pemphigus foliaceus sera, five bullous pemphigoid sera, one cicatricial pemphigoid serum and one linear IgA dermatosis serum. A mouse monoclonal anti‐PKP3 antibody raised against a 20‐amino acid peptide of human PKP3 was used as a positive control. Results Autoreactivity against both 85‐kDa and 115‐kDa recombinant PKP3 protein products was detected in all five PNP sera and in one pemphigus vulgaris serum. None of the sera of patients with basement membrane zone bullous diseases reacted with the PKP3 protein products. The presence of autoantibodies against PKP3 in PNP sera was subsequently confirmed in human epidermal lysate blots. Conclusions This is the first report of PKP3 reactivity in bullous disorders, which was present in all the PNP sera tested. The presence of PKP3 reactivity in one patient with pemphigus vulgaris is not unexpected as the desmosome is also targeted in this disease.     

Antidesmoplakin antibodies in pemphigus vulgaris

Background Besides being present in paraneoplastic pemphigus (PNP), circulating antidesmoplakin (DP) antibodies have been found anecdotally in other bullous diseases, including pemphigus foliaceus and pemphigus vulgaris. Objectives To verify how frequent anti‐DP antibodies are in pemphigus vulgaris. Methods We studied 48 sera from patients with proven pemphigus vulgaris (29 mucosal dominant pemphigus and 19 mucocutaneous pemphigus) by indirect immunofluorescence (IIF) with rat bladder epithelium (RBE) as a substrate and by immunoblotting (IB) on human keratinocyte cultures enriched in DP. Results Ten sera (21%) were positive in IIF on RBE. By IB, eight sera proved to have antibodies to both DP I (250 kDa) and DP II (210 kDa), one serum had antibodies directed to DP I only, and two sera to DP II only. Conclusions Our data confirm that RBE is not a specific IIF substrate for the serological diagnosis of PNP. It remains a sensitive and specific substrate for the detection of anti‐DP antibodies, which, in patients with pemphigus vulgaris, are probably caused by an epitope‐spreading phenomenon.     

Immunoablative high-dose cyclophosphamide without stem cell rescue in pemphigus foliaceus

BACKGROUND: There is growing evidence that immunoablative high-dose cyclophosphamide without stem cell rescue is effective and safe in patients with refractory autoimmune diseases such as paraneoplastic pemphigus, systemic lupus erythematosus, aplastic anemia, and more recently pemphigus vulgaris. METHODS: We report a 51-year-old patient with severe pemphigus foliaceus, which was recalcitrant to multiple medical regimes. The patient presented with multiple thick hyperpigmented and scaly, ill-defined plaques on the face. In addition, she had multiple superficial erosions and crusts on her scalp, thorax, upper and lower extremities. The patient also had a few discrete intact flaccid bullae. A skin biopsy and direct immunofluorescence was consistent with pemphigus foliaceus. The patient's circulating pemphigus autoantibodies were present at a titer of 1 : 2560. The patient received immunoablative high-dose cyclophosphamide (50 mg/kg/day) for 4 consecutive days, and tolerated the regime well. RESULTS: Approximately 3 months after therapy, the skin lesions had healed and her prednisone, which had been as high as 80 mg daily, was tapered to 30 mg daily. In addition, her circulating autoantibodies decreased after treatment. Nearly 10 months after treatment, the patient did relapse. However, her disease was less severe and more easily managed with lower doses of immunosuppressive therapy. CONCLUSION: This case contributes to the growing evidence of high-dose cyclophosphamide's efficacy without stem cell rescue in recalcitrant autoimmune diseases, including pemphigus foliaceus.     

Five Japanese cases of antidesmoglein 1 antibody-positive and antidesmoglein 3 antibody-negative pemphigus with oral lesions

Background Oral mucosal lesions develop in pemphigus vulgaris, but not in pemphigus foliaceus. This clinical phenomenon is explained by the ‘desmoglein (Dsg) compensation theory’. Dsg3 and Dsg1 are major autoantigens for pemphigus vulgaris and pemphigus foliaceus, respectively. Dsg3 is overexpressed and Dsg1 is weakly expressed on the oral mucosa. Thus, on the oral mucosa, suppression of Dsg3 function by anti‐Dsg3 autoantibodies is not compensated by weakly expressed Dsg1 in pemphigus vulgaris, while suppression of Dsg1 function by anti‐Dsg1 autoantibodies is perfectly compensated by richly expressed Dsg3 in pemphigus foliaceus. Objectives We present five Japanese patients with pemphigus who deviate from this theory, i.e. all patients showed oral lesions (three also had cutaneous lesions) and reacted only with Dsg1, but not with Dsg3, by enzyme‐linked immunosorbent assay. Methods To confirm whether the unique clinical phenotypes in our patients were due to a different immunological profile from that in classical pemphigus, we examined the reactivity of the patient sera by immunoprecipitation‐immunoblotting analysis using five Dsg1/Dsg2 domain‐swapped molecules. Results The sera of two patients who had only oral lesions tended to react with the extracellular (EC) 5 domain of Dsg1, the domain that is considered nonpathogenic in classical pemphigus foliaceus. Sera of three patients with mucocutaneous lesions reacted with EC1 domain or with both EC1 and EC2 domains of Dsg1, like classical pemphigus foliaceus. Conclusions These results indicate that antigenic diversity of anti‐Dsg1 antibodies in these patients may cause the unique oral mucosal and cutaneous lesions, although further studies are required to elucidate the pathomechanisms.     

Childhood pemphigus

BACKGROUND: Five children with pemphigus are reported: three with pemphigus vulgaris, one with pemphigus vegetans, and one with pemphigus foliaceus. Only one case of juvenile pemphigus vegetans has been published in the literature. MATERIALS AND METHODS: All three patients with pemphigus vulgaris were treated with oral corticosteroid; in two cases, azathioprine was added for steroid-sparing effect. The patient with pemphigus vegetans had a clinical presentation resembling pemphigus vulgaris, but the lesions in the perianal area healed as hypertrophic granulation tissue. He was treated with oral corticosteroid, azathioprine, and intralesional corticosteroid. The patient with pemphigus foliaceus presented with exfoliative dermatitis, and was treated with oral corticosteroid; methotrexate was added later for steroid-sparing purposes RESULTS: The patients were followed up for 1-4 years; the prognosis of childhood pemphigus is good. CONCLUSIONS: Long-term follow-up is needed to detect flaring of the disease and the side-effects of immunosuppressive drugs.     

Immunoblot and immunoelectronmicroscopic analysis of endemic Tunisian pemphigus

Tunisian pemphigus is a newly described form of endemic pemphigus whose clinical, histological and epidemiological characteristics have recently been detailed. The objective of this study was to analyse the binding properties of autoantibodies present in sera from patients with endemic Tunisian pemphigus using immunoblotting and indirect immunoelectron microscopy (IEM). Thirty patients with pemphigus foliaceus (PF) and six with pemphigus vulgaris (PV) seen in the dermatology department of Tunis Hospital between 1992 and 1994 were selected for this study. Seven of 30 (23%) and six of 12 (50%) PF sera tested bound to the 160 kDa band of desmoglein 1 when tested on bovine tongue and human epidermal extracts, respectively. Two of six and two of three PV sera tested bound to the 130 kDa desmoglein 3 in these two extracts. Immunoblot and indirect IEM showed that 24 of 30 (80%) PF sera contained IgG1, IgG3 or IgG4 antibodies that bound to a 185-kDa polypeptide localized on the desmosomal plaque. This immunological analysis showed that most endemic Tunisian pemphigus sera correspond to PF sera and are characterized by a high frequency of autoantibodies directed against a recently identified 185-kDa antigen of the desmosomal plaque.     

230-kDa and 190-kDa proteins in addition to desmoglein 1 as immunological targets in a subset of pemphigus foliaceus with a combined cell-surface and basement membrane zone immune staining pattern

Pemphigus erythematosus, initially described as a combination of pemphigus with lupus erythematosus, and pemphigus foliaceus are now frequently considered localized and generalized variants of superficial pemphigus. Yet diagnostic criteria for pemphigus erythematosus remain controversial. Distinct from pemphigus foliaceus, pemphigus erythematosus displays immune depositions at the dermal-epidermal junction, which suggests additional immunopathological mechanisms. We present three patients with clinical and histopathologic signs of superficial pemphigus, who all exhibited an immunomorphology characteristic of pemphigus erythematosus. Complement depositions in a granular-linear fashion were consistently found at the dermal-epidermal junction besides in vivo bound and circulating antikeratinocyte cell-surface autoantibodies. Histopathology showed subcorneal acantholysis, and all sera contained antidesmoglein 1 but not antidesmoglein 3 autoantibodies detected by enzyme-linked immunosorbent assays (ELISA). Additional autoantibodies against a 230-kDa protein and against a 190-kDa protein comigrating with bullous pemphigoid antigen 1 (BP230) and periplakin, respectively, were present in all the patients' sera. As two sera specifically reacted with BP230 by ELISA, the presence of BP230-specific autoantibodies could be associated with dermal-epidermal immune staining in these patients. In pemphigus erythematosus, dermal-epidermal immune staining is generally attributed to the deposition of immune complexes, while the presence of BP230-specific autoantibodies has not been reported in this disease previously. Perhaps, the unique autoantibody profile of the patients in the study permits discrimination between patients with superficial pemphigus that display additional dermal-epidermal immune staining from those with conventional pemphigus foliaceus on a molecular basis. Further studies will be required to substantiate the frequency of this occurrence and to unravel its pathogenic significance.     

Comparative study of pemphigus vulgaris and pemphigus foliaceus in Singapore

This is a retrospective study of all patients diagnosed to have pemphigus in our centre over a 3 year period. The case records of all patients with pemphigus from January 1995 to December 1997 were analysed. Fifty patients were diagnosed to have pemphigus during the study period. The diagnoses were pemphigus vulgaris in 31 patients, pemphigus foliaceus in 16, paraneoplastic pemphigus in two and IgA pemphigus in one. The average titre of anti-intercellular antibodies in patients with pemphigus vulgaris (1:96) was higher than the titre in patients with pemphigus foliaceus (1:69). The average initial dose of prednisolone required for disease control in patients with pemphigus vulgaris (62 mg/day) was significantly higher than that required for patients with pemphigus foliaceus (44 mg/day). In our study population, pemphigus vulgaris is a more severe and chronic disease than pemphigus foliaceus, as reflected in the higher titre of anti-intercellular antibodies, higher dose of systemic corticosteroids required for control of the disease, the longer duration to achieve complete remission and longer follow-up period.     

天疱疮发病机制的研究进展

天疱疮是自身免疫引起表皮棘层细胞松解导致的慢性复发性表皮内大疱性皮肤病,典型表现为红斑基础上的疱壁松弛性水疱、糜烂、尼氏征阳性.依据天疱疮的临床表现,分为寻常型、增殖型、落叶型和红斑型天疱疮.天疱疮主要的发病机制是患者存在针对角质形成细胞桥粒芯(糖)蛋白的自身抗体,但棘层松解的详细机制尚不清.近年来,随着对蛋白组学、免疫学和分子生物学技术的发展以及天疱疮发病机制研究的不断深入,发现天疱疮的发病机制中除传统的桥粒芯(糖)蛋白自身抗体外,非桥粒芯(糖)蛋白抗体因素也参与了棘层松解的形成,为天疱疮提供了新的潜在治疗靶位.     

Penicillamine-induced pemphigus foliaceus-like dermatosis. A case with unusual features, successfully treated by plasmapheresis

A case of a severe, widespread bullous dermatosis clinically resembling pemphigus foliaceus occurred during treatment with penicillamine hydrochloride in a patient with rheumatoid arthritis. Histologically, the disease showed changes compatible with pemphigus vulgaris as well as with a bullous drug eruption. Treatment by plasmapheresis proved to be effective in controlling the disease.     

天疱疮抗体结合靶抗原的定位研究

目的 研究天疱疮抗体铺皮细胞间抗原在超微结构水平的部位。方法 采用ＬＲＷｈｉｔｅ树脂为包埋剂,用金标记包一直接和间接免疫电镜技术,观察天疱疮患者皮损中ＩｇＧ的沉积部位和患者血清中ＩｇＧ型自身抗体结构正常人皮肤的部位。结果 寻常型天疱疮和落叶型天疱疮的直接和间接免疫电镜均在表皮细胞间的桥粒部位觅金颗粒沉积,在非桥数部位的角质形成细胞间未金颗粒沉积。结论寻常型天疱疮和落叶型天疱疮的靶抗原均是桥粒成分,