The location of binding sites of pemphigus vulgaris and pemphigus foliaceus autoantibodies: a post-embedding immunoelectron microscopic study

Pemphigus is a life-threatening autommune blistering discase of skin and mucous membranes that has two major subtypes based on clinical and histolgical features, pemphigus vulgaris (PV) and pemphigus foliaceus (PF). Autoantibodies against the PV antigen (desmoglein 3) and the PF antigen (desmoglein 1) are involved in the pathogenesis of blister formation. In the present study, the location of epitopes recognized by autoantibodies of patients with PV and PF was studied by postembedding immunogold electron microscopy. PV and PF autoantibodies were observed bound predominantly to the intercellular domains of desmosomes, but not to the non-desmosomal keratinocyte cell surface. The relationship between the location of PF antigen and other constitutive desmosomal proteins. desmocollin, desmoplakin and plakoglobin, in normal human skin was investigated using a double immunogold labelling techinique. It was observed that PF antigen and desmocollin co-localize within the intercellular domain of the desmosomes. In contrast, the antibodies against desmoplakin and plakoglobin bound predominantly to the intracellular desmosomal attachment plaque with the binding site of the antibody against plakoglobin closer to the desmosomal cell membrane than that of the antibody to desmoplakin. We show that the LR White postembedded immunogold electronmicroscopy technique is convenient and easily applied to studied to studies of autoimmune bullous skin diseases. We have used it to demonstrated the precise localization of the binding sites of PV and PF autoantibodies and their reltionship with other constitutive desmosomal proteins.     

Predominant IgG4 subclass in autoantibodies of pemphigus vulgaris and foliaceus

Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are autoimmune skin diseases caused by autoantibodies against desmoglein (Dsg) 3 and Dsg1. We have previously developed ELISAs using recombinant Dsg3 and Dsg1 expressed by baculovirus as a diagnostic tool for pemphigus. In this study, we determined the frequency of coexistence of IgA class as well as distribution of IgG subclass. Two out of 49 PV and PF sera tested had anti-Dsg1 IgA in addition to anti-Dsg1 IgG. Interestingly, one of them showed prominent pustular formation. Among IgG subclass, IgG4 was predominant and found in all of the 30 PV and 19 PF sera tested, followed by IgG1, detected in 25 out of 30 PV and 12 out of 19 PF sera. Even though IgG2 and IgG3 were detected in 13 and one PV and 6 and 4 PF sera, respectively, the ELISA titers had barely exceeded the cutoff value in most of the cases. There was no IgG subclass shift during the course of the disease in seven cases examined. These findings indicate that IgG4 subclass is the predominant autoantibodies in both PV and PF, while IgG1 is also frequently found.     

Antigenic specificity of fogo selvagem autoantibodies is similar to North American pemphigus foliaceus and distinct from pemphigus vulgaris autoantibodies

Fogo selvagem (FS) is clinically, histologically, and immunopathologically similar to sporadic pemphigus foliaceus (PF, as seen in North America and Europe), although the epidemiology of these 2 diseases differs markedly. It has been proposed that FS is identical to PF but, for some reason, occurs in an endemic focus in central Brazil. If this hypothesis is correct, the autoantibodies in FS and PF should have similar antigenic specificities. We studied sera from 13 patients with FS from central Brazil, and compared them with 20 sera from patients with PF from the United States. All these sera had circulating antibodies that bound the cell surface of epithelial cells in identical patterns by indirect immunofluorescence on monkey esophagus or normal human skin. In immunoprecipitation studies none of the 13 FS sera precipitated the pemphigus vulgaris (PV) antigen from radiolabeled extracts of cultured human keratinocytes. This is similar to the findings with PF sera of which 19 of 20 sera did not react with PV antigen, but in sharp contrast to the results with PV sera which, as previously reported, all immunoprecipitate the PV antigen. Immunoblotting performed on extracts of normal human epidermis demonstrated that 7 of 20 PF sera specifically and intensely bound an approximately 160 kD polypeptide, previously identified as desmoglein I, a desmosomal glycoprotein. Similarly, 3 of 13 FS sera specifically bound a 160 kD polypeptide. Thirteen normal sera from North America, 8 normal and disease control sera from central Brazil, 11 PV sera, and 12 bullous pemphigoid sera did not specifically bind this polypeptide. Two-dimensional gel electrophoresis confirmed that the 160 kD polypeptides identified by the subgroup of PF and FS sera were identical. These studies demonstrate that, although the exact molecular specificities of the majority of PF and FS sera remain to be determined, FS autoantibodies do not bind the PV antigen and a subgroup of FS autoantibodies have molecular specificity identical to that of a subgroup of PF autoantibodies.     

Ultrastructural localization of pemphigus vulgaris and pemphigus foliaceus antigens in cultured human squamous carcinoma cells

The ultrastructural localization of the pemphigus vulgaris (PV) and pemphigus foliaceus (PF) antigens in cultured human squamous carcinoma cells was observed using immunogold electron microscopy. Both the PV and PF autoantibodies bound only to the extracellular portion of the desmosomal structures. After incubation at 37 degrees C, the PV antigen-antibody complexes were observed within the cultured cells. PV and PF antigen expression was markedly reduced when the cells were cultured in medium with a low Ca2+ concentration.     

Treatment of pemphigus vulgaris and pemphigus foliaceus with mycophenolate mofetil

BACKGROUND: Mycophenolate mofetil is increasingly being used as a corticosteroid-sparing agent in immunosuppressive regimens. OBJECTIVE: To elucidate the effectiveness of mycophenolate as adjuvant therapy in the treatment of both pemphigus vulgaris and pemphigus foliaceus. DESIGN: Historical prospective study. SETTING: University hospital. PATIENTS: The study included 42 consecutive patients with pemphigus (31 with pemphigus vulgaris and 11 with pemphigus foliaceus) who had relapses during prednisone taper or had clinically significant adverse effects from previous drug therapy. RESULTS: Remission was achieved in 22 (71%) and 5 (45%) of patients with pemphigus vulgaris and pemphigus foliaceus, respectively. Partial remission was achieved in 1 (3%) and 4 (36%), respectively. The median time to achieve complete remission was 9 months (range, 1-13 months). The treatment was administered for a median of 22 months, and the median follow-up period was 22 months. Seventy-seven percent of patients had no adverse effect. Two patients had side effects severe enough to necessitate discontinuation of treatment, one because of symptomatic but reversible neutropenia and the other because of nausea. CONCLUSION: Mycophenolate is an effective and safe adjuvant in the treatment of both pemphigus vulgaris and pemphigus foliaceus.     

Evidence-based treatments in pemphigus vulgaris and pemphigus foliaceus

Treatment modalities in pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are many and varied, although level 1 evidence supporting their use is limited. To date, only 2 systematic reviews exist to support the use of different treatment modalities to control this group of conditions. Overall, within the literature, the quality of trials comparing treatment modalities is poor. Cohort sizes are small, methodologies are varied, and standardized outcome measurements are lacking. The authors aim to present a comprehensive view of the level 1 evidence that exists for common treatment modalities used in PV and PF.     

Transplacental passage of maternal pemphigus foliaceus autoantibodies induces neonatal pemphigus

The association of maternal pemphigus foliaceus (PF) with neonatal PF is rare and may be secondary to transplacental passage of PF autoantibodies. We describe a 25-year-old patient with PF who was delivered of two consecutive babies, one with classic skin lesions of PF and another that was normal. The neonate with PF was born when the mother had widespread skin disease; the normal newborn was born when the mother was in partial remission. The titers of PF autoantibodies were higher in the mother's serum and the cord serum of the baby with PF than in the mother during partial remission and the unaffected baby. The mother and affected baby had autoantibodies to desmoglein 1. Furthermore, cord blood from the baby with PF induced skin disease when injected into mice. In this case, maternal PF was associated with neonatal PF when the titers of maternal anti-desmoglein 1 autoantibodies were elevated. The cutaneous disease in neonatal PF is due to anti-desmoglein 1 autoantibodies.     

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.     

Comorbid mental health issues in patients with pemphigus vulgaris and pemphigus foliaceus

The term ‘pemphigus’ refers to chronic autoimmune skin disorders that cause blistering erosions on the skin and oral mucosa. The two major clinical forms are pemphigus vulgaris and pemphigus foliaceus. Although rare, they confer a stark symptomatic burden upon patients that significantly impacts daily life. Comorbid mental health issues are not routinely screened for in patients with pemphigus, and current UK guidance provides no formal provision for the identification and treatment of psychological issues. This review is the first of its kind, to our knowledge, to systematically examine the available evidence on mental health issues in pemphigus. Published work suggests that the incidence of anxiety and depression is much higher in patients with pemphigus compared with both the general population and with patients having other chronic skin disorders. Disease severity appears to be closely linked to mental health, with worsening of pemphigus associated with deteriorations in psychological wellbeing. Corticosteroids, which are associated with depression in chronic use, are the current first-line therapy for pemphigus and have been identified as a potential confounder and independent risk factor for mental health comorbidity in pemphigus. Current evidence is unclear whether a bidirectional relationship exists between mental health and pemphigus severity, and more thorough research is required to develop understanding of this issue. In conclusion, we have identified a high incidence of mental health comorbidity in pemphigus, and recommend routine screening of patients with pemphigus for mental health issues and signposting toward mental health services as an initial measure to address this.