The Frequency of Serum IgA autoantibody in Patients with Pemphigus

Jun, Jae Hong; Chang, Sung Yeoul; Lee, Chang Woo

Abstract

BACKGROUND: Pemphigus is an autoimmune bullous disease with circulating desmosomal autoantibodies of IgG. In direct IF studies with perilesional tissue, IgA or IgM antibodies can be seen in addition to IgG.
OBJECTIVE
We examined sera of patients with pemphigus for the presence/frequency of IgA autoantibodies as well as IgG by indirect IF and immunoblot assay. Patients: Twenty patients of pemphigus (PV 10, PF 10) who showed positive findings in indirect IF examinations.
METHODS
Indirect IF study with normal human skin substrates and immunoblot analysis using A431 cell extracts (with multi-step immunostaining) were performed with patients sera.
RESULTS
In indirect IF, IgA autoantibodies that bind to the epidermal keratinocyte antigens were detected in 4 cases among the 20 patients (PV 2 and PF 2). In immunoblot analysis IgA bands reacting to PV/PF antigens were observed in 7 cases from the 20 patients with pemphigus (PV 3, PF 4). The serum titers of IgA autoantibodies were lower than those of IgG in every single case.
CONCLUSION
In patients with pemphigus (PV/PF), 35% of cases have serum IgA autoantibodies as well as IgG autoantibodies specific to the pemphigus antigens (Dsg 1/Dsg 3). However, pathogenic roles of the associated IgA autoantibody are not clear.