IgA autoantibody may be the foremost pathogenic in three cases of linear IgA/IgG bullous dermatosis.

Linear IgA/IgG bullous dermatosis (LAGBD) is a relatively rare autoimmune bullous disease characterized by both IgA and IgG antibodies to basement membrane zone. The heterogeneity and pathogenesis of antibodies and the relationship between IgA and IgG in LAGBD have not been fully elucidated. We observed clinical, histological and immunological features of three LAGBD cases at different time points in the disease course. In our cohort, two cases showed IgA antibodies to epidermal antigens vanished when their lesions cleared after 3 months of treatment. One refractory case showed increasing antigens targeted by IgA antibodies with the progression of the disease. Collectively, the results suggest that IgA antibodies may play a major role in LAGBD. In addition, epitope spreading may be related to disease relapse and treatment refractory.