Does class switching contribute to remission in bullous pemphigoid?

A correlation between the titre of circulating IgG autoantibodies and disea se activity has been difficult to demonstrate in bullous pemphigoid, We pos tulate that isotype switching from "inflammatory" IgG1 to "blocking" IgG4 s ubclass antibodies might contribute to disease remission. We studied 16 pat ients with bullous pemphigoid, 3 patients with cicatricial pemphigoid and 2 patients with epidermolysis bullosa acquisita at different stages of the d isease. The titres of Ige subclass and total IgG basement membrane zone aut oantibodies were correlated with clinical activity. Ten of the 16 bullous p emphigoid patients went into remission. The total IgG autoantibody levels s howed variable changes. IgG1 autoantibody decreased in 7 patients (3 were u nchanged) and IgG4 autoantibody increased in 9 patients. The 6 patients wit h clinical activity did not show such changes in IgG1 and IgG4 autoantibodi es. Similar results were observed with the other bullous diseases. Our data suggest that isotype switching from "inflammatory" IgG1 to "blocking" IgG4 antibody correlates with improvement in bullous pemphigoid.