The immunoglobulin A antibody response in clinical subsets of mucous membrane pemphigoid

Background: Mucous membrane pemphigoid (MMP) is an immunobullous disease. In MMP there is frequently a mixed antibody response with the presence of IgA and/or IgG antibodies directed toward basement membrane zone antigens. The IgG antibody response in MMP has been studied, but the antigens to which the IgA antibodies react have not been studied. Objective: To determine the IgA autoantibody reactivity profiles in patients with MMP. Methods: Patients who had both ocular and oral MMP were compared with patients who had ocular or oral MMP and with patients who had cutaneous linear IgA disease (LABD) by Western immunoblot studies. Results: Five of 15 MMP patients and 1 of 5 LABD patients had IgA antibodies reactive with the 180-kD bullous pemphigoid antigen. Seven of 15 MMP patients had IgA antibodies reactive with the 97-kD LABD antigen. Conclusion: Major antigens in IgA MMP are the 180-kD bullous pemphigoid antigen and the 97-kD LABD antigen.