Antigen specificity in subsets of mucous membrane pemphigoid.

Mucous membrane pemphigoid (MMP) has several subsets based on target antigens recognized by their sera. MMP and ocular cicatricial pemphigoid (OCP) sera recognize beta4 integrin subunit, oral pemphigoid sera recognize alpha6 integrin subunit, and anti-epiligrin cicatricial pemphigoid sera recognize laminin 5. Our aim is to determine if autoantibodies in the sera of patients with MMP, OCP, and oral pemphigoid (OP) recognize only their target antigens, and to see if this specificity is maintained throughout the clinical course. An immunoblot assay using bovine gingival lysate was used as substrate. Fifteen MMP patients, eight with OCP, and 15 OP patients were studied before therapy and at multiple intervals during the clinical course. Absorption and blocking studies were performed to determine binding specificity. Sera of patients with MMP and OCP recognize only beta4 integrin subunit, and sera of OP patients recognize alpha6 integrin throughout the clinical course. The sera of patients in the subsets of MMP described in this report show adherence and selectivity to target antigen during the entire clinical course, without crossover, interaction, or change. Hence, these subsets of MMP provide an excellent model to study clinical correlation with antigen and antibody specificity, in autoimmunity.