Antigenic specificity of antibodies from patients with linear basement membrane deposition of IgA.

We reviewed the immunoreactivity of sera binding to the epidermal side of basement membrane split skin from 13 adults and 8 children with IgA alone, 9 adults with IgA and IgG and 7 adults with IgA and ocular pemphigoid. Immunoblots were done against previously described 45-, 97-, 180- and 230-kD antigens, and reactivity was confirmed by elution of antibody from nitrocellulose and binding to the basement membrane. Ten of 13 adults and 7 of 8 children reacted with the 97-kD antigen. Sera with both IgA and IgG reacted in varying patterns and on occasion with more than 1 antigen. All 7 patients with ocular cicatricial pemphigoid reacted uniquely with a 45-kD antigen.