The localization of the binding site of circulating IgA antibodies in linear IgA disease of adults, chronic bullous disease of childhood and childhood cicatricial pemphigoid.

Biopsies from suction blisters raised in three normal volunteers were used as substrate in the indirect immunofluorescence technique to determine the binding site of circulating IgA antibodies in serum from three patients with adult linear IgA disease (LAD), nine with chronic bullous disease of childhood (CBDC), three with childhood cicatricial pemphigoid (CCP), and four with bullous pemphigoid (BP). Direct immunofluorescence was done using suction blisters raised in two patients with LAD and one with CCP. The circulating IgA antibodies in LAD and CBDC bound mainly to the roof of the blister but also to the base, and in CCP they bound only to the base of the blister. The circulating IgG antibodies in BP bound to the roof and base of the blister. These results demonstrate that the antigens in the various linear IgA dermatoses are heterogenous and are localized at different sites. The LAD and CBDC antigens are present in the lamina lucida, and the antigen in CCP is associated with the basal lamina.