IMMUNOGOLD LOCALIZATION OF THE 97-KD ANTIGEN OF LINEAR IGA BULLOUS DERMATOSIS (LABD) DETECTED WITH PATIENTS SERA

The classification of linear IgA bullous dermatosis in the group of su bepidermal blistering diseases is still a matter of controversy. This situation is due partly to the considerable clinical heterogeneity of the disease but also results from the difficulties in characterization and localization of the specific basement membrane zone antigen(s) re cognized by immunoglobulin (Ig)A antibodies. In the present study, we have combined the Western blot detection of circulating autoantibodies with an ultrastructural immunogold labeling of human skin antigens us ing the same patients' sera. Our results, obtained with a short series of sera showing exclusive IgA class reactivity with the epidermal por tion of salt-split skin, indicate that the antibodies recognizing the 97-kD antigen on immunoblot bind to the hemidesmosomal plaques of basa l keratinocytes and the adjacent lamina lucida. These homogeneous labo ratory results remain in striking contrast to the heterogeneity of cli nical pictures in the patients studied, suggesting a participation of complementary, possibly not humoral, phenomena in the pathogenesis of linear IgA bullous dermatosis.