DRUG-INDUCED LINEAR IGA DISEASE - TARGET ANTIGENS ARE HETEROGENEOUS

No information is available concerning the target antigen(s) involved in drug-induced linear IgA disease. The purpose of this study was to d efine better drug-induced linear IgA disease by studying its immunopat hological, immunoultrastructural and immunochemical characteristics in three patients. In the first patient, IgA deposits were seen in the l amina lucida. In the second and the third patients, IgA deposits were seen on each side of the lamina densa. Immunoblotting of the first pat ient's serum showed that IgA reacted with a protein of 230 kDa similar to the bullous pemphigoid-associated antigen 1 (BPAG 1). The second p atient's serum did not react with specific bands. In the third patient IgA antibodies reacted with a protein of 97 kDa on epidermal extracts . Our findings suggest that, as in idiopathic forms, the target antige n is not unique in drug-induced linear IgA disease. In some patients, drug-induced linear IgA disease may represent an IgA class response to the BPAG 1.