Antibodies against purified pigeon IgA in pigeon breeders' disease.

It is demonstrated that previously described PDF1-A antigens from pigeon dropping extract contain pigeon IgA. The sera of patients with pigeon breeders' disease contain precipitating antibodies against pigeon IgA, in contrast to the sera of pigeon breeders suffering from unrelated forms of pulmonary dysfunction. The degree of complement consumption by PDF1A antigens, pigeon serum, and pigeon IgA turned out to be correlated. No correlation was found between precipitating anti-pigeon IgA antibodies and complement consumption by pigeon IgA in patients' sera.