The fluorescent antibody method in the study of immunopathologic conditions.

Histochemical studies of immunopathologic conditions were carried out, using Coons' fluorescent antibody technique. Experimental conditions studied were: serum sickness, generalized anaphylaxis, the Arthus reaction and experimental glomerulonephritis. Human diseases studied were those referred to as "collagen diseases". Specific immunologic reactants were localized in the lesions of all experimental conditions studied, thus offering objective evidence of a possible immunologic pathogenesis of the lesions. In human diseases, gamma globulin was localized in the lesions of rheumatic fever, rheumatoid arthritis, systemic lupus erythematosus and amyloidosis. Although the finding of gamma globulin in human lesions might suggest that it is an antibody, such an interpretation should be made with care since the gamma globulin could be deposited on a non-immunologic basis.The tissue-localizing properties of sera from different disease states showed appreciable variability within a given disease, as well as similar localizing properties among sera of different diseases. It is suggested that these serum factors ("autoantibodies") might result as a host response and are not primarily involved in the pathogenesis of the disease.