Immunohistochemical analysis of amyloid by the fluorescence technique.

The immunohistochemical composition of amyloid deposits in secondary human amyloidosis and experimental amyloidosis in rabbits was studied by means of the "fluorescent antibody" technique of Coons et al. Quantitative studies of the relative amounts of gamma globulin present in the amyloid deposits by the use of radioiodinated fluorescent antibody are reported. It is concluded that amyloid deposits in several organs from cases of secondary human amyloidosis and experimental amyloidosis in rabbits contain considerable concentrations of gamma globulin. The presence of gamma globulin in amyloid might be interpreted as either a metabolic deposition of circulating globulin present in high concentrations in the plasma or as a result of an immunologic reaction involving antigen and antibody.