Specific antiserum to rheumatoid arthritis amyloid and its cross reactivity with various amyloid preparations

Purified amyloid fibers from the liver of a patient with rheumatoid arthritis were reduced in 8 M urea and then alkylated. After chromatography on Sephadex G 100 column, 2 peaks were obtained. The first peak contained mucopolysaccharides and proteins which cross reacted immunologically with antihuman serum. The second peak was composed of a single protein moiety specific for amyloid. An antiserum specific for this protein was prepared and its IgG fraction was conjugated with fluorescein. Use of this antiserum demonstrated a marked antigenic similarity among amyloid preparations from patients with rheumatoid arthritis, familial Mediterranean fever and 'primary' amyloidosis. Very poor cross reactivity was observed with amyloid secondary to Hodgkin's disease and there was no reaction whatever with amyloid from patients with chronic lymphatic leukemia, multiple myeloma and tuberculosis.