Amyloidosis associated with juvenile rheumatoid arthritis.

Clinical and pathological findings are reported in a Japanese girl who died of secondary amyloidosis associated with juvenile rheumatoid arthritis two years after the onset of symptoms. The patient had intermittent high fever, rheumatoid rash, polyarthralgia, and hepatosplenomegaly. The joints showed the typical histologic changes of juvenile rheumatoid arthritis. Amyloid deposition was found in various tissues; however, remarkable deposition of amyloid was observed in the gastrointestinal tract, especially in the ileum. The amyloid protein in this patient was identified as protein AA using the methods of potassium permanganate treatment and the peroxidase-antiperoxidase unlabeled antibody technique.