Amyloidosis in leprosy.

Histopathologic studies were performed on systemic amyloidosis of leprosy patients in two Japanese leprosaria. Amyloid deposits were observed in 23 of 50 cases (46%) autopsied from 1955 to 1959 (Group A), and in 17 of 110 cases (15.4%) from 1962 to 1971 (Group B). These incidences are higher than those of the pre-chemotherapeutic period in Japan. The average age of amyloidal cases was significantly lower than that of nonamyloidal cases in both groups. There was no predilection for either type of leprosy in Group B. Pyelonephritis was frequently observed in both groups; the incidence of amyloidosis in Group B correlated with pyelonephritis. Amyloid deposits may be related to renal disorders associated with lepra reactions or inflammatory lesions. Amyloidosis has been classified into primary and secondary type, but the criteria seem uncertain. We referred to a classification based on immunologic finginds. In the severely affected lesion of the kidney of one case, we observed foci of foreign body type giant cells, suggesting a possibility of resorptive process in human renal amyloidosis.