IgA heavy chain disease. A case detected in the western hemisphere.

IgA heavy chain disease (alpha chain disease) was detected in a 46 year old South American (Colombian) of mixed Spanish and Indian (Mestizo) descent. The clinical course was characterized by severe malabsorption, initially thought to be a variant of tropical sprue. Jejunal mucosal biopsy revealed marked villous atrophy with heavy infiltration of the lamina propria by a single monotonous cell type which, by light microscopy, had the appearance of either a large, abnormal plasma cell or a small histiocyte. Electron microscopy of the biopsy specimen demonstrated the presence of abnormal plasma cells, lymphatic distention and abnormalities of surface epithelial cells. At autopsy a 6 by 3 cm mass was found in the right para-aortic area along with many firm 2 cm mesenteric and para-aortic lymph nodes. Histologic examination revealed the presence of a monotonous cell type similar to that found in the jejunal mucosal biopsy specimen.