A form of heavy chain disease that is related to Mediterranean lymphoma and celiac sprue. The principal organ involved is the small intestine, although respiratory tissues are occasionally affected. The symptoms and signs may include malabsorption, diarrhea, abdominal pains, and weight loss. In some patients there is peripheral adenopathy and splenomegaly with no signs of intestinal or respiratory tract changes. Diagnosis is made through tests for the abnormal immunoglobulins. Chemotherapy may produce long-term remissions.