MIDDLE-EAST LYMPHOMA AND ALPHA-CHAIN DISEASE - IMMUNOHISTOCHEMICAL STUDY

An immunoperoxidase study of the small intestinal mucosa of three patients with α-chain disease showed heavy infiltration of the mucosa by plasma cells containing α-heavy chain and J-chain but no light chains. An additional band-like and nodular mucosal infiltrate was also present and consisted of cells showing no evidence of cytoplasmic immunoglobulin synthesis. The cells comprising this infiltrate invaded and destroyed intestinal crypts, and immunoperoxidase staining showed them to be sharply distinct from the α-chain-containing plasma cells. In two cases of Middle East lymphoma, immunohistochemistry revealed a normal plasma cell population in the lamina propria of the small intestine. These results show that α-chain disease can be diagnosed in routine paraffin sections which should permit clarification of its true incidence in Meddle East lymphoma. the demonstration of a sharp distinction between the two types of mucosal infiltrate in α-chain disease is in contrast to previous immunofluorescence results and enables more ready identification of mucosal changes that may be important in the management of the disease.