Immunoblastic lymphoma: an immunologic study.

An immunologic study of a 59-year-old man with immunoblastic lymphoma is presented. Shortly after his hospital admission, an uncompensated hemolytic process developed, caused by cold agglutinins. These antibodies had anti-i specificity, were of low titer at cold temperature, but demonstrated a high thermal amplitude. An apparent paraprotein was found by further immunochemical analysis to be polyclonal. The majority of cells in the peripheral blood (over 2000/cu nm), lymph node, and bone marrow that contained cytoplasmic IgG or IgM were plasma cells, although a small number of cells resembled lymphoblasts. Their staining with anti-lambda and anti-kappa chain reagents confirmed the polyclonality of the immunoglobins. Some plasma cells displayed the concomitant presence of both IgM and IgG immunoglobulins. Free immunoglobin was also demonstrated intercellularly in the lymph node section. The patient's acute hemolysis was controlled by plasmapheresis and eventually by combination chemotherapy. After chemotherapy, the clinical improvement was rapid, immunoglobulin levels returned to normal, and the patient remains asymptomatic 40 months after completing six courses of combination chemotherapy. This report provides evidence for polyclonal proliferation of B-lymphocytes in immunoblastic lymphoma.