T helper-cell leukemia/lymphoma: presentation as an acute immune-mediated illness.

A 36-year-old man presented with an acute immune-mediated illness characterized by leukocytoclastic vasculitis and polyarthritis. Evaluation of the synovial fluid, bone marrow, and peripheral blood revealed large numbers of abnormal lymphoid cells labeling a 4B4-positive, CD4-positive, IL-2 receptor-negative, helper T cells. Hypergammaglobulinemia, immune complexes, high levels of serum IL-2 receptors, serum antibodies against foreign alloantigens, and specific cytolysis of the patient's leukemic cells by his normal CD8+ T lymphocytes suggest an interaction of the malignant cells and his normal immune cells. Thus, some of the rheumatologic symptoms leading to the diagnosis of leukemia appear to reflect an immunoregulatory imbalance manifested by B-cell hyperactivity, likely induced by the malignant helper T cells, and attempted regulation of his malignant T cells by normal lymphocytes.