Adult T-cell leukemia/lymphoma - Clinical aspects

Background data: Adult T-cell leukemia/lymphoma (ATL) is a malignant prolif eration of activated CD4+ T lymphocytes. The disease is almost exclusively found in patients living in retrovirus HTLV-1 endemic areas. Virology: In ATL, monoclonal HTLV-1 provirus is integrated into atypical ly mphocytes, called clover-leaf lymphocytes. The pathogenic mechanism leading to HTLV-1-induced leukemogenesis remains obscure. The disease generally oc curs after a long latency period. Four clinical subtypes: The diversity of the clinical presentation has led to the classification of ATL into four subtypes: acute or prototype, lympho ma, chronic, and painless. In the acute form of ATL there is a tumor syndro me associated with paraneoplastic hypercalcemia and a high rate of opportun istic infections due to the immunodepression predominated by cellular immun ity. Clinical course: Prognosis is poor for the acute and lymphomatous forms wit h a median survival of 6 and 10 months respectively infectious episodes are frequent, often caused by Pneumocystis carinii, and require systematic pro phylaxis. Screening for anguilulosis and prophylaxis is also necessary.