[Adult T-cell leukemia/lymphoma. Clinical aspects]

Adult T-cell leukemia/lymphoma (ATL) is a malignant proliferation of activated CD4+ T lymphocytes. The disease is almost exclusively found in patients living in retrovirus HTLV-1 endemic areas.

In ATL, monoclonal HTLV-1 provirus is integrated into atypical lymphocytes, called clover-leaf lymphocytes. The pathogenic mechanism leading to HTLV-1-induced leukemogenesis remains obscure. The disease generally occurs after a long latency period.

The diversity of the clinical presentation has led to the classification of ATL into four subtypes: acute or prototype, lymphoma, chronic, and painless. In the acute form of ATL there is a tumor syndrome associated with paraneoplastic hypercalcemia and a high rate of opportunistic infections due to the immunodepression predominated by cellular immunity.

Prognosis is poor for the acute and lymphomatous forms with a median survival of 6 and 10 months respectively. Infectious episodes are frequent, often caused by Pneumocystis carinii, and require systematic prophylaxis. Screening for anguilulosis and prophylaxis is also necessary.