HTLV-I-seronegative, genome-positive adult T-cell leukemia: report of a case.

An HTLV-I-seronegative case of adult T-cell leukemia (ATL) carrying the HTLV-I genome is reported. Screening serological tests were negative and Western blot analysis revealed only a faint band for HTLV-I p24. Polymerase chain reaction (PCR) disclosed the presence of HTLV-I gag, pol, env, pX, and LTR sequences in the lymph node and peripheral blood. Southern blot analysis revealed a monoclonal integration of HTLV-I in the lymph node and peripheral blood. The tumor cells expressed viral antigens after short-term culture. The clinical course was consistent with ATL in that the patient exhibited hypercalcemia and abnormal lymphocytosis as well as hepatosplenomegaly and lymphadenopathy. We recommend that PCR analysis for HTLV-I be performed even in seronegative cases when ATL is clinically suspected.