Clinical, immunological, ultrastructural, and cytogenetic studies in black patients with adult T-cell leukemia/lymphoma.

We describe studies in 14 black patients with adult T-cell leukemia/lymphoma (ATLL) born in the Caribbean (13) and west Africa (1). Lymphadenopathy, hypercalcemia, and a leukemic blood picture were seen in the majority. The clinical course was short with a median survival of 5 months. Serum antibodies to human T-cell leukemia virus (HTLV) were detected in all the 10 cases investigated. Marker studies showed a mature (post-thymic) T4+ T-cell phenotype. Functional studies in 3 cases demonstrated that the cells did not provide help but rather suppressed B-cell differentiation. Cells from 2 cases of T4+ prolymphocytic leukemia (T-PLL) were shown to have helper function. Type C viral particles were identified by electron microscopy (EM) on cultured cells from 4 ATLL patients and these were shown to react with the monoclonal antibody (McAb) to the HTLV proteins p19 and p24. Such findings were not observed in HTLV negative T-cell leukemias except for cells of a T-PLL which showed evidence of budding and extracellular release of C-type particles after 5 days culture with phytohemagglutinin (PHA). A close association between the localization of the receptor for T-cell growth factor, demonstrated by McAb anti-Tac, and areas of the cell membrane showing release of HTLV viral particles was documented at EM level by the immunogold method. This technique also demonstrated the specific binding of anti-p19 to HTLV. Cytogenetic studies on PHA stimulated cultures from 2 ATLL revealed trisomy for 7q and this was also observed in 1 of 2 T-PLL and 2 of 4 Sezary syndrome cases. The clinical, morphological, immunological, and cytogenetic features of ATLL in black patients diagnosed in the U.K. are identical to those reported from Japan and the U.S.A. There is also strong evidence that the disease is caused by HTLV-I.