T-CELL MALIGNANCIES IN BRAZIL - CLINICOPATHOLOGICAL AND MOLECULAR STUDIES OF HTLV-I-POSITIVE AND HTLV-I-NEGATIVE CASES

T-cell malignancies in Brazil have a high seroprevalence rate of HTLV- I antibodies. We have analyzed the disease features in 188 Brazilian p atients with a T-cell disorder. These included 40 with T-lymphoblastic leukaemia or lymphoma (T-ALL/T-LbLy) and 148 with mature T-cell disea ses: 5 T-prolymphocytic leukaemia, 53 adult T-cell leukaemia/lymphoma (ATLL), 54 cutaneous T-ceIl lymphomas, 29 pleomorphic T-cell lymphomas and 7 large granular lymphocyte leukaemia. The diagnosis was based on clinical, morphological and immunological features and HTLV-I serolog y. ATLL in Brazil has the same disease features as in other endemic re gions, the only apparent differences being: age, Brazilian patients be ing younger than Japanese, and ethnic grouping, one third of Brazilian s being white Caucasians of European descent. We applied a scoring sys tem based on the presence or absence of typical features associated wi th ATLL: hypercalcaemia, cell morphology, immunophenotype, histopathol ogy and HTLV-I status, to see whether it may help in diagnosing cases of ATLL. All had high scores, whereas all other T-cell diseases scored low. Only 5 ATLL cases were HTLV-I-negative by serology, but they had otherwise typical features of ATLL, and their cells did not have HTLV -I proviral sequences by DNA analysis. Such cases suggest that ATLL ma y develop in a minority of individuals living in regions where it is e ndemic, without evidence of HTLV-I infection, and that other factors m ay contribute to the pathogenesis of the disease. (C) 1995 Wiley-Liss, Inc.