Immunophenotypic analysis of T-cell acute lymphoblastic leukaemia in Madras, India.

Immunophenotypic analysis of 285 newly diagnosed previously untreated, unselected, acute lymphoblastic leukaemia cases carried out at the Cancer Institute (W.I.A) in Madras reveals that 126 (44.2%) cases showed T-immunophenotype. The study was conducted using flow-cytometric immunofluorescent or immunoperoxidase methods using an extensive panel of monoclonal antibodies comprising CD1, 2, 3, 4, 5, 7, 8, 57, 19, 20 kappa, lambda, IgG, M, D, CIg, CD10, HLA-DR, CD13, 14, 33, 34 and CD61. The study group comprised 73 (57.9%) paediatric cases (<15 years) and 53 (42.1%) adult cases (>15 years). Based on their reactivity with various anti-T-cell monoclonal antibodies, all T-ALL cases were assigned to one of the intrathymic differentiation compartments. 56.2% of paediatric T-ALLs arise from intrathymic compartment II, 34.2% from compartment III and 9.6% from compartment I. Among adults, 45.3% arise from compartment I. 33.9% from compartment III and 20.8% from compartment II. The most frequently observed CD antigens in our study group are CD7, 5, 2 and 3. A correlative study of socioeconomic status reveals that 67.5% of T-ALL cases occurred among lower socioeconomic strata.