Immunophenotypic and clinical features of T-cell receptor gammadelta+ T-lineage acute lymphoblastic leukaemia.

The immunophenotypic and clinical features of TCR-gammadelta+ T-lineage acute lymphoblastic leukaemia (T-ALL) were prospectively analysed in 52 children with membrane CD3+ T-ALL. We observed a relatively high incidence of TCR-gammadelta+ T-ALL (26/52 patients). Leukaemic blasts from 22 children demonstrated TCR-alphabeta positivity, and simultaneous expression of the TCR-beta and -delta chain was found in four children. Clinical and haematological features of TCR-alphabeta and gammadelta+ T-ALL did not differ significantly, except that haemoglobin levels were significantly lower in TCR-gammadelta+ cases. Event-free survival at 4 years was significantly better in TCR-gammadelta+ compared with TCR-alphabeta+ T-ALL, but expression of TCR molecules did not emerge as an independent prognostic factor in multivariate analysis.