Immunophenotypic cell lineage and in vitro cellular drug resistance in childhood relapsed acute lymphoblastic leukaemia.

At relapse, T-cell acute lymphoblastic leukaemia (ALL) has a worse patient outcome than B-cell precursor (BCP-) ALL. To investigate this further, we compared in vitro cellular drug resistance profiles of T-cell and BCP-ALL samples obtained at relapse. We investigated 237 paediatric relapsed ALL cases, including 151 samples taken at first relapse, of which 30 were T-cell ALL.