Clinical features and treatment outcome of children with myeloid antigen coexpression in B-lineage acute lymphoblastic leukemia: A study of 151 Malaysian children

The purpose of the study was to evaluate the incidence of myeloid antigen c oexpression and its prognostic significance in childhood acute lymphoblasti c leukemia (ALL) in Malaysia, A retrospective study was conducted of all AL L cases (less than or equal to 12 years old) diagnosed and treated in Unive rsity Hospital, Kuala Lumpur, Malaysia between 1 January 1992 and 30 May 19 95, with available immunophenotype data. Presenting features and treatment outcome of 39 B-lineage ALL patients with myeloid antigen coexpression (My( +)B) were compared with 112 B-lineage ALL patients without myeloid antigen coexpression (My(-)B) for similarity in demographic, clinical and laborator y features and their treatment outcome. My(+)B and My(-)B patients were tre ated with a uniform treatment protocol. Myeloid antigen coexpression was de fined as more than 30% isolated leukemic cells positive for CD13 and/or CD3 3, The ages at diagnoses ranged from 2 months to 12 years. Median age was 4 years. The incidence of myeloid antigen coexpression was 23 per cent. Univ ariate analyses showed that presenting features were similar between My(+)B and My(-)B with regard to age, sex, race, FAB morphology, white cell count , hemoglobin level, platelet count, liver/spleen size, central nervous syst em or mediastinal involvement, presence of lymphadenopathy, and proportion of blast cells detected in the marrow. Treatment outcome were not significa nt between the two groups. The 2-year event free survival was achieved in 4 ;1 per cent of My(+)B and 57 per cent of My(-)B (p = 0.11), The 2-year over all survival rates were 62 per cent for My(+)B vs. 77 per cent for My(-)B ( p = 0.08), This study demonstrates that myeloid antigen coexpression is fai rly common and constitutes 23 per cent of childhood ALL within the Malaysia n population and that it is not an adverse risk factor in childhood ALL.