Abstract Objective The immunophenotype, which can identify origins and differentiation phases of cells, is an important biological character of childhood acute leukemia (AL). This paper aims at studying the characteristics and distribution of childhood AL. Methods The cell surface or cytoplasma antigens were detected by flow cytometry with a standard direct or indirect immunofluorescence assay in 160 children with AL. Results Among the 160 cases of AL, 112 were acute lymphoblastic leukemia (ALL) and 48 were acute myelogenous leukemia (AML). Among the 112 cases of ALL, 12 were T lineage ALL (T ALL) ( 10.7% ) and 93 were B lineage ALL (B ALL) (apart from mature B ALL) ( 83.0% ); the myeloid antigen expression was noted in 13.8% of the cases with the most common expression of positive CD33. Among the 48 cases of AML, the lymphoid antigene expression was positive in 40%, with the highest frequency of CD7. The frequency of the lymphoid antigen expression in AML cases was higher than that of the myeloid antigen expression in ALL cases (P< 0.01 ). The frequency of CD14 expression in childhood M4 and M5 AML was 77.8% . The positive CD 34 of the B ALL cases was found in 58.5% of the cases, and that of the AML cases in 55.3% of the cases, in which those of M1 and M2 AML cases was 76.5% , higher than those of the cases with other types of AML ( 43.3% ) (P< 0.05 ). The HLA DR expression was 11.1% in M 3 AML cases, lower than that in the other types of AML cases ( 76.3% ) (P< 0.01 ). Among the B ALL cases, the CD34 expression was un related to the French American British classification, initial WBC counts and extramedullary infiltration. The incidence of infantile leukemia in cases with negative CD34 ( 17.6% ) was higher that in cases with positive CD34 ( 4.2% ) (P< 0.05 ). Conclusions The detection of HLA DR expression may be helpful in the diagnosis of M3 AML.
