Background: Immunophenotyping, as suggested by WHO, may improve diagnosis of childhood leukemia since it offers a better classification of the hematopoietic lineage of malignant cells as compared to morphology. Therefore, we aimed to determine the proportion of the immunophenotypic subtypes of acute leukemia in Indonesian children. Methods. Samples were obtained from patients (0-14 years of age) in 4 hospitals in Indonesia. We analyzed 541 suspected leukemia samples presented over a 4-year period (March 2006 - July 2010) by flow cytometry. Immunophenotyping allowed classification into acute myeloid leukemia (AML) and ALL (B-lineage and T-lineage ALL). Results. Of 541 samples, 136 were tested using a single color method and 405 with a three-color method. Concordance with morphology was very good (κ=0.82) using the three-color method with a panel of 15 monoclonal antibodies (n=387). A relatively high percentage of acute leukemia was classified as AML (23%). Of the ALL samples 83% were B-lineage ALL and 17% T- lineage ALL. Nine out of 239 morphological ALL were labeled AML, and 12/79 morphological AML were in fact ALL. Conclusion. Immunophenotyping in a multi-center study proved feasible and appears particularly important for prognostic assessment of childhood leukemia in low income countries such as Indonesia.
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