New WHO classification has been rapidly used in leukemic diagnosis. Based on the coexpression and correlation of lineage-associated antigens with multidimensional data analysis, high-resolution flow cytometry has been developed to precisely identify lineage characteristics of leukemia. In this study, 116 cases of acute myeloid leukemia at primary diagnosis with WHO classification were analyzed by high-resolution flow cytometry with a panel of 25 different monoclonal antibodies. The correlation of immunophenotypings with cytogenetic abnormal changes (88 available cases), clinical features and FAB classification were further investigated. The results demonstrated that CD33, CD38 and CD13 were the most commonly expressed antigens (94.8%, 91.3% and 89.6%, respectively). CD7 was the most commonly expressed lymphoid antigen (20.2%), followed by CD19 (16.5%)and CD2(15%)As compared with all other AMLs, some antigens including lymphoid lineage are significantly correlated with FAB subtypes, such as increasing expression of CD2 in M3; HLA-DR, CD34 and CD56 absent expressions in M3; increased frequency of CD19 in M2; increasing expressions of CD14 and CD56 in M5 and lack of MPO expression in M0. Cytogenetic abnormal features were detected in 48 cases (54.5%). CD22, CD56 and TdT expressions are remarkably associated with chromosomal abnormalities. All six cases with CD22 expression in AML demonstrated various cytogenetic abnormal changes. Significant associations between immunophenotypings and genetic features are observed: all cases with t (8; 21) highly expressed CD15, CD19, CD34 and CD56. No lymphoid lineage antigens were detected in AML-M3 with t (15; 17). In addition, the expression of both CD7 and CD14 was significantly correlated with higher WBC count; CD4 or TdT expression with increased age; CD4, CD14 or CD56 expression with higher platelet count. No significant correlation was found between hemoglobin level and markers. The relationships of immunophenotypings and genetic features with treatment and prognosis are currently being studied. Conclusion: 1. Significant correlation between immunophenotypings and cytogenetic features in AML strongly suggested that the abnormal antigen expression is tightly linked with aberrant genetic changes; 2. Analysis of high resolution flow cytometry with WHO classification is a powerful tool to be used in primary leukemia diagnosis as well as in study of understanding leukemia malignancy.

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