OBJECTIVETo analyse the clinical features and prognostic significance of cross-lineage antigen expression in patients with acute myeloid leukemia(AML) in order to establish individualized treatment for a better outcome and prognosis.

METHODSA total of 227 cases (exduding M3) were detected by flow cytometry for immune phenotype. The CD7(-)CD56(-)CD19(-) AML served as control. The clinical features, treatment response and prognosis of CD7(+) group, CD56(+) group and CD19(+) group were compared.

RESULTSThe detection rate of CD56(+),CD7(+) and CD19(+) in AML was 15.9%, 25.1% and 11.0%, respectively. There were no differences between CD56(+) AML, CD7(+) AML, CD19(+) AML, and CD56(-)CD7(-)CD19(-) AML in the proportion of blast cells, white blood cell count, hemoglobin level, platelet count and MDS transformed AML rate. The CR after the first course chemotherapy and cumulative CR in CD56(+) AML patients were lower than those in the control group (20.0% vs 58.1%, P=0.0099; 73.3% vs 87.5%, P=0.04). The median time of CR in CD56(+) AML was longer than that in the control group (118 days vs 46 days, P=0.04). The PFS time and OS time of CD56(+) AML were shorter than those in the control group (245 days vs 580 days, P=0.037; 494 days vs 809 days, P=0.04). The CR after the first course chemotherapy and cumulative CR in CD19(+) AML patients were higher than those in the control group(75.0% vs 58.1%, P=0.46; 100% vs 87.5%, P=0.02). The median time of CR in CD19(+) AML was shorter than that in the control group (28 days vs 46 days, P=0.02). The PFS time and OS time of CD19(+) AML tended to be longer than those in the control group (P=0.13, P=0.07, respectively). The median PFS and OS were not reached at the time of last follow-up. The CR after the first course chemotherapy, cumulative CR and median time to CR in CD7(+) AML patients were not different from those in the control group (53.1% vs 58.1%, P=0.67; 87.1% vs 87.5%, P=0.44; 50 days vs 46 days, P=0.44). No differences of PFS and OS were observed between CD7(+) AML and the control.

CONCLUSIONCD56(+) AML patients respond poorly to treatment, frequently relapse after complete remission and have a low survival rate. These patients need more intensive chemotherapy or in combination with other treatments. The interval of MRD detection should be shortened to find out relapse earlier. CD19(+) AML patients have a good treatment outcome and often accompanies with AML1/ETO fusion gene, which is known to be a good prognostic marker. Aberrant expression of CD7 on AML cells is not a poor prognostic factor in this study.