Application of CD7 antigen in detection of minimal residual disease of acute myeloid leukemia

Luan Chunlai; Meng Junxia; He Ziyan; Zhang Xiaonan; Tang Guang; Chen Jiefu; Wu Yongqiang

doi:10.3969/j.issn.1004-437X.2017.11.003

Abstract：Objective To study the expression of CD7 antigen in acute myeloid leukemia (AML) and the significance of CD7 in detection of AML minimal residual disease (MRD).Methods One hundred and eighty-six cases of newly diagnosed AML were collected from May of 2012 to June of 2015 in Anyang District Hospital, and immunophenotyping was performed by flow cytometry (FCM).The expression of CD7 antigen in bone marrow primitive cells was observed.For CD7+ AML patients with complete remission, a variety of other myeloid antibodies were combined with CD7 to detect the MRD.And for CD7-AML patients with complete remission, according to the initial immunophenotype, a variety of myeloid antibodies were combined to detect the MRD.MRD≥1.0×10-4 was positive, MRD<1.0×10-4 was negative.All patients were followed up for 3~24 months, and MRD value, whether recurrence and recurrence time accrording to bone marrow were recorded.Results A total of 51 patients with CD7+ were detected in 186 patients with AML.Among the 33 patients with complete remission, 21 cases of bone marrow recurrence were detected in 26 cases of MRD positive patients using FCM,and 3 cases of bone marrow recurrence in 7 cases of negative patients.MRD positive recurrence rate was 63.6% in the CD7+ group. Among the 135 patients in the CD7-group, using FCM to track the MRD,90 cases were complete remission, and 20 cases of bone marrow recurrence were detected in the 35 cases of MRD positive patients.17 cases were detected as bone marrow recurrence in 55 cases of MRD negative.In the MRD+ group, the recurrence rate was 22.2%.The relapse rate of CD7+ group was significantly higher than the corresponding group (P<0.05).Conclusion In the detection of MRD of CD7+ AML patients, CD7 antigen combined with other myeloid antigen can distinguish between normal cells and leukemia cells, and it can be used as as an important index for MRD detection,provide the basis for adjustment of AML treatment strategies.