Objective To evaluate the efficacy of consolidation chemotherapy combined with allogeneic natural killer (NK) cell infusion in the treatment of low or intermediate-risk(LIR) AML. Methods 23 cases of LIR AML patients with hematologic complete remission (CR) were enrolled from January 2014 to June 2019 and treated with mIL-21/4-1BBL actived NK cell transfusion combined with consolidation chemotherapy after 3 consolidation courses. Control group were concurrent patients from Department of Hematology and their gender, age, diagnosis, risk stratification of prognosis, CR and the number of courses of consolidate chemotherapy before NK cell transfusion were matched with LIR AML patients. Results A total of 45 times of NK cells were injected into 23 LIR AML patients during 4 to 7 courses of chemotherapy. The median NK cell infusion quantity was 7.5 (6.6~8.64) x 109/L, and the median survival rate of NK cells was 95.4 (93.9~96.9) %. Among them, the median CD3-CD56 + cell number is 5.0(1.4 ~ 6.4) × 109/L, which accounts for 76.8(30.8 ~ 82.9) %; The number of CD3+CD56+ cells was 0.55 (0.24~1.74) x 109/L, accounting for 8.8 (4.9~20.9) %. Before NK cell infusion, the number of patients with positive MRD in the treatment group was 9/23 (39.1%), and the control group was 19/46 (41.3%) (X2=0.03, P=0.862). After NK cell infusion, There was no significant difference in MRD that went from negative to positive between the treatment group and the control group(14.3%vs 22.2%, X2=0.037, P=0.847). In the treatment group, 66.7% (6/9) of the MRD were converted from positive to negative, which was significantly higher than that in the control group10.5% (2/19) (X2=6.811, P=0.009). Morphological recurrence occurred in 1 case of MRD negative in the treatment group and 2 cases of MRD positive in the control group. By the end of the follow-up, the median follow-up was 35 (10~59) months, the number of patients with morphological recurrence in the treatment group was 30.4% (7/23), which is significantly lower than that in the control group (50.2%, 24/46)(X2=2.929, P=0.087),although there was no statistically significant difference between the two groups. There was no significant difference on MRD-negative between the treatment group and the control group(43.5% vs 43.5%, X2=1.045, P=0.307).The 3-year leukemia -free survival were better in the treatment group(65.1±11.1)% than that in the control group (50.0±7.4)%(P=0.047). The 3year overall survival in the treatment and chemotherapy groups were(78.1±10.2)%and (65.8±8.0)%(P=0.212), respectively. Conclusion The consolidation of chemotherapy combined with allogeneic NK cell infusion contributes to the further remission of patients with LMR AML and the reduction of long-term recurrence.
No relevant conflicts of interest to declare.
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