ABSTRACT
Objective:To investigate the clinical and molecular features of patients with CD7 +relapsed or refractory acute myeloid leukemia(r/rAML)and the prognosis of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods:172 r/rAML patients who underwent allo-HSCT in department of hematology, Aerospace Center Hospital between January 1st 2017 and December 31st 2020 were retrospectively analyzed The patients were were divided into CD7 + group( n=75) and CD7 - group( n=97) according to the expression CD7 in the initial immunophenotype. Mann-Whitney U and Chi-square test were used to compare the clinical data, molecular and cytogenetic characteristics of the two groups of patients. Kaplan-Meier method was used to analyze the median progression-free survival (PFS) and median overall survival (OS) of the two groups of patients, and Cox regression screenthe prognostic factors of the patients. Results:The median follow-up time was 19 months. The recurrence rates were 23.71% and 50.67%, respectively in CD7 - and CD7 + group (χ 2=13.428 P<0.001). In relapsed patients, 86.96 percentage of CD7 - group did not express CD7 while 86.84 percentage of CD7 + group expressed CD7. The median PFS was 25 and 5 months in CD7 - and CD7 + group (χ 2=8.695, P=0.003), and the medianOS was 34 and 15 months in CD7 - and CD7 + group (χ 2=2.579, P=0.108). Univariate analysis showed that the CD7 +group, had the lower rates of morphological remission (χ 2=10.014, P=0.002), molecular remission (χ 2=22.809, P<0.001), and more male patients (χ 2=5.281, P=0.022). The incidence of CEBPA double-site mutation was higher (23.4% vs 8.2%, χ 2=8.180, P=0.004) and the rearrangement of RUNX1::RUNX1T1 was lower(4.0% vs18.6%, χ 2=8.362, P=0.004)in CD7 +group than in CD7 -group. Multivariate analysis showed that pre-transplant tumor load was the only prognostic factor for PFS (HR, 1.600; 95% CI, 1.203 to 2.127; P=0.001) and OS (HR, 1.737; 95% CI, 1.273 to 2.369; P<0.001) in r/r AML patients. Conclusion:CD7 expression is a risk factor for poor prognosis in r/r AML patients, and CD7 expression is stable after relapse. Positive CD7 can be used as a target for immune targeted therapy.