HIGH EXPRESSION WITH PD-1+ FOXP3+ ΓΔ T REGULATORY SUBSETS IN CHRONIC MYELOID LEUKEMIA PATIENTS

Abstract

Objective Tyrosine kinase inhibitor (TKI) has achieved certain efficacy in treatment of chronic myeloid leukemia (CML), but there are still many cases of drug resistance and relapse. Anti-leukemia immunity of γδ T cells may play an important role in protecting against the development of leukemia. But γδ T cells have different subsets with different functions and their immunity may be defective in CML patients, so we investigate the expression of γδ T cells functional subsets in CML patients. Methods The peripheral blood samples from 41 CML patients in chronic phase (CML-CP) were collected. Twenty healthy individuals (HIs) were served as the controls. The flow cytometry was used to detect the expression of γδ T cells and their subfamilies. Results We found that there was no difference in expression proportions of γδ, Vδ1 and Vδ2 T cells between the CML-CP groups and HIs. However, the expression proportions of PD-1+ γδ T cells and Foxp3+ γδ T cells of CML-CP were significantly higher than that of HIs. There was a significant positive correlation between the expression of PD-1+ γδ T cells and Foxp3+ γδ T cells in CML-CP. It is noteworthy that the expression proportions of the novel regulatory subsets (PD-1+ Foxp3+ γδ T, PD-1+ Foxp3+ Vδ1 T, and PD-1+ Foxp3+ Vδ2 T cells) in CML-CP patients were significantly higher than that of HIs. In addition, the expression proportions of Foxp3+ NKG2D+ γδ T and Foxp3+ NKG2D+ Vδ2 T cells were also significantly higher than HIs. Logistic regression analysis showed that the expression proportion of Foxp3+ Vδ1+ T cells and PD-1+ Foxp3+ Vδ1+ T cells was the risk factors for the occurrence of refractory of CML-CP patients after first-line TKI treatment. Conclusions The PD-1+ Foxp3+ γδ T regulatory subsets were highly expressed in CML-CP patients, and might associate with pathogenesis and progress in CML.