Re-balance of memory T cell subsets in peripheral blood from patients with CML after TKI treatment

// Danlin Yao 1,2,* , Ling Xu 1,2,* , Jiaxiong Tan 1,2 , Yikai Zhang 1,2 , Shuai Lu 1 , Mingde Li 1,2 , Sichun Lu 1,2 , Lijian Yang 1 , Shaohua Chen 1 , Jie Chen 2 , Jing Lai 2 , Yuhong Lu 2 , Xiuli Wu 1,2 , Xianfeng Zha 3 and Yangqiu Li 1,2 1 Key Laboratory for Regenerative Medicine of Ministry of Education, Institute of Hematology, Jinan University, School of Medicine, Jinan University, Guangzhou, China 2 Department of Hematology, First Affiliated Hospital, Jinan University, Guangzhou, China 3 Department of Clinical Laboratory, First Affiliated Hospital, Jinan University, Guangzhou, China * These authors have contributed equally to this work Correspondence to: Yangqiu Li, email: // Keywords : memory T cells, TSCM, CML, TKI, Immunology and Microbiology Section, Immune response, Immunity Received : June 28, 2017 Accepted : August 27, 2017 Published : September 16, 2017 Abstract T cell immune surveillance is considered an important host protection process for inhibiting carcinogenesis. The full capacity of T cell immune surveillance is dependent on T cell homeostasis, particularly for central memory T (T CM ) cells and stem cell memory T (T SCM ) cells. In this study, distribution of T cell subsets in peripheral blood from 12 patients with chronic myeloid leukemia (CML) and 12 cases with CML in complete remission (CR) was analyzed using a multicolor flow cytometer, and 16 samples from healthy individuals (HIs) served as control. The proportion of CD8 + T SCM and CD4 + and CD8 + T CM cells were lower, while CD4 + effector memory T (T EM ) cells and CD4 + and CD8 + terminal effector T (T EF ) cells were higher in CML patients compared with HIs. Moreover, the proportion of CD8 + CD28 - T cells, which were found to have the immune suppressive function, increased in the naive T (T N ) cell and T CM subsets in CML patients compared with HIs. Our study reveals that elimination of leukemia cells by treating with tyrosine kinase inhibitors (TKIs) restores the memory T cell distribution from a skewed pattern in CML patients who are under leukemia burden, indicating that leukemia-specific immune responses mediated by T cells might be induced and maintained in CML patients, however, these responsive T cells might gradually become exhausted due to the continued existence of leukemia cells and their environment; therefore, T cell activation using a different approach remains a key point for enhancing global T cell immunity in CML patients, even for those with CR status.