Linyu Cai,1 Liping Zuo,1 Guangqi Wang,1 Qun Li,1 Chi Ma,1 Jianghua Wu,1 Chunyan Sun,1 Yu Hu1,2 

1Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430022, People’s Republic of China; 2Key Laboratory of Biological Targeted Therapy (Huazhong University of Science and Technology), Ministry of Education, Wuhan, Hubei, 430022, People’s Republic of China

Correspondence: Chunyan Sun, Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Dadao, Wuhan, 430022, People’s Republic of China, Email suncy0618@163.com Yu Hu, Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Dadao, Wuhan, 430022, People’s Republic of China, Email dr_huyu@126.com

Abstract: Multiple myeloma (MM) is a kind of plasma cell hematologic malignancy. Notable advancements in patient survival have been achieved due to the clinical application of anti-CD38 monoclonal antibody, chimeric antigen receptor T cells (CAR-T) and bispecific T cell engagers (TCEs). However, the immunosuppressive microenvironment of the bone marrow hinders the effectiveness of these novel immunotherapies, consequently restricting their efficacy. Hence, it is imperative to clarify the exact mechanisms to devise strategies aimed at improving the efficacy of immunotherapy. In this review, we provide a systematic overview of recent research concerning the different T cell subtypes in the immune evasion mechanisms of MM. The review emphasizes the imbalance between the immune surveillance and the immune suppression, and highlight recent studies about unconventional T cells, the metabolic control of immune reactions, and novel therapeutic strategies aimed at addressing immune evasion mechanisms that promote the progression of MM.

Keywords: multiple myeloma, immune escape, immunosuppressive cells, Th17, CTL, Treg