[The Role of Tumor-Associated Macrophages in Anti-PD-1/PD-L1 Immunotherapy for Lymphoma--Review]

Lymphoma is a malignant tumor originating from lymphatic tissue, which can be roughly divided into two types: Hodgkin's lymphoma and non-Hodgkin's lymphoma. It has the characteristics of high recurrence rate, high mortality rate, and short survival time. Tumor cells in lymphoma form a tumor microenvironment (TME) that inhibits host anti-tumor immunity with surrounding immune cells, while tumor-associated macrophages (TAMs) are a key cell in TME. TAMs promote immune evasion of tumor cells in some ways by producing various cytokines and/or abnormal expression of immune checkpoint molecules. Programmed death receptor-1 (PD-1) and its ligand 1 (PD-L1) are important negative regulatory factors for immune cell activation. Recent studies have shown that anti-PD-1/PD-L1 therapy represents a new strategy for lymphoma immunotherapy. This article will focus on the role and expression of TAMs and PD-1/PD-L1 in lymphoma, and explore the efficacy of anti-PD-1/PD-L1 immunotherapy in different types of lymphoma.