Abstract:  Objective To investigate the relationship between tumor-associated macrophages (TAMs) and the prognosis of diffuse large B-cell lymphoma (DLBCL). Methods The clinical data of 95 DLBCL patients admitted to Guangxi Medical University Cancer Hospital from July 2015 to May 2018 were collected. The expression levels of CD68 and CD163 in 95 DLBCL tissues were detected by immunohistochemistry. The relationship between the TAMs infiltration level and the clinical characteristics and prognosis of DLBCL patients was analyzed, and verified in the public database GSE31312 and GSE10846 gene expression datasets. The ssGSEA method was used to investigate the potential immunobiological mechanism behind the influence of M2-type TAMs on the prognosis. Results Among 95 DLBCL patients, 50 cases (52.6%) had low expression of CD68+TAMs, and 45 cases (47.4%) had high expression; 34 cases (35.8%) and 61 cases (64.2%) had low and high expression of CD163+TAMs, respectively. The level of CD68+TAMs infiltration was correlated with lactate dehydrogenase level, AnnArbor stage and bone marrow invasion (all P<0.05), while the level of CD163+TAMs infiltration were not correlated with patients clinicopathological parameters (all P>0.05). Kaplan-Meier survival analysis showed that high infiltration of CD68+TAMs and CD163+TAMs in DLBCL tissues was associated with shorter survival time of patients (all P<0.05). Multivariable Cox regression analysis showed that high infiltration level of CD163+TAMs in DLBCL tissues was an independent risk factor for prognosis of patients (HR=2.695, 95%CI: 1.126-6.455, P=0.026). ssGSEA enrichment analysis showed 6 immune-related signaling pathways (Adaptive immune system pathway, MHC classⅠantigen presentation pathway, TypeⅠinterferon signaling pathway, Treg differentiation signaling pathway, TCR signaling pathway and Chemokine signaling pathway) were significantly enriched in the M2-type TAMs low infiltration group (all P<0.05, FDR<0.25). Conclusions The high infiltration level of CD163+TAMs in DLBCL tissues is an independent risk factor affecting the prognosis of patients, which may affect the prognosis of DLBCL by regulating immune-related signaling pathways.

Key words: Diffuse large B-cell lymphoma, Tumor-associated macrophages, Immune-related signaling pathway, Prognosis