Prognostic impact of tumor-associated macrophages, lymphocyte-to-monocyte and neutrophil-to-lymphocyte ratio in diffuse large B-cell lymphoma

Introduction: Microenvironment has a prognostic influence in diffuse large B-cell lymphoma (DLBCL); among its components, tumor-associated macrophages (TAM) play a leading role. TAM can be classified into M1 (anti-tumor) and M2 (pro-tumor). Another prognostic factor could be represented by lymphocyte-to-monocyte and neutrophil-to-lymphocyte ratio (LMR and NLR). Objective: The aim of the study is to evaluate the prognostic impact of M1 and M2 TAM subtypes, LMR and NLR in DLBCL. Methods: We analyzed 37 consecutive patients between 2009 and 2013. Out of 37 patients, 28/37 (75.6%) received R-CHOP/CHOP-like regimens, 9/37 (24.4%) less intensive therapies. Immunohistochemistry was performed with antibodies against CD68 and CD163. We divided our cohort into 2 categories according to the Steidl score. TAM who coexpressed CD68 and CD163 were considered as M2. For LMR and NLR we used previously published cut-offs of 2.71 and 2.81. Results: CR rate was 70.3%; we did not record a significant correlation between CD68+ TAM, CD163+ TAM, CD68+/CD163+ TAM, LMR, NLR and CR. We observed a reduced PFS in patients with IPI >= 2 and high M2 TAM expression and a trend between higher expression of CD68+ TAM and improved PFS. Conclusion: M2 TAM could have a prognostic role for IPI >= 2 DLBCL patients receiving R-CHOP, which thus warrants further investigation.