Systemic immune response associated with radiation therapy in B­cell non­Hodgkin's lymphoma of Waldeyer's ring.

Radiation therapy (RT) is one of the most effective therapeutic modalities for B­cell non­Hodgkin's lymphoma of Waldeyer's ring (WR­B­NHL). However, the responsiveness of RT remains controversial and clinical biomarkers are required to predict survival in RT­treated patients with WR­B­NHL. Previous studies have suggested an association between RT and systemic immune responses. In the present retrospective study, the lymphocyte to monocyte ratio (LMR) was identified as a systemic immune indicator in RT­treated patients with WR­B­NHL, and the prognostic value of the LMR with RT and systemic immune responses were evaluated. The optimal cut­off value of the LMR was selected as 3.14, and a high LMR demonstrated improved prognosis and was considered an independent prognostic indicator in RT­treated patients, particularly in patients with distant non­irradiated lesions. Furthermore, reverse transcription­quantitative polymerase chain reaction and ELISA analysis of irradiated lymphoma cell lines and serum samples from patients with WR­B­NHL demonstrated the upregulated expression levels of 4­1BB ligands, calreticulin and high mobility group box 1 compared with non­irradiated groups. Additionally, CD8+ T cells and expression levels of interferon­Î³ in T cells co­cultured with irradiated cells were significantly increased compared with non­irradiated cells. The results indicated that the anti­programmed cell death protein 1 (PD­1) antibody may serve a role in lymphoma therapy when combined with RT. The results of the present study demonstrated the prognostic significance of the LMR associated with RT in patients with WR­B­NHL and acknowledged the potential use of PD­1 antibody in RT­treated lymphomas.