The prognostic value of CD8 + CTLs, CD163 + TAMs, and PDL1 expression in the tumor microenvironment of primary central nervous system lymphoma

To explore immune cell infiltration and PDL1 expression in the tumor microenvironment (TME) of primary central nervous system lymphoma (PCNSL), we performed immunohistochemical staining on paraffin-embedded tumor tissues from 34 patients diagnosed with PCNSL. CD8 and CD163 positive cells were manually counted, and PDL1 expression was quantified by the H-score scoring method in the tumor center and around the tumor. The Kaplan-Meier method was used to analyze the prognostic value of the TME. We found obvious infiltration of CD8⁺ CTLs and CD163⁺ TAMs in the TME of PCNSL patients. And PDL1 was expressed in the tumor center as well as around the tumor. Survival analysis showed that high CD8⁺ CTLs levels and high intratumoral PDL1 expression were significantly correlated with longer OS. High CD8⁺ CTLs and CD163⁺ TAMs levels were associated with longer PFS.