immune checkpoint molecules in primary diffuse large b-cell lymphoma of the central nervous system

Introduction: primary diffuse large b cell lymphoma of cns (pcnsl) is a rare variant of diffuse large b cell lymphoma (dlbcl) and presents with an aggressive clinical course and usually resistant to commonly used therapy regimens. recently, role of immune checkpoint molecules including pd-1 and pd-l1 confirmed in some solid tumors and lymphoma resulting tumor cells escape the immune system and help to survive and to spread. inhibitors of pd-1 and pd-l1 have shown lasting responses in several solid and some hematological tumors, while limited studies evaluate checkpoint molecules on pcnsl. method: in this study, we investigated pd-1 and pd-l1 expression by immunostaining on 71 patients with pcnsl and correlation with demographic data, location of the tumor, proliferation rate, cell of origin, and cd8 positive t cell infiltration in tumor microenvironment. results: 16 from71 showed pd-1 expression, while pd-l1 expression were 42/71. no association was determined between pd-1/pd-l1 expression and gender, cell of origin, and proliferation rate, but a highly significant difference was determined between the infiltration of cd8 positive t cells in two groups of pd-1/pd-l1 positive and negative. conclusion: this study revealed expression of check point molecules in remarkable number of pcnsl which may open new therapeutic recommendations in this aggressive lymphoma type.