Tumor microenvironment (TME) and limited immune surveillance play important roles in lymphoma pathogenesis. Here, we aimed to characterize immunological profiles of diffuse large B-cell lymphoma (DLBCL), and predict the outcome in response to immunochemotherapy. We profiled the expression of 730 immune-related genes in tumor tissues of 81 patients with DLBCL utilizing the Nanostring platform, and used multiplex immunohistochemistry to characterize T-cell phenotypes, including cytotoxic T-cells (CD8, Granzyme B, OX40, Ki67), T-cell immune checkpoint (CD3, CD4, CD8, PD1, TIM3, LAG3), as well as regulatory T-cells and Th1 effector cells (CD3, CD4, FOXP3, TBET) in 188 patients. We observed a high degree of heterogeneity at the transcriptome level. Correlation matrix analysis identified gene expression signatures with highly correlating genes - the main cluster containing genes for cytolytic factors, immune checkpoint molecules, T-cells and macrophages, together entitled as a TME immune cell signature. Immunophenotyping of the distinct cell subsets revealed that a high proportion of immune checkpoint positive T-cells translated to unfavorable survival. Together, our results demonstrate that the immunological profile of DLBCL TME is heterogeneous and clinically meaningful. This highlights the potential impact of T-cell immune checkpoint in regulating survival and resistance to immunochemotherapy.

Author Info: (1) University of Helsinki and Helsinki University Hospital Comprehensive Cancer Centre. (2) University of Helsinki and Helsinki University Hospital Comprehensive Cancer Centre. (3 ) University of Helsinki and Helsinki University Hospital Comprehensive Cancer Centre. (4) University of Helsinki and Helsinki University Hospital Comprehensive Cancer Centre. (5) Aarhus University Hospital. (6) Helsinki University Hospital. (7) Oslo University Hospital. (8) Oslo University Hospital. (9) Institute for Molecular Medicine Finland. (10) University of Helsinki and Helsinki University Hospital Comprehensive Cancer Centre; sirpa.leppa@helsinki.fi.