Tumor-activated lymph node fibroblasts suppress T cell function in diffuse large B cell lymphoma
Benedetta Apollonio, Filomena Spada, Nedyalko Petrov, Domenico Cozzetto, Despoina Papazoglou, Peter Jarvis, Shichina Kannambath, Manuela Terranova-Barberio, Rose‐Marie Amini, Gunilla Enblad, Charlotte Graham, Reuben Benjamin, Elizabeth H. Phillips, Richard J. Ellis, Rosamond Nuamah, Mansoor Saqi, Dinis Pedro Calado, Richard Rosenquist, Lesley Ann Sutton, J R Salisbury, Georgios Zacharioudakis, Anna Vardi, Patrick R. Hagner, Anita K. Gandhi, Marina Bacac, Christina Claus, Pablo Umaña, Ruth F. Jarrett, Christian Klein, Alexander Deutsch, Alan G. Ramsay
Abstract
Recent transcriptomic-based analysis of diffuse large B cell lymphoma (DLBCL) has highlighted the clinical relevance of LN fibroblast and tumor-infiltrating lymphocyte (TIL) signatures within the tumor microenvironment (TME). However, the immunomodulatory role of fibroblasts in lymphoma remains unclear. Here, by studying human and mouse DLBCL-LNs, we identified the presence of an aberrantly remodeled fibroblastic reticular cell (FRC) network expressing elevated fibroblast-activated protein (FAP). RNA-Seq analyses revealed that exposure to DLBCL reprogrammed key immunoregulatory pathways in FRCs, including a switch from homeostatic to inflammatory chemokine expression and elevated antigen-presentation molecules. Functional assays showed that DLBCL-activated FRCs (DLBCL-FRCs) hindered optimal TIL and chimeric antigen receptor (CAR) T cell migration. Moreover, DLBCL-FRCs inhibited CD8+ TIL cytotoxicity in an antigen-specific manner. Notably, the interrogation of patient LNs with imaging mass cytometry identified distinct environments differing in their CD8+ TIL-FRC composition and spatial organization that associated with survival outcomes. We further demonstrated the potential to target inhibitory FRCs to rejuvenate interacting TILs. Cotreating organotypic cultures with FAP-targeted immunostimulatory drugs and a bispecific antibody (glofitamab) augmented antilymphoma TIL cytotoxicity. Our study reveals an immunosuppressive role of FRCs in DLBCL, with implications for immune evasion, disease pathogenesis, and optimizing immunotherapy for patients.