HIV and prior exposure to antiretroviral therapy alter tumour composition and tumour: T‐cell associations in diffuse large B‐cell lymphoma

Summary Diffuse large B‐cell lymphoma (DLBCL) is the most common subtype of lymphoma worldwide, accounting for up to 40% of new non‐Hodgkin Lymphoma (NHL) globally. People living with HIV are up to 17 times more likely to develop NHL, and as such, DLBCL is the leading cause of cancer death in this high‐risk population. While histologically indistinguishable, HIV‐associated (HIV+) and HIV‐negative (HIV−) DLBCL are molecularly distinct, and biological differences may have implications for the development of future therapeutic interventions. Further, the impact of immunologic differences in people with HIV, including preceding ART, remains largely unknown. Here, we investigate the impact of HIV infection and ART exposure on the clinical features of DLBCL and T‐cell immune response by performing imaging mass cytometry on our unique patient cohort in Malawi. In this cohort, HIV infection is positively prognostic, and HIV+/ART‐naïve patients have the best outcomes. No established biomarkers other than Ki67 are associated with HIV or ART status, and the only tumour‐intrinsic biomarkers that remain prognostic are MYC and MYC/BCL2 protein co‐expression. Finally, TCR clonality is associated with distinct tumour‐T cell interactions by HIV/ART status, indicating differential anti‐tumour immune responses. We demonstrate previously undescribed HIV and ART‐related differences in the DLBCL tumour microenvironment.