Tertiary lymphoid structures are associated with enhanced macrophage activation and immune checkpoint expression, and predict outcome in cervical cancer

Abstract Cervical tumors are usually treated using surgery, chemotherapy, and radiotherapy, and would benefit from immunotherapies. However, the immune microenvironment in cervical cancer remains poorly described. Tertiary lymphoid structures (TLS) were recently described as markers for better immunotherapy response and overall better prognosis in cancer patients. We evaluated the cervical tumor immune microenvironment, specifically focusing on TLS, using combined high-throughput phenotyping, soluble factor concentration dosage in the TME and spatial interaction analyses. We found that TLS presence was associated with a more inflammatory soluble microenvironment, with the presence of B cells as well as more activated macrophages and dendritic cells (DCs). Furthermore, this myeloid cell activation was associated with expression of immune checkpoints, such as PD-L1 and CD40, and proximity of activated conventional type 2 DCs (DC2) to CD8+ T cells, indicating better immune interactions and tumor control. Finally, we associated TLS presence, greater B cell density, and activated DC density with improved progression-free survival, substantiating TLS presence as a potential prognostic marker. Our results provide evidence that TLS presence denotes cell activation and immunotherapy target expression.