Lymphocyte Function in Tertiary Lymphoid Structures Predicts Hepatocellular Carcinoma Outcome.

An increasing number of studies have revealed a correlation between tertiary lymphoid structures (TLS) and the outcome of hepatocellular carcinoma (HCC). Nevertheless, the associations between the heterogeneity of cellular composition and the overall survival (OS) in HCC remain unexplored. Herein, we evaluated the cancer tissues from 150 HCC individuals treated at the Tumor Hospital Affiliated with Nantong University using multiplex immunofluorescence to determine the presence and characteristics of TLS and to investigate the relationship between intra-TLS immunologic activity, TLS maturation and intratumoral immune cell infiltration. Prognostic factors influencing the outcome were identified through both univariate and multivariate analyses. Additionally, the levels of cytotoxic T-lymphocyte antigen-4 (CTLA-4), programmed death 1 (PD-1), programmed death-ligand 1 (PD-L1) and lymphocyte activation gene-3 (LAG3) were determined, as well as their relationship with TLS features. TLS was detected in 71 (47.3%) of the 150 HCC cases and was related to higher intratumoral infiltration levels of lymphocytes. Additionally, intra-TLS lymphocyte proliferation correlated with that of intratumoral lymphocytes, and the presence of TLS and a high proportion of mature TLS demonstrated a significant correlation with better prognosis (p=0.013 and p=0.03, respectively). Among TLS-positive tumors, a high proportion of B-cells expressing activation-induced cytidine deaminase (AID) and a high proportion of CD8⁺ T-cells expressing CD45RO were significantly related to improved OS (p=0.01 and p<0.001, respectively). Comparatively, a high proportion of CD21⁺CD20⁺ B-cells demonstrated a significant correlation with poorer OS (p<0.002). A markedly reduced number of CTLA4⁺ cells in the stromal regions in TLS-negative tumors was observed compared to TLS-positive tumors (p=0.01). These findings reveal a correlation between TLS presence and improved OS in HCC patients. However, TLS exhibited significant variation in maturation state, T and B cell proliferation, and expression of markers related to B and T cell function. Notably, these characteristics were also found to possess prognostic significance, indicating that certain TLS might hinder tumor immunity by inhibiting immune cells while others may foster antigen-driven immune responses, likely influenced by the composition and functional status of intra-TLS lymphocytes.