T cell exhaustion markers in hepatitis C virus-related hepatocellular carcinoma: Expression patterns and prognostic significance in an Egyptian cohort.

[BACKGROUND] Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality, particularly in Egypt, where hepatitis C virus (HCV) prevalence is high. T cell exhaustion markers such as programmed death 1 (PD-1), T cell immunoglobulin and ITIM domain, and T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3) play a crucial role in HCC immune evasion; however, their expression patterns in Egyptian patients remain underexplored.

[AIM] To characterize the expression of PD-1, T cell immunoglobulin and ITIM domain, and TIM-3 on CD4+ and CD8+ T cells across HCV-related liver disease stages and to determine their association with disease severity and survival in an Egyptian cohort.

[METHODS] This prospective case-control study included 200 Egyptian participants: 50 with HCV-related HCC, 50 with HCV-related cirrhosis, 50 with chronic HCV infection, and 50 healthy controls (HCV-negative by polymerase chain reaction). Flow cytometry quantified immune exhaustion markers, and clinical data were analyzed using multivariate and survival modeling frameworks, adjusting for key confounders.

[RESULTS] HCC patients showed significantly higher expression of all T-cell exhaustion markers than other groups ( < 0.001). Alpha-fetoprotein (AFP) levels were markedly elevated in HCC (median 13210 ng/mL, < 0.001). Marker expression showed strong positive correlations with Child-Pugh class, AFP, and Barcelona Clinic Liver Cancer stage, and a negative correlation with model for end-stage liver disease score (all < 0.001). Non-survivors (34%) had higher marker expression and AFP levels than survivors ( < 0.001). Receiver operating characteristic analysis demonstrated excellent mortality prediction for CD4/PD-1 [area under the curve (AUC) = 0.92] and AFP (AUC = 0.89), while combining AFP with CD8/TIM-3 achieved the best accuracy (AUC = 0.95). Cox regression identified high CD8/TIM-3 expression and Barcelona Clinic Liver Cancer stage D as independent mortality predictors, and CD4/PD-1 partially mediated AFP's effect on mortality ( = 0.45, < 0.001).

[CONCLUSION] Elevated T cell exhaustion markers were linked to advanced disease and poor survival in Egyptian patients with HCV-related HCC. Machine learning and mediation analyses identified CD4/PD-1 and CD8/TIM-3 as independent prognostic biomarkers, reinforcing their potential as therapeutic targets. These findings provide novel insights from a high-HCV-prevalence setting, supporting the integration of immune exhaustion profiling into risk stratification for HCC.