Dynamic Changes of T Lymphocyte Subsets in Chronic Hepatitis B and Their Predictive Significance for HBV Viral Load

Background: To investigate the relationship between T lymphocyte subset levels (CD4+, CD8+, CD4+/CD8+ ratio) and hepatitis B virus (HBV) load in patients with chronic hepatitis B (CHB), and to evaluate their predictive value for high viral load. Methods: A total of 120 CHB patients were categorized into high, medium, and low viral load groups based on their HBV DNA levels. Baseline characteristics and T lymphocyte subset levels were compared across the three groups. The predictive efficacy of individual subsets and their combination for high viral load (high load group vs. medium/low load groups) was assessed using Receiver Operating Characteristic (ROC) curve analysis. Furthermore, a restricted cubic spline method, combining spline functions with Logistic regression, was employed to analyze the dose-response relationship between T lymphocyte subset levels and HBV viral load in CHB patients. Results: T lymphocyte subset analysis revealed that compared to the high load group, the medium and low load groups had significantly higher CD4+ percentages and CD4+/CD8+ ratios, but significantly lower CD8+ percentages (all P < 0.001). ROC curve analysis showed that the areas under the curve (AUC) for CD4+, CD8+, CD4+/CD8+ ratio, and their combination were 0.748, 0.740, 0.760, and 0.877, respectively. The optimal cut-off values were determined as 36.78% for CD4+, 30.12% for CD8+, and 1.12 for the CD4+/CD8+ ratio. Furthermore, restricted cubic spline analysis confirmed nonlinear dose-response relationships between these parameters and viral load: both CD4+ level and CD4+/CD8+ ratio were negatively associated with high-risk status, with ORs increasing significantly (OR > 1) below their respective thresholds and stabilizing into a plateau thereafter. In contrast, CD8+ level showed a positive correlation, with a sharp rise in OR beyond 30.12%, indicating a substantially elevated risk. Conclusions: T lymphocyte subset levels are closely associated with HBV load in CHB patients. Decreased CD4+, increased CD8+, and a reduced CD4+/CD8+ ratio are independent risk factors for high viral load. The combination of these three parameters demonstrates excellent predictive efficacy for high viral load. The established cut-off values provide crucial references for clinically assessing immune status, warning of active viral replication, and formulating individualized intervention strategies.