Background: Chronic hepatitis B virus (HBV) infection remains a major global health challenge and a leading cause of liver cirrhosis and hepatocellular carcinoma. Interleukin-6 (IL-6), a key pro-inflammatory cytokine, plays an important role in immune regulation and hepatic inflammation. However, its relationship with HBV viral load and disease severity remains incompletely understood. Methods: A hospital-based cross-sectional study was conducted among 293 HBsAg-positive patients. Serum IL-6 levels were measured using ELISA, and HBV DNA was quantified using real-time quantitative PCR. Patients were stratified according to viral load. Statistical analyses included non-parametric tests, Spearman correlation, principal component analysis (PCA), and multiple linear regression. Results: The median age was 45 years (IQR: 34–57), among which 54.6% were male. The median HBV DNA was 3.37 log₁₀ IU/mL (IQR: 2.45–3.75), and IL-6 concentration was 2.38 log₁₀ pg/mL (IQR: 2.21–2.49). IL-6 levels increased significantly across viral load categories (p < 0.001) and were higher in HBeAg-positive patients (p = 0.002), with no significant differences across age, sex, or cirrhosis. IL-6 levels correlated with HBV DNA (r = 0.40, p < 0.001). PCA identified distinct viral-inflammatory and biochemical axes. Regression analysis confirmed HBV DNA as the significant independent predictor (β = 0.461, p < 0.001; adjusted R² = 0.206). Conclusion: IL-6 was closely associated with HBV DNA levels, while the association with conventional biochemical markers of hepatocellular injury was significantly less in this cohort, suggesting that IL-6 may serve as an adjunct biomarker of disease activity in patients with chronic hepatitis B.

Background: Dengue fever is one of the most common mosquito-borne viral infections, with severe cases characterized by plasma leakage, hemorrhage, and multi-organ involvement. Identification of dengue serotypes and reliable biomarkers is essential for predicting disease progression and guiding timely interventions. Methods: This prospective cohort study was conducted at a super-speciality tertiary care hospital in southern India from July 2024 to July 2025. A total of 69 patients presenting with dengue warning signs were included in the study. Patients were categorized into the severe dengue group (n = 25) and non severe dengue group (n = 44). Clinical data, laboratory findings, dengue serotype, and serial serum samples collected on Days 1, 4, and 8 were analyzed to evaluate the predictive and monitoring efficacy of Interleukin-6 (IL-6) and Interleukin-8 (IL-8), and followed up till discharge. Results: Out of 69 dengue patients with warning signs, 32 dengue-positive patients were serotyped, which included DEN V-1 (31.3%), DEN V-2 (31.3%), DEN V-3 (15.6%), DEN V-4 (18.8%), and mixed DEN V-(2 + 3) (3.1%). Severe dengue patients exhibited a higher frequency of secondary dengue infection (IgG) than primary dengue infection (88% vs. 12%), with statistically significantly higher packed cell volume, hemoglobin levels, high AST levels, and prolonged activated partial thromboplastin time, as well as lower platelet counts and albumin levels. Platelet transfusion was given to 35 dengue patients, which had also resulted in significant length of stay in hospital in comparison to non-transfused patients. IL-6 and IL-8 levels were significantly elevated in severe dengue patients when compared to non-severe dengue patients on Day 1 and Day 4, followed by a decline on Day 8, corresponding with clinical recovery. However, the elevated IL-8 levels were observed to be significantly associated with longer hospital stays, indicating its potential role as an early predictor of disease progression. Conclusions: The observed co-circulation of multiple serotypes reflects the hyper-endemic pattern reported across India. Early measurement of these cytokines IL-6 and IL-8 helps distinguish severe from non-severe dengue among patients presenting with warning signs. IL-6 and IL-8 may have potential as biomarkers for disease severity. However their role in guiding platelet transfusion requires further investigation in non-severe cases and prioritizing timely management for those at higher risk of severe disease.