Viral Co-Infections and Their Influence on IL-35 in Adult Type 1 Diabetes Mellitus

Background: Type 1 diabetes mellitus (T1DM) is an autoimmune disorder characterized by the destruction of insulin-producing beta cells in the pancreas, causing severe insulin deficiency and chronic hyperglycemia. Interleukin 35 (IL-35), a regulatory cytokine primarily produced by regulatory T cells, plays a crucial role in maintaining immune tolerance. Emerging evidencefrom several studies suggests that exposure to viral infections may trigger or exacerbate autoimmune processes associated with T1DM. Objective: This study aimed to investigate the effect of viral co-infections on IL-35 levels in adult T1DM patients. Methods: The study included 120 patients with T1DM, aged 17–58 years, and a control group of 90 age-matched healthy individuals. The ELISA technique was employed to assess the IL-35 and islet cell antibody (ICA) levels, while diagnostic tests were performed to identify different types of viral infections. Results: There was a significant decrease in IL-35 levels in T1DM patients (145.26 ± 45.26 pg/mL) compared to healthy controls (312.37 ± 86.27 pg/mL). Viral infections were associated with differences in IL-35 levels. The results also revealed a positive correlation between IL-35 and ICA, while the correlation was negative with disease duration. Conclusion: Our results showed that IL-35 levels were significantly decreased in adult T1DM patients. Additionally, viral infection was found to affect increasing IL-35 levels in T1DM patients, although these levels remained lower than those in the control group. The role of viral infection in modulating IL-35 levels warrants further investigation and underscores the need for additional research to investigate which viruses mostly affect IL-35 levels in diabetic patients and the potential mechanisms by which viral pathogens may influence the development of autoimmune diabetes.