Interleukin-40 and Oxidative Stress in Patients With Generalized Anxiety Disorder

Objective Interleukin (IL)-40 is a recently identified cytokine implicated in inflammatory diseases. Increasing evidence links anxiety disorders to heightened inflammation. This study aimed to investigate IL-40 levels and oxidative stress in patients with generalized anxiety disorder (GAD). Methods Fourty-four patients with GAD and 44 healthy controls were recruited for this study. All patients were assessed for severity of anxiety symptoms using the Hamilton Anxiety Rating Scale (HAM-A). Results The serum IL-40 levels were observed to be elevated in patients diagnosed with GAD in comparison to healthy controls (p<0.001). A significant positive correlation was observed between IL-40 and HAM-A scores (r=0.329, p=0.029). IL-40 demonstrated predictive value in receiver operating characteristic analysis, with an area under the curve value of 0.871 (p=0.001). The levels of native thiol and total thiol were found to be significantly lower, while the levels of disulfide were significantly higher in comparison to the control group (p<0.001, p=0.001, p=0.027, respectively). However, IL-40 levels showed no significant correlation with oxidative stress markers, including native thiol, total thiol, and disulfide levels. Conclusion This is the first study to explore the potential relationship between IL-40 and the pathophysiology of GAD. The observed elevation in IL-40 levels may reflect a possible immune regulatory imbalance in GAD. While these findings suggest that IL-40 could be a candidate biomarker for further investigation, their clinical utility for diagnosis or monitoring remains speculative. Additional large-scale and longitudinal studies are required to confirm these preliminary observations and to better understand the immunological aspects of GAD.