COVID-19 is a pandemic disease that has a wide spectrum of symptoms from asymptomatic to severe fatal cases due to hyperactivation of the immune system and secretion of pro-inflammatory cytokines. This study aimed to assess the level and impact of interleukin (IL)-13, IL-33, and tumor necrosis factor (TNF)-α cytokines on immune responses in mild and moderate COVID-19-infected Iraqi patients. A prospective case-control study was conducted from January 2023 to January 2024; it included 80 patients infected with moderate COVID-19 infection who consulted in different private clinics and 40 healthy controls. The serum of both groups was tested for quantification of serum IL-13, IL-33, and TNF-α using the human enzyme-linked immunosorbent assay method. The mean age of the moderate COVID-19 patient group was 43.67±1.85 years, while the mean age of the healthy control group was 34.45±3.12 years with a statistically significant (p=0.0081), but there was no statistically significant difference in IL-13, IL-33, and TNF-α levels between the patients and control groups. This study highlights the importance of age, gender, and body mass index as risk factors associated with COVID-19 infection. There were no significant differences in IL-13, IL-33, and TNF-α levels between moderate COVID-19 patients and healthy controls. The receiver operating characteristic curve analysis of IL-13, IL-33, and TNF-α shows moderate potential (non-significant) as a biomarker for predicting mild and moderate COVID-19. Pearson correlation analysis showed a strong potential correlation between IL-13, IL-33, and TNF-α.
