Interleukin-35 as a New Biomarker for SARS-CoV-2 in Iraqi Patients

Abstract

ABSTRACT Background: Interleukin-35 (IL-35) is a newly discovered heterodimeric cytokine that belongs to the IL-12 family. It works as an inhibitory cytokine in the immune system, modulating malfunctioning T cells and regulating various immune-related inflammatory factors. As a result, the control of IL-35 may be critical to manage a cytokine storm that occurs in COVID-19 patients. Materials and Methods: A total of 125 severe COVID-19 patients, including 56 (44.8%) males and 69 (55.2%) females, were enrolled in this study as well as 60 persons involved as a control group. Between February 2022 and July 2022, these patients were admitted to Marjan medical city and Al-Sadeq hospital. Patients were classified as severe cases according to the guidelines released by National Health World depending on SpO2 percentage. The inflammatory cytokine (IL-35) was measured using the ELISA technique. Results: IL-35 showed statically significant differences between patients 6.86 ± 2.31 (pg/ml) and control group 3.86 ± 2.07 (pg/ml) (p < 0.0001). IL-35 revealed a significant positive strong correlation with glucose level in patients with COVID-19 (r = 0.0241; P = 0.007). as Also, a positive significant correlation observed between IL-35 and creatinine (r = 0.182; P = 0.043). Correlations between IL-35 and each gender, age, death status, SpO2, and computed tomography (CT) scan were nonsignificant (p > 0.05). Age group 62–74 years showed more IL-35 titer (8.40 pg/ml) than other groups followed by the age group 16–61 years (6.78 pg/ml) with significant differences (p = 0.004). Conclusion: This study further confirms the growing evidence on the direct role of regulatory or anti-inflammatory cytokines in the development and controlling COVID-19. IL-35 revealed a positive significant correlation with creatinine (r = 0.182; P = 0.043) that may reflect the impact of IL-35 level on the kidney function test distributions such as acute kidney injury.