Predicting roles of IL-27 and IL-32 in determining the severity and outcome of COVID-19

Immune changes play fundamental roles in the pathogenesis and severity of coronavirus disease 2019 (COVID-19). Previous studies have revealed alterations in immune responses of patients with non-severe and severe COVID-19. Therefore, this study investigated whether interleukin-27 (IL-27) and interleukin-32 (IL-32) levels may be considered as predicting factors for determining the severity and outcome of COVID-19.

The blood samples were collected from 50 non-severe and severe patients infected with COVID-19 and 25 healthy subjects. The serum samples were isolated from the whole blood. The levels of IL-27 and IL-32 were measured by enzyme-linked immunosorbent assay and percentages of some immune cells were studied by cell counter.

The levels of IL-27 and IL-32 were significantly higher in COVID-19 patients than healthy subjects (p < 0.0001-0.01). IL-27 was significantly reduced in severe COVID-19 patients who needed to undergo ICU therapy (p < 0.05). Disease severity was significantly associated with IL-27 level in patients with COVID-19 (p < 0.05), unlike IL-32 level. There was a significant association between IL-27 and IL-32 in participants (p < 0.0001, odds ratio (OR) = 0.9873; 95% confidence interval (CI) = 0.9998 to 1.000; p < 0.05, OR = 0.4462; 95% CI = 0.08,579 to 0.7802; p < 0.01, OR = 0.6640, 95% CI = 0.3007-0.8590). IL-27 level was significantly higher in the recovered subjects than dead cases (p < 0.0001). IL-27 and IL-32 levels in patients who had fever were significantly higher than those who did not have (p < 0.01-0.05), unlike patients who suffered from cough (p < 0.001-0.01). The IL-27 level in patients with non-severe COVID-19 was directly correlated with CRP value (p < 0.05, OR = 0.5,722,357, 95% CI = 0.06,807,176-0.8,435,928). IL-27 and IL-32 levels in non-severe patients were positively associated with NLR (p < 0.01, OR = 0.7292; 95% CI = 0.2809 to 0.9163; p < 0.01, OR = 0.6537, 95% CI = 0.1425-0.8896). Patients with severe COVID-19 had a significant increase in NLR (p < 0.0001-0.05). NLR was significantly correlated with the disease severity (p < 0.0001-0.05). Survivors had a significant reduction in NLR compared with those who succumbed to COVID-19 (p < 0.05).

Change in IL-27 level along with the frequencies of some immune cells may serve as a predictor of the severity and outcome of COVID-19.