IL-17A in COVID-19 Cases: A meta-analysis

Abstract

Introduction: Numerous reviews, commentaries and opinion pieces have suggested targeting IL-17A as part of managing Coronavirus disease 2019 (COVID-19), the notorious pandemic caused by the Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). IL-17A is a proinflammatory cytokine attributed with homeostatic roles but that is also involved in autoimmune disease pathogenesis. While some studies have reported an increase in IL-17A in COVID-19 cases, no significant associations were found by others. Hence, we undertook this meta-analysis to study serum IL-17A levels in COVID-19 patients in relation to disease severity. Methodology: Multiple databases were systematically reviewed for literature published on the topic from January 1, 2019 to April 30, 2021. A random effects model was used to calculate weighted mean differences (WMDs) and 95% confidence interval (CIs) as well as the τ2 and I2 statistics for heterogeneity analysis. Results: We report that IL-17A increases in COVID-19 subjects irrespective of disease severity compared to controls [WMD = 2.51 pg/ml (95% CI 1.73-3.28), p < 0.00001]. It is also higher in patients with moderate disease compared to controls [WMD = 2.41 pg/ml (95% CI:1.40-3.43), p < 0.00001] as well as higher in patients with severe COVID-19 [WMD = 4.13 pg/ml (95% CI:1.65-6.60), p = 0.001]. While the increase in serum levels in subjects with severe disease over those with moderate disease was statistically significant, the association was not as robust as the other comparisons [WMD = 2.07 pg/ml (95% CI:0.20-3.95), p = 0.03]. Variable heterogeneity was observed in the various analyses with no significant publication bias detected. Conclusions: Hence, IL-17A may be of relevance when considering management approaches to COVID-19.