Evaluation of erythrocyte membrane fatty-acid compositions in association with interleukin-6 levels in patients with COVID-19

•Polyunsaturated fatty acids and the ratio of arachidonic acid to eicosopentaenoic acid, like interleukin-6, are markers of inflammation in people with COVID-19.•The ratio of arachidonic acid to eicosopentaenoic acid showed a significant positive correlation with only interleukin-6.•Levels of γ-linolenic acid and the ω-6/ω-3 ratio were significantly increased in all comparison groups.•The ω-3 index showed a moderately negative correlation with interleukin-6. The cytokine storm presented in the hyperimmune response is related to poor prognosis in people with COVID-19. Interleukin-6 (IL-6) is one of the most prominent cytokines, especially on mucosal surfaces during infection, causing the cytokine storm. Polyunsaturated fatty acids (PUFAs) are the precursors of eicosanoids, which play critical roles in immune regulation and inflammation. The balance between ω-3 and ω-6 levels in the cell membrane has a critical role in regulating the equilibrium between proinflammatory and antiinflammatory processes and inducing IL-6 production. The present study focused on inflammatory and antiinflammatory mechanisms in COVID-19 over PUFAs and on relating their levels with disease prognosis and severity. A total of 106 participants were included in the study. They were divided into three groups according to IL-6 level— 1: 300 pg/mL. Erythrocyte membrane PUFA compositions were analyzed by group. Levels of γ-linolenic acid and ω-6/ω-3 ratios were significantly increased in all comparison groups (P < 0.05). Total ω-6 and the ratio of arachidonic acid to eicosopentaenoic acid showed a statistically significant difference only between groups 1 and 3 (P < 0.05). There was a moderately negative correlation between total ω-3 and IL-6 and procalcitonin. There were positive correlations with ω-6/ω-3 ratio inflammatory markers, and the total ω-6 index also showed a moderately positive correlation with IL-6, procalcitonin, and D-dimer levels. The ratio of arachidonic acid to eicosopentaenoic acid, and ω-3 PUFAs, can be systemic signs of poor prognosis, increased lung damage, and high mortality in COVID-19, together with IL-6.