Higher inflammatory cytokines in individuals with long-covid with respiratory symptoms after acute severe COVID-19: a longitudinal nested cohort

<bold>Objective:</bold> to longitudinally assess the level of pro-inflammatory cytokines (IL-1β and TNF-α) in individuals with lingering respiratory disturbances two years after acute severe COVID-19. <bold>Methods and results:</bold> this was a longitudinal nested cohort of hospitalized individuals who had severe COVID-19 in 2020 (pre-vaccine), developed Long COVID (LC), and present respiratory clinical symptomology after two years of disease. The pro-inflammatory profile was assessed at five time points: in acute disease (D1, D14, and D28), at 120 days and 720 days post-acute disease. 69 individuals completed all assessments. The participants were stratified into two groups: those reporting respiratory symptomology (Lcresp) and those without (Lcnoresp). Reported respiratory symptoms were dyspnea and chest pain. 36/80 (22%) presented respiratory symptoms two years after acute severe COVID-19. Age was different between groups (51±11 vs 58±15 years, p=0.081, in Lcresp and Lcnoresp, respectively). Individuals in the Lcresp group were predominantly women (19/36, 53% vs 26/44, 59%, p<0.05). The longitudinal assessment of cytokine levels among participants with Lcresp showed significantly higher levels of IL-1β and TNF-α (Figure 1). <bold>Conclusion:</bold> The pro-inflammatory profile of individuals with LC-associated respiratory symptoms is significantly elevated two years after acute severe COVID-19. <fig><object-id>erj;64/suppl_68/PA5262/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>