Higher levels of urinary extracellular vesicles and immune mediators are related to acute infection severity during the post-COVID period.

INTRODUCTION

We investigated circulating and urinary inflammatory mediators and extracellular vesicles (EVs) in association with clinical and laboratory findings during the post-COVID-19 (coronavirus disease 2019) period.

METHODS

A cross-sectional study was conducted with individuals with history of COVID-19 stratified according to the presence of post-COVID condition (PCC) and hospitalization during the acute phase. Circulating and urinary levels of 27 inflammatory mediators were quantified by multiplex assays. EVs were isolated by differential centrifugation and assessed by nanoscale flow cytometry, nanoparticle tracking analysis, and transmission electron microscopy.

RESULTS

We included 78 participants (55 ± 14.6 years-old, 79.5 % females), of whom 56 (71.8 %) had PCC. Of these, 18 (32 %) required hospitalization during COVID-19. No differences between groups were observed regarding plasma EVs, but hospitalized PCC patients presented lower levels of circulant interleukin (IL)-9 (p = 0.03), higher monocyte-to-lymphocyte ratio (p = 0.03), prothrombin time (p = 0.02), and lactate dehydrogenase (p = 0.01). In addition, higher levels of total urinary EVs (uEVs, p = 0.006) and uIL-4 (p = 0.01), chemokine (CC motif) ligand (CCL)-2 (p = 0.02), CCL-11 (p = 0.002), and granulocyte-macrophage colony-stimulating factor (p = 0.04) were observed in the same group. Likewise, individuals infected before vaccination presented higher total uEVs (p = 0.003) and urinary CCL-11 (p = 0.01), and multiple episodes of COVID-19 were associated with higher urinary interferon-γ (p = 0.04) and IL-1Ra (p = 0.03).

CONCLUSION

Our results may suggest a possible remnant renal inflammatory process in PCC patients who had moderate-to-severe acute COVID-19.