ABSTRACT
Background: Uncontrolled systemic infammation characterizes COVID-19 and autoinfammatory diseases such as adult-onset Still's disease (AOSD). Biosynthesis of pro-resolving mediators (SPMs), i.e. lipoxins (LX), resolvins (Rv), pro-tectins (PD), and maresins (MaR), ensures infammation shutdown and tissue repair, limiting neutrophils recruitment and stimulating macrophages to remove apoptotic cells. Among protectins, reduction of PD1 was found in the lungs of mice infected with the H5N1 infuenza virus and experimental treatment with PD1 resulted in increased animals' survival (Morita M et al 2013). Objectives: We investigated the effects of SPMs in pathogenesis and clinical evolution of AOSD and compared these data with mild and severe COVID-19. Finally, we analyzed the potential role of PD1 in modulating the infammatory response of macrophages obtained from AOSD patients, COVID-19 patients and healthy donors (HDs). Methods: 21 patients hospitalized for COVID-19 (10 ICU and 11 hospitalized in medical clinical unit) and 13 patients with AOSD were enrolled. Plasma PD1 levels from patients and controls were analyzed by ELISA, and mono-cytes-derived macrophages were polarized into M1 and M2 phenotype. We analyzed the effect of PD-1 on macrophages differentiation. At 10 days, macrophages were analyzed for surface expression of subtypes markers by flow cytometry. Cytokines production was measured in supernatants by Bio-Plex Assays. Peripheral blood mononuclear cells (PBMCS) from 3 AOSD patients, 2 COVID-19 patients and 3 HDs were obtained. Next-generation deep sequencing was then performed to identify the differences in PBMCs transcripts profiles. Results: AOSD patients with systemic scored (SS) ≥1 showed an increase of PD1 levels compared to AOSD patients with lower systemic score (p=0.04) (Figure 1A). Similarly, plasma levels of PD1 were increased in COVID-19 patients independently from their clinical subsets, compared to HDs (p=0.02). In vitro treatment with PD1 of monocytes-derived macrophages from AOSD and COVID-19 patients induced a signifcant increase of M2 polarization vs control (p<0.05) (Figure 1B). Furthermore, a signifcant release of IL-10 and CCL4 from M2 macrophages was observed when compared to control (p<0.05) (Figure 1C). In the transcriptomes from 3 AOSD patients (2 mild and 1 severe), 2 COVID-19 patients (1 mild and 1 ICU) and 2 HDs, we observed that genes involved in infammation, lipid catabolism and monocytes activation were spe-cifcally dysregulated in AOSD and COVID-19 patients when compared to HDs. Among them pla2g15, pla2g12a, pla2g2d, involved in mobilization of SPMs precursors, were signifcant upregulated in patients compared to HDs (p<.01, ;log2FoldChange;>1.2) (Figure 1D). The largest part of the genes involved in infammation, lipid catabolism, and monocytes activation are less expressed in AOSD patients when compared to COVID19 patients, as reported in Table 1. Conclusion: The counterbalance by SPMs during infammation is still a largely unexplored pathway. Our study suggests that an imbalance of SPMs in autoin-fammatory diseases as well as COVID-19. The modulation of SPMs as observed in our experiments, might represent a new possible therapeutic strategy during AOSD and COVID-19.