ABSTRACT
Background: Although our understanding of immunopathology in the risk and severity of COVID-19 disease is evolving, a detail of immune response in long-term consequences of COVID-19 infection remains unclear. Recently, few studies have detailed the immune and cytokine profiles associated with PASC. However, dysregulation of immune system driving pulmonary PASC is still largely unknown. Method(s): To characterize the immunological features of PPASC, we performed droplet-based scRNA-sequencing using 10X genomics to study the transcriptomic profiles of peripheral blood mononuclear cells (PBMCs) from participants naive to SARS-CoV-2 (NP, n=2) and infected with SARS-CoV-2 with chronic pulmonary symptoms (PPASC, n=2). Result(s): Analysis of more than 34,000 PBMCs by integrating our dataset with previously reported control datasets generated cell distribution and identified 11 immune cell types based on canonical gene expression. The proportion of myeloid-lineage cells (CD14+monocyte, CD16+monocyte, and dendritic cells) and platelets were increased in PPASC compared with those of NP. Specifically, PPASC displayed up-regulation of VEGFA and transcription factors, such as ATF2, ELK, and SMAD in myeloid-lineage cells. Also, TGF-beta and WNT signaling pathways were up-regulated in these cell population. Cell-cell interaction analysis identified that myeloid-lineage cells in PPASC participated in regulation of fibrosis and immune response, such as VEGFA (increased) and MIF (decreased) interactions. Conclusion(s): Together, this study provides high-resolution insights into immune landscape in PPASC. Our results emphasize differences in myeloid lineage-mediated fibrosis and immunity between PPASC and NP, suggesting they could act as potential pathological drivers of PPASC. (Figure Presented).
ABSTRACT
SESSION TITLE: Long COVID: It Can Take Your Breath Away SESSION TYPE: Original Investigations PRESENTED ON: 10/16/2022 10:30 am - 11:30 am PURPOSE: Nearly one third of patients who recover from acute SARS-CoV2 infection will experience persistent symptoms known as Post-Acute Sequelae of SARS-CoV2 infection (PASC). Among individuals with PASC, pulmonary complications are common. Patients with severe COVID-19 have observed high systemic levels of cytokines and profound immune dysregulation. During acute SARS-CoV-2 infection, CD169, a type I interferon-inducible receptor, is overexpressed on monocytes. CD169+ macrophages are involved in hyperinflammation, viral spread, and immune regulatory function. Although monocytes/macrophage play a pivotal role in inflammation during acute SARS-CoV2 infection, less is known about how these cells contribute to lung sequelae and immunopathology in PPASC. METHODS: Cross section study conducted comparing three groups: participants with PPASC with a reduced predicted diffusing capacity for carbon monoxide (DLCOc, <80%) on pulmonary function test;participants who fully recovered (RC) from SARS-CoV-2 with no residual symptoms;and healthy participants (HC) negative for SARS-CoV-2. These groups were age and gender matched from similar community settings. Among the groups, we compared the numbers of monocyte subsets (classical, intermediate and non-classical monocytes) and monocyte activation by assessing CD169 expression using flow cytometry analysis of peripheral blood mononuclear cells. RESULTS: Ten participants enrolled in each group with median age 53 years, 38.7% males. We found that PPASC and RC had higher median levels of total circulating monocytes than in HC, 59374 (IQR: 43161-91523), 65661 (40049-89490) and 2689 (1378-28125), respectively (p<0.01, p<0.01). Regarding monocyte subsets based on CD14+CD16+ expression, we observed significant increase in the number of classical (CD14+CD16-), intermediate (CD14+CD16+), and non-classical (CD14-CD16+) monocytes in PPASC and RC, compared to HC (p<0.01, p=0.01, respectively). There was no difference in the number of monocytes and in the proportion of each subset between PPASC and RC. We observed increased CD169+ monocyte counts in PPASC and RC compared to HC 56.8 (23.0-92.5), 66.75 (4.3-968.7), and 2.095 (0-16.9), respectively (p<0.01, p<0.01). Furthermore, a rising trend of CD169 expression was observed in intermediate and non-classical monocytes from PPASC compared to HC. In addition, CD169+ non-classical monocytes were positively correlated with D-dimer levels in PPASC (ρ=0.72, p=0.03). CONCLUSIONS: This study present evidence that patients with COVID infection exhibit persistent alterations in monocytes even after the acute COVID infection period. Correlation of D-dimer level with CD169+ non-classical monocytes in patients with PPASC provides a further rational for determining if a specific monocyte subset contributes to the pathogenesis of PPASC. CLINICAL IMPLICATIONS: Further studies are required for understanding of the development and progression of PPASC. DISCLOSURES: No relevant relationships by Dominic Chow No relevant relationships by Logan Dean No relevant relationships by Gehan Devendra No relevant relationships by FRITZIE IGNO No relevant relationships by Boonyanudh Jiyarom No relevant relationships by Juwon Park No relevant relationships by Parthav Shah No relevant relationships by Cecilia Shikuma No relevant relationships by Chathura Siriwardhana