ABSTRACT
BACKGROUNDCoronavirus disease 2019 (COVID-19) triggers distinct patterns of pneumonia progression with multiorgan disease, calling for cell- and/or tissue-type specific host injury markers. METHODSAn integrated hypothesis-free single biomarker analysis framework was performed on nasal swabs (n = 484) from patients with COVID-19 in GSE152075. The origin of candidate biomarker was assessed in single-cell RNA data (GSE145926). The candidate biomarker was validated in a cross-sectional cohort (n = 564) at both nucleotide and protein levels. RESULTSPhospholipase A2 group VII (PLA2G7) was identified as a candidate biomarker in COVID-19. PLA2G7 was predominantly expressed by proinflammatory macrophages in lungs emerging with progression of COVID-19. In the validation stage, PLA2G7 was found in patients with COVID-19 and pneumonia, especially in severe pneumonia, rather than patients suffered mild H1N1 influenza infection. Up to 100% positive rates of PLA2G7 were positively correlated with not only viral loads in patients with COVID-19 but also severity of pneumonia in non-COVID-19 patients. Although Ct values of PLA2G7 in severe pneumonia was significantly lower than that in moderate pneumonia (P = 7.2e-11), no differences were observed in moderate pneumonia with COVID-19 between severe pneumonia without COVID-19 (P = 0.81). Serum protein levels of PLA2G7, also known as lipoprotein-associated phospholipase A2 (Lp-PLA2), were further found to be elevated and beyond the upper limit of normal in patients with COVID-19, especially among the re-positive patients. CONCLUSIONSWe firstly identified and validated PLA2G7, a biomarker for cardiovascular diseases (CVDs), was abnormally enhanced in COVID-19 patients at both nucleotide and protein aspects. These findings provided indications into the prevalence of cardiovascular involvements seen in COVID-19 patients. PLA2G7 could be a hallmark of COVID-19 for monitoring disease progress and therapeutic response. FUNDINGThis study was supported by grants from China Mega-Projects for Infectious Disease (2018ZX10711001), National Natural Science Foundation of China (82041023).