Background Interleukin-6 (IL-6) plays an important role in the development of cytokine storm in COVID-19 patients, and is one of the predictors for disease severity. Studies have shown that fibrinogen-like protein 1 (FGL1) can be induced by IL-6 during acute infection and plays an important role in the maintenance of hepatic cell homeostasis.
Objective To investigate the expression of FGL1 in the COVID-19 patients and its relationship with disease severity.
Methods Thirty-seven COVID-19 patients and 14 healthy controls admitted to the Fifth Medical Center of Chinese PLA General Hospital from January to March in 2020 were enrolled. The COVID-19 patients were classified into mild group and moderate/severe group according to the disease severity. Enzyme-linked immunosorbent assay was used to detect the expression level of plasma FGL1, IL-6 and other cytokine level. The diagnostic value of FLG1 for COVID-19 was analyzed by ROC curve.
Results Plasma FGL1 in the COVID-19 patients was significantly up-regulated compared with the healthy controls (222.05 ± 83.78 ng/mL vs 74.87 ± 29.28 ng/mL, P＜0.001). The level of plasma FGL1 in the moderate/severe patients was even higher than that in the mild patients (271.33 ± 85.27 ng/mL vs 189.22 ± 51.19 ng/mL, P=0.004). ROC curve analysis showed that the area under curve (AUC) (95% CI) of plasma FGL1 in evaluating moderate/severe COVID-19 patients was 0.780 (0.631 - 0.928), and its sensitivity and specificity were 78.57% and 73.91%, respectively. Pearson correlation analysis showed that plasma FGL1 in COVID-19 patients was positively correlated with IL-6, IFN-γ (r=0.588, P＜0.001; r=0.378, P=0.017).
Conclusion Plasma FGL1 level is significantly up-regulated in COVID-19 patients and is positively correlated with disease severity, which can be used as an important auxiliary method in the disease severity assessment of COVID-19.
DownLoad: