Background: Delayed diagnosis and inadequate treatment caused by limited biomarkers are associated with the outcomes of COVID-19 patients. It is necessary to identify other promising biomarkers and candidate targets for defining dysregulated inflammatory states.
Methods: The triggering receptors expressed on myeloid cell (TREM)-1 and TREM-2 expression from hospitalized COVID-19 patients were characterized using ELISA and flow cytometry, respectively. Their correlation with disease severity and contrast with the main clinical indicators were evaluated.
Results: Increased expression of soluble TREM-1 and TREM-2 in the plasma of COVID-19 patients was found compared to the control group. Moreover, membrane-bound TREM-1 and TREM-2 expression was upregulated on the cell surface of circulating blood T cells from COVID-19 patients. Correlation analysis showed that sTREM-2 levels were negatively correlated with PaO2/FiO2, but positively correlated with C-reactive protein (CRP), procalcitonin (PCT) and interleukin (IL)-6 levels. Receiver operating characteristic curve analysis indicated that the predictive efficacy of sTREM-1 and sTREM-2 was equivalent to CRP and IL-6, and a little better than absolute leukocyte or neutrophil count and PCT in distinguishing disease severity.
Conclusion: TREM-2 and TREM-1 are critical host immune factors that response to SARS-COV-2 infection and could serve as potential diagnostic biomarkers and therapeutic targets for COVID-19.
Keywords: COVID-19; TREM-1; TREM-2; disease severity.
The expression of soluble TREM-1 and TREM-2 in plasma and membrane-bound TREM-1 and TREM-2 on the cell surface was upregulated in COVID-19 patients.sTREM-2 level was negatively correlated with PaO2/FiO2, but positively correlated with CRP, PCT and IL-6 level, respectively.sTREM-1 and sTREM-2 exhibited potential predictive abilities, and their expression was equivalent to CRP and IL-6, and better than the absolute leukocytes or neutrophil counts and PCT in distinguishing disease severity.