TREM-1, TREM-2 and their association with disease severity in patients with COVID-19

Abstract

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 PaO 2 /FiO 2 , 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.

sTREM-1 as a Predictive Biomarker for Disease Severity and Prognosis in COVID-19 Patients

“…In a recent study, the area under the ROC curve (AUC) for sTREM-1 in predicting severe COVID-19 was reported as 0.656, but the optimal cut-off value and its predictive value for prognosis were not specified. 35 However, a study has indicated that sTREM-1 has high predictive value for severe COVID-19, with an AUC of 0.96 (95% CI: 0.94–0.98). 36 Regarding prognosis, an earlier study involving 76 COVID-19 patients found that sTREM-1 had an AUC of 0.86 (95% CI: 0.77–0.95) for predicting intubation/death at 30 days, with an optimal cut-off value of 689 pg/mL.…”

Dynamics of host immune responses and a potential function of Trem2hi interstitial macrophages in Pneumocystis pneumonia

“…Finally, our findings suggested that Trem2 participated in the clearance of Pneumocystis . An emerging role for Trem2 in regulating immune functions of macrophages in infectious diseases, including bacterial, viral, and parasitic infections [ 32 – 34 ]. In mycobacterial infections, Lizasa et al indicated that Trem2 suppressed the activation of macrophages and ultimately lead to mycobacterial evasion of host immunity [ 35 ].…”