Circulating plasma miR-155 is a potential biomarker for the detection of SARS-CoV-2 infection.

Identification of human miRNAs involved in coronavirus-host interplay is important due to the current COVID-19 pandemic. Therefore, this study aimed to measure the circulating plasma miR-155 expression level in COVID-19 patients and healthy controls to investigate its roles in the pathogenesis and severity of COVID-19 disease and to assess its usefulness as a clinical biomarker for the detection of COVID-19 disease and the severity of infection. A total of 150 COVID-19 patients and 50 controls were enrolled into our study. Beside the routine laboratory work and chest computed tomography (CT) scans of COVID-19 patients, plasma miR-155 expression level was measured using reverse transcription quantitative real-time PCR (RT-qPCR) technique. Our results demonstrated increased miR-155 expression level in COVID-19 patients compared to controls, in severe compared to moderate COVID-19 patients, and in non-survival compared to survival COVID-19 patients. miR-155 expression level also had significant correlation with clinicopathological characteristics of COVID-19 patients such as chest CT findings, CRP, ferritin, mortality, D-dimer, WBC count, and lymphocytes and neutrophils percentages. Also, our results showed that the area under the curve (AUC) for miR-155 was 0.986 with 90% sensitivity and 100% specificity when used as a biomarker for the detection of COVID-19 disease; while in detection of severity of COVID-19 disease, AUC for miR-155 was 0.75 with 76% sensitivity and specificity. From these results we can conclude that miR-155 has a crucial role in the pathogenesis and severity of COVID-19; also, it could be a good diagnostic clinical biomarker for the detection of COVID-19 disease and the severity of infection.