Long non-coding RNAs ANRIL, THRIL, and NEAT1 as potential circulating biomarkers of SARS-CoV-2 infection and disease severity

•Innate immunity contributes to the primary defense against infections and new studies revealed that lncRNAs play a key role in these responses.•The expression levels of lncRNAs ANRIL and THRIL were significantly up-regulated in moderate and severe patients compared to the control group.•Higher levels of lncRNAs ANRIL and THRIL were observed in severe patients compared to moderate patients.•LncRNA NEAT1 levels in moderate and severe COVID-19 patients were significantly higher than the healthy group.•Blood levels of lncRNAs ANRIL and THRIL are linked with COVID-19 severity and can be considered as a circulating biomarker of disease progression. The current outbreak of coronavirus disease 2019 (COVID-19) is a global emergency, as its rapid spread and high mortality rate, which poses a significant threat to public health. Innate immunity plays a crucial role in the primary defense against infections, and recent studies have highlighted the pivotal regulatory function of long non-coding RNAs (lncRNAs) in innate immune responses. This study aims to assess the circulating levels of lncRNAs namely ANRIL, THRIL, NEAT1, and MALAT1 in the blood of moderate and severe SARS-CoV-2 infected patients, in comparison to healthy individuals. Additionally, it aims to explore the potential of these lncRNAs as biomarkers for determining the severity of the disease. The blood samples were collected from a total of 38 moderate and 25 severe COVID-19 patients, along with 30 healthy controls. The total RNA was extracted and qPCR was performed to evaluate the blood levels of the lncRNAs. The results indicate significantly higher expression levels of lncRNAs ANRIL and THRIL in severe patients when compared to moderate patients (P value = 0.0307, P value = 0.0059, respectively). Moreover, the expression levels of lncRNAs ANRIL and THRIL were significantly up-regulated in both moderate and severe patients in comparison to the control group (P value