SummaryMelanoma differentiation-associated gene 5 (MDA5) is one of the three members in the retinoic acid-inducible gene I-like receptor (RLR) family, which are cytoplasmic pathogen recognition receptors recognizing intracellular viruses. In the present study, MDA5 and its spliced shorter forms, named as MDA5a and MDA5b, were identified in zebrafish. MDA5a and MDA5b can be up-regulated in cell lines following the infection of a negative ssRNA virus, the spring viraemia of carp virus (SVCV), and an intracellular Gram-negative bacterial pathogen Edwardsiella tarda, implying that the RLR may also be able to sense elements released from bacteria. The over-expression of MDA5a and MDA5b in fish cells resulted in significant induction of type I interferon promoter activity and enabled the protection of transfected cells against SVCV infection. Furthermore, the shorter spliced form, MDA5b when co-transfected with MDA5a or mitochondrial antiviral signalling protein (MAVS), induced a significantly higher level of interferon promoter activity, indicating that MDA5b may function as an enhancer in the interaction between MDA5 and MAVS.

No abstract

Background: Comorbidities are commonly seen in patients with coronavirus disease 2019 , but the clinical implication is not yet well-delineated. We aim to characterize the prevalence and clinical implications of comorbidities in patients with COVID-19. Methods: This is a retrospective multi-centre study involving patients admitted between January 16th and March 10th 2020. The composite endpoint was defined as the presence of at least one of the following, intensive care unit (ICU) admission, or the need for mechanical ventilation, or death. Results: A total of 472 consecutive cases admitted to 51 certified COVID-19 tertiary care hospitals were enrolled (median age was 43 [32-53.5] years and 53.0% were male). There were 101 (21.4%) patients presented with comorbidities, including hypertension (15.0%), diabetes mellitus (7.8%), coronary artery disease (2.6%), chronic obstructive pulmonary disease (1.3%) and cerebrovascular disease (1.9%). The composite endpoint occurred in 65 (13.8%) patients. Multivariate stepwise logistic regression analysis indicated that older age (odds ratio [OR] 1.39, 95% confidence interval (CI) 1.05-1.85, per 10-year increment), antecedent hypertension (OR 2.82, 95% CI 1.09-7.29), neutrophil counts (OR 1.33, 95% CI 1.14-1.56) and lactate dehydrogenase level (OR 1.01, 95% CI 1.00-1.01) were independently associated with the presence of composite endpoint. Hypertensive patients, compared with controls, had a greater chance of experiencing the composite endpoint (p < .001) and each individual endpoint, i.e. ICU admission (p < .001), mechanical ventilation (p < .001) and death (p ¼ .012). In the stepwise regression analysis of antihypertensive medications, none of the therapy predicted the composite endpoint. Conclusions: Hypertension is a common comorbidity in patients with COVID-19 and associated with adverse outcomes. KEY MESSAGES1. Hypertension was identified as the comorbidity associated with the prognosis of COVID-19 in this retrospective cohort. 2. Patients with hypertension could experience an increased risk of the composite endpoint. 3. Anti-hypertensive therapy did not affect patient outcomes.