Screening and characterization of myositis-related autoantibodies in COVID-19 patients.

An efficient host immune response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) appears to be crucial for controlling and resolving this viral infection. However, many studies have reported autoimmune characteristics in severe COVID-19 patients. Moreover, clinical observations have revealed that COVID-19-associated acute distress respiratory syndrome shares many features in common with inflammatory myopathy including interstitial lung disease (ILD), most particularly rapidly progressive (RP)-ILD. This study explored this phenomenon by seeking to identify and characterize myositis-specific and related autoantibodies in 25 COVID-19 patients with mild or severe symptoms. Line blot analysis with the EUROLINE Myopathies Ag kit identified 9 (36%) patients with COVID-19 with one or more autoantibodies against several myositis-related antigens (Jo-1, Ku, Mi-2ß, PL-7, PL-12, PM-Scl 75, PM-Scl 100, Ro-52, and SRP); no anti-MDA5 antibodies were detected. As the presence of antibodies identified by line blots was unrelated to disease severity, we further characterized the autoantibodies by radioimmunoassay, in which [35 S]methionine-labeled K562 cellular antigens were precipitated and visualized by gel electrophoresis. This result was confirmed by an immunoprecipitation assay and immunoblotting; 2 patients exhibited anti-Ku70 and anti-Ku80 antibodies. Our data suggest that it is necessary to use more than one method to characterize and evaluate autoantibodies in people recovered from COVID-19, in order to avoid misinterpreting those autoantibodies as diagnostic markers for autoimmune diseases.

Interleukin-18 Is a Potential Biomarker to Discriminate Active Adult-Onset Still's Disease From COVID-19.

Background: Hyperinflammation with dysregulated production of galectins and cytokines may develop in COVID-19 or adult-onset Still's disease (AOSD). Given the similar clinical features in both diseases, it is necessary to identify biomarkers that can differentiate COVID-19 from AOSD. However, the related data remain scarce currently. Methods: In this cross-sectional study, plasma levels of galectin-3, galectin-9, and soluble TIM-3 (sTIM-3) were determined by ELISA in 55 COVID-19 patients (31 non-severe and 24 severe), 23 active AOSD patients, and 31 healthy controls (HC). The seropositivity for SARS-CoV-2 was examined using an immunochromatographic assay, and cytokine profiles were determined with the MULTIPLEX platform. Results: Significantly higher levels of galectin-3, galectin-9, IL-1ß, IL-1Ra, IL-10, IFN-α2, IL-6, IL-18, and TNF-α were observed in severe COVID-19 and active AOSD patients compared with HC (all p<0.001). AOSD, but not COVID-19, showed significantly higher IFN-γ and IL-17A compared with HC (both p<0.01). Moreover, active AOSD patients had 68-fold higher IL-18 levels and 5-fold higher ferritin levels than severe COVID-19 patients (both p<0.001). IL-18 levels at the cut-off value 190.5pg/mL had the highest discriminative power for active AOSD and severe COVID-19, with AUC 0.948, sensitivity 91.3%, specificity 95.8%, and accuracy of 91.5% (p<0.005). Multivariate regression analysis revealed IL-18 as a significant predictor of active AOSD (p<0.05). Conclusion: Active AOSD patients share features of hyperinflammation and cytokine storm with severe COVID-19 patients but possess a distinct cytokine profile, including elevated IL-18, IL-6, IFN-γ, and IL-17A. IL-18 is a potential discriminator between AOSD and COVID-19 and may significantly predict active AOSD.

Epidemiological observations on breaking COVID-19 transmission: from the experience of Taiwan.

With almost no community-transmitted cases and without any complete lockdown throughout 2020, Taiwan is one of very few countries worldwide that has recorded minimal impact from the COVID-19 pandemic attack. This is despite being only 130 km from China and having frequent business communications with that country, where COVID-19 first emerged. At the end of December 2020, Taiwan had recorded just 873 cases and 7 deaths, in a country of around 24 million people. How to determine the effectiveness of public health policies is an important issue that must be resolved, especially in those countries that have experienced few cases of community-transmitted COVID-19. Our analysis of epidemiological data in Taiwan relating to influenza-like illness (ILI), enterovirus and diarrhoea from the past 3 years reveals dramatic reductions in the incidence of ILI and enterovirus in 2020, compared with 2018 and 2019. These reductions occurred within 2 weeks of the government issuing public health policies for COVID-19 and indicate that such policies can effectively reduce infectious diseases overall. In contrast, no such reduction in ILI activity was observed in 2020 after the first COVID-19 case was reported in the USA. We suggest that infectious diseases data can be used to inform effective public health policies needed to break the transmission chain of COVID-19 and that ongoing monitoring of infectious diseases data can provide confidence about nationwide health.