Identifying Age-Related Risk Factors in COVID-19 Independent of Disease Severity

Abstract

COVID-19 emerged as the most lethal pandemic in the last century. Although it can affect persons with any age, patients with advanced age represent a significantly higher fraction of severe disease. The molecular and cellular mechanisms that render patients with advanced age susceptible to severe disease remains unknown. Here we revealed that older subjects (>=30 years) had significantly elevated levels of anti-inflammatory cytokine IL-10, but no change in any of the pro-inflammatory cytokines. While an expansion of NKT cell fraction was observed in older patients, a decrease in CD8+ T cell fraction was observed in these patients. In addition, older subjects had a delayed humoral response measured as IgM and IgG levels. Overall, these patients had significantly elevated viral load compared to young subjects. These data demonstrate altered early inflammatory and antiviral responses contributing to the age-related susceptibility to COVID-19.Funding Statement: This study was supported by funding from Beijing Nova Program Interdisciplinary Cooperation Project (DC; No. Z191100001119021), Chinese PLA General Hospital Youth Project (DC; No.QNF19074) and China 13th Five-year National Key Grant (LXX; No.2018ZX09201013). Declaration of Interests: The authors declare that there are no competing interests.Ethics Approval Statement: This study was approved by the ethics committee of Guangzhou Eighth People’s Hospital, with a waiver of informed consent.