Serum Soluble ST2 as a Novel Biomarker Reflecting Inflammatory Status and Disease Severity in Patients with COVID-19

Background: The COVID-19 pandemic, caused by a novel coronavirus (SARS-CoV-2), currently impacts over 100 countries. Soluble ST2 (sST2) is secreted and detectable in human serum, which acts as a decoy receptor for interleukin (IL)-33 to prevent IL-33-mediated T cell immune responses. Serum sST2 has been found to be a novel biomarker in several viral infectious diseases. Here, we studies the role of sST2 in COVID-19 and its relationship with inflammatory status and disease severity. Methods: A total of 80 subjects diagnosed as COVID-19 were recruited in this study, including 36 mild, 41 severe and 3 asymptomatic cases. On admission the levels of C-reactive protein (CRP), serum amyloid protein (SAA), IL-6 and procalcitonin (PCT) were collected, and T lymphocyte subsets were tested by flow cytometry. Serum levels of sST2 and IL-33 were measured using enzyme-linked immunosorbent assay. Findings: Serum sST2 levels were significantly increased in patients with COVID-19. Line regression analysis indicated that there was a positive correlation between serum sST2 and CRP level in COVID-19 patients. Conversely, serum sST2 levels negatively correlated with CD4+ and CD8 + T lymphocyte counts. Moreover, dynamic changes of serum sST2 persisted at a high level in severe cases. No obvious difference in the levels of serum IL-33 was observed between the control subjects and COVID-19 patients. Interpretation: Surveillance of serum sST2 is helpful in the early screening of inflammatory status and critical illness of COVID-19. High sST2 level combined with the decreased T lymphocytes may reflect the dysregulated T cell immune response and infection severity. Funding Statement: This study was supported by the National Natural Science Foundation of China (No. 81501033). Declaration of Interests: All authors have not any financial conflict of interest. Ethics Approval Statement: The study was approved by the ethics committee of Zhongnan Hospital of Wuhan University (No. 2019125). Written informed consent was obtained from patients.