Serum-soluble ST2 as a novel biomarker reflecting inflammatory status and illness severity in patients with COVID-19

Aim: The authors studied the role of soluble ST2 (sST2) in COVID-19 and its relationship with inflammatory status and disease severity. Materials & methods: Serum levels of sST2 and interleukin (IL)-33, C-reactive protein (CRP), serum amyloid protein (SAA), IL-6 and procalcitonin (PCT), and T lymphocyte subsets from 80 subjects diagnosed with COVID-19 including 36 mild, 41 severe and three asymptomatic cases were tested. Results: Serum sST2 levels were significantly increased in COVID-19 patients, which were positively correlated with CRP, but negatively correlated with CD4^{+} and CD8^{+} T lymphocyte counts. Serum sST2 levels in nonsurviving severe cases were persistently high during disease progression. Conclusion: Serum sST2 level test is helpful for reflecting inflammatory status and illness severity of COVID-19.