SARS-CoV-2 as a superantigen in multisystem inflammatory syndrome in children.

Multisystem inflammatory syndrome in children (MIS-C) is a rare but deadly new disease in children that rapidly progresses to hyperinflammation and shock, and can lead to multiple organ failure if unrecognized. It has been found to be temporally associated with the COVID-19 pandemic and is often associated with SARS-CoV-2 exposure in children. In this issue of the JCI, Porritt, Paschold, et al. identify restricted T cell receptor (TCR) β-chain variable domain (Vβ) usage in patients with severe MIS-C, indicating a potential role for SARS-CoV-2 as a superantigen. These findings suggest that a blood test that determines the presence of specific TCRβ variable gene (TRBV) segments may identify patients at risk for severe MIS-C.