Polyclonal expansion of TCR Vβ 21.3 + CD4 + and CD8 + T cells is a hallmark of multisystem inflammatory syndrome in children

Consistently, the T cell expansion was not associated with specific classical HLA alleles. Thus, our data suggested that MIS-C is characterized by a polyclonal Vβ21.3 T cell expansion not directed against SARS-CoV-2 antigenic peptides, which is not seen in KD, TSS and acute COVID-19.