Why multisystem inflammatory syndrome in children (MIS-C) develops after SARS-CoV-2 infection in a subset of children is unknown. We hypothesized that aberrant virus–specific T cell responses contribute to MIS-C pathogenesis. We quantified SARS-CoV-2–reactive T cells, serologic responses against major viral proteins, and cytokine responses from plasma and peripheral blood mononuclear cells in children with convalescent COVID-19, in children with acute MIS-C, and in healthy controls. Children with MIS-C had significantly lower virus-specific CD4+ and CD8+ T cell responses to major SARS-CoV-2 antigens compared with children convalescing from COVID-19. Furthermore, T cell responses in participants with MIS-C were similar to or lower than those in healthy controls. Serologic responses against spike receptor binding domain (RBD), full-length spike, and nucleocapsid were similar among convalescent COVID-19 and MIS-C, suggesting functional B cell responses. Cytokine profiling demonstrated predominant Th1 polarization of CD4+ T cells from children with convalescent COVID-19 and MIS-C, although cytokine production was reduced in MIS-C. Our findings support a role for constrained induction of anti–SARS-CoV-2–specific T cells in the pathogenesis of MIS-C.
Vidisha Singh, Veronica Obregon-Perko, Stacey A. Lapp, Anna Marie Horner, Alyssa Brooks, Lisa Macoy, Laila Hussaini, Austin Lu, Theda Gibson, Guido Silvestri, Alba Grifoni, Daniela Weiskopf, Alessandro Sette, Evan J. Anderson, Christina A. Rostad, Ann Chahroudi