AUTHOR=Pavan Kumar Nathella , Abbas Kadar M. , Renji Rachel M. , Venkataraman Aishwarya , Nancy Arul , Varadarjan Poovazhagi , Selladurai Elilarasi , Sangaralingam Thankgavelu , Selvam Ramya , Thimmaiah Akshith , Natarajan Suresh , Ramasamy Ganesh , Hissar Syed , Ranganathan Uma Devi , Nutman Thomas B. , Babu Subash TITLE=Multisystem inflammatory syndrome in children characterized by enhanced antigen-specific T-cell expression of cytokines and its reversal following recovery JOURNAL=Frontiers in Pediatrics VOLUME=11 YEAR=2023 URL=https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2023.1235342 DOI=10.3389/fped.2023.1235342 ISSN=2296-2360 ABSTRACT=Background

Multisystem inflammatory syndrome (MIS) in children is considered to be a post-infectious complication of COVID-19. T-cell responses in children with this condition have not been well-studied.

Methods

We aimed to study the immune responses in children with MIS in comparison to children with acute COVID-19 and children with other infections. Whole blood was stimulated with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)–specific antigens and flow cytometry was performed to examine CD4+ and CD8+ T-cell responses.

Results

Children with MIS had higher frequencies of CD4+ and CD8+ T cells expressing cytokines at baseline and upon SARS-CoV-2 antigen–specific stimulation in comparison to children with COVID-19 and/or other infections. Children with COVID-19 also exhibited higher frequencies of CD4+ and CD8+ T cells expressing cytokines at baseline and upon SARS-CoV-2 antigen–specific stimulation in comparison to children with other infections. At 6–9 months following treatment and recovery, this enhanced response against SARS-CoV-2 antigens was down modulated in children with MIS.

Conclusion

Our study, therefore, provides evidence of enhanced activation of CD4+ and CD8+ T-cell responses in children with MIS and reversal following recovery.