Search

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., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Pavan Kumar, Abbas, Renji, Venkataraman, Nancy, Varadarjan, Selladurai, Sangaralingam, Selvam, Thimmaiah, Natarajan, Ramasamy, Hissar, Ranganathan, Nutman and Babu.)

Introduction: Multisystem Inflammatory Syndrome in children (MIS-C) is a serious inflammatory sequela of SARS-CoV2 infection. The pathogenesis of MIS-C is vague and matrix metalloproteinases (MMPs) may have an important role. Matrix metalloproteinases (MMPs) are known drivers of lung pathology in many diseases., Methods: To elucidate the role of MMPs in pathogenesis of pediatric COVID-19, we examined their plasma levels in MIS-C and acute COVID-19 children and compared them to convalescent COVID-19 and children with other common tropical diseases (with overlapping clinical manifestations)., Results: Children with MIS-C had elevated levels of MMPs ( P < 0.005 statistically significant) in comparison to acute COVID-19, other tropical diseases (Dengue fever, typhoid fever, and scrub typhus fever) and convalescent COVID-19 children. PCA and ROC analysis (sensitivity 84-100% and specificity 80-100%) showed that MMP-8, 12, 13 could help distinguish MIS-C from acute COVID-19 and other tropical diseases with high sensitivity and specificity. Among MIS-C children, elevated levels of MMPs were seen in children requiring intensive care unit admission as compared to children not needing intensive care. Similar findings were noted when children with severe/moderate COVID-19 were compared to children with mild COVID-19. Finally, MMP levels exhibited significant correlation with laboratory parameters, including lymphocyte counts, CRP, D-dimer, Ferritin and Sodium levels., Discussion: Our findings suggest that MMPs play a pivotal role in the pathogenesis of MIS-C and COVID-19 in children and may help distinguish MIS-C from other conditions with overlapping clinical presentation., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Pavan Kumar, Venkataraman, Varadarjan, Nancy, Rajamanickam, Selladurai, Sankaralingam, Thiruvengadam, Selvam, Thimmaiah, Natarajan, Ramaswamy, Putlibai, Sadasivam, Sundaram, Hissar, Ranganathan, Nutman and Babu.)

The clinical presentation of MIS-C overlaps with other infectious/non-infectious diseases such as acute COVID-19, Kawasaki disease, acute dengue, enteric fever, and systemic lupus erythematosus. We examined the ex-vivo cellular parameters with the aim of distinguishing MIS-C from other syndromes with overlapping clinical presentations. MIS-C children differed from children with non-MIS-C conditions by having increased numbers of naïve CD8+ T cells, naïve, immature and atypical memory B cells and diminished numbers of transitional memory, stem cell memory, central and effector memory CD4+ and CD8+ T cells, classical, activated memory B and plasma cells and monocyte (intermediate and non-classical) and dendritic cell (plasmacytoid and myeloid) subsets. All of the above alterations were significantly reversed at 6-9 months post-recovery in MIS-C. Thus, MIS-C is characterized by a distinct cellular signature that distinguishes it from other syndromes with overlapping clinical presentations. Trial Registration: ClinicalTrials.gov clinicaltrial.gov. No: NCT04844242., Competing Interests: The authors have declared that no competing interests exist.

Background: Multisystem inflammatory syndrome in children (MIS-C) presents with inflammation and pathology of multiple organs in the pediatric population in the weeks following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection., Methods: We characterized the SARS-CoV-2 antigen-specific cytokine and chemokine responses in children with MIS-C, coronavirus disease 2019 (COVID-19), and other infectious diseases., Results: MIS-C is characterized by elevated levels of type 1 (interferon-γ, interleukin [IL] 2), type 2 (IL-4, IL-13), type 17 (IL-17), and other proinflammatory cytokines (IL-1α, IL-6, IL-12p70, IL-18, and granulocyte-macrophage colony-stimulating factor) in comparison to COVID-19 and other infectious diseases following stimulation with SARS-CoV-2-specific antigens. Similarly, upon SARS-CoV-2 antigen stimulation, CCL2, CCL3, and CXCL10 chemokines were significantly elevated in children with MIS-C in comparison to the other 2 groups. Principal component analysis based on these cytokines and chemokines could clearly distinguish MIS-C from both COVID-19 and other infections. In addition, these responses were significantly diminished and normalized 6-9 months after recovery., Conclusions: Our data suggest that MIS-C is characterized by an enhanced production of cytokines and chemokines that may be associated with disease pathogenesis., Competing Interests: Potential conflicts of interest. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)