Antibody response in children with multisystem inflammatory syndrome related to COVID-19 (MIS-C) compared to children with uncomplicated COVID-19

• Published in: Frontiers in immunology Vol. 14; p. 1107156
• Main Authors: Thiriard, Anaïs, Meyer, Benjamin, Eberhardt, Christiane S, Loevy, Natasha, Grazioli, Serge, Adouan, Wafae, Fontannaz, Paola, Marechal, Fabienne, L'Huillier, Arnaud G, Siegrist, Claire-Anne, Georges, Daphnée, Putignano, Antonella, Marchant, Arnaud, Didierlaurent, Arnaud M, Blanchard-Rohner, Geraldine
• Format: Journal Article Web Resource
• Language: English
• Published: Switzerland Frontiers Media S.A 2023
• Subjects: Antibodies, Viral; Antibody Formation; antibody response; Blood Group Antigens; Child; commensals; common coronavirus; Connective Tissue Diseases; COVID-19; functional antibody; Human health sciences; Humans; Immunoglobulin A; Immunoglobulin G; Immunoglobulin M; Immunologie & maladie infectieuse; Immunology; Immunology & infectious disease; Immunology and Allergy; MIS-C multisystem inflammatory syndrome in children; SARS-CoV-2; Sciences de la santé humaine; MIS-C multisystem inflammatory syndrome in children; SARS-CoV-2; common coronavirus; antibody response; commensals; functional antibody
• ISSN: 1664-3224; 1664-3224
• DOI: 10.3389/fimmu.2023.1107156

To comprehensively analyze the quality of the antibody response between children with Multisystem inflammatory syndrome (MIS-C) and age-matched controls at one month after SARS-CoV-2 exposure, and infected in the same time-period. Serum from 20 MIS-C children at admission, and 14 control children were analyzed. Antigen specific antibody isotypes and subclasses directed against various antigens of SARS-CoV-2 as well as against human common coronavirus (HCoVs) and commensal or pathogenic microorganisms were assessed by a bead-based multiplexed serological assay and by ELISA. The functionality of these antibodies was also assessed using a plaque reduction neutralization test, a RBD-specific avidity assay, a complement deposition assay and an antibody-dependent neutrophil phagocytosis (ADNP) assay. Children with MIS-C developed a stronger IgA antibody response in comparison to children with uncomplicated COVID-19, while IgG and IgM responses are largely similar in both groups. We found a typical class-switched antibody profile with high level of IgG and IgA titers and a measurable low IgM due to relatively recent SARS-CoV-2 infection (one month). SARS-CoV-2-specific IgG antibodies of MIS-C children had higher functional properties (higher neutralization activity, avidity and complement binding) as compared to children with uncomplicated COVID-19. There was no difference in the response to common endemic coronaviruses between both groups. However, MIS-C children had a moderate increase against mucosal commensal and pathogenic strains, reflecting a potential association between a disruption of the mucosal barrier with the disease. Even if it is still unclear why some children develop a MIS-C, we show here that MIS-C children produce higher titers of IgA antibodies, and IgG antibodies with higher functionality, which could reflect the local gastro-intestinal mucosal inflammation potentially induced by a sustained SARS-CoV-2 gut infection leading to continuous release of SARS-CoV-2 antigens.