Systemic and T cell-associated responses to SARS-CoV-2 immunisation in gut inflammation (STAR SIGN study): effects of biologics on vaccination efficacy of the third dose of mRNA vaccines against SARS-CoV-2.

BACKGROUND: Immunosuppressed patients with inflammatory bowel disease (IBD) experience increased risk of vaccine-preventable diseases such as COVID-19. AIMS: To assess humoral and cellular immune responses following SARS-CoV-2 booster vaccination in immunosuppressed IBD patients and healthy controls. METHODS: In this prospective, multicentre, case-control study, 139 IBD patients treated with biologics and 110 healthy controls were recruited. Serum anti-SARS-CoV-2 spike IgG concentrations were measured 2-16 weeks after receiving a third mRNA vaccine dose. The primary outcome was to determine if humoral immune responses towards booster vaccines differ in IBD patients under anti-TNF versus non-anti-TNF therapy and healthy controls. Secondary outcomes were antibody decline, impact of previous infection and SARS-CoV-2-targeted T cell responses. RESULTS: Anti-TNF-treated IBD patients showed reduced anti-spike IgG concentrations (geometric mean 2357.4 BAU/ml [geometric SD 3.3]) when compared to non-anti-TNF-treated patients (5935.7 BAU/ml [3.9]; p < 0.0001) and healthy controls (5481.7 BAU/ml [2.4]; p < 0.0001), respectively. In multivariable modelling, prior infection (geometric mean ratio 2.00 [95% CI 1.34-2.90]) and vaccination with mRNA-1273 (1.53 [1.01-2.27]) increased antibody concentrations, while anti-TNF treatment (0.39 [0.28-0.54]) and prolonged time between vaccination and antibody measurement (0.72 [0.58-0.90]) decreased anti-SARS-CoV-2 spike antibodies. Antibody decline was comparable in IBD patients independent of anti-TNF treatment and antibody concentrations could not predict breakthrough infections. Cellular and humoral immune responses were uncoupled, and more anti-TNF-treated patients than healthy controls developed inadequate T cell responses (15/73 [20.5%] vs 2/100 [2.0%]; p = 0.00031). CONCLUSIONS: Anti-TNF-treated IBD patients have impaired humoral and cellular immunogenicity following SARS-CoV-2 booster vaccination. Fourth dose administration may be beneficial for these patients.

Immunopathological signatures in multisystem inflammatory syndrome in children and pediatric COVID-19.

Pediatric Coronavirus Disease 2019 (pCOVID-19) is rarely severe; however, a minority of children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) might develop multisystem inflammatory syndrome in children (MIS-C), with substantial morbidity. In this longitudinal multi-institutional study, we applied multi-omics (analysis of soluble biomarkers, proteomics, single-cell gene expression and immune repertoire analysis) to profile children with COVID-19 (n = 110) and MIS-C (n = 76), along with pediatric healthy controls (pHCs; n = 76). pCOVID-19 was characterized by robust type I interferon (IFN) responses, whereas prominent type II IFN-dependent and NF-κB-dependent signatures, matrisome activation and increased levels of circulating spike protein were detected in MIS-C, with no correlation with SARS-CoV-2 PCR status around the time of admission. Transient expansion of TRBV11-2 T cell clonotypes in MIS-C was associated with signatures of inflammation and T cell activation. The association of MIS-C with the combination of HLA A*02, B*35 and C*04 alleles suggests genetic susceptibility. MIS-C B cells showed higher mutation load than pCOVID-19 and pHC. These results identify distinct immunopathological signatures in pCOVID-19 and MIS-C that might help better define the pathophysiology of these disorders and guide therapy.

Infections in the monogenic autoimmune syndrome APECED.

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is caused by mutations in the Autoimmune Regulator (AIRE) gene, which impair the thymic negative selection of self-reactive T-cells and underlie the development of autoimmunity that targets multiple endocrine and non-endocrine tissues. Beyond autoimmunity, APECED features heightened susceptibility to certain specific infections, which is mediated by anti-cytokine autoantibodies and/or T-cell driven autoimmune tissue injury. These include the 'signature' APECED infection chronic mucocutaneous candidiasis (CMC), but also life-threatening coronavirus disease 2019 (COVID-19) pneumonia, bronchiectasis-associated bacterial pneumonia, and sepsis by encapsulated bacteria. Here we discuss the expanding understanding of the immunological mechanisms that contribute to infection susceptibility in this prototypic syndrome of impaired central tolerance, which provide the foundation for devising improved diagnostic and therapeutic strategies for affected patients.

An immune-based biomarker signature is associated with mortality in COVID-19 patients.

Immune and inflammatory responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contribute to disease severity of coronavirus disease 2019 (COVID-19). However, the utility of specific immune-based biomarkers to predict clinical outcome remains elusive. Here, we analyzed levels of 66 soluble biomarkers in 175 Italian patients with COVID-19 ranging from mild/moderate to critical severity and assessed type I IFN-, type II IFN-, and NF-κB-dependent whole-blood transcriptional signatures. A broad inflammatory signature was observed, implicating activation of various immune and nonhematopoietic cell subsets. Discordance between IFN-α2a protein and IFNA2 transcript levels in blood suggests that type I IFNs during COVID-19 may be primarily produced by tissue-resident cells. Multivariable analysis of patients' first samples revealed 12 biomarkers (CCL2, IL-15, soluble ST2 [sST2], NGAL, sTNFRSF1A, ferritin, IL-6, S100A9, MMP-9, IL-2, sVEGFR1, IL-10) that when increased were independently associated with mortality. Multivariate analyses of longitudinal biomarker trajectories identified 8 of the aforementioned biomarkers (IL-15, IL-2, NGAL, CCL2, MMP-9, sTNFRSF1A, sST2, IL-10) and 2 additional biomarkers (lactoferrin, CXCL9) that were substantially associated with mortality when increased, while IL-1α was associated with mortality when decreased. Among these, sST2, sTNFRSF1A, IL-10, and IL-15 were consistently higher throughout the hospitalization in patients who died versus those who recovered, suggesting that these biomarkers may provide an early warning of eventual disease outcome.