Accelerated biological aging in people with Down syndrome with full and segmental trisomy 21 begins in childhood as revealed by immunoglobulin G glycosylation

Cells from people with Down syndrome (DS) show faster accumulation of DNA damage and epigenetic aging marks. Causative mechanisms remain un-proven and hypotheses range from amplified chromosomal instability to actions of several supernumerary chromosome 21 genes. Plasma immunoglobulin G (IgG) glycosylation profiles are established as a reliable predictor of biological and chronological aging. We performed IgG glycan profiling of n=246 individuals with DS (208 adults and 38 children) from three European populations and compared these to age-, sex- and demography-matched general populations. We uncovered very significantly increased IgG glycosylation aging marks associated with DS. Average levels of IgG glycans without galactose (G0) and those with two galactoses (G2) as a function of age in persons with DS corresponded to levels detected in 19 years older euploid individuals. Some aging marks were significant already in children with DS. Remarkably, the IgG glycan profiles of a child with segmental duplication of only 31 genes on chromosome 21 had values similar to those of age-matched DS children, outside the normal children’s range. This is the first non-epigenetic evidence of accelerated systemic biological aging in DS, suggesting it begins very early in childhood. It points to a causative contribution of the overdose of genes in a short segment of chromosome 21, not previously linked to accelerated aging, opening a route to discovery of hitherto unrecognised mechanisms.

Micro-Fourier-Transform Infrared Reflectance Spectroscopy as Tool for Probing IgG Glycosylation in COVID-19 Patients

It has been reported that patients diagnosed with COVID-19 become critically ill primarily around the time of activation of the adaptive immune response. However the role of antibodies in the worsening of disease is not obvious. Higher titers of anti-spike immunoglobulin IgG1 associated to low fucosylation of the antibody Fc tail have been associated to excessive inflammatory response. In contrast it has been also reported in literature that NP-, S-, RBD- specific IgA, IgG, IgM are not associated with SARS-CoV-2 viral load, indicating that there is no obvious correlation between antibody response and viral antigen detection. In the present work the micro-Fourier-Transform Infrared reflectance spectroscopy (micro-FTIR) was employed to investigate blood serum samples of healthy and COVID-19 (mild or oligosynthomatic) individuals (82 healthcare workers volunteers in “Instituto de Infectologia Emilio Ribas”, São Paulo, Brazil). The molecular-level-sensitive, multiplexing quantitative and qualitative FTIR data probed on 1 mL of dryed biofluidwas compared to Signal-to-Cutoff index of chemiluminescent immunoassays CLIA and ELISA (IgG antibodies against SARS-CoV-2). Our main result indicated that 1702-1785 cm-1 spectral window (carbonyl C=O vibration) appeared to be a spectral marker of the degree of IgG glycosylation, allowing to probe distinctive subpopulations of COVID-19 patients, depending on their degree of severity. The specificity was 87.5 % while the detection rate of true positive was 100%. The computed area under the receiver operating curve was equivalent to CLIA, ELISA and other ATR-FTIR methods (> 0.85). In summary, overall discrimination of healthy and COVID-19 individuals and severity prediction as well could also be potentially implemented using micro-FTIR reflectance spectroscopy on blood serum samples. Considering the minimal and reagent-free sample preparation procedures combined to fast (few minutes) outcome of FTIR we can state that this technology is very suitable for fast screening of immune response of individuals with COVID-19. It would be an important tool in prospective studies, helping investigate the physiology of the asymptomatic, oligosymptomatic, or severe individuals and measure the extension of infection dissemination in patients.

Significant Associations of IgG Glycan Structures With Chronic Graft-Versus-Host Disease Manifestations: Results of the Cross-Sectional NIH Cohort Study

Chronic graft-versus-host disease (cGvHD) is a systemic alloimmune and autoimmune disorder and a major late complication of allogeneic hematopoietic stem cell transplantation (alloHSCT). The disease is characterized by an altered homeostasis of the humoral immune response. Immunoglobulin G (IgG) glycoprotein is the main effector molecule of the humoral immune response. Changes in IgG glycosylation are associated with a number of autoimmune diseases. IgG glycosylation analysis was done by the means of liquid chromatography in the National Institutes of Health (NIH) cohort of 213 cGvHD patients. The results showed statistically significant differences with regards to cGvHD NIH joint/fascia and skin score, disease activity and intensity of systemic immunosuppression. ROC analysis confirmed that IgG glycosylation increases specificity and sensitivity of models using laboratory parameters and markers of inflammation associated with cGvHD (eosinophil count, complement components C3 and C4 and inflammation markers: albumin, CRP and thrombocyte count). This research shows that IgG glycosylation may play a significant role in cGvHD pathology. Further research could contribute to the understanding of the disease biology and lead to the clinical biomarker development to allow personalized approaches to chronic GvHD therapy.

Changes of Serum IgG Glycosylation Patterns in Primary Biliary Cholangitis Patients

ObjectivePrimary biliary cholangitis (PBC) is an autoimmune cholestatic liver disease whose diagnosis is based significantly on autoantibody detection. This study aims to investigate the glycosylation profile of serum IgG in PBC patients using high-throughput lectin microarrays technology.MethodLectin microarray containing 56 lectins was used to detect and analyze the expression of serum IgG glycosylation in 99 PBC patients, 70 disease controls (DCs), and 38 healthy controls (HCs). Significant differences in PBC from control groups as well as across PBC subgroups positive for various autoantibodies were explored and verified by lectin blot technique.ResultsLectin microarray detection revealed that compared to DC and HC groups, the specific glycan level of serum IgG sialic acid in PBC patients was increased. For each PBC subgroup, glycan levels of IgG mannose and galactose were decreased in AMA-M2 positive PBC patients compared to the AMA-M2 negative group. IgG N-Acetylgalactosamine (GalNAc) and fucose were decreased in anti-sp100 positive patients. IgG galactose was increased in anti-gp210 positive patients. IgG mannose was decreased in ACA-positive patients. Although the difference in overall sialic acid level was not observed using lectin blot, all results among the above PBC subgroups were consistent with the results of the technique.ConclusionLectin microarray is an effective and reliable technique for analyzing glycan structure. PBC patients positive for different autoantibody exhibits distinct glycan profile. Altered levels of glycosylation may be related to the occurrence and development of the disease, which could provide a direction for new biomarker identification.

Effects of Estradiol on Immunoglobulin G Glycosylation: Mapping of the Downstream Signaling Mechanism

Glycans attached to immunoglobulin G (IgG) directly affect this antibody effector functions and regulate inflammation at several levels. The composition of IgG glycome changes significantly with age. In women, the most notable change coincides with the perimenopausal period. Aiming to investigate the effect of estrogen on IgG glycosylation, we analysed IgG and total serum glycomes in 36 healthy premenopausal women enrolled in a randomized controlled trial of the gonadotropin-releasing hormone analogue (GnRHAG) leuprolide acetate to lower gonadal steroids to postmenopausal levels and then randomized to transdermal placebo or estradiol (E2) patch. The suppression of gonadal hormones induced significant changes in the IgG glycome, while E2 supplementation was sufficient to prevent changes. The observed glycan changes suggest that depletion of E2 primarily affects B cell glycosylation, while liver glycosylation stays mostly unchanged. To determine whether previously identified IgG GWAS hits RUNX1, RUNX3, SPINK4, and ELL2 are involved in downstream signaling mechanisms, linking E2 with IgG glycosylation, we used the FreeStyle 293-F transient system expressing IgG antibodies with stably integrated CRISPR/dCas9 expression cassettes for gene up- and downregulation. RUNX3 and SPINK4 upregulation using dCas9-VPR resulted in a decreased IgG galactosylation and, in the case of RUNX3, a concomitant increase in IgG agalactosylation.

AB0016 THE IMPACT OF IL-17A THERAPY ON IGG SIALYLATION IN HUMANS

Background:Rheumatoid arthritis (RA) is characterized by autoreactive B- and T cells. Autoantibodies are a hallmark of RA and contribute to synovial inflammation. We have recently demonstrated that Th17 cells suppress the enzyme ST6 a-galactoside b-2,6-sialyltransferase (ST6GAL1) in developing plasma cells. Thereby, Th17 cells regulate the degree of autoantibody sialylation leading to the increased inflammatory activity of autoantibodies. These events correlate with the onset of RA, arguing for a crucial role of the IL-23/Th17 axis during the transition of asymptomatic autoimmunity into active RA. Therefore, treatment against the IL-23/TH17-axis might present an attractive therapeutic approach to halt or delay RA’s onset. However, the effects of Th17 cytokines like IL-17 on IgG glycosylation in humans are so far poorly studied.Objectives:To explore whether anti-IL17A treatment can inhibit pro-inflammatory IgG glycosylation patterns in humans.Methods:Total IgG from patient cohorts suffering from psoriatic arthritis (PsA) treated with Secukinumab (anti-IL-17 blockade, n=26) or Ustekinumab (anti-IL12/23 blockade, n=14) was compared with patients treated with anti-TNFa blockade as a control (n=20). The cohorts were age- and sex-matched and included patients being on therapy for at least six months. Total IgG was isolated using Protein G columns, and IgG glycopeptides of IgG1, IgG2, and IgG4 were analyzed using the LC-MS technique. The effect of IL-17 depletion on IgG glycosylation was analyzed in psoriatic arthritis patients who have been treated with secukinumab for at least six months. Furthermore, in a longitudinal approach, IgG1, IgG2, and IgG4 glycosylation were analyzed from samples, isolated before the beginning of anti-IL-17 blockade and after at least six months of therapy (n=16).Results:Cross-sectional comparison of cohorts treated with Ustekinumab, Sekukinumab, and anti-TNFa therapy did not show any significant differences in sialylation, galactosylation, or fucosylation of IgG1 and IgG2. IgG4 from anti-TNFa treated patients displayed a small increase of sialylation when compared to the Ustekinumab treated cohort.Longitudinal analyses, however, showed that IL-17A blockade during Secukinumab therapy caused a significant increase of sialic acid-rich IgG glycoforms on IgG1, IgG2 IgG4 patients, while the galactosylation, fucosylation remained unaffected.Conclusion:This data indicates that IL-17A blockade specifically affects IgG sialylation, while other Fc-glycan modifications remain unaltered. This data confirms our recent findings in mice, where cytokines of the IL-23/Th17 axis specifically induce the production of hypo-sialylated, proinflammatory autoantibodies in rheumatoid arthritis (RA) [2]. Therefore, neutralizing IL-17 might be a therapeutic option during the asymptomatic autoimmune prodromal phase in autoimmune diseases like RA, where TH17 cytokines orchestrate the emergence of a pro-inflammatory autoantibody response and the transition into active RA.References:[1]McInnes IB, G. Schett, The pathogenesis of rheumatoid arthritis. N Engl J Med 2011; 365: 2205-19.[2]Pfeifle R et al, Regulation of autoantibody activity by the IL-23-Th17 axis determines the onset of autoimmune disease. Nat Immunol. 2017, Jan;18(1):104-113.Disclosure of Interests:Rene Pfeifle Grant/research support from: Novartis AG., Julia Kittler: None declared, Manfred Wuhrer: None declared, Georg Schett: None declared, Gerhard Krönke Grant/research support from: Novartis AG

Knowledge Domain and Emerging Trends of IgG Glycosylation: A Bibliometric Study Based on CiteSpace

Background: The purpose of this paper is to evaluate the international scientific output of Igg glycosylation research by a stoichiometric analysis of the related papers published in the field of IGG glycosylation from 2009 to 2020, to explore the hot spot of IGG glycosylation and the evolution path of IGG glycosylation.Methods: Using the Web of Science core database (WoSCC) to collect the articles related to IgG glycosylation from 2009 to 2020 as the research object, using CiteSpace visualization software to analyze the co-occurrence of countries and institutions, core authors, and keywords. Cited authors and literature, Co-citation analysis of journals, obtaining cooperation maps of research countries / institutions and core authors, literature citation and clustering maps, co-occurrence maps of high-frequency subject headings, displaying related clusters, mutual influences between clusters and Keyword timeline view spectrum of the historical span of important keywords in clustering.Results: We searched 482 articles related to IgG glycosylation published in 227 journals, and observed that in the past 10 years, the number of articles published has generally increased year by year; it has been cited 13262 times, with an average of 27.5 citations per article, showing an upward trend year by year. The core team in the field of IGG glycosylation is mainly from University and research institutes in USA, Australia, Netherlands, Croatia, England, Germany, Ireland, Scotland, China and Japan. A total of 2408 authors participated in the writing of literature on Igg glycosylation, Among them, Wuhrer, Manfred、Lauc, Gordan、Irena Trbojevic Akmacic, Wei Wang and other scholars are the representatives of this research field and have important influence. There are 281 keywords under the theme of IgG glycosylation, of which there are 4 keywords with word frequency ≥100, and hot keywords that serve as bridges are pregnancy、complex、glycan、biosimilar、N-linked glycosylation、hilic-uplc、glycation and form 8 clusters. IgG glycosylation, as the "biomarker" of disease diagnosis and its mechanism has been a research hotspot in recent years.Conclusion: The use of CiteSpace software for quantitative analysis of IgG glycosylation related literature can intuitively demonstrate its development history and current research hotspots and trends, and can provide researchers with reference to the topic selection and research direction. Value and meaning.