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Diabetes Care Apr 2020Most individuals with two or more islet autoantibodies progress to clinical type 1 diabetes. However, in some individuals, autoantibodies are subsequently lost. Here,...
OBJECTIVE
Most individuals with two or more islet autoantibodies progress to clinical type 1 diabetes. However, in some individuals, autoantibodies are subsequently lost. Here, our objectives were to determine the frequency of autoantibody loss (reversion) in multiple-autoantibody-positive individuals and to determine the association between reversion and progression to clinical disease.
RESEARCH DESIGN AND METHODS
We analyzed multiple-autoantibody-positive individuals participating in TrialNet's Pathway to Prevention Study for reversion and determined the effect of reversion on progression to clinical disease using a Cox regression analysis.
RESULTS
Of 3,284 multiple-autoantibody-positive subjects, reversion occurred in 134 (4.1%) and was associated with reduced incidence of clinical disease. Reversion occurred more frequently with older age, lower autoantibody titers, and fewer positive autoantibodies.
CONCLUSIONS
Although reversion of multiple-autoantibody positivity is rare, when it occurs, the risk of progressing to clinical disease is reduced. This suggests unknown mechanisms promoting immune remission in some individuals.
Topics: Adolescent; Adult; Autoantibodies; Child; Child, Preschool; Diabetes Mellitus, Type 1; Disease Progression; Female; Humans; Incidence; Infant; Infant, Newborn; Islets of Langerhans; Male; Middle Aged; Remission, Spontaneous; Young Adult
PubMed: 32019856
DOI: 10.2337/dc19-1731 -
PloS One 2022Sarcoidosis, a multi-systemic granulomatous disease, is a predominantly T-cell disease but evidence for a role for humoral immunity in disease pathogenesis is growing....
BACKGROUND
Sarcoidosis, a multi-systemic granulomatous disease, is a predominantly T-cell disease but evidence for a role for humoral immunity in disease pathogenesis is growing. Utilizing samples from the Genomic Research in Alpha-1 anti-trypsin Deficiency and Sarcoidosis (GRADS) study, we examined the prevalence of autoantibodies in sarcoidosis patients with pulmonary-only and extra-pulmonary organ involvement compared to normal controls.
STUDY DESIGN AND METHODS
We analyzed serum samples from sarcoidosis patients who participated in the GRADS study utilizing an autoantigen microarray platform for both IgM and IgG antibodies. The cohort included sarcoidosis patients with pulmonary-only disease (POS, n = 106), sarcoidosis patients with extra-pulmonary disease (EPS, n = 120) and a normal control cohort (NC, n = 101). Organ involvement was assessed following a standardized format across all GRADS participating centers.
RESULTS
Sarcoidosis patients overall had increased levels of IgM and IgG autoantibodies compared to normal controls. In addition, several autoantibodies were elevated in the POS and EPS cohorts compared to the NC cohort. Differences in autoantibody levels were also noted between the POS and the EPS cohorts. When comparing organ involvement with sarcoidosis, bone, spleen and ear, nose and throat involvement had higher IgM expression than other organs.
CONCLUSION
Sarcoidosis patients have elevated IgM and IgG autoantibody levels compared to normal controls. In addition, individuals with pulmonary as well as additional organ involvement had higher IgM expression. Further research is needed focusing on specific organ-autoantibody pairs and role of autoantibodies in disease pathogenesis.
Topics: Humans; Autoantibodies; Sarcoidosis; Immunoglobulin G; Autoantigens; Lung Diseases; Immunoglobulin M
PubMed: 36264970
DOI: 10.1371/journal.pone.0274381 -
Frontiers in Immunology 2021Detecting autoantibodies provides foundational information for the diagnosis of most autoimmune diseases. An important pathophysiological distinction is whether... (Review)
Review
Detecting autoantibodies provides foundational information for the diagnosis of most autoimmune diseases. An important pathophysiological distinction is whether autoantibodies are directed against extracellular or intracellular proteins. Autoantibodies targeting extracellular domains of proteins, such as membrane receptors, channels or secreted molecules are often directly pathogenic, whereby autoantibody binding to the autoantigen disrupts the normal function of a critical protein or pathway, and/or triggers antibody-dependent cell surface complement killing. By comparison, autoantibodies directed against intracellular proteins are recognized as useful diagnostic biomarkers of abnormal autoimmune activity, but the link between antigenicity and pathogenicity is less straightforward. Because intracellular autoantigens are generally inaccessible to autoantibody binding, for the most part, they do not directly contribute to pathogenesis. In a few diseases, autoantibodies to intracellular targets cause damage indirectly by immune complex formation, immune activation, and other processes. In this review, the general features of and differences between autoimmune diseases segregated on the basis of intracellular or extracellular autoantigens are explored using over twenty examples. Expression profiles of autoantigens in relation to the tissues targeted by autoimmune disease and the temporal appearance of autoantibodies before clinical diagnosis often correlate with whether the respective autoantibodies mostly recognize either intracellular or extracellular autoantigens. In addition, current therapeutic strategies are discussed from this vantage point. One drug, rituximab, depletes CD20+ B-cells and is highly effective for autoimmune disorders associated with autoantibodies against extracellular autoantigens. In contrast, diseases associated with autoantibodies directed predominately against intracellular autoantigens show much more complex immune cell involvement, such as T-cell mediated tissue damage, and require different strategies for optimal therapeutic benefit. Understanding the clinical ramifications of autoimmunity derived by autoantibodies against either intracellular or extracellular autoantigens, or a spectrum of both, has practical implications for guiding drug development, generating monitoring tools, stratification of patient interventions, and designing trials based on predictive autoantibody profiles for autoimmune diseases.
Topics: Autoantibodies; Autoantigens; Autoimmune Diseases; Autoimmunity; B-Lymphocytes; Extracellular Space; Humans; Intracellular Space; Proteins; T-Lymphocytes
PubMed: 33763057
DOI: 10.3389/fimmu.2021.548469 -
Frontiers in Immunology 2023The chronic airway inflammation in severe eosinophilic asthma (SEA) suggests potential autoimmune aetiology with unidentified autoantibodies analogous to myeloperoxidase...
BACKGROUND
The chronic airway inflammation in severe eosinophilic asthma (SEA) suggests potential autoimmune aetiology with unidentified autoantibodies analogous to myeloperoxidase (MPO) in ANCA-positive EGPA (eosinophilic granulomatosis with polyangiitis). Previous research has shown that oxidative post-translational modification (oxPTM) of proteins is an important mechanism by which autoantibody responses may escape immune tolerance. Autoantibodies to oxPTM autoantigens in SEA have not previously been studied.
METHODS
Patients with EGPA and SEA were recruited as well as healthy control participants. Autoantigen agnostic approach: Participant serum was incubated with slides of unstimulated and PMA-stimulated neutrophils and eosinophils, and autoantibodies to granulocytes were identified by immunofluorescence with anti-human IgG FITC antibody. Target autoantigen approach: Candidate proteins were identified from previous literature and FANTOM5 gene set analysis for eosinophil expressed proteins. Serum IgG autoantibodies to these proteins, in native and oxPTM form, were detected by indirect ELISA.
RESULTS
Immunofluorescence studies showed that serum from patients with known ANCA stained for IgG against neutrophils as expected. In addition, serum from 9 of 17 tested SEA patients stained for IgG to PMA-stimulated neutrophils undergoing NETosis. Immunofluorescent staining of eosinophil slides was evident with serum from all participants (healthy and with eosinophilic disease) with diffuse cytoplasmic staining except for one SEA individual in whom subtle nuclear staining was evident. FANTOM5 gene set analysis identified TREM1 (triggering receptor expressed on myeloid cells 1) and IL-1 receptor 2 (IL1R2) as eosinophil-specific targets to test for autoantibody responses in addition to MPO, eosinophil peroxidase (EPX), and Collagen-V identified from previous literature. Indirect ELISAs found high concentrations of serum autoantibodies to Collagen-V, MPO, and TREM1 in a higher proportion of SEA patients than healthy controls. High concentrations of serum autoantibodies to EPX were evident in serum from both healthy and SEA participants. The proportion of patients with positive autoantibody ELISAs was not increased when examining oxPTM compared to native proteins.
DISCUSSION
Although none of the target proteins studied showed high sensitivity for SEA, the high proportion of patients positive for at least one serum autoantibody shows the potential of more research on autoantibody serology to improve diagnostic testing for severe asthma.
CLINICAL TRIAL REGISTRATION
ClinicalTrials.gov, identifier, NCT04671446.
Topics: Humans; Antibodies, Antineutrophil Cytoplasmic; Triggering Receptor Expressed on Myeloid Cells-1; Churg-Strauss Syndrome; Granulomatosis with Polyangiitis; Autoantigens; Autoantibodies; Asthma; Pulmonary Eosinophilia; Immunoglobulin G
PubMed: 37334358
DOI: 10.3389/fimmu.2023.1164941 -
Translational Psychiatry Sep 2021Autoimmune processes are suspected to play a role in the pathophysiology of psychotic disorders. Better understanding of the associations between auto-immunoglobulin G...
Autoimmune processes are suspected to play a role in the pathophysiology of psychotic disorders. Better understanding of the associations between auto-immunoglobulin G (IgG) repertoires and clinical features of mental illness could yield novel models of the pathophysiology of psychosis, and markers for biological patient stratification. We undertook cross-sectional detection and quantification of auto-IgGs in peripheral blood plasma of 461 people (39% females) with established psychotic disorder diagnoses. Broad screening of 24 individuals was carried out on group level in eight clinically defined groups using planar protein microarrays containing 42,100 human antigens representing 18,914 proteins. Autoantibodies indicated by broad screening and in the previous literature were measured using a 380-plex bead-based array for autoantibody profiling of all 461 individuals. Associations between autoantibody profiles and dichotomized clinical characteristics were assessed using a stepwise selection procedure. Broad screening and follow-up targeted analyses revealed highly individual autoantibody profiles. Females, and people with family histories of obesity or of psychiatric disorders other than schizophrenia had the highest overall autoantibody counts. People who had experienced subjective thought disorder and/or were treated with clozapine (trend) had the lowest overall counts. Furthermore, six autoantibodies were associated with specific psychopathology symptoms: anti-AP3B2 (persecutory delusions), anti-TDO2 (hallucinations), anti-CRYGN (initial insomnia); anti-APMAP (poor appetite), anti-OLFM1 (above-median cognitive function), and anti-WHAMMP3 (anhedonia and dysphoria). Future studies should clarify whether there are causal biological relationships, and whether autoantibodies could be used as clinical markers to inform diagnostic patient stratification and choice of treatment.
Topics: Autoantibodies; Cross-Sectional Studies; Delusions; Female; Humans; Male; Psychotic Disorders; Schizophrenia
PubMed: 34518517
DOI: 10.1038/s41398-021-01596-0 -
Eye (London, England) Feb 2017Glaucoma, a leading cause of irreversible blindness worldwide, is often not diagnosed until many years after disease onset. Early and objective diagnostic measures are...
Glaucoma, a leading cause of irreversible blindness worldwide, is often not diagnosed until many years after disease onset. Early and objective diagnostic measures are yet missing. Besides the main risk factor, an elevated intraocular pressure (IOP), age, sex, and ethnicity are known to affect disease progression and severity. Furthermore, oxidative stress, elevated glutamate concentrations, and an autoimmune component are considered possible risk factors. We could identify several potential proteomic biomarkers in glaucoma and examine distinct changes in the glaucomatous human retina proteome. Using an experimental autoimmune glaucoma animal (EAG) model we could demonstrate an IOP-independent loss of retinal ganglion cells (RGC), which is accompanied by antibody depositions and increased levels of microglia. In a different animal model we showed that intermittent IOP elevations provoke neurodegeneration in the optic nerve and the retina and elicit changes of IgG autoantibody reactivities. The correlation between neuronal damage and changes in autoantibody reactivity suggests that autoantibody profiling could be a useful biomarker for glaucoma. In vivo studies on neuroretinal cells and porcine retinal explants demonstrated a protective effect of antibodies (eg, anti-GFAP) on RGC, which seems to be the result of reduced stress levels in the retina. We conclude that the absence of some autoantibodies in glaucoma patients reflects a loss of the protective potential of natural autoimmunity and may thus encourage neurodegenerative processes. Concluding, autoantibody profiles resemble useful biomarkers for diagnosis, progression and severity of glaucoma. Future longitudinal studies will help to improve early detection and enable better monitoring of disease progression.
Topics: Animals; Autoantibodies; Autoimmunity; Biomarkers; Disease Models, Animal; Disease Progression; Glaucoma; Humans; Immunoglobulin G; Intraocular Pressure; Microglia; Proteomics; Retina; Retinal Ganglion Cells; Swine
PubMed: 28085137
DOI: 10.1038/eye.2016.300 -
Iranian Journal of Allergy, Asthma, and... Jun 2018Neutrophils are the forerunner in innate immunity by defending the host organisms against infectious pathogens. During such process, neutrophils reach the site of... (Review)
Review
Neutrophils are the forerunner in innate immunity by defending the host organisms against infectious pathogens. During such process, neutrophils reach the site of inflammation/infection and eliminate the pathogens by phagocytosis as well as by forming the neutrophil extracellular traps (NETs). NETs trap and eradicate a number of microbes including bacteria, fungi, protozoa, viruses. NETs consist of DNA which is decorated with histones and granular proteins such as neutrophil elastase (NE), gelatinase, myeloperoxidase. NETosis (a process of NETs formation) is also involved in many inflammatory and autoimmune disorders with a major contribution to acute respiratory distress syndrome, sepsis, cystic fibrosis, periodontitis. Hyper NETosis or ineffective clearance of NETs would likely increase the risk of auto-antibody generation against NETs components and contribution in auto-inflammatory diseases. The purpose of this review is intended to highlight the molecular mechanisms of NETosis and its antimicrobial effect. Furthermore, a current status of NETosis in the pathogenesis of inflammatory and autoimmune disorders has been reviewed for better understanding.
Topics: Animals; Autoantibodies; Autoimmune Diseases; Extracellular Traps; Humans; Immunity, Innate; Infections; Inflammation; Neutrophils; Respiratory Distress Syndrome
PubMed: 29908538
DOI: No ID Found -
Frontiers in Immunology 2024Immunoglobulins are an essential part of the humoral immune response. IgG4 antibodies are the least prevalent subclass and have unique structural and functional... (Review)
Review
Immunoglobulins are an essential part of the humoral immune response. IgG4 antibodies are the least prevalent subclass and have unique structural and functional properties. In this review, we discuss IgG4 class switch and B cell production. We review the importance of IgG4 antibodies in the context of allergic responses, helminth infections and malignancy. We discuss their anti-inflammatory and tolerogenic effects in allergen-specific immunotherapy, and ability to evade the immune system in parasitic infection and tumour cells. We then focus on the role of IgG4 autoantibodies and autoantigens in IgG4-autoimmune diseases and IgG4-related disease, highlighting important parallels and differences between them. In IgG4-autoimmune diseases, pathogenesis is based on a direct role of IgG4 antibodies binding to self-antigens and disturbing homeostasis. In IgG4-related disease, where affected organs are infiltrated with IgG4-expressing plasma cells, IgG4 antibodies may also directly target a number of self-antigens or be overexpressed as an epiphenomenon of the disease. These antigen-driven processes require critical T and B cell interaction. Lastly, we explore the current gaps in our knowledge and how these may be addressed.
Topics: Humans; Immunoglobulin G4-Related Disease; Autoantigens; Autoantibodies; Immunoglobulin G; Autoimmune Diseases
PubMed: 38433835
DOI: 10.3389/fimmu.2024.1272084 -
Haematologica Jan 2021Immune thrombocytopenia is a common bleeding disease caused by autoantibody-mediated accelerated platelet clearance and impaired thrombopoiesis. Accumulating evidence...
Immune thrombocytopenia is a common bleeding disease caused by autoantibody-mediated accelerated platelet clearance and impaired thrombopoiesis. Accumulating evidence suggests that desialylation affects platelet life span in immune thrombocytopenia. Herein, we report on novel effector functions of autoantibodies from immune thrombocytopenic patients which might interfere with the clinical picture of the disease. Data from our study show that a subgroup of autoantibodies is able to induce cleave of sialic acid residues from the surface of human platelets and megakaryocytes. Moreover, autoantibody-mediated desialylation interferes with the interaction between cells and extracellular matrix proteins leading to impaired platelet adhesion and megakaryocyte differentiation. Using a combination of ex vivo model of thrombopoiesis, a humanized animal model, and a clinical cohort study, we demonstrate that cleavage of sialic acid induces significant impairment in production, survival as well as function of human platelets. These data may indicate that prevention of desialylation should be investigated in the future in clinical studies as a potential therapeutic approach to treat bleeding in immune thrombocytopenia.
Topics: Animals; Autoantibodies; Blood Platelets; Cohort Studies; Humans; Megakaryocytes; Thrombopoiesis
PubMed: 31857361
DOI: 10.3324/haematol.2019.236117 -
Pediatric Diabetes Dec 2022Limited information is available regarding youth-onset diabetes in Mali. We investigated demographic, clinical, biochemical, and genetic features in new diabetes cases...
OBJECTIVE
Limited information is available regarding youth-onset diabetes in Mali. We investigated demographic, clinical, biochemical, and genetic features in new diabetes cases in children and adolescents.
RESEARCH DESIGN AND METHODS
The study was conducted at Hôpital du Mali in Bamako. A total of 132 recently-diagnosed cases <21 years were enrolled. Demographic characteristics, clinical information, biochemical parameters (blood glucose, HbA1c, C-peptide, glutamic acid decarboxylase-65 (GAD-65) and islet antigen-2 (IA2) autoantibodies) were assessed. DNA was genotyped for HLA-DRB1 using high-resolution genotyping technology.
RESULTS
A total of 130 cases were clinically diagnosed as type 1 diabetes (T1D), one with type 2 diabetes (T2D), and one with secondary diabetes. A total of 66 (50.8%) T1D cases were males and 64 (49.2%) females, with a mean age at diagnosis of 13.8 ± 4.4 years (range 0.8-20.7 years) peak onset of 15 years. 58 (44.6%) presented in diabetic ketoacidosis; with 28 (21.5%) IA2 positive, 76 (58.5%) GAD-65 positive, and 15 (11.5%) positive for both autoantibodies. HLA was also genotyped in 195 controls without diabetes. HLA-DRB1 genotyping of controls and 98 T1D cases revealed that DRB1*03:01, DRB1*04:05, and DRB1*09:01 alleles were predisposing for T1D (odds ratios [ORs]: 2.82, 14.76, and 3.48, p-values: 9.68E-5, 2.26E-10, and 8.36E-4, respectively), while DRB1*15:03 was protective (OR = 0.27; p-value = 1.73E-3). No significant differences were observed between T1D cases with and without GAD-65 and IA2 autoantibodies. Interestingly, mean C-peptide was 3.6 ± 2.7 ng/ml (1.2 ± 0.9 nmol/L) in T1D cases at diagnosis.
CONCLUSIONS
C-peptide values were higher than expected in those diagnosed as T1D and autoantibody rates lower than in European populations. It is quite possible that some cases have an atypical form of T1D, ketosis-prone T2D, or youth-onset T2D. This study will help guide assessment and individual management of Malian diabetes cases, potentially enabling healthier outcomes.
Topics: Adolescent; Adult; Child; Child, Preschool; Female; Humans; Infant; Male; Young Adult; Autoantibodies; C-Peptide; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Genetic Predisposition to Disease; Glutamate Decarboxylase; HLA-DRB1 Chains; Mali
PubMed: 36062396
DOI: 10.1111/pedi.13411