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Autoantibodies - Top 30 Publications

Early prediction of autoimmune (type 1) diabetes.

Underlying type 1 diabetes is a genetic aetiology dominated by the influence of specific HLA haplotypes involving primarily the class II DR-DQ region. In genetically predisposed children with the DR4-DQ8 haplotype, exogenous factors, yet to be identified, are thought to trigger an autoimmune reaction against insulin, signalled by insulin autoantibodies as the first autoantibody to appear. In children with the DR3-DQ2 haplotype, the triggering reaction is primarily against GAD signalled by GAD autoantibodies (GADA) as the first-appearing autoantibody. The incidence rate of insulin autoantibodies as the first-appearing autoantibody peaks during the first years of life and declines thereafter. The incidence rate of GADA as the first-appearing autoantibody peaks later but does not decline. The first autoantibody may variably be followed, in an apparently non-HLA-associated pathogenesis, by a second, third or fourth autoantibody. Although not all persons with a single type of autoantibody progress to diabetes, the presence of multiple autoantibodies seems invariably to be followed by loss of functional beta cell mass and eventually by dysglycaemia and symptoms. Infiltration of mononuclear cells in and around the islets appears to be a late phenomenon appearing in the multiple-autoantibody-positive with dysglycaemia. As our understanding of the aetiology and pathogenesis of type 1 diabetes advances, the improved capability for early prediction should guide new strategies for the prevention of type 1 diabetes.

A Critical Role for IL-21 Receptor Signaling in the Coxsackievirus B3-Induced Myocarditis.

To determine whether IL-21 receptor signaling plays a significant role in promoting Tfh cell-mediated cardiac injury in viral myocarditis (VMC), we compared IL-21R-deficient mice for some parameters of VMC. Balb/c and IL-21R(-/-) mice were infected with CVB3. Frequencies of splenic Tfh cells were determined by flow cytometric analysis, and productions of anti-adenine nucleotide translocator (ANT) autoantibodies were detected by enzyme-linked immunosorbent assay. To determine the effects of IL-21R signal on the proliferation of B cells, lymphocytes from spleens of the IL-21R(-/-) and Balb/c mice infected by CVB3 were tagged with carboxyfluorescein succinimidyl ester (CFSE) and then were stimulated with lipopolysaccharides plus IL-21 or anti-IL-21 neutralizing antibody for 3 days. The proliferation of B cells was analyzed by flow cytometry. Anti-ANT antibodies in the supernatants were detected by ELISA. Results showed that IL-21R(-/-) mice developed significantly less inflammation of the myocardium than Balb/c mice. Numbers of the Tfh cells and levels of anti-ANT antibody were decreased in IL-21R(-/-) mice, indicating IL-21 signaling plays a role on the Tfh cell response. The percentage of CD19(+)CFSE(+) B cells decreased in IL-21R(-/-) mice compared to VMC mice. And anti-ANT antibodies were detected at lower levels in cultured supernatant from IL-21R(-/-) mice than in those from VMC mice. These data suggest that IL-21R signal may contribute to anti-ANT antibody production and expansion of B cells in VMC mice.

Antibodies against linear epitopes on Goodpasture autoantigen in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis.

In a substantial number of patients with crescentic glomerulonephritis, both anti-glomerular basement membrane (GBM) antibodies and anti-neutrophil cytoplasmic antibodies (ANCA) are detected simultaneously. ANCA is presumed to be the initial event but the mechanism is unknown. In the present study, we investigated the antibodies against linear epitopes on Goodpasture autoantigen in sera from patients with ANCA-associated vasculitis, aiming to reveal the mechanisms of the coexistence of the two kinds of autoantibodies. Thirty-one patients with ANCA-associated vasculitis were enrolled in this study. Twenty-four overlapping linear peptides were synthesized across the whole sequence of Goodpasture autoantigen. Serum antibodies against linear peptides were detected by ELISA and their associations with clinical features were further analyzed. Twenty-five out of the thirty-one (80.6%) sera from patients with ANCA-associated vasculitis possessed antibodies against linear peptides on Goodpasture autoantigen. These antibodies could be detected in 50% of patients with normal renal function (Scr ≤ 133 μmol/L), 70% of patients with moderate renal dysfunction (133 μmol/L < Scr ≤ 600 μmol/L), and 94% of patients with renal failure (Scr > 600 μmol/L) (P = 0.032). The highest recognition frequencies were found for peptides P4 (51.6%), P14 (54.8%), and P24 (54.8%), which contained the sequences that constitute the conformational epitopes of EA (P4) and EB (P14) recognized by anti-GBM antibodies. The level of anti-P4 antibodies was positively correlated with the percentage of crescents in glomeruli (r = 0.764, P = 0.027). Patients with anti-P24 antibodies had a significantly higher prevalence of renal dysfunction on diagnosis (88.2 vs. 42.9%, P = 0.018). Antibodies against linear epitopes on Goodpasture autoantigen could be detected in sera of patients with ANCA-associated vasculitis, which might mediate the production of antibodies towards the conformational epitopes on Goodpasture autoantigen, namely, the anti-GBM antibodies.

Diagnostic and treatment guidelines for thrombotic thrombocytopenic purpura (TTP) 2017 in Japan.

Thrombotic thrombocytopenic purpura (TTP) can rapidly progress into a life-threatening condition, thus the importance of appropriate diagnosis and treatment cannot be overstated. Until recently, TTP has mainly been diagnosed by clinical findings such as thrombocytopenia and non-immune hemolytic anemia. In addition to these clinical findings, however, reduced activity of a disintegrin-like and metalloprotease with thrombospondin type 1 motif 13 (ADAMTS13) below 10% has been accepted internationally as a diagnostic criterion for TTP. In the present guidelines, we have taken all of these criteria into consideration. TTP is classified as acquired if the patient is positive for anti-ADAMTS13 autoantibodies, and as congenital if ADAMTS13 gene abnormalities are detected. Fresh-frozen plasma (FFP) transfusion is performed in patients with congenital TTP to supplement ADAMTS13. Plasma exchange therapy using FFP is conducted in patients with acquired TTP to supplement ADAMTS13 and remove anti-ADAMTS13 autoantibodies. To suppress autoantibody production, corticosteroid therapy may be administered in conjunction with plasma exchange. Recent reports show that the monoclonal anti-CD-20 antibody rituximab is effective in patients with refractory or relapsed TTP.

Microglial and Neuronal TDP-43 Pathology in Anti-IgLON5-Related Tauopathy.

A novel neuronal tauopathy, mainly confined to hypothalamus and brainstem tegmentum, has recently been reported in patients with autoantibodies to the neuronal cell-adhesion molecule IgLON5. We describe a patient with anti-IgLON5 syndrome, who presented with dysautonomia and sleep disorder, followed by subacute dementia. Postmortem brain examination disclosed neuronal tau pathology prevailing in the hippocampus, amygdala, and locus coeruleus, in addition to microglial/neuronal TDP-43 pathology, with overexpression of aberrantly phosphorylated forms and neurotoxic truncated fragments, in basal ganglia, nucleus basalis, thalamus, and midbrain. These findings suggest that neurodegeneration in anti-IgLON5 syndrome might also occur via a microglia-triggered non-cell autonomous pathway.

Comparison of enzyme-linked immunosorbent assay and rapid chemiluminescent analyser in the detection of myeloperoxidase and proteinase 3 autoantibodies.

Antibodies to myeloperoxidase (MPO) and proteinase 3 (PR3) are vital in the diagnosis and management of ANCA-associated vasculitis. A chemiluminescent immunoassay (CLIA; Quanta Flash) provides MPO and PR3 antibody results in 30 minutes, which is much faster than enzyme-linked immunosorbent assay (ELISA). We compared the performance of ELISA (Orgentec) and CLIA (Quanta Flash) for MPO and PR3 antibody quantitation on 303 samples, comprising 196 consecutive samples received in a single diagnostic laboratory over a 3 month period, and 107 samples collected from 42 known vasculitis patients over a 40 month period. We observed a correlation between both methods using spearman correlation coefficients (MPO, rs = 0.63, p < 0.01; PR3, rs = 0.69, p < 0.01). There was agreement between both methods in determining a positive or negative result. In the vasculitis cohort, CLIA performed well at clinically important stages of disease; diagnosis (eight samples all positive by both assays) and disease relapse (correlation for both MPO and PR3 antibody quantitation rs = 0.84, p = 0.03 and rs = 0.78, p < 0.01, respectively). Three samples were discordant at clinical relapse, testing positive by CLIA, including one high positive associated with relapse requiring a change in treatment. In summary, CLIA appears to be at least as accurate as ELISA for measurement of MPO and PR3 antibodies.

Autoantibodies in Melanoma-Associated Retinopathy Recognize an Epitope Conserved Between TRPM1 and TRPM3.

Melanoma-associated retinopathy (MAR) is a paraneoplastic syndrome associated with malignant melanoma and the presence of anti-retinal autoantibodies, including autoantibodies against transient receptor potential melanopsin 1 (TRPM1), a cation channel expressed by both melanocytes and retinal bipolar cells. The goal of this study was to further map the antigenic epitope.

Multiple sclerosis: Serum anti-CNS autoantibodies.

It is uncertain whether there are autoantibodies detectable by indirect immunofluorescence in the serum of patients with multiple sclerosis (MS).

Investigation of anti-neuronal antibodies in status epilepticus of unknown etiology: a prospective study.

There have been recent reports of antibody-mediated status epilepticus. The objective of our study was to investigate the prevalence of neuronal autoantibodies in patients with status epilepticus (SE) with unresolved etiology. The presence of neuronal autoantibodies was investigated prospectively in adult patients with SE who presented to our clinic between February 2012 and December 2013 with unresolved etiology. Clinical and electrophysiologic features of seropositive patients were recorded. Also, seronegative and seropositive patient groups were compared in terms of demographic and clinical features, treatment responses, and outcomes. Neuronal antibodies against N-methyl-D-aspartate receptor (NMDA-R) were positive in 2 patients, against glycine receptor (Gly-R) in 2 patients, and against gamma-aminobutyric acid-A receptor [GABA(A)R] in 1 patient, which constituted a total of 5 (22.7%) of 22 patients with SE with unidentified etiology. One of three patients with systemic tumors was positive for GABA(A)R antibody. Four patients had a short epilepsy duration, while one of the NMDA-R antibody-positive patients had chronic epilepsy and double cortex finding in MRI. There was no significant difference between seropositive and seronegative patient groups in terms of demographic and clinical features, treatment responses, and outcomes. Neuronal antibodies are found in a sizeable portion of de novo SE patients, who are potential candidates of autoimmune encephalitis. Alternatively, these antibodies may presumably also emerge in SE patients with a chronic epilepsy history as an epiphenomenon. Further research is required to make the distinction between these two different antibody formation mechanisms.

Glial fibrillary acidic protein (GFAP) is a novel biomarker for the prediction of autoimmune diabetes.

Glial fibrillary acidic protein (GFAP) is expressed in peri-islet Schwann cells as well as in glia cells and has been reported to be an autoantigen candidate for type 1 diabetes mellitus (T1DM). We confirmed that the production of the autoantibodies GFAP and glutamic acid decarboxylase 65 (GAD65) was increased and inversely correlated with the concentration of secreted C peptide in female nonobese diabetic mice (T1DM model). Importantly, the development of T1DM in female nonobese diabetic mice at 30 wk of age was predicted by the positive GFAP autoantibody titer at 17 wk. The production of GFAP and GAD65 autoantibodies was also increased in KK-A(y) mice [type 2 diabetes mellitus (T2DM) model]. In patients with diabetes mellitus, GFAP autoantibody levels were increased in patients with either T1DM or T2DM, and were significantly associated with GAD65 autoantibodies but not zinc transporter 8 autoantibodies. Furthermore, we identified a B-cell epitope of GFAP corresponding to the GFAP autoantibody in both mice and diabetic patients. Thus, these results indicate that autoantibodies against GFAP could serve as a predictive marker for the development of overt autoimmune diabetes.-Pang, Z., Kushiyama, A., Sun, J., Kikuchi, T., Yamazaki, H., Iwamoto, Y., Koriyama, H., Yoshida, S., Shimamura, M., Higuchi, M., Kawano, T., Takami, Y., Rakugi, H., Morishita, R., Nakagumi, H. Glial fibrillary acidic protein (GFAP) is a novel biomarker for the prediction of autoimmune diabetes.

Pemphigus vulgaris induced by 5-aminolaevulinic acid-based photodynamic therapy.

Pemphigus vulgaris (PV) is an autoimmune disorder resulting from the interaction between autoantibodies and desmoglein. Here, we report a case of PV developed after 5-aminolaevulinic acid-based photodynamic therapy (ALA-PDT). The harmful and deleterious effects of UV radiation on the onset, during course, and perpetuation of PV have been observed for decades. Correlation between reactive oxygen species (ROS) and PV have also been reported. Oxidative proteins, which are modified by ROS, and subsequent production of antibodies by immune system seem to be responsible for PV developed following ALA-PDT. We emphasize that ALA-PDT should be added to the list of possible factors triggering PV and this condition should be considered if blistering arises following ALA-PDT.

Association between antibodies to carbamylated proteins and subclinical atherosclerosis in rheumatoid arthritis patients.

Rheumatoid arthritis (RA) patients carry a high risk of cardiovascular morbidity and mortality. The excess of cardiovascular disease cannot be entirely explained by traditional risk factors and the immune system contributes to the development of atherosclerosis. Moreover, post-translational modifications such as citrullination and carbamylation have been linked to inflammation and atherosclerosis. Anti-carbamylated proteins antibodies (anti-CarP) are a new subset of autoantibodies identified in RA patients. This study aimed to investigate a possible association between anti-CarP and subclinical atherosclerosis in RA patients.

Hashimoto thyroiditis, anti-thyroid antibodies and systemic lupus erythematosus.

To study the prevalence of Hashimoto thyroiditis (HT), anti-thyroid autoantibodies (anti-thyroglobulin or TgAb and thyroperoxidase or TPOAb) in systemic lupus erythematosus (SLE) patients. To analyze if associated HT, TgAb and/or TPOAb influence clinical or serological profiles, disease activity and/or its cumulative damage.

Clinical heterogeneity of type 1 diabetes (T1D) found in Asia.

Diabetes mellitus among young patients in Asia is caused by a complex set of factors. Although T1D remains the most common form of diabetes in children, the recent unabated increase in obesity has resulted in the emergence of T2D as a new type of diabetes at adolescent and young adult age. In addition to the typical autoimmune type 1 diabetes (T1aD) and type 2 diabetes (T2D) patients, there is a variable incidence of cases of non-autoimmune types of T1D associated with insulin deficiency (T1bD). Additional forms have been described, including fulminant T1D (FT1D). Although the majority of diagnoses of T1D is classified as T1aD, FT1D exists as a hyper-acute subtype of T1D that affects older children, without causing autoimmunity. Being a rare etiology of diabetes, they showed a complete loss of β-cell secretory capacity without evidence of recovery, necessitating long-term treatment with insulin. In addition, latent autoimmune diabetes in adults (LADA) is a form of autoimmune-mediated diabetes, usually diagnosed during insulin-dependent stage after certain period of non-insulin requiring phase, which can be diagnosed earlier based on anti-islet autoantibody positivity. Some reports are discussing on the T1bD and others are elaborating on the presence of 'atypical T1b diabetes', such as flatbush diabetes. The prevalence of diabetes mellitus in young adults continues to rise in Asian populations as T2D increases. With improved characterization of patients with diabetes, the range of diabetic subgroups will become even more diverse in the future. Distinguishing T1D, T2D and other forms of diabetes in patients with young age is challenging in Asian populations, as the correct diagnosis is clinically important and has implications for prognosis and management. Despite etiological heterogeneity, in the usual clinical setting, early diagnosis and classification of patients with diabetes relying on clinical grounds including measuring islet autoantibodies and fasting plasma c-peptide could be a possible viable method to minimize complications.

The pathogenesis of dermatomyositis.

This review looks at the many different factors thought to play a role in idiopathic inflammatory myopathies (IIM), concentrating mainly on the dermatomyositis (DM) subtype. Subject areas addressed include looking at the different clinical features of IIM, paying particular attention to the skin manifestations. There is a discussion around investigations needed with their perceived value, followed by a description of the immunohistochemical findings of DM. This review goes on to address other attributing factors such as genetic associations with the different subtypes of IIM, and environmental factors including infections, ultraviolet radiation and vitamin D deficiency and drugs. Finally, the potential immunopathogenesis of DM is summarized, looking at T cells, B cells, autoantibodies, dendritic cells, cytokines and nonimmune-mediated endoplasmic reticulum stress.

Fatigue in patients with neuromyelitis optica spectrum disorder and its impact on quality of life.

Fatigue is a prevalent symptom and major burden in neuroimmunological diseases. In neuromyelitis optica spectrum disorder (NMOSD), a severe autoimmune central nervous system (CNS) inflammatory disease with autoantibodies reactive to aquaporin-4, there are few reports about fatigue and quality of life (QOL). We aimed to evaluate the severity of fatigue and its relationship with QOL in patients with NMOSD. We prospectively studied patients with NMOSD who were in remission and seropositive for anti-aquaporin-4 antibody, and they were divided into 2 groups based on the presence of fatigue assessed using the Functional Assessment of Chronic Illness Therapy-fatigue score. Sleep quality, depression, pain, and QOL were also evaluated. A total of 35 patients were enrolled (mean age, 46.5 ± 14.1 years; female: male = 29:6), and the median Expanded Disability Status Scale (EDSS) score was 2.0 (range, 0 to 8.0). The patients with fatigue (N = 25, 71.4%) had poorer sleep quality and more severe depression than those without fatigue (p = 0.009 and p = 0.001). Both the physical and mental QOL scores were lower in patients with fatigue than in those without fatigue (p = 0.033 and p = 0.004). Multiple linear regression analyses showed that the degree of fatigue with EDSS score and pain were independent predictors of physical aspects of QOL (B = 0.382, p = 0.001), whereas depression was the only predictor of the mental components of QOL (B = -0.845, p = <0.001). Fatigue is a common symptom and an important predictor of QOL in patients with NMOSD.

Anti-transglutaminase 6 Antibody Development in Children With Celiac Disease Correlates With Duration of Gluten Exposure.

Antibodies against transglutaminase 6 (anti-TG6) have been implicated in neurological manifestations in adult patients with genetic-gluten intolerance and it is unclear whether autoimmunity to TG6 develops following prolonged gluten exposure. We measured the anti-TG6 in children with celiac disease (CD) at the diagnosis time to establish a correlation between these autoantibodies and the duration of gluten exposure. We investigated a correlation between anti-TG6 and the presence of neurological disorders.

Antinuclear antibody testing - misunderstood or misbegotten?

Antinuclear antibodies (ANAs) are a diverse group of autoantibodies that recognize nuclear macromolecules and their complexes. ANAs represent key biomarkers in the evaluation of rheumatic diseases, most prominently systemic lupus erythematosus (SLE), and ANA testing is commonly performed in the clinical setting. In addition, ANA testing is now used to assess eligibility for participation in clinical trials of new therapeutic agents for SLE. ANAs can be assayed by various techniques, with the fluorescent ANA assay often viewed as the gold standard. Whereas a positive ANA test represents a classification criterion for SLE, up to 20-30% of the healthy population, depending on the assay used, is positive for an ANA, complicating the use of this test for diagnosis or the detection of preclinical autoimmunity. Furthermore, ANAs might be expressed in SLE less commonly than often thought. This Perspectives article discusses important questions about the use of ANA testing in both the clinical and research settings.

Successful Treatment of Transplantation-associated Atypical Hemolytic Uremic Syndrome With Eculizumab.

We herein reported a 4-month-old boy with transplantation-associated atypical hemolytic uremic syndrome (TA-aHUS) who was successfully treated with eculizumab. The patient diagnosed with type 3 of familial hemophagocytic lymphohistiocytosis underwent cord blood transplantation. After transplantation, he developed TA-aHUS, but plasma exchanges were unsuccessful. We identified deletions in CFH-related gene 1 (del-CFHR1) by the multiplex ligation-dependent probe amplification testing procedure and CFH autoantibodies. Eculizumab has been administered to the patient, with a marked improvement being achieved in thrombocytopenia. He has been well except for the persistent microhematuria for a year after transplantation. Uncontrolled complement activation might be involved in the pathophysiology of TA-aHUS.

Pathophysiology of ANCA-associated Vasculitis.

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is characterized as inflammation of small-sized to medium-sized blood vessels and encompasses several clinicopathologic entities including granulomatosis with polyangiitis, microscopic polyangiitis, eosinophilic granulomatosis with polyangiitis, and renal-limited ANCA-associated vasculitis. Over the past several decades, significant progress has been made in understanding the pathophysiology of ANCA-associated vasculitis. Although neutrophils contain a multitude of granular proteins, clinically significant autoantibodies are only recognized against myeloperoxidase and proteinase 3, both of which are present in the azurophilic granules. The propensity to develop these antibodies depends on a variety of predisposing factors such as microbial infection, genetic factors, environmental agents, and therapeutic drugs among others. These factors are usually associated with production of proinflammatory cytokines with capacity to prime the neutrophils. As a result a high proportion of neutrophils in circulation may be primed resulting in exposure of cytoplasmic proteins including myeloperoxidase and proteinase 3 on the surface of the neutrophils. Primed neutrophils are activated by interaction with ANCA in circulation. Activated neutrophils attach to and transmigrate through endothelium and accumulate within the vessel wall. These neutrophils degranulate and produce reactive oxygen radicals and ultimately die, causing tissue injury. Endothelial injury results in leakage of serum proteins and coagulation factors causing fibrinoid necrosis. B cells produce ANCAs, as well as neutrophil abnormalities and imbalances in different T-cell subtypes with excess of Th17, which perpetuate the inflammatory process.

Thyroid Autoimmunity: Role of Anti-thyroid Antibodies in Thyroid and Extra-Thyroidal Diseases.

Autoimmune diseases have a high prevalence in the population, and autoimmune thyroid disease (AITD) is one of the most common representatives. Thyroid autoantibodies are not only frequently detected in patients with AITD but also in subjects without manifest thyroid dysfunction. The high prevalence raises questions regarding a potential role in extra-thyroidal diseases. This review summarizes the etiology and mechanism of AITD and addresses prevalence of antibodies against thyroid peroxidase, thyroid-stimulating hormone receptor (TSHR), and anti-thyroglobulin and their action outside the thyroid. The main issues limiting the reliability of the conclusions drawn here include problems with different specificities and sensitivities of the antibody detection assays employed, as well as potential confounding effects of altered thyroid hormone levels, and lack of prospective studies. In addition to the well-known effects of TSHR antibodies on fibroblasts in Graves' disease (GD), studies speculate on a role of anti-thyroid antibodies in cancer. All antibodies may have a tumor-promoting role in breast cancer carcinogenesis despite anti-thyroid peroxidase antibodies having a positive prognostic effect in patients with overt disease. Cross-reactivity with lactoperoxidase leading to induction of chronic inflammation might promote breast cancer, while anti-thyroid antibodies in manifest breast cancer might be an indication for a more active immune system. A better general health condition in older women with anti-thyroid peroxidase antibodies might support this hypothesis. The different actions of the anti-thyroid antibodies correspond to differences in cellular location of the antigens, titers of the circulating antibodies, duration of antibody exposure, and immunological mechanisms in GD and Hashimoto's thyroiditis.

Geoepidemiology, clinical manifestations and outcome of primary biliary cholangitis in Greece.

Primary biliary cholangitis (PBC) is a disease with rising prevalence and considerable geographical variation. To describe the prevalence, spatial and time distribution, baseline characteristics, response to treatment, outcome and the validity of GLOBE score in a large cohort of Greek PBC patients as an independent validation of this score has not been done so far.

Independence of carbohydrate-deficient isoforms of transferrin and cyclic citrullinated peptides in rheumatoid arthritis.

The aim of this study was to assess the relationship between the two types of posttranslational modifications of proteins in RA: glycosylation on the example of carbohydrate-deficient transferrin and citrullination by means of autoantibodies to cyclic citrullinated peptides.

The immunological personality of close relatives of SLE patients.

Immunological abnormalities seen in relatives of patients with autoimmune disorders can be useful in understanding the pathogenesis of the disease since, unlike in patients, they cannot result from the disease process or drug treatment. In this article we present a brief overview of our studies of the basic immunological status of close relatives of SLE patients. We looked at blood levels of IgG, IgM and antibodies to double-stranded DNA, as well as at NK cell numbers and cytotoxic activity and the levels of NKT, B and T cells. As many as 60% of relatives showed one or more abnormalities in these assays. Most notably there were increased levels of IgG in male and female relatives and a reduction of IgM in females. IgG correlated inversely with NKT cell numbers adding strength to the concept that the presence of IgG autoantibodies in patients is due to impaired regulation by NKT cells. IgM, on the other hand, correlated inversely with NK cells which may thus have a role in bringing about the reduced IgM seen in some patients. Immunological abnormalities were found to be more often associated with parents and offspring of patients than with their siblings, pointing to the involvement of environmental or epigenetic influences in lupus pathogenesis.

Immunoglobulin M gene association with autoantibody reactivity and type 1 diabetes.

Several lines of evidence show that autoimmune responses evolving in type 1 diabetes (T1D) patients include the generation of multi-reactive autoantibody (AutoAb) repertoires, but their role in T1D pathogenesis remains elusive. We tested the hypothesis that variants at the immunoglobulin heavy chain (IGH) locus are genetic determinants of AutoAbs against pancreatic antigens and contribute to T1D susceptibility. With this aim, two independent study designs were used: a case-control study and a family-based cohort comprising a total of 240 T1D patients, 172 first-degree relatives (mother and/or father), and 130 unrelated healthy controls living in Portugal. We found that three SNPs in the IGH locus show suggestive association with T1D with the highest nominal association at rs1950942 (in the IGHM-IGHJ gene region) in both the case-control study (P = 9.35E-03) and the family-based cohort (P = 3.08E-03). These SNPs were also associated with IgG AutoAbs against pancreatic antigens and with AutoAb multi-reactivity in T1D patients. Notably, we found that the SNP with the highest association with T1D susceptibility and IgG autoantibody reactivity (rs1950942) was also associated with anti-GAD IgM reactivity in T1D patients (P = 5.98E-03) and in non-affected parents (P = 4.17E-03). This finding implies that IGH association with autoreactive IgM is detectable irrespective of disease status.These results suggest that genetic variants at the IgM gene region of the IGH locus contribute to antibody autoreactivity and are associated with T1D. We propose that the control of autoantibody generation by IGH polymorphisms is a component of the complex architecture of T1D genetic susceptibility.

Autoantibodies to Osteoprotegerin are Associated with Low Hip Bone Mineral Density and History of Fractures in Axial Spondyloarthritis: A Cross-Sectional Observational Study.

Osteoporosis is a recognised complication of axial spondyloarthritis (axSpA) and is thought to be due to functional impairment and the osteoclast-activating effects of proinflammatory cytokines. The development of autoantibodies to OPG (OPG-Ab) has been associated with severe osteoporosis and increased bone resorption in rheumatoid arthritis. In this study, we screened for the presence of OPG-Ab in axSpA and reviewed their clinical significance. We studied 134 patients, recruited from two centres in the United Kingdom. Their mean age was 47.5 years and 75% were male. Concentrations of OPG-Ab were related to bone mineral density (BMD) and fracture history using linear and logistic regression models adjusting for age, gender, disease duration and activity, body mass index and bisphosphonate use. We detected OPG-Ab in 11/134 patients (8.2%). Femoral neck and total hip BMD were significantly reduced in OPG-Ab positive patients (0.827 vs. 0.967 g/cm(2), p = 0.008 and 0.868 vs. 1.028 g/cm(2), p = 0.002, respectively). Regression analysis showed that the presence of OPG-Ab was independently associated with total hip osteopenia (ORadj 24.2; 95% CI 2.57, 228) and history of fractures (ORadj 10.5; 95% CI 2.07, 53.3). OPG-Ab concentration was associated with total hip BMD in g/cm(2) (ß = -1.15; 95% CI -0.25, -0.04). There were no associations between OPG-Ab concentration and bone turnover markers, but free sRANKL concentrations were lower in OPG-Ab-positive patients (median 0.04 vs. 0.11 pmol/L, p = 0.050). We conclude that OPG-Ab are associated with hip BMD and fractures in axSpA suggesting that they may contribute to the pathogenesis of bone loss in some patients with this condition.

Serum prolidase activity in systemic sclerosis.

Systemic sclerosis, also known as scleroderma, is a complex systemic inflammatory autoimmune disease that targets the vasculature and connective tissue-producing cells and components of the innate and adaptive immune systems. The disease is characterized by a hardening of the skin and an increased synthesis of collagen . Prolidase is a specific imidodipeptidase involved in collagen degradation. The aim of this study was to search the serum prolidase activity (SPA) in the two subtypes of systemic sclerosis: diffuse and limited cutaneous systemic sclerosis. For this purpose, 35 patients diagnosed with systemic sclerosis (24 diffuse and 11 limited) and 41 healthy control subjects were included in the study. SPA was determined using Myara's method, which is a modification of Chinard's method. SPA did not differ between the scleroderma patients and controls (p = 0.467). However, SPA was significantly lower in diffuse form than in both limited form and control subjects (p = 0.021 and p = 0.024, respectively). SPA also did not differ between the limited form and control subjects (p = 0.145). Scleroderma is characterized by excessive deposition of collagen and tissue fibrosis due to the reduced collagen degradation. SPA is reduced in scleroderma patients, especially in diffuse form. Circulating autoantibodies, oxidative stress, and decreased physical activity may contribute to this process.

Thiol/disulphide homeostasis in celiac disease.

To determine dynamic thiol/disulphide homeostasis in celiac disease and to examine the associate with celiac autoantibodies and gluten-free diet.

Myelin Oligodendrocyte Glycoprotein: Deciphering a Target in Inflammatory Demyelinating Diseases.

Myelin oligodendrocyte glycoprotein (MOG), a member of the immunoglobulin (Ig) superfamily, is a myelin protein solely expressed at the outermost surface of myelin sheaths and oligodendrocyte membranes. This makes MOG a potential target of cellular and humoral immune responses in inflammatory demyelinating diseases. Due to its late postnatal developmental expression, MOG is an important marker for oligodendrocyte maturation. Discovered about 30 years ago, it is one of the best-studied autoantigens for experimental autoimmune models for multiple sclerosis (MS). Human studies, however, have yielded controversial results on the role of MOG, especially MOG antibodies (Abs), as a biomarker in MS. But with improved detection methods using different expression systems to detect Abs in patients' samples, this is meanwhile no longer the case. Using cell-based assays with recombinant full-length, conformationally intact MOG, several recent studies have revealed that MOG Abs can be found in a subset of predominantly pediatric patients with acute disseminated encephalomyelitis (ADEM), aquaporin-4 (AQP4) seronegative neuromyelitis optica spectrum disorders (NMOSD), monophasic or recurrent isolated optic neuritis (ON), or transverse myelitis, in atypical MS and in N-methyl-d-aspartate receptor-encephalitis with overlapping demyelinating syndromes. Whereas MOG Abs are only transiently observed in monophasic diseases such as ADEM and their decline is associated with a favorable outcome, they are persistent in multiphasic ADEM, NMOSD, recurrent ON, or myelitis. Due to distinct clinical features within these diseases it is controversially disputed to classify MOG Ab-positive cases as a new disease entity. Neuropathologically, the presence of MOG Abs is characterized by MS-typical demyelination and oligodendrocyte pathology associated with Abs and complement. However, it remains unclear whether MOG Abs are a mere inflammatory bystander effect or truly pathogenetic. This article provides deeper insight into recent developments, the clinical relevance of MOG Abs and their role in the immunpathogenesis of inflammatory demyelinating disorders.

Reactivity to Novel Autoantigens in Patients with Coexisting Central Nervous System Demyelinating Disease and Autoimmune Thyroid Disease.

Several lines of evidence suggest a definite and unique link between CNS demyelinating diseases and autoimmune thyroid disease (AITD). The aim of the current study was to systematically compare the clinical and laboratory features of patients with coexistent AITD and CNS demyelinating disease with those of patients with just CNS demyelinating disease. Forty-four patients with coexisting CNS demyelinating disease and AITD were identified and their clinical and radiological features were recorded. Blood and DNA were collected and tested for HLA type and for the response of T cells and antibodies to a variety of antigens. Patients with multiple sclerosis (MS) without AITD and healthy individuals were included as controls. Patients with coexisting AITD and CNS demyelinating disease were almost exclusively female (43/44) and had prominent spinal cord involvement as the main neurological finding. The HLA molecules carried by individuals with CNS demyelinating disease and AITD differed from both other MS patients and healthy individuals. Furthermore, patients with both CNS disease and AITD showed less T cell reactivity than patients with MS alone to myelin proteolipid protein, but, compared to other groups, showed elevated levels of T cell reactivity to the calcitonin gene-related peptide, which is present in both the CNS and the thyroid, and elevated levels of T cell and antibody to the leucine-rich repeat-containing G-protein coupled receptor 4 (LGR4), a molecule that is expressed in the brainstem and spinal cord, and which is a homolog of the thyroid-stimulating hormone receptor. We suggest that reactivity of autoreactive immune cells in these patients against antigens present in both the thyroid and the spinal cord is a potential mechanism underlying the pattern of lesion development in the CNS in patients with coexisting AITD and MS and might indicate a novel mechanism of disease pathogenesis in these patients.