Autoantibody-negative Patients Research Articles

The abnormal distribution of peripheral B1 cells and transition B cells in patients with idiopathic dilated cardiomyopathy: a pilot study

BackgroundThe aberrant distribution of peripheral B cell subsets is associated with the pathogenesis of a variety of inflammatory and autoimmune diseases. However, the distribution of peripheral B cell subsets in patients with idiopathic dilated cardiomyopathy (DCM) remains to be elucidated.MethodsTwenty-seven patients with idiopathic DCM (DCM group), 18 control patients with heart failure (HF group) and 21 healthy individuals (HC group) were included in this study. Peripheral B cell subsets were analysed using multicolour flow cytometry. The plasma β1 adrenergic receptor (β1-AR) autoantibody titre was determined using ELISA. Additionally, clinical features were also collected.ResultsCompared with the HF and HC groups, the percentage of B1 cells was significantly decreased, whereas the percentage of transitional B cells (Tr) was significantly increased in the DCM group. Notably, the percentage of B1 cells was significantly lower in patients with β1-AR autoantibody-positive DCM than in β1-AR autoantibody-negative patients. The correlation analysis showed that the percentage of B1 cells was negatively correlated with N-terminal pro-brain natriuretic peptide (NT-proBNP) levels and positively correlated with the left ventricular ejection fraction in patients with DCM.ConclusionAs shown in the present study, the percentage of B1 cells in the peripheral blood of patients with idiopathic DCM is abnormally decreased, especially in β1-AR autoantibody-positive patients, while the percentage of Tr cells is significantly increased, indicating that B1 cells and Tr cells may be implicated in the pathogenesis of idiopathic DCM. The decrease in the percentage of B1 cells is directly related to the severity of DCM.

Screening for pathogenic neuronal autoantibodies in serum and CSF of patients with first-episode psychosis

Patients with autoimmune encephalitides, especially those with antibodies to the N-methyl-d-aspartate receptor (NMDAR), often present with prominent psychosis and respond well to immunotherapies. Although most patients progress to develop various neurological symptoms, it has been hypothesised that a subgroup of patients with first-episode psychosis (FEP) suffer from a forme fruste of autoimmune encephalitis. Without accurate identification, this immunotherapy-responsive subgroup may be denied disease-modifying treatments. Thirty studies addressing aspects of this hypothesis were identified in a systematic review. Amongst other shortcomings, 15/30 reported no control group and only 6/30 determined cerebrospinal fluid (CSF) autoantibodies. To ourselves address these—and other—limitations, we investigated a prospectively ascertained clinically well-characterised cohort of 71 FEP patients without traditional neurological features, and 48 healthy controls. Serum and CSF were tested for autoantibodies against seven neuronal surface autoantigens using live cell-based assays. These identified 3/71 (4%) patient sera with weak binding to either contactin-associated protein-like 2, the NMDAR or glycine receptor versus no binding from 48 control samples (p = 0.28, Fisher’s test). The three seropositive individuals showed no CSF autoantibodies and no differences from the autoantibody-negative patients in their clinical phenotypes, or across multiple parameters of peripheral and central inflammation. All individuals were negative for CSF NMDAR antibodies. In conclusion, formes frustes of autoimmune encephalitis are not prevalent among FEP patients admitted to psychiatric care. Our findings do not support screening for neuronal surface autoantibodies in unselected psychotic patients.

Association Between Neuronal Autoantibodies and Cognitive Impairment in Patients With Lung Cancer

Paraneoplastic neurological syndromes are associated with neuronal autoantibodies, and some of these autoantibodies are associated with neuropsychological symptoms. The most common underlying tumor is lung cancer. The association of neuronal autoantibodies with cognitive deficits has not been systematically investigated in patients with small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). To assess the frequency of neuronal autoantibodies in patients with lung cancer and analyze their association with cognitive function. This prospective, cross-sectional study included 167 patients with lung cancer (both SCLC and NSCLC) recruited at a single lung cancer center in Berlin, Germany, between June 2015 and April 2016. Detailed neuropsychological testing was performed in a carefully selected subgroup of 97 patients (from which patients with potential confounding factors were excluded). Investigators were blinded to patients' autoantibody status and cognitive test results. Data were analyzed from May 2016 to December 2019. Prevalence of neuronal autoantibodies and their association with cognitive impairment. The evaluation of autoantibodies as potential risk factors for cognitive impairment was performed using bayesian logistic regression models. Among 167 patients with lung cancer (median age, 66.0 years [interquartile range, 59.0-72.0 years]; 105 men [62.9%]), 127 had NSCLC, and 40 had SCLC. Brain-directed autoantibodies were detected in 61 of 167 patients (36.5%); 33 patients (19.8%) had known autoantibodies and 28 patients (16.8%) had autoantibodies against currently unknown antigens that were detected through immunohistochemical analysis. Cognitive impairment was found in 65 of 97 patients (67.0%). Among patients with SCLC, the odds of cognitive impairment for those with any autoantibodies was 11-fold higher (odds ratio [OR], 11.0; 95% credible interval [CrI], 1.2-103.6) than that of autoantibody-negative patients, and the increased odds were independent of age, sex, and neurological deficit. Among patients with NSCLC, those with immunoglobin A autoantibodies targeting the N-methyl-d-aspartate receptor had a relevantly increased odds of verbal memory deficits (OR, 182.8; 95% CrI, 3.1-10 852.4). Autoantibodies against currently unknown antigens were also associated with increased odds of cognitive impairment (OR, 2.8; 95% CrI, 0.6-12.1). In this prospective, cross-sectional study, more than one-third of patients with lung cancer had neuronal autoantibodies that were found to be associated with cognitive impairment. These autoantibodies might represent a potentially treatable mechanism of immune-mediated cognitive impairment among patients with lung cancer.

Reduced PTEN Involved in Primary Immune Thrombocytopenia Via Contributing to B Cell Hyper-Responsiveness

Background:Phosphatase and tensin homolog (PTEN) is thought to mediate B cell activation by negatively regulating the phosphoinositide 3-kinase (PI3K) signaling pathway. This pathway is important for activation, growth, and proliferation. PTEN is involved in maintaining normal B cell function. In immune thrombocytopenia (ITP), enhanced BCR signaling contributes to increased B cell activity, but the role of PTEN in human ITP has remained unclear. Both IL-21/IL-21R signaling and PI3K-PTEN molecules are involved in maintaining normal humoral immunity and deletion of autoreactive B cells. Since B cell overactivity is characteristic ofImmune thrombocytopenia(ITP) we sought to determine whether abnormalities in PTEN might contribute to increase B cell responsiveness in this disease.Methods:This study recruited 45 active CITP patients and 33 sex and age matched health volunteers as health controls(HC) Peripheral blood mononuclear cells were isolated from collected anti-coagulated blood. Flow cytometry and real time quantitative PCR were used for detecting the level of PTEN from PBMC cells of HC and CITP patients. Purified B cells from PBMC cells were incubated with human rIL-2 rIL-21r CD40L or anti-IgM alone or in combination for 72h and after that the PTEN level was detected by flow cytometry.The plasma cell generation via IL-21 induction were determined byflow cytometry.Results:The expression of PTEN was lower in B cell subpopulations of ITP patients compared with HCs, including IgD+CD38int/high immature B cells, IgD+CD38low/−naïve B cells, and IgD−CD38int/high plasma cells (P<0.001). The levels of PTEN in CD19+B cells from patients with active ITP tended to positively correlate with platelet count (r2=0.5472, P=0.0012). In patients with positive platelet-specific autoantibodies, PTEN levels were lower when compared with platelet autoantibody negative patients (717.8±93.4 vs. 990.2 ± 74.4. P=0.0287). After effective treatment, the expression of PTEN was increased (P=0.0011).The patients with active ITP had a significantly higher proportion of CD19+IgD+CD38int/hi immature B cells when compared with HCs (14.58±0.89% vs . 7.21± 0.63%,P<0.0001) . Immature B cells from patients with ITP were also found to express a greater density of the activation marker CD95(P=0.0036) and lower IL-21R expression(P=0.0030) compared with HCs. We found that IL-21, CD40L, or anti-IgM resulted in enhanced PTEN expression in normal B cells. However, neither IL-21 alone, CD40L plus anti-IgM, nor the three in combination stimulated PTEN protein upregulation in B cells isolated from patients with ITP. We found that IL-21 increased the proportion of plasma cells that were CD19+CD27+CD38hi or CD138+CD38hi in PBMCs from patients with ITP, although this did not occur in cells from HCs.Summary/Conclusions:In summary, PTEN expression is lower in the B cells of patients with ITP, especially in immature B cells. The capacity of IL-21 to induce PTEN was defective in B cells isolated from patients with ITP compared with HCs. B cells from patients with active ITP tend to differentiate into plasma cells through stimulation by IL-21 alone. Our data have established the role that B cell over-activity plays during ITP and decreased expression of PTEN may contribute to B cell hyper-responsiveness and disturbed B cell homeostasis. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Clinical findings of Talaromyces marneffei infection among patients with anti-interferon-\u03b3 immunodeficiency: a prospective cohort study

BackgroundTalaromyces marneffei (T. marneffei) infection has been associated with adult-onset immunodeficiency due to anti-IFN-γ autoantibodies. We aimed to investigate the clinical features of non-HIV-infected patients with T. marneffei infection in southern China.MethodsBetween January 2018 and September 2020, we enrolled patients with T. marneffei infection who were HIV-negative (group TM, n = 42), including anti-IFN-γ autoantibody-positive (group TMP, n = 22) and anti-IFN-γ autoantibody-negative (group TMN, n = 20) patients and healthy controls (group HC, n = 40). Anti-IFN-γ autoantibodies were detected by ELISA. Clinical characteristics and clinical laboratory parameters were recorded.ResultsCompared with anti-IFN-γ autoantibody-negative patients with T. marneffei infection, anti-IFN-γ autoantibody-positive patients did not have underlying respiratory disease; more frequently exhibited dissemination of systemic infections with severe pleural effusion; had higher WBC counts, C-reactive protein levels, erythrocyte sedimentation rates, and neutrophil and CD8+ T cell counts; had lower hemoglobin levels; and were more likely to have other intracellular pathogen infections. Most of these patients had poor outcomes despite standardized antimicrobial therapy.ConclusionT. marneffei-infected patients with higher anti-IFN-γ autoantibody titers have more severe disease and complex clinical conditions.

POS1258 MISSING THE WINDOW OF OPPORTUNITY: EARLY ARTHRITIS CLINICS IN TIMES OF COVID-19

Background:The outcomes of patients with chronic inflammatory arthritis (IA), such as rheumatoid arthritis (RA), have dramatically improved over the past 20 years. Earlier identification of IA and prompter treatment institution have been key advancements, promoted by the constitution of Early Arthritis Clinics (EAC) and the development of more sensitive classification criteria for RA. The outbreak of new COronaVIrus Disease 2019 (COVID-19) has quickly become a global health emergency and has forced a rearrangement in the management of other non-COVID-19 diseases. The impact of the lock-down of the healthcare systems on chronic inflammatory diseases such as RA is expected to be significant but is at present unknown.Objectives:To assess the effects of the lock-down imposed by the COVID-19 pandemic on the referral and clinical presentation of patients with new-onset RA.Methods:Data were retrieved from the Pavia EAC inception cohort, established in 2005 for the early identification of patients with new-onset IA. Referral criteria to the EAC include: ≥3 swollen joints (SJ) and/or &lt;3 SJ and positive squeeze test and/or &lt;3 SJ and morning stiffness &gt;30 min. Demographic and clinical characteristics of the patients are assessed at baseline and regularly over follow-up.At 31 Dec 2020, the Pavia EAC collects information on 2.508 patients. For this study, baseline characteristics of the patients referred in the semester following the COVID-19 lock-down (Jul-Dec 2020) were compared with: (i) patients referred in the semester immediately preceding the lock-down (Jul-Dec 2019); (ii) patients referred in the semester following the publication of the 2010 RA classification criteria (Jan-Jun 2011); (iii) patients referred in the semester preceding the publication of the 2010 criteria (Jul-Dec 2009).Results:In the semester following the lock-down imposed by the COVID-19 pandemic, there was a decrease in the referral of patients with new-onset suspected IA compared with previous periods (n=71 vs n=91 in the semester before the lock-down, n=96 in the first semester of 2011, n=101 in the second semester of 2009). Furthermore, fewer of the referred patients fulfilled RA criteria at presentation (36.6% vs 44.3%, 46.5% and 42.9% in the other semesters). Among patients with RA, more were autoantibody-positive (72% vs 50%, 49.1% and 52.2%). There was a trend for increased diagnostic delay in the overall cohort of RA after the COVID-19 lock-down (Figure 1A). The delay was particularly longer in autoantibody-positive patients, returning to the values seen before the introduction of the 2010 RA criteria (Figure 1B). In contrast, the few autoantibody-negative patients were referred earlier (Figure 1C). Disease activity at presentation was significantly higher in RA patients presenting after the lock-down compared with the progressive trend for reduction observed over the previous years, irrespective of the autoantibody status (Figure 1D-F). Such increase was determined by an inversion of the trend towards lower levels of objective parameters of inflammation, such as the swollen joint count (Figure 1G-I) and acute phase reactants, and a further increase in the secular trend towards worsening of patient-derived measures, such as the tender joint count and patient global assessment (Figure 1J-L).Figure 1.Effects of COVID-19 lock-down on new-onset RA at presentation.Conclusion:The COVID-19 pandemic is posing unprecedented challenges in the management of patients suffering from chronic diseases. RA has returned to be diagnosed outside the window of opportunity, with a significantly higher inflammatory burden at presentation. The many benefits of early diagnosis, which have dramatically changed the outcomes of autoantibody-positive RA, are at risk of vanishing in short times. Equally important, autoantibody-negative RA is at risk of further under-diagnosis and under-treatment.Disclosure of Interests:Bernardo D’Onofrio: None declared, Ludovico De Stefano: None declared, Bianca Lucia Palermo: None declared, Blerina Xoxi: None declared, Antonio Manzo: None declared, Carlomaurizio Montecucco Speakers bureau: BMS, Lilly, Sanofi, Pfizer, Galapagos, Roche, Novartis, Serena Bugatti Speakers bureau: BMS, Lilly, Sanofi, Pfizer, Galapagos

Effectiveness of pirfenidone in idiopathic pulmonary fibrosis according to the autoantibody status: a retrospective cohort study

BackgroundPirfenidone is an anti-fibrotic agent shown to slow the progression of idiopathic pulmonary fibrosis (IPF). However, its effectiveness in association with serological autoimmune features in IPF remains unclear.MethodsWe retrospectively reviewed the medical records of patients with IPF treated at a tertiary care hospital in South Korea. The autoantibody status was defined as positive if we detected autoantibodies meeting the serological domain criteria for interstitial pneumonia with autoimmune features or anti-neutrophil cytoplasmic antibodies.ResultsWe included 142 patients with IPF treated with pirfenidone for over six months (93 were autoantibody-positive and 49 were autoantibody-negative). The mean age was 69.5 ± 7.3 years, and 77.5% of the patients were male. The adjusted mean changes over one year were − 34.4 and − 112.2 mL (p = 0.168) in forced vital capacity (FVC), and − 0.53 and − 0.72 mL/mmHg/min (p = 0.356) in the lungs diffusion capacity for carbon monoxide (DLCO) in the autoantibody-negative and autoantibody-positive groups, respectively.ConclusionsReductions in FVC and DLCO were similar in autoantibody-positive and autoantibody-negative patients with IPF treated with pirfenidone. Pirfenidone is effective in attenuating the progression of IPF, irrespective of the autoantibody status.

Autoantibodies in severe COVID-19-related acute respiratory distress syndrome: Just innocent bystanders?

Autoantibodies in severe COVID-19-related acute respiratory distress syndrome: Just innocent bystanders?

Prognostic value of peripheral blood markers in patients with myositis-associated interstitial lung diseases

Objectives: The aim of this study was to investigate the association between survival of anti-MDA5 autoantibody-positive/negative patients with myositis-associated interstitial lung disease (MA-ILD) and neutrophil–lymphocyte ratio (NLR), platelet–lymphocyte ratio (PLR), monocyte–lymphocyte ratio (MLR), C-reactive protein–albumin ratio (CAR), and erythrocyte sedimentation rate–albumin ratio (EAR). Method: The study included 104 patients diagnosed with MA-ILD between January 2017 and February 2019 at the First Affiliated Hospital, University of Science and Technology of China. The clinical and laboratory results were compared between survivors and non-survivors in anti-MDA5 autoantibody-positive and anti-MDA5 autoantibody-negative patients. Cox proportional hazard models were used for univariable and multivariate analyses to determine survival-related factors. A logistic regression model was used to establish a joint diagnosis, and the feasibility of the combined diagnosis to evaluate the prognosis of MA-ILD was explored. Results: Among 47 anti-MDA5-positive patients with MA-ILD, EAR was an independent predictor of survival. When separated into high and low subgroups, high MLR (> 0.604) and EAR (> 1.458) were predictive of survival (p < 0.05). High MLR, high EAR, and age combined with lactate dehydrogenase were the highest (0.886) in predicting the prognosis of MA-ILD, and were higher than the area under the curve diagnosed separately. In 57 anti-MDA5-negative patients with MA-ILD, NLR and high EAR (> 0.872) were independent predictors of survival (p < 0.05). Conclusion: MLR and EAR are associated with prognosis in anti-MDA5-positive patients. NLR and EAR are associated with prognosis in anti-MDA5-negative patients. Using NLR, MLR, and EAR, inflammatory conditions of MA-ILD can be predicted and possible outcomes estimated.

Limiting factors to Boolean remission differ between autoantibody-positive and -negative patients in early rheumatoid arthritis.

Background:The patient global assessment of disease activity (PGA) is the major limiting factor to Boolean remission in patients with established rheumatoid arthritis (RA). Here, we investigated the limiting variables to disease remission in patients with early RA treated with conventional synthetic disease modifying anti-rheumatic drugs, also in relation to autoantibody status.Methods:Data were retrieved from 535 early RA patients (<12 months of symptoms) with an observation period of 6–12 months upon initiation of therapy with methotrexate aimed at the achievement of low disease activity based on the 28-joints disease activity score. Near-remission was defined as any of the four core items of Boolean remission >1 with the remaining three all ⩽1. Reasons for missing Boolean remission and predictors of near-remission subcategories were analyzed in relation to baseline disease variables.Results:After 6 and 12 months, near-remission was two-times more frequent than Boolean remission (25.6% and 26.9% at the two time-points). A 28-swollen joint count (SJC28) >1 was responsible for the majority of near-remission (56.2% and 57.6% at 6 and 12 months, respectively), and PGA > 1 accounted for approximatively 35% of the cases. Autoantibody-positivity independently predicted the risk of missing remission because of SJC28 > 1 [adjusted odds ratio (OR) 95% confidence interval (CI) 2.81 (1.59–4.9) at 6 months and 1.73 (1.01–3.01) at 12 months], whilst autoantibody-negativity was an independent predictor of PGA near-remission [adjusted OR (95% CI) 2.45 (1.25–4.80) at 6 months and 5.71 (2.47–13.2) at 12 months].Conclusion:In early RA, Boolean remission is more frequently missed because of persistent swollen joints. However, barriers to full-remission vary in relation to the autoantibody status. Autoantibody-positive patients more commonly experience residual swollen joints, whilst PGA more frequently impairs remission in autoantibody-negative patients. Efforts to target full-remission in early RA may thus require different strategies according to autoantibody profile.

Anti-MDA5 autoantibodies associated with juvenile dermatomyositis constitute a distinct phenotype in North America.

Myositis-specific autoantibodies have defined distinct phenotypes of patients with juvenile myositis (JIIM). We assessed the frequency and clinical significance of anti-melanoma differentiation-associated gene 5 (MDA5) autoantibody-associated JIIM in a North American registry. Retrospective examination of the characteristics of 35 JIIM patients with anti-MDA5 autoantibodies was performed, and differences from other myositis-specific autoantibody groups were evaluated. Anti-MDA5 autoantibodies were present in 35/453 (7.7%) of JIIM patients and associated with older age at diagnosis, and lower serum creatine kinase and aldolase levels. Patients with anti-MDA5 autoantibodies had more frequent weight loss, adenopathy, arthritis, interstitial lung disease (ILD), and less frequent falling compared with anti-transcriptional intermediary factor 1 (TIF1), anti-nuclear matrix protein 2 (NXP2)and myositis-specific autoantibody/myositis-associated autoantibody-negative patients. They had a different season of diagnosis and less frequent mechanic's hands and ILD compared with those with anti-synthetase autoantibodies. Anti-MDA5 patients received fewer medications compared with anti-TIF1, and corticosteroid treatment was shorter compared with anti-TIF1 and anti-nuclear matrix protein 2 autoantibody groups. The frequency of remission was higher in anti-MDA5 than anti-synthetase autoantibody-positive JIIM. In multivariable analyses, weight loss, arthritis and arthralgia were most strongly associated with anti-MDA5 autoantibody-positive JIIM. Anti-MDA5 JIIM is a distinct subset, with frequent arthritis, weight loss, adenopathy and less severe myositis, and is also associated with ILD. Anti-MDA5 is distinguished from anti-synthetase autoantibody-positive JIIM by less frequent ILD, lower creatine kinase levels and differing seasons of diagnosis. Anti-MDA5 has comparable outcomes, but with the ability to discontinue steroids more rapidly and less frequent flares compared with anti-TIF1 autoantibodies, and more frequent remission compared with anti-synthetase JIIM patients.

Towards stratified treatment of rheumatoid arthritis

Background: To compare the clinical efficacy of different initial treatment strategies in autoantibodynegative rheumatoid arthritis(RA) patients. Methods and findings: Data of the tREACH trial, a stratified single-blinded randomized clinical trial with a treat-to-target strategy, were used. For this analysis, we selected all autoantibodynegative RA patients, defined as fulfillment of 2010-criteria and absence of both rheumatoid factor and anti-citrullinated protein antibody, within the intermediate probability stratum. We compared the following initial treatment strategies in our autoantibody-negative RA population: 25mg methotrexate(iMTX) per week, 400mg hydroxychloroquine(iHCQ) daily or 15mg glucocorticoids(iGCs) orally in a 10-week tapering scheme without any DMARDs. Primary outcome was the proportion of patients with active disease, defined as a disease activity score(DAS)≥2.4, after 3 months of treatment. Secondary outcomes were DAS and functional ability(HAQ) over time using a linear mixed model(LMM), in which we respectively corrected for baseline DAS and HAQ. 116 patients were included and started with iMTX(n=44), iHCQ(n=35) or iGCs(n=37). After 3 months 34%, 34% and 76% of patients respectively treated with iMTX, iHCQ and iGCs had an active disease(p<.0005 for iHCQ and iMTX versus iGCs). Our corrected LMM showed no significant difference in DAS and HAQ over time between the different initial treatment strategies. Conclusions: Initial GCs without csDMARDs are also not indicated for autoantibody-negative RA patients. However, iHCQ and iMTX show similar (early) treatment responses in this subgroup of patients, which suggests that initial treatment can be stratified for autoantibody-negative and autoantibody-positive RA, but validation is needed.

Human leukocyte antigen-G upregulates immunoglobulin-like transcripts and corrects dysfunction of immune cells in immune thrombocytopenia.

Human leukocyte antigen-G (HLA-G) is a non-classical major histocompatibility complex class I antigen with potent immune-inhibitory function. HLA-G benefit patients in allotransplantation and autoimmune diseases by interacting with its receptors, immunoglobulinlike transcripts. Here we observed significantly less HLA-G in plasma from immune thrombocytopenia (ITP) patients positive for anti-platelet autoantibodies compared with autoantibodies-negative patients or healthy controls, while we found that HLA-G is positively correlated with platelet counts in both patients and healthy controls. We also found less membranebound HLA-G and immunoglobulin-like transcripts on CD4+ and CD14+ cells in patients. Recombinant HLA-G upregulated immunoglobulin-like transcript 2 expression on CD4+ and immunoglobulin-like transcript 4 on CD14+ cells. HLA-G upregulated IL-4 and IL-10, and downregulated tumor necrosis factor-a, IL-12 and IL-17 secreted by patient peripheral blood mononuclear cells, suggesting a stimulation of Th2 differentiation and downregulation of Th1 and Th17 immune response. HLA-G-modulated dendritic cells from ITP patients showed decreased expression of CD80 and CD86, and suppressed CD4+ T-cell proliferation compared to unmodulated cells. Moreover, HLA-G-modulated cells from patients induced less platelet apoptosis. HLA-G administration also significantly alleviated thrombocytopenia in a murine model of ITP. In conclusion, our data demonstrated that impaired expression of HLA-G and immunoglobulin-like transcripts is involved in the pathogenesis of ITP; recombinant HLA-G can correct this abnormality via upregulation of immunoglobulin-like transcripts, indicating that HLA-G can be a diagnostic marker and a therapeutic option for ITP.

The reliability of immunoassays to detect autoantibodies in patients with myositis is dependent on autoantibody specificity.

ObjectivesIn order to address the reliability of commercial assays to identify myositis-specific and -associated autoantibodies, we aimed to compare the results of two commercial immunoassays with the results obtained by protein immunoprecipitation.MethodsAutoantibody status was determined using radio-labelled protein immunoprecipitation for patients referred to our laboratory for myositis autoantibody characterization. For each autoantibody of interest, the sera from 25 different patients were analysed by line blot (Euroline Myositis Antigen Profile 4, EuroImmun, Lübeck, Germany) and dot blot (D-Tek BlueDiver, Diagnostic Technology, Belrose, NSW, Australia). Sera from 134 adult healthy controls were analysed.ResultsOverall commercial assays performed reasonably well, with high agreement (Cohen’s κ >0.8). Notable exceptions were the detection of rarer anti-synthetases with κ < 0.2 and detection of anti-TIF1γ, where κ was 0.70 for the line blot and 0.31 for dot blot. Further analysis suggested that the proportion of patients with anti-TIF1γ may recognize a conformational epitope, limiting the ability of blotting-based assays that utilize denatured antigen to detect this clinically important autoantibody. A false-positive result occurred in 13.7% of samples analysed by line blot and 12.1% analysed by dot blot.ConclusionThe assays analysed do not perform well for all myositis-specific and -associated autoantibodies and overall false positives are relatively common. It is crucial that clinicians are aware of the limitations of the methods used by their local laboratory. Results must be interpreted within the clinical context and immunoprecipitation should still be considered in selected cases, such as apparently autoantibody-negative patients where anti-synthetase syndrome is suspected.

Prevalence of autoantibody responses in acute coronavirus disease 2019 (COVID-19)

Immunopathology may play a significant role in the pathogenesis of Coronavirus-Induced Disease-19 (COVID-19). Immune-mediated tissue damage could result from development of rapid autoimmune responses, characterized by production of self-reactive autoantibodies. In this study, we tested specimens from acutely ill patients hospitalized with COVID-19 for autoantibodies against nuclear, vasculitis-associated, and phospholipid antigens. Detectable autoantibodies were present in 30% of the patients in our cohort, with the majority of reactive specimens demonstrating antibodies to nuclear antigens. However, antinuclear antibodies were only weakly reactive and directed to single antigens, as is often seen during acute infection. We identified strongly reactive antibodies to nuclear antigens only in patients with a prior history of autoimmune disease. In our cohort, the prevalence of antiphospholipid antibodies was low, and we did not detect any vasculitis-associated autoantibodies. We found similar levels of inflammatory markers and total immunoglobulin levels in autoantibody positive versus negative patients, but anti-SARS-CoV-2 antibody levels were increased in autoantibody positive patients. Together, our results suggest that acute COVID-19 is not associated with a high prevalence of clinically significant autoantibody responses of the type usually associated with autoimmune rheumatic disease.

Absence of Islet Autoantibodies and Modestly Raised Glucose Values at Diabetes Diagnosis Should Lead to Testing for MODY: Lessons From a 5-Year Pediatric Swedish National Cohort Study.

OBJECTIVEIdentifying maturity-onset diabetes of the young (MODY) in pediatric populations close to diabetes diagnosis is difficult. Misdiagnosis and unnecessary insulin treatment are common. We aimed to identify the discriminatory clinical features at diabetes diagnosis of patients with glucokinase (GCK), hepatocyte nuclear factor-1A (HNF1A), and HNF4A MODY in the pediatric population.RESEARCH DESIGN AND METHODSSwedish patients (n = 3,933) aged 1–18 years, diagnosed with diabetes May 2005 to December 2010, were recruited from the national consecutive prospective cohort Better Diabetes Diagnosis. Clinical data, islet autoantibodies (GAD insulinoma antigen-2, zinc transporter 8, and insulin autoantibodies), HLA type, and C-peptide were collected at diagnosis. MODY was identified by sequencing GCK, HNF1A, and HNF4A, through either routine clinical or research testing.RESULTSThe minimal prevalence of MODY was 1.2%. Discriminatory factors for MODY at diagnosis included four islet autoantibody negativity (100% vs. 11% not-known MODY; P = 2 × 10−44), HbA1c (7.0% vs. 10.7% [53 vs. 93 mmol/mol]; P = 1 × 10−20), plasma glucose (11.7 vs. 26.7 mmol/L; P = 3 × 10−19), parental diabetes (63% vs. 12%; P = 1 × 10−15), and diabetic ketoacidosis (0% vs. 15%; P = 0.001). Testing 303 autoantibody-negative patients identified 46 patients with MODY (detection rate 15%). Limiting testing to the 73 islet autoantibody-negative patients with HbA1c <7.5% (58 mmol/mol) at diagnosis identified 36 out of 46 (78%) patients with MODY (detection rate 49%). On follow-up, the 46 patients with MODY had excellent glycemic control, with an HbA1c of 6.4% (47 mmol/mol), with 42 out of 46 (91%) patients not on insulin treatment.CONCLUSIONSAt diagnosis of pediatric diabetes, absence of all islet autoantibodies and modest hyperglycemia (HbA1c <7.5% [58 mmol/mol]) should result in testing for GCK, HNF1A, and HNF4A MODY. Testing all 12% patients negative for four islet autoantibodies is an effective strategy for not missing MODY but will result in a lower detection rate. Identifying MODY results in excellent long-term glycemic control without insulin.

High Prevalence of a Monogenic Cause in Han Chinese Diagnosed With Type 1 Diabetes, Partly Driven by Nonsyndromic Recessive WFS1 Mutations.

It is estimated that ∼1% of European ancestry patients clinically diagnosed with type 1 diabetes (T1D) actually have monogenic forms of the disease. Because of the much lower incidence of true T1D in East Asians, we hypothesized that the percentage would be much higher. To test this, we sequenced the exome of 82 Chinese Han patients clinically diagnosed with T1D but negative for three autoantibodies. Analysis focused on established or proposed monogenic diabetes genes. We found credible mutations in 18 of the 82 autoantibody-negative patients (22%). All mutations had consensus pathogenicity support by five algorithms. As in Europeans, the most common gene was HNF1A (MODY3), in 6 of 18 cases. Surprisingly, almost as frequent were diallelic mutations in WFS1, known to cause Wolfram syndrome but also described in nonsyndromic cases. Fasting C-peptide varied widely and was not predictive. Given the 27.4% autoantibody negativity in Chinese and 22% mutation rate, we estimate that ∼6% of Chinese with a clinical T1D diagnosis have monogenic diabetes. Our findings support universal sequencing of autoantibody-negative cases as standard of care in East Asian patients with a clinical T1D diagnosis. Nonsyndromic diabetes with WSF1 mutations is not rare in Chinese. Its response to alternative treatments should be investigated.

Autoantibody-positivity in lean type II diabetes patients was associated with elevated Th17-like CD4+CXCR5+ T cell responses

The pathophysiology of type II diabetes (T2D) in patients with normal body-mass index (BMI) remains unclear. In this study, we investigated the circulating CD4+CXCR5+ T cells in lean T2D patients. Compared with age-, gender-, and BMI-matched healthy controls, the lean T2D patients presented similar frequency and number of CD4+CXCR5+ T cells; however, the composition of CD4+CXCR5+ T subsets was altered. The CD4+CXCR5+ T cells in lean T2D patients were enriched with a Th17-like subset, characterized by an increase in the frequency of IL-17-secreting cells, and an increase in the frequency of CCR6+ cells. Compared to CCR6− CD4+CXCR5+ T cells, CCR6+ CD4+CXCR5+ T cells secreted significantly higher IL-17. Neither the frequency of IL-17-secreting CD4+CXCR5+ T cells, nor the frequency of CCR6+ CD4+CXCR5+ T cells, was associated with the BMI of the T2D patients. Interestingly, 10 out of 30 lean T2D patients in our cohort presented islet-reactive autoantibodies. Compared to the autoantibody-negative T2D patients, the autoantibody-positive T2D patients had significantly higher levels of IL-17-secreting CD4+CXCR5+ T cells and CCR6+ CD4+CXCR5+ T cells. In addition, compared to the CCR6− CD4+CXCR5+ T cells, the CCR6+ CD4+CXCR5+ T cells were more effective at promoting Ig secretion from autologous B cells. Together, this study demonstrated that an upregulation of Th17-like CD4+CXCR5+ T cells was present in lean T2D patients and was associated with autoantibody positivity.

Clinical, radiological and laboratory comparison between autoantibody-negative and autoantibody-positive Autoimmune Encephalitis patients. (P2.2-006)

Clinical, radiological and laboratory comparison between autoantibody-negative and autoantibody-positive Autoimmune Encephalitis patients. (P2.2-006)

Absence of Islet Autoantibodies and Modestly Raised Glucose Values at Diabetes Diagnosis Are Critical Features of MODY: Lessons from a 5-Year Paediatric Swedish National Cohort Study

Background: Identifying monogenic diabetes in paediatric populations close to diabetes diagnosis is important but challenging. Misdiagnosis and unnecessary insulin treatment are common. Islet autoantibodies aid recognition of 'non Type 1' diabetes but are not universally advocated or comprehensively performed. This study aimed to identify the discriminatory clinical features at diabetes diagnosis of patients with GCK, HNF1A and HNF4A MODY in the paediatric population. Methods: Patients (n=3933) aged between 1-18 years, with a new diagnosis of diabetes were recruited between May 2005 to December 2010 from the Swedish national consecutive prospective cohort 'Better Diabetes Diagnosis'(BDD). Clinical data, acute biochemistry, islet autoantibodies against GADA, IA-2A, ZnT8A and insulin, HLA type and C-peptide were collected at diagnosis. Monogenic diabetes was identified by sequencing, either through routine clinical or research testing. Findings: At least 1·2% of paediatric diabetes patients had MODY. Negativity to all 4 islet autoantibodies was the strongest discriminatory clinical feature of MODY (100% (46/46) vs 11% (416/3887) non-MODY; p=2x10-44) with MODY confirmed in 46/303 (15%) of autoantibody negative patients tested. Individuals with MODY had lower random plasma glucose (mean 11·7 vs 26·7mmol/L, p=3x10-19), lower HbA1c (53 vs 93 mmol/mol, p=1x10-20) and absent DKA (0/26 MODY vs 545/3342, p=0·02) compared to non-MODY patients. Testing the 100 autoantibody negative patients with the predefined HbA1c <58mmol/mol at diagnosis identified 36/46 (78%) MODY patients. On follow-up 42/46 (91%) MODY patients were not on insulin with excellent glycaemic control (mean HbA1c 47mmol/mol). Interpretation: At diagnosis of paediatric diabetes absence of islet autoantibodies and modest hyperglycaemia are key clinical features of MODY allowing differentiation from Type 1 diabetes. All paediatric patients negative for 4 islet autoantibodies and HbA1c <58mmol/mol at diabetes diagnosis should be tested for GCK, HNF1A and HNF4A MODY. This will improve treatment and allow excellent long term glycaemic control without insulin. Funding Statement: The Swedish Child Diabetes Foundation, the National Institutes of Health (DK063861) and the Wellcome Trust. Declaration of Interests: The authors state: There are no conflicts of interest to declare. Ethics Approval Statement: The Regional Ethics Board at the Karolinska Institute, Stockholm, Sweden approved the BDD study (Dnrs 2004-826/1, 2006/1082-32, 2009/1684-32). The study is written in line with STROBE guidelines for cohort studies.