Autoantibody Titers Research Articles

Evaluation of Biochemical Characteristics and Performance of the 3 Screen ICA ELISA Kit

We conducted a fundamental evaluation of the 3 Screen ICA ELISA kit, which can simultaneously measure three major anti-islet autoantibodies important in diagnosing and predicting type 1 diabetes, to assess its usefulness as a measuring reagent. In autoantibody-positive samples, the coefficient of variation for intra-assay variation ranged from 1.37% to 2.50%, inter-assay variation from 2.81% to 3.61%, and lot-to-lot variation from 2.01% to 8.61%, demonstrating good reproducibility. Additionally, interfering substances did not affect the autoantibody titers, and satisfying performance was observed in tests examining the sample freeze-thaw stability. Notably, even when the titer of GAD autoantibodies was below the cut-off value of the GAD autoantibody ELISA, the 3 Screen ICA signal was completely absorbed by recombinant GAD65 protein, indicating that the detection sensitivity for GAD autoantibody in the 3 Screen ICA ELISA is higher than that of the GAD autoantibody ELISA kit. Furthermore, in a study using IASP2020 samples from the Immunology and Diabetes Society, which aims to standardize anti-islet autoantibody assays, this kit achieved excellent results with a sensitivity of 96.0%, specificity of 100%, and accuracy of 98.57%. Measuring multiple anti-islet autoantibodies in combination is crucial for diagnosing and predicting type 1 diabetes. The ELISA kit used in this study is highly versatile and can be used in any measurement facility, making it extremely useful for routine testing.

Different patterns of longitudinal changes in antinuclear antibodies titers in children with systemic lupus erythematosus and Sjögren's syndrome.

to investigate the trend of autoantibody titers during a 2-year follow-up in pediatric systemic lupus erythematosus (pSLE) and pediatric Sjögren's syndrome (pSS). Autoantibodies testing was performed every 3-4 months during 2 years from disease onset in a cohort of children with pSLE and pSS. We enrolled 21 children with pSLE and 22 children with pSS. All pSLE patients at 2 years showed ANA titers significantly lower compared to disease onset. Eleven patients (73%) were still ANA positive at 2 years, while 4 (26%) became ANA negative. At diagnosis, 12 (80%) patients showed a homogeneous pattern, while 3 (20%) patients showed a speckled pattern. The latter remained ANA positive with the same pattern; only 2 patients with a homogenous pattern converted to speckled, 4 patients with a homogeneous pattern became ANA negative. ANA negative pSLE patients showed lower levels of interferon score compared to ANA positive patients. Anti-dsDNA titers declined equally in the two groups. All patients with pSS, at disease onset, were ANA and anti-Ro positive and 14 (66%) were anti-La positive. After 2 years of follow-up, 100% remained ANA positive but showed significant lower titers. During follow-up anti-Ro and anti-La titers remained stable. different patterns in changes of ANA and ENA titers in pSLE and pSS were shown. At 2 years of follow-up, all pSLE patients had a lower ANA titer and 26% became negative; however, all pSS patients remained both ANA and ENA positive. This evidence may be due to different pathogenetic pathways in SLE and pSS.

TM9SF1 expression correlates with autoimmune disease activity and regulates antibody production through mTOR-dependent autophagy

BackgroundTransmembrane 9 superfamily member 1 (TM9SF1) is involved in inflammation. Since both inflammatory and autoimmune diseases are linked to immune cells regulation, this study investigated the association between TM9SF1 expression and autoimmune disease activity. As B cell differentiation and autoantibody production exacerbate autoimmune disease, the signaling pathways involved in these processes were explored.MethodsTm9sf1−/− mouse rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) models were used to verify the relationship between gene expression and disease severity. Peripheral blood mononuclear cells (PBMCs) from 156 RA and 145 SLE patients were used to explore the relationship between TM9SF1 expression and disease activity. The effectiveness of TM9SF1 as a predictor of disease activity was assessed using multiple logistic regression and receiver operating characteristic (ROC) curves. The signaling pathways regulated by TM9SF1 in B cell maturation and antibody production were conducted by plasma cell induction experiment in vitro.ResultsThe Tm9sf1−/− RA and SLE model mice produced fewer autoantibodies and showed reduced disease severity relative to wild-type (WT) mice. TM9SF1 levels in PBMCs of patients were higher than those in healthy controls, and were reduced in patients with low disease activity relative to those with active RA and SLE. Furthermore, TM9SF1 levels were positively linked with autoantibody titers and pro-inflammatory cytokine levels in both diseases. ROC analyses indicated TM9SF1 outperformed several important clinical indicators in predicting disease activity (area under the curve (AUC) were 0.858 and 0.876 for RA and SLE, respectively). In vitro experiments demonstrated that Tm9sf1 knockout blocked differentiation of B cells into antibody-producing plasma cells by activating mTOR and inhibiting autophagy, and mTOR inhibitors such as rapamycin could reverse this effect.ConclusionsThe primary finding was the identification of the molecular mechanism underlying autophagy regulation in B cells, in which Tm9sf1 knockout was found to modulate mTOR-dependent autophagy to block B cell differentiation into antibody-secreting plasma cells. It was also found that TM9SF1 expression level in PBMCs was an accurate indicator of disease activity in patients with RA and SLE, suggesting its clinical potential for monitoring disease activity in these patients.

7923 Latent Autoimmune Diabetes of Adulthood (LADA) Complicating Common Variable Immunodeficiency (CVID)

Abstract Disclosure: L. Pathak: None. M.G. Jakoby: None. Introduction: CVID is caused by defective B-lymphocyte maturation that results in immunoglobulin deficiency. Patients with CVID are predisposed to both infections and autoimmune disorders, with approximately 20% experiencing at least one autoimmune complication. We present a patient with LADA complicating CVID. Case A 31-year-old woman was referred for newly diagnosed diabetes mellitus (DM). Medical history was notable for primary hypothyroidism and apparent chronic lymphocytic thyroiditis. A presumptive diagnosis of type 2 DM was made due to obesity, and the patient was treated with metformin. However, she could not tolerate the medication due to diarrhea. Semaglutide was substituted and tolerated without adverse effects. During the first six months of treatment with semaglutide 0.5 mg weekly, HbA1c improved from 6.4 to 5.6%. However, in the next six months, HbA1c increased to 6.6% despite full compliance with medication and stable weight. Anti-glutamic acid decarboxylase (GADA) titer was unequivocally elevated at 69.8 IU/mL (0.0-5.0), though anti-insulin and islet antigen-2 (IA-2) antibodies were undetectable. Insulin glargine was added to the patient’s diabetes regimen, and HbA1c improved to 5.5% three months later. Discussion This patient meets Immunology of Diabetes Society diagnostic criteria for LADA, namely diabetes diagnosed in adulthood (≥ 30 y), elevated diabetes-associated autoantibody titer, and insulin independence for at least six months after diagnosis. Patients with high-titer GADA tend to be younger and have more rapid and significant loss of β-cell function than patients with low GADA titers, and this patient’s rapidly waning glycemic response to semaglutide conforms with this observation. Until recently, autoimmune diabetes in the setting of CVID was thought to be an unusual complication, though the prevalence of type 1 diabetes among CVID patients in the European Society for Immunodeficiency registry is 1.6%, approximately four-fold higher than the general European population. LADA shares genetic features linked to childhood-onset type 1 DM, making it possible or evenly likely that LADA has occurred in cases of CVID, though a careful search of PubMed failed to identify reported cases. This patient illustrates the importance of considering LADA in CVID, particularly with abrupt loss of glycemic response to noninsulin therapeutic agents. Presentation: 6/1/2024

7454 Angiotensin AT1 Receptor Type 1 (AT1) Autoantibodies In Patients with Primary Aldosteronism

Abstract Disclosure: J.K. Waraich: None. G. Kline: None. M.Y. Choi: None. R.J. Sigal: None. C. Caughlin: None. S.J. Przybojewski: None. A. Leung: None. Background: Primary aldosteronism (PA) is a condition characterized by excessive aldosterone secretion, and accounts for at least 10% - 20% of all cases of hypertension. Determination of PA subtype (i.e., unilateral vs. bilateral aldosterone hypersecretion) is clinically important to inform targeted treatment. We hypothesized that pathogenesis of PA is immune-mediated and autoantibodies to angiotensin receptor type 1 (AT1) may determine PA subtype. Aims: The aim of this study was to examine whether AT1 autoantibodies predict PA subtype. Methods: We conducted a cross-sectional study of patients with PA who were referred for adrenal vein sampling (AVS) for subtyping. AT1 autoantibody titres were measured using an enzyme-linked immunosorbent assay. AT1 antibodies were defined as present when the titre was >17 U/mL, negative if <10 U/mL, and indeterminate if between 10-17 U/mL. AVS was used as a gold standard to determine lateralization and PA . The frequency of positive AT1 autoantibodies was determined according to PA subtype and clinical predictors of lateralization. Baseline patient characteristics were reported as means (and standard deviations) for normally distributed variables, and medians (and interquartile ranges) for non-normally distributed variables. Fisher’s exact test was performed for categorical variables and Kruskal-Wallis test for continuous variables. Results: 54 patients had successful cannulation of both adrenal veins (mean age, 52.7 years; 46.3% male; mean body mass index, 31.2 kg/m2). AT1 antibodies were detected in 14 (25.9%) of the patients, absent in 32 (59.3%), and indeterminate in 8 (14.8%). Among the 25 patients with unilateral PA, 8 (32.0%) had positive AT1 antibodies, 15 (60.0%) negative, and 2 (8.0%) indeterminate. Similarly, among the 29 patients with bilateral PA, 6 (20.7%) had positive AT1 antibodies, 17 (58.6%) negative, and 6 (20.7%) indeterminate. There was no significant association detected between AT1 antibody status and lateralization (p=0.39). There were no associations between AT1 autoantibody status and any of the clinical factors traditionally predictive of PA, including sex (p=0.94), older age (p=0.76), hypokalemia (p=0.91), higher estimated glomerular filtration rate (p=0.46), or magnitude of aldosterone-to-renin ratio elevation (p=0.58). There was also no association between AT1 titres and these factors. Conclusion: AT1 autoantibodies are common in patients with PA; over a quarter of patients who underwent AVS in our study. Although they were not predictive of PA subtype, these results may still suggest that PA is immune-mediated. Future studies comparing AT1 autoantibodies in PA to other controls are underway. Presentation: 6/1/2024

The role of kidney biopsy in the diagnosis of membranous nephropathy.

The discovery of the target antigen M-type phospholipase A2 receptor (PLA2R) with the possibility to detect anti-PLA2R antibodies in serum as well as the identification of several other antigens, overall accounting for almost all cases of membranous nephropathy, paved the way to a revolutionary change in the classification of membranous nephropathy. Serum anti-PLA2R autoantibody titers have been found to be highly specific diagnostic and prognostic biomarkers. Therefore, a positive test for anti-PLA2R serology in patients who present with nephrotic syndrome, normal kidney function, and no evidence of another process to account for proteinuria is believed to suffice to make a diagnosis of primary membranous nephropathy, thus removing the need for a renal biopsy. While technological advances will likely allow this proposal to prevail in the near future, the reasons why renal biopsy could still remain a critical tool for the management of membranous nephropathy in real life are discussed.

Mitochondrial Dysfunction in Systemic Lupus Erythematosus: Insights and Therapeutic Potential.

Systemic lupus erythematosus (SLE) is a complex autoimmune disorder characterized by the presence of various serum autoantibodies and multi-system effects, predominantly affecting young female patients. The pathogenesis of SLE involves a combination of genetic factors, environmental triggers, and pathogen invasions that disrupt immune cell activation, leading to the release of autoantibodies and chronic inflammation. Mitochondria, as the primary cellular powerhouses, play a crucial role in SLE development through their control of energy generation, reactive oxygen species (ROS) production, and cellular apoptotic pathways. Dysregulation of mitochondrial structure and function can contribute to the immune dysregulation, oxidative stress, and inflammation seen in SLE. Recent research has highlighted the impact of mitochondrial dysfunction on various immune cells involved in SLE pathogenesis, such as T-lymphocytes, B-lymphocytes, neutrophils, and plasmacytoid dendritic cells. Mitochondrial dysfunction in these immune cells leads to increased ROS production, disrupted mitophagy, and alterations in energy metabolism, contributing to immune dysregulation and inflammation. Moreover, genetic variations in mitochondrial DNA (mtDNA) and abnormalities in mitochondrial dynamics have been linked to the pathogenesis of SLE, exacerbating oxidative stress and immune abnormalities. Targeting mitochondrial function has emerged as a promising therapeutic approach for SLE. Drugs such as sirolimus, N-acetylcysteine, coenzyme Q10, and metformin have shown potential in restoring mitochondrial homeostasis, reducing oxidative stress, and modulating immune responses in SLE. These agents have demonstrated efficacy in preclinical models and clinical studies by improving disease activity, reducing autoantibody titers, and ameliorating organ damage in SLE patients. In conclusion, this review underscores the critical role of mitochondria in the pathogenesis of SLE and the potential of targeting mitochondrial dysfunction as a novel therapeutic strategy for improving outcomes in SLE patients. Further investigation into the mechanisms underlying mitochondrial involvement in SLE and the development of targeted mitochondrial therapies hold promise for advancing SLE treatment and enhancing patient care.

Autoantibodies to ADAMTS13 in human immunodeficiency virus-associated thrombotic thrombocytopenic purpura.

Thrombotic thrombocytopenic purpura (TTP) is a potentially fatal thrombotic microangiopathic disorder that can result from human immunodeficiency virus (HIV) infection. The pathogenesis involves a deficiency of the von Willebrand factor (vWF) cleaving protease ADAMTS13 (a disintegrin and metalloprotease with thrombospondin motifs member 13) and the presence of anti-ADAMTS13 autoantibodies. However, there is insufficient information regarding the epitope specificity and reactivity of these autoantibodies. This study aimed to perform epitope-mapping analysis to provide novel insights into the specific epitopes on ADAMTS13 domains affected by autoantibodies. The study analysed 59 frozen citrate plasma samples from HIV-associated TTP patients in South Africa, measuring ADAMTS13 activity using Technozyme® ADAMTS13 activity test, total immunoglobulin (Ig) M and IgA antibodies levels using ELISA kit and purifying IgG antibodies using NAb™ Protein G spin columns. A synthetic ADAMTS13 peptide library was used for epitope mapping. Overall, 90% of samples showed anti-ADAMTS13 IgG autoantibodies, with 64% of these antibodies being inhibitory, as revealed by mixing studies. Samples with ADAMTS13 antigen levels below 5% showed high anti-ADAMTS13 IgG autoantibody titres (≥50 IU/mL), whereas those with 5%-10% levels had low autoantibody titres (<50 IU/mL).The metalloprotease, cysteine-rich and spacer domains were 100% involved in binding anti-ADAMTS13 IgG antibodies, with 58% of samples containing antibodies binding to the C-terminal part of the ADAMTS13 disintegrin-like domain, indicating different pathogenic mechanisms. The metalloprotease, cysteine-rich and spacer domains are the primary targets for anti-ADAMTS13 IgG autoantibodies in patients with HIV-associated TTP. These findings suggest potential effects on the proteolytic activity of ADAMTS13, highlighting the complex nature of the pathogenic mechanisms involved.

Clonal landscape of autoantibody-secreting plasmablasts in COVID-19 patients.

Whereas severe COVID-19 is often associated with elevated autoantibody titers, the underlying mechanism behind their generation has remained unclear. Here we report clonal composition and diversity of autoantibodies in humoral response to SARS-CoV-2. Immunoglobulin repertoire analysis and characterization of plasmablast-derived monoclonal antibodies uncovered clonal expansion of plasmablasts producing cardiolipin (CL)-reactive autoantibodies. Half of the expanded CL-reactive clones exhibited strong binding to SARS-CoV-2 antigens. One such clone, CoV1804, was reactive to both CL and viral nucleocapsid (N), and further showed anti-nucleolar activity in human cells. Notably, antibodies sharing genetic features with CoV1804 were identified in COVID-19 patient-derived immunoglobulins, thereby constituting a novel public antibody. These public autoantibodies had numerous mutations that unambiguously enhanced anti-N reactivity, when causing fluctuations in anti-CL reactivity along with the acquisition of additional self-reactivities, such as anti-nucleolar activity, in the progeny. Thus, potentially CL-reactive precursors may have developed multiple self-reactivities through clonal selection, expansion, and somatic hypermutation driven by viral antigens. Our results revealed the nature of autoantibody production during COVID-19 and provided novel insights into the origin of virus-induced autoantibodies.

Effect of intravenous methylprednisolone on serum antibody levels in thyroid eye disease

Background/aimsWe evaluated longitudinal autoantibody changes after intravenous methylprednisolone (IVMP), compared them with those in untreated patients and identified prognostic factors for treatment response.MethodsIn this single-centre, retrospective, observational study, a total...

Absence of Pathogenic Mutations and Strong Association With HLA-DRB1*11:01 in Statin-Naïve Early-Onset Anti-HMGCR Necrotizing Myopathy.

Immune-mediated necrotizing myopathy (IMNM) caused by antibodies against 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) is an inflammatory myopathy that has been epidemiologically correlated with previous statin exposure. We characterized in detail a series of 11 young statin-naïve patients experiencing a chronic disease course mimicking a limb-girdle muscular dystrophy. With the hypothesis that HMGCR upregulation may increase immunogenicity and trigger the production of autoantibodies, our aim was to expand pathophysiologic knowledge of this distinct phenotype. Clinical and epidemiologic data, autoantibody titers, creatine kinase (CK) levels, response to treatment, muscle imaging, and muscle biopsies were assessed. HMGCR expression in patients' muscle was assessed by incubating sections of affected patients with purified anti-HMGCR+ serum. Whole-exome sequencing (WES) with a special focus on cholesterol biosynthesis-related genes and high-resolution human leukocyte antigen (HLA) typing were performed. Patients, aged 3-25 years and mostly female (90.9%), presented with subacute proximal weakness progressing over many years and high CK levels (>1,000 U/L). Diagnostic delay ranged from 3 to 27 years. WES did not reveal any pathogenic variants. HLA-DRB1*11:01 carrier frequency was 60%, a significantly higher proportion than in the control population. No upregulation or mislocalization of the enzyme in statin-exposed or statin-naïve anti-HMGCR+ patients was observed, compared with controls. WES of a cohort of patients with dystrophy-like anti-HMGCR IMNM did not reveal any common rare variants of any gene, including cholesterol biosynthesis-related genes. HLA analysis showed a strong association with HLA-DRB1*11:01, previously mostly described in statin-exposed adult patients; consequently, a common immunogenic predisposition should be suspected, irrespective of statin exposure. Moreover, we were unable to conclusively demonstrate muscle upregulation/mislocalization of HMGCR in IMNM, whether or not driven by statins.

Chronic recurrent multifocal osteomyelitis: A challenging diagnosis

Introduction. Chronic recurrent multifocal osteomyelitis (CRMO) is a pediatric autoinflammatory disorder that is characterized by multiple sterile inflammatory bone lesions with a relapsing and remitting course. CRMO belongs to the autoinflammatory family of rheumatologic disorders based on absence of significant titers of autoantibodies and autoreactive T-lymphocytes. In absence of pathognomonic clinical, radiographic or pathological features, diagnosis can be challenging. Case presentation. We report an unusual case of a 3-year-old girl presenting back pain, neurogenic bladder and syringomyelia. A tethered cord was diagnosed and treated, improving urinary function. Despite the surgical treatment, back pain was persistent. A whole body MRI showed multiple lesions compatible with chronic recurrent multifocal osteomyelitis. Conclusion. CRMO shares imaging features with other diseases. It is important for neurosurgeons and radiologists to be able to differentiate other diseases from CRMO because prognosis varies from completely benign to frankly malignant.

KIR2DL5+CD8+ T cells associate with dietary lipid intake and are active in type 1 diabetes

BackgroundRecent studies have shown that KIR+CD8+ T cells play a role in suppressing autoimmunity by eliminating pathogenic CD4+ T cells. However, their specific role in type 1 diabetes (T1D) remains unclear. MethodsIn this study, we enrolled 108 patients diagnosed with T1D and 86 healthy individuals. We conducted flow cytometric analysis to examine the various subtypes of KIR+CD8+ T cells derived from peripheral blood mononuclear cells. Additionally, CD8+ T cells were isolated from the peripheral blood of T1D patients to assess the functions of different KIR+CD8+ T cell subtypes. To investigate the influence of lipids on the characteristics and activities of these T cell subtypes, the isolated CD8+ T cells were cultured with varying concentrations of palmitic acid (PA). Furthermore, we utilized an NSG (NOD scid gamma) mouse adoptive transfer model to assess the impact of dietary lipid intake on the functionality of KIR2DL5+CD8+ T cells in vivo. ResultsWe observed variations in circulating KIR+CD8+ T cell subtypes between patients with T1D and healthy controls. Notably, we observed a significant negative correlation between the frequencies of circulating KIR+CD8+ T cells and the titers of ZnT8 autoantibodies in individuals with T1D. Among these subtypes, KIR2DL5+CD8+ T cells demonstrated a positive association with dietary fat intake, characterized by increased perforin expression and reduced PD-1 expression. Importantly, KIR2DL5+CD8+ T cells exhibited enhanced proliferative capacity compared to other KIR+CD8+ T cell subsets. Palmitic acid (PA) was found to enhance the activation of KIR2DL5+CD8+ T cells and strengthened their ability to suppress CD4+ T cell proliferation in T1D patients. Moreover, dietary lipid intake significantly enhanced the functionality of KIR2DL5+CD8+ T cells in an NSG mouse adoptive transfer model. ConclusionOur findings suggest that lipid intake enhances the functionality of human KIR2DL5+CD8+ T cells and may offer implications for immunotherapy in T1D.

Intermittent fasting attenuates cognitive dysfunction and systemic disease activity in mice with neuropsychiatric systemic lupus erythematosus

AimsCognitive dysfunction and systemic disease activity are common manifestations of neuropsychiatric systemic lupus erythematosus (NPSLE), a condition that affects a patient's health and quality of life. Clinical and preclinical studies have demonstrated that intermittent fasting (IF) improves health conditions and quality of life. Therefore, we aimed to test whether IF improves cognitive dysfunction and systemic disease activities in mice with NPSLE and to examine the underlying mechanisms. Main methodsNPSLE-prone MRL/lpr mice underwent 8 weeks of alternate-day fasting or ad libitum feeding, followed by behavioral tests to assess cognitive manifestations and biochemical tests to evaluate systemic disease activities. Key findingsIF significantly improved cognitive functionality, decreased blood-brain barrier permeability, and reduced the activation of astrocytes and microglia in the hippocampi of MRL/lpr mice. IF also improved systemic disease activities, including reduced kidney glomerular injury and interstitial inflammation, peripheral blood autoantibody titer, and splenic T lymphocyte contents. Mechanistic studies demonstrated that IF attenuates cognitive dysfunction by facilitating the microglial transition to the M2-like phenotype via the AMPK/PPARγ/NF-κB pathway. SignificanceTogether, observations from this study suggest a potential therapeutic benefit of IF in the treatment of cognitive dysfunction in patients with NPSLE.

The Pathogenic Role of Anti-Granulocyte-Macrophage Colony-Stimulating Factor Autoantibodies in the Nocardiosis with the Central Nervous System Involvement.

Anti-granulocyte-macrophage colony-stimulating factor autoantibodies (anti-GM-CSF Abs) are implicated in the pathogenesis of Cryptococcus gattii (C. gattii) infection and pulmonary alveolar proteinosis (PAP). Their presence has also been noted in nocardiosis cases, particularly those with disseminated disease. This study delineates a case series characterizing clinical features and specificity of anti-GM-CSF Abs in nocardiosis patients. In this study, eight patients were recruited to determine the presence or absence of anti-GM-CSF Abs. In addition to the detailed description of the clinical course, we thoroughly investigated the autoantibodies regarding the characteristics, isotypes, subclasses, titers, and neutralizing capacities by utilizing the plasma samples from patients. Of eight patients, five tested positive for anti-GM-CSF Abs, all with central nervous system (CNS) involvement; patients negative for these antibodies did not develop CNS nocardiosis. Distinct from previously documented cases, none of our patients with anti-GM-CSF Abs exhibited PAP symptoms. The titer and neutralizing activity of anti-GM-CSF Abs in our cohort did not significantly deviate from those found in C. gattii cryptococcosis and PAP patients. Uniquely, one individual (Patient 3) showed a minimal titer and neutralizing action of anti-GM-CSF Abs, with no relation to disease severity. Moreover, IgM autoantibodies were notably present in all CNS nocardiosis cases investigated. The presence of anti-GM-CSF Abs suggests an intrinsic immunodeficiency predisposing individuals toward CNS nocardiosis. The presence of anti-GM-CSF Abs helps to elucidate vulnerability to CNS nocardiosis, even with low titer of autoantibodies. Consequently, systematic screening for anti-GM-CSF Abs should be considered a crucial diagnostic step for nocardiosis patients.

Identification of type 1 diabetes risk phenotypes using an outcome-guided clustering analysis.

Although statistical models for predicting type 1 diabetes risk have been developed, approaches that reveal the heterogeneity of the at-risk population by identifying clinically meaningful clusters are lacking. We aimed to identify and characterise clusters of islet autoantibody-positive individuals who share similar characteristics and type 1 diabetes risk. We tested a novel outcome-guided clustering method in initially non-diabetic autoantibody-positive relatives of individuals with type 1 diabetes, using the TrialNet Pathway to Prevention study data (n=1123). The outcome of the analysis was the time to development of type 1 diabetes, and variables in the model included demographic characteristics, genetics, metabolic factors and islet autoantibodies. An independent dataset (the Diabetes Prevention Trial of Type 1 Diabetes Study) (n=706) was used for validation. The analysis revealed six clusters with varying type 1 diabetes risks, categorised into three groups based on the hierarchy of clusters. Group A comprised one cluster with high glucose levels (median for glucose mean AUC 9.48 mmol/l; IQR 9.16-10.02) and high risk (2-year diabetes-free survival probability 0.42; 95% CI 0.34, 0.51). Group B comprised one cluster with high IA-2A titres (median 287 DK units/ml; IQR 250-319) and elevated autoantibody titres (2-year diabetes-free survival probability 0.73; 95% CI 0.67, 0.80). Group C comprised four lower-risk clusters with lower autoantibody titres and glucose levels (with 2-year diabetes-free survival probability ranging from 0.84-0.99 in the four clusters). Within group C, the clusters exhibit variations in characteristics such as glucose levels, C-peptide levels and age. A decision rule for assigning individuals to clusters was developed. Use of the validation dataset confirmed that the clusters can identify individuals with similar characteristics. Demographic, metabolic, immunological and genetic markers may be used to identify clusters of distinctive characteristics and different risks of progression to type 1 diabetes among autoantibody-positive individuals with a family history of type 1 diabetes. The results also revealed the heterogeneity in the population and complex interactions between variables.

Ascorbic acid alleviates rheumatoid arthritis by inhibiting the production of autoantibodies

BackgroundAscorbic acid can regulate the function of the immune system. This study aimed to investigate the underlying mechanisms of ascorbic acid in plasma cell differentiation and rheumatoid arthritis (RA).MethodsMice were intraperitoneally injected with either ascorbic acid or an equivalent volume of phosphate-buffered saline (PBS). To elucidate the effects of ascorbic acid on arthritis, we utilized a collagen induced arthritis mouse model (CIA). To investigate the effects of ascorbic acid on antibody response, mice were immunized with (4-Hydroxy-3-nitrophenylacetyl)-Ficoll (NP-Ficoll) or (4-hydroxy-3-nitrophenyl) acetyl-keyhole limpet hemocyanin (NP-KLH) to elicit a T-cell independent (TI) or T-cell dependent (TD) antibody response. To clarify the ability of ascorbic acid on plasma cell production, we tracked the B cell differentiation fate on the NP-specific B1-8hi BCR transgenic background.ResultsAscorbic acid-injected mice demonstrated significantly delayed disease incidence and decreased disease severity compared to PBS-injected mice. Ascorbic acid can reduce the titers of autoantibodies in both arthritis and lupus mice models. Ascorbic acid can significantly reduce the number of plasma cells and the production of antigen-specific antibodies in TI and TD antibody response. In addition, ascorbic acid can disrupt the antibody affinity maturation. Through B1-8hi adoptive transfer experiments, it has been demonstrated that ascorbic acid restrains B cell differentiation into plasma cells in a cell-intrinsic manner. After in-depth exploration, we found that ascorbic acid can block the cell cycle of B cells and promote cell apoptosis. Mechanistically, ascorbic acid inhibited the production of autoreactive plasma cells by inhibiting the Stat3 signaling pathway.ConclusionOur study demonstrates that ascorbic acid has the ability to suppress the generation of autoreactive plasma cells, diminish the production of autoantibodies, and consequently delay the onset of rheumatoid arthritis.

A novel long noncoding RNA ENST00000597482 serves as a potential biomarker for disease activity and diagnosis of systemic lupus erythematosus.

Emerging evidence indicate that long noncoding RNAs (lncRNAs) may play an important role in the pathogenesis of systemic lupus erythematosus (SLE) however, the contribution of lncRNAs to SLE remains largely unclear. Our study aimed to explore the lncRNA expression profiles in peripheral blood mononuclear cells (PBMCs) from SLE patients. LncRNA sequencing was used to detect differentially expressed genes in PBMCs from 5 SLE-MIX samples and 3 healthy controls (HC)-MIX samples, and the expression of selected lncRNAs was further verified by real-time quantitative polymerase chain reaction (RT‒qPCR). The correlation of lncRNA expression with laboratory indicators as well the SLE disease activity index 2000 (SLEDAI‒2K) score from 72 SLE patients was assessed by Spearman's test. The association between lncRNA ENST00000597482 and organ involvement in SLE patients was determined by the Mann‒Whitney U test. Moreover, lymphocyte subsets in peripheral blood from SLE patients were measured by flow cytometry. In addition, the diagnostic value of lncRNAs in predicting SLE was evaluated by receiver operating characteristic (ROC) curve analysis. The lncRNA expression profiles demonstrated 218 differentially expressed lncRNAs, including 121 upregulated genes and 97 downregulated genes, in PBMCs from SLE patients compared to HCs. Among the 10 candidate genes selected, only lncRNA ENST00000597482, which was lower in SLE PBMCs than in HCs, was consistent with the sequencing results. LncRNA ENST00000597482 expression was negatively correlated with SLEDAI-2K score and the titres of ANA antibodies and anti-double-stranded DNA (anti-dsDNA) antibodies. Of note, SLE patients with lower expression of lncRNA ENST00000597482 were prone to develop organ involvement. Furthermore, lncRNA ENST00000597482 exhibited potential diagnostic value in differentiating SLE patients from HCs. LncRNA ENST00000597482 expression was lower in PBMCs from SLE patients than HCs and was negatively correlated with the SLEDAI-2K score and autoantibody titres. In addition, lncRNA ENST00000597482 could act as a novel biomarker for disease activity and diagnosis of SLE.

Mixed Autoimmune Hemolytic Anemia - A Rare Case Report

Abstract Mixed autoimmune hemolytic anemia (MAIHA) is a rare clinical condition where both warm and cold antibodies cause red cell destruction, leading to anemia. MAIHA can present as a blood group discrepancy or crossmatch incompatibility, which can be very challenging for transfusion medicine services to diagnose and issuing of best-matched blood. Therefore, a comprehensive immunohematology workup, including a monospecific direct antiglobulin test, and indirect antiglobulin test is performed to determine the thermal amplitude and titer of autoantibodies. It is important to be aware of this phenomenon because, like warm AIHA and MAIHA should be treated immediately, with steroids. We hereby report a case of a 14-year-old girl presenting with a history of generalized weakness and dizziness; preliminary investigations revealed anemia, increased reticulocyte count, and antinuclear antibodies positive. Hence, further diagnosis of MAIHA associated with systemic lupus erythematosus was made. A high-dose steroid therapy was given to the patient, and significant improvement was seen clinically.

Criteria and non-criteria antiphospholipid autoantibodies screening in patients with late pregnancy morbidity: A cross-sectional study

IntroductionAntiphospholipid syndrome (APS) is a cause of pregnancy morbidity. We aim to determine the frequency of criteria and non-criteria anti-phospholipid (aPL) autoantibodies in patients admitted for unexplained fetal death (UFD), pre-eclampsia (PE) and/or fetal growth restriction (FGR). MethodsAll consecutive patients with UFD, PE and/or FGR followed in the department of Obstetrics, Bichat Hospital, University of Paris, Paris, between January 2019 and December 2021 were screened. Patients with available serum stored from the index pregnancy were included. Patients with previously known APS or twin pregnancy were excluded. Testing for aPL autoantibodies included anti-cardiolipin (aCL), anti-β2GPI (aβ2GPI), anti-phosphatidylethanolamine (aPE), anti-phosphatidylserine/prothrombin (aPS/PT) IgG/IgM and anti-annexin V IgG. When available, placenta specimens were analyzed by a pathologist blinded to the aPL status. All clinical characteristics, pregnancy features, and comorbidities were extracted from electronic medical records. ResultsOverall 167 (32 (28.8–35.7) years) patients with UFD (n = 28; 16.8 %), PE (n = 60; 35.9 %) and/or FGR (n = 105; 62.9 %) were screened for aPL autoantibodies. Moderate titers of aPL autoantibodies were detected in 33 (n = 33/167, 19.8 %) patients. aPL autoantibodies were non-criteria aPE IgG/IgM in most cases (n = 28/33, 84.8 %). aPS/PT IgG/IgM were found in 11 (n = 11/33, 33.3 %) cases and aCL or aβ2GP1 IgG/IgM in 4 (n = 4/33, 12.1 %). Multivariable logistic regression showed that aPL autoantibodies were mostly associated with UFD (OR 4.37 [1.72–11.20], p = 0.002), PE ≤ 34th week of gestation (3.22 [0.86–11.90], p = 0.070) and chronic deciduitis (8.03 [0.89–67.2], p = 0.060) DiscussionThe frequency of aPL autoantibodies, mostly aPE, is high in patients with late pregnancy morbidity and may qualify obstetrical APS.