Demographic associations for autoantibodies in disease-free individuals of a European population

Prevalence of a large panel of systemic autoantibodies in the Bavarian adult population

Objective

Autoimmune diseases commonly feature the presence of specific humoral autoantibodies. However, the prevalence of a large panel of systemic autoantibodies has never been assessed in the general population. We, therefore, described the prevalence of about 50 humoral systemic autoantibodies in a sample of the general Bavarian adult population.

Methods

Non-fasting venous serum samples from 331 participants were analyzed for 7 autoantibody screening tests (nuclear, cytoplasmic, and mitotic ANA, ANCA, cANCA and pANCA, anti-ENA autoantibodies) and 44 different monospecific humoral non-organ specific/systemic autoantibodies using indirect immunofluorescence tests, ELISAs, and line blots. In order to assess associations between sex, age, BMI, education level, smoking status and the presence of systemic autoantibodies, logistic regression analyses were conducted.

Results

At least one screening test was positive in 29.9% of the participants, and 42.3% of the participants were seropositive for at least one monospecific autoantibody. The most frequently found monospecific autoantibodies were rheumatoid factor (35.6%), ß2-glycoprotein 1 IgM (4.8%), and cardiolipin IgG (1.8%). Only few associations between sex, age, BMI, education, smoking status and autoantibody frequencies were observed.

Conclusion

Systemic autoantibodies are common in the general Bavarian population, and largely independent of sex, age, BMI, education, or smoking status. The study results may give orientation to clinicians about the occurrence of autoantibodies in the population, not (yet) associated with clinical symptoms.

Endocrinological Involvement in Children and Adolescents Affected by COVID-19: A Narrative Review

Since the advent of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, an increased incidence of several endocrinological anomalies in acute-phase and/or long-term complications has been described. The aim of this review is to provide a broad overview of the available literature regarding changes in the worldwide epidemiology of endocrinological involvement in children since December 2019 and to report the evidence supporting its association with coronavirus disease 2019 (COVID-19). Although little is known regarding the involvement of endocrine organs during COVID-19 in children, the current evidence in adults and epidemiological studies on the pediatric population suggest the presence of a causal association between the virus and endocrinopathies. Untreated transient thyroid dysfunction, sick euthyroid syndrome, nonthyroidal illness syndrome, and hypothalamic-pituitary-adrenal (HPA) axis and central precocious puberty have been observed in children in acute infection and/or during multisystem inflammatory syndrome development. Furthermore, a higher frequency of ketoacidosis at onset in children with a new diagnosis of type 1 diabetes is reported in the literature. Although the direct association between COVID-19 and endocrinological involvement has not been confirmed yet, data on the development of different endocrinopathies in children, both during acute infection and as a result of its long-term complications, have been reported. This information is of primary importance to guide the management of patients with previous or current COVID-19.

Clinical and prognostic associations of autoantibodies recognizing adrenergic/muscarinic receptors in patients with heart failure

AIMS

The importance of autoantibodies (AABs) against adrenergic/muscarinic receptors in heart failure (HF) is not well-understood. We investigated the prevalence and clinical/prognostic associations of four AABs recognizing the M2-muscarinic receptor or the β1-, β2-, or β3-adrenergic receptor in a large and well-characterized cohort of patients with HF.

METHODS AND RESULTS

Serum samples from 2256 patients with HF from the BIOSTAT-CHF cohort and 299 healthy controls were analysed using newly established chemiluminescence immunoassays. The primary outcome was a composite of all-cause mortality and HF rehospitalization at 2-year follow-up, and each outcome was also separately investigated. Collectively, 382 (16.9%) patients and 37 (12.4%) controls were seropositive for ≥1 AAB (P = 0.045). Seropositivity occurred more frequently only for anti-M2 AABs (P = 0.025). Amongst patients with HF, seropositivity was associated with the presence of comorbidities (renal disease, chronic obstructive pulmonary disease, stroke, and atrial fibrillation) and with medication use. Only anti-β1 AAB seropositivity was associated with the primary outcome [hazard ratio (95% confidence interval): 1.37 (1.04-1.81), P = 0.024] and HF rehospitalization [1.57 (1.13-2.19), P = 0.010] in univariable analyses but remained associated only with HF rehospitalization after multivariable adjustment for the BIOSTAT-CHF risk model [1.47 (1.05-2.07), P = 0.030]. Principal component analyses showed considerable overlap in B-lymphocyte activity between seropositive and seronegative patients, based on 31 circulating biomarkers related to B-lymphocyte function.

CONCLUSIONS

AAB seropositivity was not strongly associated with adverse outcomes in HF and was mostly related to the presence of comorbidities and medication use. Only anti-β1 AABs were independently associated with HF rehospitalization. The exact clinical value of AABs remains to be elucidated.

Serological intermolecular epitope spreading in a patient with primary Sjögren's syndrome

Sjögren's syndrome (SS) is one of the prototypic systemic autoimmune diseases characterised by autoreactive T and B cells, sicca symptoms and various extraglandular manifestations. SS is characterised by autoantibodies (anti-Ro52/tripartite motif containing-21 [TRIM21], anti-Ro60 and anti-La) that are important diagnostic biomarkers. Patients have typically stable serostatus; that is, patients who are positive for one or more of these autoantibodies tend to remain thus and vice versa. We describe a rare instance where a woman in her 50s was diagnosed with primary SS and developed new autoantibodies subsequently through serological epitope spreading. She demonstrated primarily glandular features only and clinical stability despite serological evolution. In this case report, we discuss the significance of this molecular feature and the clinical implications for our understanding of autoimmunity.

Chronic spontaneous urticaria: Focus on pathophysiology to unlock treatment advances

Chronic spontaneous urticaria (CSU) is a debilitating skin disease characterized by intensely itchy wheals, angioedema, or both. Symptoms recur spontaneously, on a near-daily basis, over >6 weeks; many patients experience flare-ups over several years and, consequently, reduced quality of life. Differences between the inflammatory profiles of the skin of CSU patients (wheals and nonlesional sites) and healthy controls indicate that key drivers such as mast cells, eosinophils, and basophils interact, release vasoactive mediators, and prime the skin, leaving patients predisposed to symptoms. Many cytokines and chemokines involved in these inflammatory networks and their corresponding intracellular signaling cascades have been identified. These insights informed the development of therapies such as omalizumab, dupilumab, and Bruton's tyrosine kinase (BTK) inhibitors, marking a renewed focus on pathogenesis in CSU clinical research. Despite progress, current therapies provide symptomatic control but do not appear to redress the inflammatory balance in the skin permanently. A deeper understanding of CSU pathogenesis will permit a more targeted approach to developing novel treatments with curative intent. Here, we review what is known about the pathogenesis of CSU and consider how this can be used to identify rational targets to improve patient care further.

Pediatric reference interval verification for 17 specialized immunoassays and cancer markers on the Abbott Alinity i system in the CALIPER cohort of healthy children and adolescents

OBJECTIVES

Clinical laboratory investigation of autoimmune, metabolic, and oncologic disorders in children and adolescents relies on appropriateness of reference intervals (RIs). The Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) previously established comprehensive pediatric RIs for specialized immunoassays on the Abbott ARCHITECT system. Herein, we aim to verify performance on new Alinity i assays by evaluating sera collected from healthy children as per Clinical and Laboratory Standards Institute (CLSI) EP-28A3C guidelines.

METHODS

Precision, linearity, and method comparison experiments were completed for 17 specialized Alinity immunoassays, including cancer antigens, autoimmune peptides, and hormones. Sera collected from healthy children and adolescents (birth-18 years, n=100) were evaluated. CLSI-based verification was completed using previously established CALIPER RIs for ARCHITECT assays as the reference.

RESULTS

Of 17 specialized immunoassays assays, only anti-cyclic citrullinated peptides (anti-CCP) did not meet acceptable verification criterion (i.e., ≥90% of results within ARCHITECT reference CI). Anti-thyroglobulin, anti-thyroid peroxidase, and carcinoembryonic antigen did not require age-specific consideration beyond one year of age, with 63, 91, and 80% of samples equalling the limit of detection, respectively. Estimates were separated by sex for relevant assays (e.g., sex hormone binding globulin, total and free prostate specific antigen).

CONCLUSIONS

Findings support transferability of pediatric RIs on ARCHITECT system to the Alinity system for 16 specialized immunoassays in the CALIPER cohort and will be a useful resource for pediatric clinical laboratories using Alinity assays. Further work is needed to establish evidence-based interpretative recommendations for anti-CCP and continue to evaluate pediatric RI acceptability for newly available assay technologies.

TLR7 and IgM: Dangerous Partners in Autoimmunity

The B cell antigen receptor (BCR)-repertoire is capable of recognizing a nearly unlimited number of antigens. Inevitably, the random nature of antibody gene segment rearrangement, needed in order to provide mature B cells, will generate autoreactive specificities. Once tolerance mechanisms fail to block the activation and differentiation of autoreactive B cells, harmful autoantibodies may get secreted establishing autoimmune diseases. Besides the hallmark of autoimmunity, namely IgG autoantibodies, IgM autoantibodies are also found in many autoimmune diseases. In addition to pathogenic functions of secreted IgM the IgM-BCR expressing B cell might be the initial check-point where, in conjunction with innate receptor signals, B cell mediated autoimmunity starts it fateful course. Recently, pentameric IgM autoantibodies have been shown to contribute significantly to the pathogenesis of various autoimmune diseases, such as rheumatoid arthritis (RA), autoimmune hemolytic anemia (AIHA), pemphigus or autoimmune neuropathy. Further, recent studies suggest differences in the recognition of autoantigen by IgG and IgM autoantibodies, or propose a central role of anti-ACE2-IgM autoantibodies in severe COVID-19. However, exact mechanisms still remain to be uncovered in detail. This article focuses on summarizing recent findings regarding the importance of autoreactive IgM in establishing autoimmune diseases.

Are Thyroid Functions Affected in Multisystem Inflammatory Syndrome in Children?

OBJECTIVE

Multisystem inflammatory syndrome in children (MIS-C), associated with Coronavirus disease-2019, is defined as the presence of documented fever, inflammation, and at least two signs of multisystem involvement and lack of an alternative microbial diagnosis in children who have recent or current Severe acute respiratory syndrome-Coronavirus-2 infection or exposure. In this study, we evaluated thyroid function tests in pediatric cases with MIS-C in order to understand how the hypothalamus-pituitary-thyroid axis was affected and to examine the relationship between disease severity and thyroid function.

METHODS

This case-control study was conducted between January 2021 and September 2021. The patient group consisted of 36 MIS-C cases, the control group included 72 healthy children. Demographic features, clinical findings, inflammatory markers, thyroid function tests, and thyroid antibody levels in cases of MIS-C were recorded. Thyroid function tests were recorded in the healthy control group.

RESULTS

When MIS-C and healthy control groups were compared, free triiodothyronine (fT3) level was lower in MIS-C cases, while free thyroxine (fT4) level was found to be lower in the healthy group (p<0.001, p=0.001, respectively). Although the fT4 level was significantly lower in controls, no significant difference was found compared with the age-appropriate reference intervals (p=0.318). When MIS-C cases were stratified by intensive care requirement, fT3 levels were also lower in those admitted to intensive care and also in those who received steroid treatment (p=0.043, p<0.001, respectively).

CONCLUSION

Since the endocrine system critically coordinates and regulates important metabolic and biochemical pathways, investigation of endocrine function in MIS-C may be beneficial. These results show an association between low fT3 levels and both diagnosis of MIS-C and requirement for intensive care. Further studies are needed to predict the prognosis and develop a long-term follow-up management plan.

Detection of serum IgG autoantibodies to FcεRIα by ELISA in patients with chronic spontaneous urticaria

Background

Mast cells are a key effector cell in the pathogenesis of chronic spontaneous urticaria (CSU) and activated by circulating FcεRI-specific IgG as well as IgE. This study evaluated the prevalence of circulating autoantibodies to FcεRIα in the sera of CSU patients.

Methods

Eighty-eight patients with CSU and 76 healthy controls (HCs) were enrolled. To detect circulating autoantibodies (IgG/IgA/IgM) to FcεRIα, ELISA was done using YH35324 (as a solid phase antigen), and its binding specificity was confirmed by the ELISA inhibition test. The antibody levels were presented by the ratio of YH35324-preincubated to mock-preincubated absorbance values. Clinical and autoimmune parameters, including atopy, urticaria activity score (UAS), serum total/free IgE levels, serum antinuclear antibody (ANA) and autologous serum skin test (ASST) results, were assessed. The autoimmune group was defined if CSU patients had positive results to ASST and/or ANA.

Results

The ratio of serum IgG to FcεRIα was significantly lower in CSU patients than in HCs (P<0.05), while no differences were noted in serum levels of IgG to recombinant FcεRIα or IgA/IgM autoantibodies. The autoimmune CSU group had significantly lower ratios of IgG/IgA (not IgM) autoantibodies to FcεRIα than the nonautoimmune CSU group (P<0.05 for each). No significant associations were found between sex, age, atopy, urticaria duration, UAS, or serum total/free IgE levels according to the presence of IgG/IgA/IgM antibodies.

Conclusions

This study confirmed the presence of IgG to FcεRIα in the sera of CSU patients, especially those with the autoimmune phenotype.

Adaptive tolerance: Protection through self-recognition

The random nature of immunoglobulin gene segment rearrangement inevitably leads to the generation of self-reactive B cells. Avoidance of destructive autoimmune reactions is necessary in order to maintain physiological homeostasis. However, current central and peripheral tolerance concepts fail to explain the massive number of autoantibody-borne autoimmune diseases. Moreover, recent studies have shown that in physiological mouse models autoreactive B cells were neither clonally deleted nor kept in an anergic state, but were instead able to mount autoantibody responses. We propose that activation of autoreactive B cells is induced by polyvalent autoantigen complexes that can occur under physiological conditions. Repeated encounter of autoantigen complexes leads to the production of affinity-matured autoreactive IgM that protects its respective self-targets from degradation. We refer to this novel mechanism as adaptive tolerance. This article discusses the discovery of adaptive tolerance and the unexpected role of high affinity IgM autoantibodies.

A mouse monoclonal antibody against influenza C virus attenuates acetaminophen-induced liver injury in mice

Molecular mimicry is one of the main processes for producing autoantibodies during infections. Although some autoantibodies are associated with autoimmune diseases, the functions of many autoantibodies remain unknown. Previously, we reported that S16, a mouse (BALB/c) monoclonal antibody against the hemagglutinin-esterase fusion glycoprotein of influenza C virus, recognizes host proteins in some species of animals, but we could not succeed in identifying the proteins. In the present study, we found that S16 cross-reacted with acetyl-CoA acyltransferase 2 (ACAA2), which is expressed in the livers of BALB/c mice. ACAA2 was released into the serum after acetaminophen (APAP) administration, and its serum level correlated with serum alanine aminotransferase (ALT) activity. Furthermore, we observed that S16 injected into mice with APAP-induced hepatic injury prompted the formation of an immune complex between S16 and ACAA2 in the serum. The levels of serum ALT (p < 0.01) and necrotic areas in the liver (p < 0.01) were reduced in the S16-injected mice. These results suggest that S16 may have a mitigation function in response to APAP-induced hepatotoxicity. This study shows the therapeutic function of an autoantibody and suggests that an antibody against extracellular ACAA2 might be a candidate for treating APAP-induced hepatic injury.

Latent Autoimmune Diabetes of Adults (LADA) Is Likely to Represent a Mixed Population of Autoimmune (Type 1) and Nonautoimmune (Type 2) Diabetes

Latent autoimmune diabetes of adults (LADA) is typically defined as a new diabetes diagnosis after 35 years of age, presenting with clinical features of type 2 diabetes, in whom a type 1 diabetes-associated islet autoantibody is detected. Identifying autoimmune diabetes is important since the prognosis and optimal therapy differ. However, the existing LADA definition identifies a group with clinical and genetic features intermediate between typical type 1 and type 2 diabetes. It is unclear whether this is due to 1) true autoimmune diabetes with a milder phenotype at older onset ages that initially appears similar to type 2 diabetes but later requires insulin, 2) a disease syndrome where the pathophysiologies of type 1 and type 2 diabetes are both present in each patient, or 3) a heterogeneous group resulting from difficulties in classification. Herein, we suggest that difficulties in classification are a major component resulting from defining LADA using a diagnostic test-islet autoantibody measurement-with imperfect specificity applied in low-prevalence populations. This yields a heterogeneous group of true positives (autoimmune type 1 diabetes) and false positives (nonautoimmune type 2 diabetes). For clinicians, this means that islet autoantibody testing should not be undertaken in patients who do not have clinical features suggestive of autoimmune diabetes: in an adult without clinical features of type 1 diabetes, it is likely that a single positive antibody will represent a false-positive result. This is in contrast to patients with features suggestive of type 1 diabetes, where false-positive results will be rare. For researchers, this means that current definitions of LADA are not appropriate for the study of autoimmune diabetes in later life. Approaches that increase test specificity, or prior likelihood of autoimmune diabetes, are needed to avoid inclusion of participants who have nonautoimmune (type 2) diabetes. Improved classification will allow improved assignment of prognosis and therapy as well as an improved cohort in which to analyze and better understand the detailed pathophysiological components acting at onset and during disease progression in late-onset autoimmune diabetes.

The Association of Thyroid Hormone Changes with Inflammatory Status and Prognosis in COVID-19

BACKGROUND

COVID-19 infection may have multiorgan effects in addition to effects on the lungs and immune system. Recently, studies have found thyroid function abnormalities in COVID-19 cases which were interpreted as euthyroid sick syndrome (ESS) or destructive thyroiditis. Therefore, in this study, we aimed to evaluate the thyroid function status and thyroid autoimmunity in COVID-19 patients. Material and Method. 205 patients were included. The medical history and laboratory parameters at admission were collected from medical records. Serum thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), thyroid peroxidase antibody, and thyroglobulin antibody were measured, and patients were classified according to thyroid function status.

RESULTS

34.1% of the patients were euthyroid. Length of hospitalization (p < 0.001), rate of oxygen demand (p < 0.001), and intensive care unit (ICU) admission (p=0.022) were lower, and none of the euthyroid patients died. 108 (52.6%) patients were classified to have ESS, 57 were classified as mild, and 51 were moderate. The inflammatory parameters were higher in patients with moderate ESS. In cluster analysis, a high-risk group with a lower median FT3 value (median = 2.34 ng/L; IQR = 0.86), a higher median FT4 value (median = 1.04 ng/dL; IQR = 0.33), and a lower median TSH value (median = 0.62 mIU/L; IQR = 0.59) included 8 of 9 died patients and 25 of the 31 patients that were admitted to ICU. Discussion. Length of hospitalization, oxygen demand, ICU admission, and mortality were lower in euthyroid patients. Moreover, none of the euthyroid patients died. In conclusion, evaluation of thyroid function tests during COVID-19 infection may give information about the prognosis of disease.

Proteomic Data Analysis for Differential Profiling of the Autoimmune Diseases SLE, RA, SS, and ANCA-Associated Vasculitis

Early and correct diagnosis of inflammatory rheumatic diseases (IRD) poses a clinical challenge due to the multifaceted nature of symptoms, which also may change over time. The aim of this study was to perform protein expression profiling of four systemic IRDs, systemic lupus erythematosus (SLE), ANCA-associated systemic vasculitis (SV), rheumatoid arthritis (RA), and Sjögren’s syndrome (SS), and healthy controls to identify candidate biomarker signatures for differential classification. A total of 316 serum samples collected from patients with SLE, RA, SS, or SV and from healthy controls were analyzed using 394-plex recombinant antibody microarrays. Differential protein expression profiling was examined using Wilcoxon signed rank test, and condensed biomarker panels were identified using advanced bioinformatics and state-of-the art classification algorithms to pinpoint signatures reflecting each disease (raw data set available at https://figshare.com/s/3bd3848a28ef6e7ae9a9.). In this study, we were able to classify the included individual IRDs with high accuracy, as demonstrated by the ROC area under the curve (ROC AUC) values ranging between 0.96 and 0.80. In addition, the groups of IRDs could be separated from healthy controls at an ROC AUC value of 0.94. Disease-specific candidate biomarker signatures and general autoimmune signature were identified, including several deregulated analytes. This study supports the rationale of using multiplexed affinity-based technologies to reflect the biological complexity of autoimmune diseases. A multiplexed approach for decoding multifactorial complex diseases, such as autoimmune diseases, will play a significant role for future diagnostic purposes, essential to prevent severe organ- and tissue-related damage.

Prevalence of red-blood-cell and non-red-blood-cell-targeted autoantibodies in alloimmunized postpartum women

BACKGROUND AND OBJECTIVES

Alloantibodies against red-blood-cell (RBC) antigens often coincide with alloantibodies against leucocytes and platelets and sometimes with autoantibodies towards various antigens. Chimerism may be one of the factors responsible for the combination of allo- and autoantibodies. Women with alloantibodies against RBC antigens causing haemolytic disease of the fetus and neonate may need to receive intrauterine transfusions. These transfusions increase not only maternal antibody formation but also fetomaternal bleeding and may enhance fetal chimerism. We determined the prevalence of and risk factors for autoantibodies against some common clinical target antigens, in alloimmunized women after IUT.

MATERIALS AND METHODS

We tested for autoantibodies against RBC, anti-thyroid peroxidase, anti-extractable nuclear antigens, anti-cyclic citrullinated proteins and anti-tissue transglutaminase. Women with and without autoantibodies were compared for age; number of RBC alloantibodies, pregnancies and IUTs, and other factors that may play a role in immunization.

RESULTS

Non-RBC-targeted autoantibodies were present in 40 of 258 tested women (15·5%, with 90% anti-TPO specificity), comparable to the prevalence reported in healthy Dutch women of these ages. Surprisingly, compared with women who had a single RBC alloantibody, a significantly higher proportion of women with multiple RBC alloantibodies had autoantibodies (5·3% and 18·4%, respectively; odds ratio 4·06, 95% CI: 1·20-13·7). Other characteristics of women with and without autoantibodies were not different.

CONCLUSION

Multiple RBC alloantibodies after extensive allogeneic exposure during pregnancy and presumed increased fetomaternal chimerism are not associated with (selected) autoantibodies. Lack of allo-RBC multi-responsiveness seems associated with decreased auto(-TPO) antibody formation.

Immunological history governs human stem cell memory CD4 heterogeneity via the Wnt signaling pathway

The diversity of the naïve T cell repertoire drives the replenishment potential and capacity of memory T cells to respond to immune challenges. Attrition of the immune system is associated with an increased prevalence of pathologies in aged individuals, but whether stem cell memory T lymphocytes (TSCM) contribute to such attrition is still unclear. Using single cells RNA sequencing and high-dimensional flow cytometry, we demonstrate that TSCM heterogeneity results from differential engagement of Wnt signaling. In humans, aging is associated with the coupled loss of Wnt/β-catenin signature in CD4 TSCM and systemic increase in the levels of Dickkopf-related protein 1, a natural inhibitor of the Wnt/β-catenin pathway. Functional assays support recent thymic emigrants as the precursors of CD4 TSCM. Our data thus hint that reversing TSCM defects by metabolic targeting of the Wnt/β-catenin pathway may be a viable approach to restore and preserve immune homeostasis in the context of immunological history.

Immune System Sex Differences May Bridge the Gap Between Sex and Gender in Fibromyalgia

The fibromyalgia syndrome (FMS) is characterized by chronic widespread pain, sleep disturbances, fatigue, and cognitive alterations. A limited efficacy of targeted treatment and a high FMS prevalence (2–5% of the adult population) sums up to high morbidity. Although, altered nociception has been explained with the central sensitization hypothesis, which may occur after neuropathy, its molecular mechanism is not understood. The marked female predominance among FMS patients is often attributed to a psychosocial predisposition of the female gender, but here we will focus on sex differences in neurobiological processes, specifically those of the immune system, as various immunological biomarkers are altered in FMS. The activation of innate immune sensors is compatible with a neuropathy or virus-induced autoimmune diseases. Considering sex differences in the immune system and the clustering of FMS with autoimmune diseases, we hypothesize that the female predominance in FMS is due to a neuropathy-induced autoimmune pathophysiology. We invite the scientific community to verify the autoimmune hypothesis for FMS.

Population-based estimates of humoral autoimmunity from the U.S. National Health and Nutrition Examination Surveys, 1960-2014

Objective

Based on US National Health and Nutrition Examination Survey (NHANES) data, we attempted to provide an unbiased, population-based estimate of autoantibody prevalence overall and by age and sex.

Methods

US autoantibody prevalence estimates for detectable rheumatoid factor, anti-thyroglobulin, anti-thyroperoxidase, anti-transglutaminase, anti-endomysial, anti-GAD65, antinuclear autoantibodies, and autoantibodies to extractable nuclear antigens were estimated from the 1960–1962 National Health Examination Survey, NHANES III (1988–1994), and the NHANES 1999–2014 cross-sectional surveys. Survey design variables and sample weights were used to account for differential probabilities of selection within the complex survey design. Data analysis used SAS^TM and SUDAAN^™ software. US Census Bureau data were used to estimate the absolute numbers of persons with autoantibodies.

Results

NHANES III data show that the overall US prevalence of having a detectable serum autoantibody is substantial in adults, in both women and men. Thyroid autoantibodies were present in 18% of US adults (31 million persons) including 10% of younger adults and 25% of older persons. Overall autoantibody prevalences increased significantly with age: 32% of US adults 60+ years of age (12.8 million persons) had at least one of the four autoantibodies rheumatoid factor, anti-thyroglobulin, anti-thyroperoxidase, or anti-tissue transglutaminase. Older women had higher levels of autoantibodies, but this was a relative difference. Autoantibody prevalence in both sexes was substantial (women 39%; men 22%). Fourteen percent of adults 60+ years of age have multiple autoantibodies.

Conclusions

Autoantibodies are present in a significant fraction of the general population, especially in older adults and women relative to men. Although all known clinically significant autoantibodies were not analyzed, these data provide an important population perspective on the scope and magnitude of humoral autoimmunity in the US. This is vital for prevention efforts to reduce autoimmune disease and helps clarify the potential impact of autoimmunity on the general population.

Antibodies targeting circulating protective molecules in lupus nephritis: Interest as serological biomarkers

Lupus nephritis (LN) is one of the most frequent and severe manifestations of systemic lupus erythematosus (SLE), considered as the major predictor of poor prognosis. An early diagnosis of LN is a real challenge in the management of SLE and has an important implication in guiding treatments. In clinical practice, conventional parameters still lack sensitivity and specificity for detecting ongoing disease activity in lupus kidneys and early relapse of nephritis. LN is characterized by glomerular kidney injury, essentially due to deposition of immune complexes involving autoantibodies against cellular components and circulating proteins. One of the possible mechanisms of induction of autoantibodies in SLE is a defect in apoptotic cells clearance and subsequent release of intracellular autoantigens. Autoantibodies against soluble protective molecules involved in the uptake of dying cells, including complement proteins and pentraxins, have been described. In this review, we present the main autoantibodies found in LN, with a focus on the antibodies against these protective molecules. We also discuss their pathogenic role and conclude with their potential interest as serological biomarkers in LN.

Development of a robust and standardized immunoserological assay for detection of anti-measles IgG antibodies in human sera

Because of measles outbreaks there is a need for continuous monitoring of immunological protection against infection at population level. For such monitoring to be feasible, a cost-effective, reliable and high-throughput assay is necessary. Herein we describe an ELISA protocol for assessment of anti-measles antibody levels in human serum samples that fulfills the above criteria and is easily adaptable by various laboratories. A serum bank of anonymous patient sera was established (N > 3000 samples). Sera were grouped based on measles immunization schedules and/or changes in vaccine components since the introduction of the first measles vaccine in Hungary in 1969. Newly designed ELISA was performed by using Siemens BEP 2000 Advance System and data were confirmed using commercially available kits. Our indirect ELISA was compared to indirect immunfluoresence and to anti-measles nucleocapsid (N) monoclonal antibody-based sandwich ELISA. The results obtained are in high agreement with the confirmatory methods, and reflect measles vaccination history in Hungary ranging from pre-vaccination era, through the initial period of measles vaccination, to present. Based on measurement of 1985 sera, the highest ratio of low/questionable antibody level samples was detected in cluster '1978-1987' (~25.4%), followed by cluster '1969-1977' (~15.4%).Our assay is suitable for assessment of anti-measles immunity in a large cohort of subjects. The assay is cost-effective, allows high-throughput screening and has superior signal-to-noise ratio. This assay can serve as a first step in assessment of the effectiveness of all three components of the MMR vaccine.