Autoantibodies Associated With Connective Tissue Diseases: What Meaning for Clinicians?

A Practical Multidisciplinary Approach to Identifying Interstitial Lung Disease in Systemic Autoimmune Rheumatic Diseases: A Clinician's Narrative Review

Interstitial lung disease (ILD) is one of the common and potentially lethal manifestations of systemic autoimmune rheumatic diseases (SARDs). ILD's prevalence, clinical patterns, imaging, and natural history are variable. Each of the representative diseases-systemic sclerosis (SSc), idiopathic inflammatory myopathies (IIMs), rheumatoid arthritis (RA), Sjӧgren's syndrome (SjS), mixed connective tissue disease (MCTD), systemic lupus erythematosus (SLE)-have distinct clinical, paraclinical and evolutionary features. Risk factors with predictive value for ILD have been identified. This review summarizes, from the clinician's perspective, recent data from the literature regarding the specificity of ILD for each of the autoimmune rheumatic diseases, with an emphasis on the role of the multidisciplinary team in early diagnosis, case management, as well as the particularities of the clinical approach to the progressive phenotype of ILD in SARDs.

Impact of autoantibody status on stratifying the risk of organ involvement and mortality in SSc: experience from a multicentre French cohort of 1605 patients

INTRODUCTION

Systemic sclerosis (SSc) is a rare autoimmune disease currently classified into two subgroups based on skin extension. The aim of this study was to determine in a large cohort whether the determination of autoantibody (AAb) profile among a full antinuclear AAbs panel including nine specificities had a higher impact than skin phenotype on stratifying the risk of organ involvement and mortality in SSc.

METHODS

Data for patients with SSc followed in seven French university hospitals were retrospectively analysed in terms of skin phenotype, AAbs (anti-topoisomerase I (ATA), anticentromere (ACA), anti-RNA polymerase III (anti-RNAPIII), anti-U1RNP, anti-U3RNP, anti-Pm/Scl, anti-Ku, anti-Th/To, anti-NOR90), organ involvement and mortality. Multivariate analyses were performed to identify independent factors associated with organ involvement and mortality.

RESULTS

We included 1605 patients with SSc (367 with diffuse cutaneous SSc). On multivariate analysis, ATAs were associated with interstitial lung disease and mortality (OR=3.27 (95% CI 2.42 to 4.42); HR=1.9 (95% CI 1.01 to 3.58)), anti-RNAPIII with scleroderma renal crisis and mortality (OR=7.05 (95% CI 2.98 to 16.72); HR=2.35 (95% CI 1.12 to 4.93)), anti-U1RNP with arthritis (OR=3.79 (95% CI 2.16 to 6.67)), anti-Pm/Scl and anti-Ku with myositis (OR=7.09 (95% CI 3.87 to 12.98) and 7.99 (95% CI 2.41 to 26.46)). The skin phenotype was not associated with survival or organ involvement on multivariate analysis without stepwise selection.

CONCLUSION

This study unravels, by contrast with skin phenotype, a strong association between AAbs specificities, organ involvement and outcome in SSc and suggests that patients' classification based on only skin extension is not sufficient for defining prognosis and phenotype.

Circulating Autoantibodies in Adults with Hashimoto's Thyroiditis: New Insights from a Single-Center, Cross-Sectional Study

BACKGROUND

Hashimoto's thyroiditis (HT) is a common autoimmune thyroid disorder characterized by elevated anti-thyroid peroxidase (A-TPO) antibodies. HT frequently coexists with other autoimmune conditions, which are marked by organ-specific and non-organ-specific autoantibodies, reflecting a deregulated immune response. However, the burden and clinical significance of these circulating autoantibodies in adult patients with HT remains unclear.

METHODS

A cross-sectional study was conducted at the University Hospital "R. Dulbecco" in Catanzaro, Italy, from November 2023 to May 2024, involving 200 euthyroid adults. The study population comprised 100 A-TPO-positive HT patients and 100 A-TPO-negative controls, matched for age and sex. Laboratory assessments included thyroid function tests and detection of autoantibodies [e.g., antinuclear antibodies (ANA), anti-parietal cell antibodies (APCA), and anti-neutrophil cytoplasmic antibodies (ANCA)]. Cytokine profiles were also measured using sensitive chemiluminescent multi-array technology.

RESULTS

HT patients were predominantly female (77.0%) with a median age of 56 years. Compared to controls, HT patients had higher median thyroid stimulating hormone (TSH) levels (2.215 vs. 1.705 μIU/mL, p = 0.025). Circulating autoantibodies were more prevalent in the HT group, with higher rates of APCA positivity (16.3% vs. 4.1%, p = 0.008) and atypical ANCA positivity (27.3% vs. 10.2%, p = 0.003). This suggests an increased risk for autoimmune gastritis and systemic inflammation. Additionally, HT patients with positive atypical ANCA showed elevated inflammatory cytokines, particularly interleukin-1 alpha (IL-1α), in female patients (p = 0.035).

CONCLUSIONS

HT is significantly associated with a higher prevalence of circulating autoantibodies, such as APCA and atypical ANCA, which may indicate a heightened risk for autoimmune gastritis and broader autoimmune involvement. Detecting these autoantibodies in HT patients could serve as markers for more severe autoimmune dysfunction. These findings emphasize the need for proactive screening, especially in older patients and those with elevated A-TPO levels. Further research is essential to better understand the clinical implications and develop targeted management strategies for these patients.

Exposure to Gold Induces Autoantibodies against Nuclear Antigens in A.TL Mice

To demonstrate causation or/and assess pathogenic mechanisms of environment-induced autoimmunity, various animal models that mimic the characteristics of the human autoimmune diseases need to be developed. Experimental studies in mice reveal the genetic factors that contribute to autoimmune diseases. Here, the immune response of two mouse strains congenic for non-H-2 genes, A.TL (H-2tl) and A.SW (H-2s), was evaluated after 15 weeks' exposure to gold aurothiomalate (AuTM). AuTM-treated A.TL mice showed anti-nuclear antibodies (ANA) with homogenous and/or fine speckled staining patterns and serum autoantibodies to ds-DNA, chromatin, histones, and ribonucleoproteins (RNP). Female A.TL mice showed a stronger immune response than males, as well as an increase of B cells in their spleen after 15 weeks of gold exposure. A.SW exposed for AuTM showed the induction of anti-nucleolar antibodies (ANoA) with a clumpy staining pattern, as well as an increase in splenic B and T cells. The serum autoantibodies levels in A.SW mice were limited compared to those of A.TL mice. Overall, A.TL presents a stronger immune response after gold exposure than A.SW. The immune response developed in A.TL presents similarities with the clinical manifestations in human autoimmune diseases. Thus, gold-exposed A.TL could constitute a potential experimental mouse model for the study of autoimmunity.

Autoantibodies to nuclear valosin-containing protein-like protein: systemic sclerosis-specific antibodies revealed by in vitro human proteome

OBJECTIVES

To identify and characterize undescribed systemic sclerosis (SSc)-specific autoantibodies targeting nucleolar antigens and to assess their clinical significance.

METHODS

We conducted proteome-wide autoantibody screening (PWAS) against serum samples from SSc patients with nucleolar patterned anti-nuclear antibodies (NUC-ANAs) of specific antibodies (Abs) unknown, utilizing wet protein arrays fabricated from in vitro human proteome. Controls included SSc patients with already-known SSc-specific autoantibodies, patients with other connective tissue diseases and healthy subjects. The selection of nucleolar antigens was performed by database search in the Human Protein Atlas. The presence of autoantibodies was certified by immunoblots and immunoprecipitations. Indirect immunofluorescence assays on HEp-2 cells were also conducted. Clinical assessment was conducted by retrospective review of electronic medical records.

RESULTS

PWAS identified three candidate autoantibodies, including anti-nuclear valosin-containing protein-like (NVL) Ab. Additional measurements in disease controls revealed that only anti-NVL Abs are exclusively detected in SSc. Detection of anti-NVL Abs was reproduced by conventional assays such as immunoblotting and immunoprecipitation. Indirect immunofluorescence assays demonstrated homogeneous nucleolar patterns. Anti-NVL Ab-positive cases were characterized by significantly low prevalence of diffuse skin sclerosis and interstitial lung disease, compared with SSc cases with NUC-ANAs other than anti-NVL Abs, such as anti-U3-RNP and anti-Th/To Abs.

CONCLUSION

Anti-NVL Ab is an SSc-specific autoantibody associated with a unique combination of clinical features, including limited skin sclerosis and lack of lung involvement.

Carpal tunnel syndrome related to rheumatic disease (Review)

Carpal tunnel syndrome (CTS) is the most commonly occurring type of entrapment neuropathy in the world. Several conditions may contribute to the development of CTS, such as obesity, repetitive wrist movements, pregnancy, genetic predisposition and rheumatoid arthritis (RA) inflammation. CTS is characterized by a wide range of pathophysiological factors, including increased pressure, mechanical trauma and ischemic damage to the median nerve that runs through the wrist tunnel. In the present narrative literature review, the way rheumatic diseases (RDs) contribute to CTS occurrence is investigated. The epidemiological, clinical, paraclinical and pathogenesis aspects of the relationship are examined. CTS is the most common neurological finding in RA, and incidences of RA, psoriatic arthritis and CTS are closely related. The association of CTS with systemic lupus erythematosus, Sjögren's syndrome, Behcet's disease and systemic sclerosis is weaker. In these cases, the prevalence of CTS is similar to that in the general population. As the occurrence of CTS is increasing, understanding the common mechanism and making an early diagnosis are required to limit pain and costs. When patients with RD present with symptoms such as wrist pain, tingling sensations or numbness in their fingers, CTS should be suspected. This suspicion should not be interpreted in terms of RD. To accurately evaluate patients with RD, a detailed electrophysiological examination should be included in the evaluation process. A diagnostic algorithm should include neuromuscular ultrasound or magnetic resonance imaging for patients with RD.

Screening for autoimmune diseases in apparently healthy antinuclear antibody positive individuals

Background

Anti-nuclear antibodies (ANA) assessed by immunofluorescence (IF) microscopy are associated with systemic autoimmune rheumatic diseases (SARD) and can be detected years before onset of clinical symptoms. Recent data indicate dysregulation of the immune system with increased levels of proinflammatory cytokines, including type I interferons (IFN), in ANA-positive versus ANA-negative individuals. Herein, the aims were to investigate IF-ANA, ANA fine specificities, and IFN-α protein levels in relation to self-reported symptoms, as well as clinical signs, of SARD in a large group of healthy blood donors (HBD).

Methods

Sera from 825 HBD (48.8% females) were included. IF-ANA was assessed, using HEp-2 cells, according to the routine at the accredited laboratory of Clinical Immunology, Linköping University Hospital. All samples were analyzed for IgG-ANA fine specificities using addressable laser bead assay (ALBIA) at the same laboratory. IFN-α was determined using ELISA. Antibody-positive individuals, and their sex- and age-matched antibody-negative controls, were asked to fill a questionnaire regarding symptoms associated with SARD.

Results

In total, 130 HBD (15.8%) were positive with IF-ANA and/or ALBIA. Anti-U1RNP was significantly more common among women. Generally, self-reported symptoms correlated poorly with IF-ANA and/or ALBIA results. Two females with high levels of Ro60/SSA, Ro52/SSA and IFN-α reported mild sicca symptoms and were diagnosed with Sjögren's disease after clinical evaluation.

Conclusion

A considerable proportion of apparently HBD are autoantibody positive, but without clear association to self-reported symptoms. Nevertheless, the combination of autoantibodies, relevant symptoms and high IFN-α levels identified the small proportion of individuals with SARD in the study population.

Assessing the COX-2/PGE2 Ratio and Anti-Nucleosome Autoantibodies as Biomarkers of Autism Spectrum Disorders: Using Combined ROC Curves to Improve Diagnostic Values

Autism spectrum disorder (ASD) is a neurodevelopmental condition marked by restricted and repetitive behaviors as well as difficulties with social interaction. Numerous studies have revealed aberrant lipid mediators and autoimmunity as a recognized etiological cause of ASD that is amenable to therapeutic intervention. In this study, the relationship between the relative cyclooxygenase-2/prostaglandin E2 ratio (COX-2/PGE2) as a lipid mediator marker and anti-nucleosome autoantibodies as an autoimmunity marker of ASD was investigated using multiple regression and combined receiver operating characteristic (ROC) curve analyses. The study also sought to identify the linear combination of these variables that optimizes the partial area under the ROC curves. There were forty ASD children and forty-two age- and gender-matched controls included in the current study. Using combined ROC curve analysis, a notable increase in the area under the curve was seen in the patient group, using the control group as a reference group. Additionally, it was reported that the combined markers had improved specificity and sensitivity. This study demonstrates how the predictive value of particular biomarkers associated with lipid metabolism and autoimmunity in children with ASD can be measured using a ROC curve analysis. This technique should help us better understand the etiological mechanism of ASD and how it may adversely affect cellular homeostasis, which is essential to maintaining healthy metabolic pathways. Early diagnosis and intervention may be facilitated by this knowledge.

Ophthalmologic Implications of Connective Tissue Diseases: A Comprehensive Review of Current Knowledge and Innovations

Connective tissue diseases (CTDs), including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Sjögren's syndrome, and systemic sclerosis (SSc), represent a diverse group of disorders characterized by abnormalities in the proteins that support tissues and organs. These diseases can affect multiple organ systems and are often associated with significant morbidity and mortality. The eyes are frequently affected among the various organ systems involved, with ocular manifestations ranging from benign conditions such as dry eye syndrome to severe, sight-threatening complications like scleritis, retinal vasculitis, and optic neuritis. Recognizing and managing these ophthalmologic implications is crucial for preventing severe complications, providing diagnostic clues, and improving patients' quality of life. This comprehensive review aims to elucidate the current knowledge and innovations related to the ophthalmologic implications of CTDs. It details the ocular manifestations associated with major CTDs, explores diagnostic approaches to identifying and differentiating these conditions, and discusses management strategies, including pharmacological and surgical interventions. Additionally, the review highlights recent advancements and emerging therapies in diagnosing and treating CTD-related ophthalmologic conditions. The review also addresses this field's challenges and future directions, emphasizing the importance of interdisciplinary collaboration and continuous research. By synthesizing the latest research and clinical insights, this review seeks to enhance the understanding of healthcare professionals regarding the interplay between CTDs and ocular health, ultimately contributing to improved patient care and outcomes.

Could Gas6/TAM Axis Provide Valuable Insights into the Pathogenesis of Systemic Sclerosis?

Systemic sclerosis (SSc) is a connective tissue disorder characterized by microvascular injury, extracellular matrix deposition, autoimmunity, inflammation, and fibrosis. The clinical complexity and high heterogeneity of the disease make the discovery of potential therapeutic targets difficult. However, the recent progress in the comprehension of its pathogenesis is encouraging. Growth Arrest-Specific 6 (Gas6) and Tyro3, Axl, and MerTK (TAM) receptors are involved in multiple biological processes, including modulation of the immune response, phagocytosis, apoptosis, fibrosis, inflammation, cancer development, and autoimmune disorders. In the present manuscript, we review the current evidence regarding SSc pathogenesis and the role of the Gas6/TAM system in several human diseases, suggesting its likely contribution in SSc and highlighting areas where further research is necessary to fully comprehend the role of TAM receptors in this condition. Indeed, understanding the involvement of TAM receptors in SSc, which is currently unknown, could provide valuable insights for novel potential therapeutic targets.

Carbon Monoxide Poisoning: From Occupational Health to Emergency Medicine

Carbon monoxide poisoning remains a leading cause of accidental poisoning worldwide (both at home and at work), and it is also a cause of suicidal poisoning. Such poisoning can arise following prolonged exposure to low levels of CO or following brief exposure to high concentrations of the gas. In fact, despite exposure limits, high safety standards, and the availability of CO alarms, nearly 50,000 people in the United States visit the emergency department each year due to poisoning. Additionally, CO poisoning in the United States causes up to 500 deaths each year. Despite the widespread nature of this form of poisoning, known about for centuries and whose damage mechanisms have been recognized (or rather hypothesized about) since the 1800s, early recognition, especially of late complications, and treatment remain a medical challenge. A well-designed therapeutic diagnostic process is necessary so that indication for hyperbaric or normobaric therapy is correctly made and so that patients are followed up even after acute exposure to diagnose late complications early. Furthermore, it is necessary to consider that in the setting of emergency medicine, CO poisoning can be part of a differential diagnosis along with other more frequent conditions, making its recognition difficult. The last thirty years have been marked by a significant increase in knowledge regarding the toxicity of CO, as well as its functioning and its importance at physiological concentrations in mammalian systems. This review, taking into account the significant progress made in recent years, aims to reconsider the pathogenicity of CO, which is not trivially just poisonous to tissues. A revision of the paradigm, especially as regards treatment and sequelae, appears necessary, and new studies should focus on this new point of view.

Associations of Digital Ulcers in Patients with Systemic Sclerosis: An 8-Year Retrospective Study

INTRODUCTION

This study aimed to investigate the associations of digital ulcers (DUs) in patients with systemic sclerosis (SSc).

METHODS

This retrospective study investigated the demographic characteristics, specific autoantibodies, organ involvement, and laboratory tests in patients with SSc from our hospital.

RESULTS

This study enrolled 144 patients with SSc. The DU+ group consisted of 15 (10.4%) patients. Patients with SSc having DUs have longer disease duration, higher fibrinogen, higher fibrin degradation product, and lower cholesterol. None of the patients used cholesterol-lowering drugs before onset of DUs. The study also demonstrated a higher prevalence of anti-dsDNA and anti-histone antibodies in patients with SSc with DUs. Anti-dsDNA antibody is a specific antibody for SLE with a specificity of 96-99%. A total of 86.1% (124/144) of patients suffered from diffuse cutaneous SSc, and 28.5% (41/144) of patients suffered from overlap syndrome.

CONCLUSION

Our study indicated that patients with SSc with fibrinogen of >2.895 g/L (p = 0.043) and cholesterol of <3.340 mmol/L (p = 0.036), which is equal to 129.258 mg/dL, are at high risk of developing DUs.

Clinical Characteristics of Patients With Acquired Partial Lipodystrophy: A Multicenter Retrospective Study

BACKGROUND

Barraquer-Simons syndrome (BSS) is a rare, acquired form of lipodystrophy characterized by progressive loss of upper body subcutaneous fat, which affects face, upper limbs, and trunk. The pathogenesis of the disease is not entirely known and may involve autoimmune mechanisms.

AIM

This study aimed to provide a comprehensive picture of the clinical, immunological, and metabolic features of a large cohort of patients with BSS. Our primary objectives included the validation of existing diagnostic tools, the evaluation of novel diagnostic approaches, and the exploration of potential disease triggers or genetic predispositions.

SUBJECTS AND METHODS

Twenty-six patients were diagnosed with BSS based on accepted criteria defined by international guidelines. Anthropometric parameters, biochemical tests, organ- and non-organ-specific autoantibodies, HLA status, and screening of the LMNB2 gene were performed.

RESULTS

Patients were predominantly females (73%); fat loss occurred mostly during childhood (77%) at a median age of 8 years. Among various anthropometric measures, the ratio between the proportion of fat mass in upper limbs and lower limbs showed the best predictive value for diagnosis. A total of 11.5% of patients had diabetes, 34.6% dyslipidemia, and 26.9% hepatic steatosis. Seventy-five percent of children and 50% of adults had C3 hypocomplementemia; 76% of patients were positive for 1 or more autoantibodies. HLA-DRB1 11:03 had higher allelic frequencies compared with the general population. A single variant in the LMNB2 gene was found in 1 patient.

CONCLUSION

BSS has a childhood onset and is often associated with autoimmune diseases. Skinfold thickness measurements and fat assessment by dual energy X-ray absorptiometry are useful tools to identify the disease. C3 hypocomplementemia and the presence of autoantibodies may be used as additional diagnostic supportive criteria but the prevalence of C3 hypocomplementemia may be lower than previously reported.

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.

Recommendations for the use of anti-dsDNA autoantibodies in the diagnosis and follow-up of systemic lupus erythematosus - A proposal from an expert panel

Anti-dsDNA autoantibodies are listed as one of the classification criteria for systemic lupus erythematosus (SLE) and are relatively effective indicators for monitoring disease activity and treatment response. Therefore, clinicians rely on them to diagnose and adjust medication and treatment strategies for SLE patients. However, the use of anti-dsDNA antibodies is not free from controversy. Part of this controversy stems from the fact that anti-dsDNA antibodies are found in several disorders, besides SLE. In addition to this, anti-dsDNA antibodies are a heterogeneous group of antibodies, and their determination still lacks proper standardization. Moreover, anti-dsDNA testing specificity and diagnostic performance change depending on the population under study. These and other issues result in inconsistency and encumber the clinical use of anti-dsDNA antibodies. A panel of medical laboratory and clinical experts on SLE discussed such issues based on their clinical experience in a first meeting, establishing a series of recommendations. The proceedings of this first meeting, plus an exhaustive review of the literature, were used to compose a paper draft. The panel subsequently discussed and refined this draft in a second meeting, the result of which is this paper. This document is relevant to clinical laboratories as it guides to improving diagnosis and monitoring of SLE. Simultaneously, it will help laboratories compile more informative reports, not limited to a mere number. It is also relevant to clinical doctors who wish to better understand laboratory methods so that they can do a more efficient, better-aimed laboratory test ordering.

Extended autoantibody panel in Turkish patients with early-stage systemic sclerosis: Coexpressions and their influences on clinical phenotypes

BACKGROUND/AIM

To investigate the frequency and clinical relevance of an extended autoantibody profile in patients with systemic sclerosis (SSc).

MATERIALS AND METHODS

In this cross-sectional study, serum from 100 consecutive patients was subjected to indirect immunofluorescence (IIF) (HEp-20-10/primate liver mosaic) and Systemic Sclerosis Profile by EUROIMMUN to evaluate anti-nuclear antibodies (ANA) and autoantibodies against 13 different autoantibodies in patients with SSc less than 3 years.

RESULTS

Ninety-three of 100 patients were positive for ANA by IIF. Fifty-three patients showed single positivity, 26 anti-topoisomerase antibodies (anti-Scl70 ab), 16 anticentromere antibodies (ACAs), six anti-RNA polymerase III antibodies (anti-RNAPIII ab), one anti-Ku antibody, one anti-PM/Scl100 antibody, two anti-PM/Scl75 antibodies, one anti-Ro52 antibody, whereas 32 patients had multiple autoantibody positivities. Among classic SSc-specific autoantibodies, anti-Scl70 and anti-RNAPIII abs showed the highest cooccurrence (n = 4). One patient was simultaneously positive for anti-RNAPIII ab and ACA, and one was positive for ACA and anti-Scl70 ab. The clinical features were not statistically different between single and multiple autoantibody-positivity for classic SSc-specific autoantibodies (ACA, anti-Scl70 ab, and anti-RNAPIII ab), except for digital ulcer in the multiantibody positive ACA group (p = .019).

CONCLUSION

Based on our results, coexpression of autoantibodies is not uncommon in SSc patients. Although autoantibodies specific to SSc in early disease show generally known clinical features, it remains to be investigated how the coexpression of autoantibodies will affect clinical presentation.

Assessing the causal relationship between immune traits and systemic lupus erythematosus by bi-directional Mendelian randomization analysis

Previous studies have observed relationships between immune cells and systemic lupus erythematosus (SLE), but their causal links remain undetermined. Based on the public available genome-wide association studies (GWAS) summary statistics, we conducted two-sample Mendelian randomization (MR) to evaluate the associations between 731 immune phenotypes and SLE pairs. Pairwise pleiotropy analysis was performed to identify pleiotropic genes for significant immunophenotype-SLE pairs. A comprehensive gene function analysis was undertaken to explore the mechanisms of immune cells in SLE. By using the instrumental variables extracted from GWAS data, we observed that increased levels of five immune phenotypes were causally associated with SLE risk (FDR < 0.05), that were CD20 on IgD+ CD38- naïve, BAFF-R on IgD+ CD38dim, CD39+ secreting Treg AC, CD14- CD16+ monocyte AC, and HLA DR on CD14+ monocyte. Pairwise gene-based analyses identified a total of 38 pleiotropic genes for 5 significant pairs identified and gene set enrichment analysis revealed the involvement of the identified pleiotropic genes in complex pathways (i.e., systemic lupus erythematosus, an integral component of luminal side of endoplasmic reticulum membrane, C-type lectin receptor signaling pathway and regulation of hormone secretion). This study demonstrates that the immune response influences the progression of SLE in a complex pattern. These findings greatly improve our understanding of the interaction between immune response and SLE risk and also aid in the design of therapeutic strategies from an immunological perspective.

Neurological Manifestations of Connective Tissue Disorders

Connective tissue disorders (CTD) are a group of disorders affecting the connective tissues. Usually the musculoskeletal and the vascular system is impacted. Along with these systems, the nervous system is also involved in CTD, which leads to various neurological manifestations. The pathophysiology of neurological complications of CTD is caused by various factors and is complicated. Disturbed immune complexes, chronic inflammation, and autoimmunity in which the body attacks its cells are considered to be responsible for the neurological complications of CTD. Additionally, the vascular symptoms that lead to decreased blood flow to the brain are also responsible for the neurological manifestations of CTD in diseases like systemic lupus erythematosus (SLE). In SLE, vessel wall integrity is compromised, which may lead to decreased blood flow leading to neurological complications. CTD can manifest a variety of neurological complications. These neurological complications can be classified into symptoms affecting the peripheral nervous system, central nervous system, and the autonomic nervous system. Some of the common neurological complications of CTD are headaches, seizures, ataxia, neuropathies leading to cranial nerve palsies, myelopathies, tremors, encephalitis, and cerebral infarction. Cranial nerve palsies can disturb sensations, vision, hearing, and mastication. Neuropsychiatric symptoms are also commonly observed in CTD. Cognitive dysfunction can be caused due to neuropsychiatric problems. Some of the cognitive dysfunctions are lack of concentration, memory loss, confusion, and coma. In this review, we will address various neurological manifestations of CTD.

Evaluation of Antinuclear Antibody and Subserology Reflex Testing for the Diagnosis of Systemic Autoimmune Rheumatic Disorders in an Academic Teaching Hospital

OBJECTIVE

The aim of this study was to examine appropriate utilization of antinuclear antibody (ANA) screening tests with follow-up subserology tests (reflex testing) for diagnosing systemic autoimmune rheumatic disorder (SARD).

METHODS

We conducted a retrospective chart review of 3003 SARD-test orders at an academic teaching hospital from January to December 2019. Testing patterns were categorized as American College of Rheumatology (ACR)-recommended reflex testing, panel testing, or single subserology testing. We described testing patterns, assessed their diagnostic accuracy, and explored factors associated with reflex testing.

RESULTS

Reflex testing accounted for 79.7% of SARD test-ordering, whereas improper testing (panel or single subserology) accounted for the other 20.3%. Reflex testing was associated with significantly more SARD diagnoses than improper testing (P = .004). Testing patterns were significantly associated with race/ethnicity (P = .008), with reflex testing being less frequent than improper testing in Hispanics and Whites.

CONCLUSION

In summary, one-fifth (20.3%) of testing patterns for suspected SARD did not follow the ACR-recommended guidelines for using reflex testing. Use of reflex testing was associated with an increased frequency of SARD diagnosis.

Dense fine speckled nuclear immunofluorescence: A mildly reassuring antinuclear antibody pattern meriting consideration

INTRODUCTION

Antinuclear antibodies (ANAs) are regarded as a hallmark of connective tissue diseases (CTDs) and play a key role in their diagnosis, but the value of some particular antibodies in management of patients and the disease prognosis is controversial. The mechanism underlying the production of ANAs in CTDs, other chronic inflammatory conditions and even in healthy people, is not completely elucidated. Anti-DFS70 antibodies connected with the dense fine speckled autoantigen of 70 kD, known as the lens epithelium-derived growth factor p75, are a subgroup of ANAs. Their presence and coexistence with other antibodies and their clinical significance are the matter of debate.

METHODS

Based on literature data, the authors focused on current knowledge explaining the role of anti-DFS70 antibodies in selected CTDs.

RESULTS

However, the literature data is ambiguous and does not fully support the validity of the anti-DFS70 assay for a specific CTD diagnosis. Most researchers claim that the presence of anti-DFS70 as the only one usually exclude the diagnosis of CTD. Nevertheless, its coexistence with other ANAs is not an excluding factor but has predictive value due to more favorable course of CTD. Such situations may also suggest an enhanced risk of the development of a CTD in the future.

CONCLUSIONS

Although more studies are needed in this field, it seems reasonable to ascertain the presence of anti-DFS70 in routine clinical practice.

Autoantibody status according to multiparametric assay accurately estimates connective tissue disease classification and identifies clinically relevant disease clusters

OBJECTIVE

Assessment of circulating autoantibodies represents one of the earliest diagnostic procedures in patients with suspected connective tissue disease (CTD), providing important information for disease diagnosis, identification and prediction of potential clinical manifestations. The purpose of this study was to evaluate the ability of multiparametric assay to correctly classify patients with multiple CTDs and healthy controls (HC), independent of clinical features, and to evaluate whether serological status could identify clusters of patients with similar clinical features.

METHODS

Patients with systemic lupus erythematosus (SLE), systemic sclerosis (SSc), Sjogren's syndrome (SjS), undifferentiated connective tissue disease (UCTD), idiopathic inflammatory myopathies (IIM) and HC were enrolled. Serum was tested for 29 autoantibodies. An XGBoost model, exclusively based on autoantibody titres was built and classification accuracy was evaluated. A hierarchical clustering model was subsequently developed and clinical/laboratory features compared among clusters.

RESULTS

908 subjects were enrolled. The classification model showed a mean accuracy of 60.84±4.05% and a mean area under the receiver operator characteristic curve of 88.99±2.50%, with significant discrepancies among groups. Cluster analysis identified four clusters (CL). CL1 included patients with typical features of SLE. CL2 included most patients with SjS, along with some SLE and UCTD patients with SjS-like features. CL4 included anti-Jo1 patients only. CL3 was the largest and most heterogeneous, including all the remaining subjects, overall characterised by low titre or lower-prevalence autoantibodies.

CONCLUSION

Extended multiparametric autoantibody assay allowed an accurate classification of CTD patients, independently of clinical features. Clustering according to autoantibody titres is able to identify clusters of CTD subjects with similar clinical features, independently of their final diagnosis.

Comprehensive autoantibody profiling in systemic autoimmunity by a highly-sensitive multiplex protein array

Comprehensive autoantibody evaluation is essential for the management of autoimmune disorders. However, conventional methods suffer from poor sensitivity, low throughput, or limited availability. Here, using a proteome-wide human cDNA library, we developed a novel multiplex protein assay (autoantibody array assay; A-Cube) covering 65 antigens of 43 autoantibodies that are associated with systemic sclerosis (SSc) and polymyositis/dermatomyositis (PM/DM). The performance of A-Cube was validated against immunoprecipitation and established enzyme-linked immunosorbent assay. Further, through an evaluation of serum samples from 357 SSc and 172 PM/DM patients, A-Cube meticulously illustrated a diverse autoantibody landscape in these diseases. The wide coverage and high sensitivity of A-Cube also allowed the overlap and correlation analysis between multiple autoantibodies. Lastly, reviewing the cases with distinct autoantibody profiles by A-Cube underscored the importance of thorough autoantibody detection. Together, these data highlighted the utility of A-Cube as well as the clinical relevance of autoantibody profiles in SSc and PM/DM.

Positive and negative regulation of the Fcγ receptor-stimulating activity of RNA-containing immune complexes by RNase

The U1RNP complex, Ro/SSA, and La/SSB are major RNA-containing autoantigens. Immune complexes (ICs) composed of RNA-containing autoantigens and autoantibodies are suspected to be involved in the pathogenesis of some systemic autoimmune diseases. Therefore, RNase treatment, which degrades RNA in ICs, has been tested in clinical trials as a potential therapeutic agent. However, no studies to our knowledge have specifically evaluated the effect of RNase treatment on the Fcγ receptor-stimulating (FcγR-stimulating) activity of RNA-containing ICs. In this study, using a reporter system that specifically detects FcγR-stimulating capacity, we investigated the effect of RNase treatment on the FcγR-stimulating activity of RNA-containing ICs composed of autoantigens and autoantibodies from patients with systemic autoimmune diseases such as systemic lupus erythematosus. We found that RNase enhanced the FcγR-stimulating activity of Ro/SSA- and La/SSB-containing ICs, but attenuated that of the U1RNP complex-containing ICs. RNase decreased autoantibody binding to the U1RNP complex, but increased autoantibody binding to Ro/SSA and La/SSB. Our results suggest that RNase enhances FcγR activation by promoting the formation of ICs containing Ro/SSA or La/SSB. Our study provides insights into the pathophysiology of autoimmune diseases involving anti-Ro/SSA and anti-La/SSB autoantibodies, and into the therapeutic application of RNase treatment for systemic autoimmune diseases.

Clinical diagnoses associated with a positive antinuclear antibody test in patients with and without autoimmune disease

BACKGROUND

Antinuclear antibodies (ANA) are antibodies present in several autoimmune disorders. However, a large proportion of the general population (20%) also have a positive test; very few of these individuals will develop an autoimmune disease, and the clinical impact of a positive ANA in them is not known. Thus, we test the hypothesis that ANA + test reflects a state of immune dysregulation that alters risk for some clinical disorders in individuals without an autoimmune disease.

METHODS

We performed high throughput association analyses in a case-control study using real world data from the de-identified electronic health record (EHR) system from Vanderbilt University Medical Center. The study population included individuals with an ANA titer ≥ 1:80 at any time (ANA +) and those with negative results (ANA-). The cohort was stratified into sub-cohorts of individuals with and without an autoimmune disease. A phenome-wide association study (PheWAS) adjusted by sex, year of birth, race, and length of follow-up was performed in the study cohort and in the sub-cohorts. As secondary analyses, only clinical diagnoses after ANA testing were included in the analyses.

RESULTS

The cohort included 70,043 individuals: 49,546 without and 20,497 with an autoimmune disease, 26,579 were ANA + and 43,464 ANA-. In the study cohort and the sub-cohort with autoimmune disease, ANA + was associated (P ≤ 5 × 10-5) with 88 and 136 clinical diagnoses respectively, including lupus (OR ≥ 5.4, P ≤ 7.8 × 10-202) and other autoimmune diseases and complications. In the sub-cohort without autoimmune diseases, ANA + was associated with increased risk of Raynaud's syndrome (OR ≥ 2.1) and alveolar/perialveolar-related pneumopathies (OR ≥ 1.4) and decreased risk of hepatitis C, tobacco use disorders, mood disorders, convulsions, fever of unknown origin, and substance abuse disorders (OR ≤ 0.8). Analyses including only diagnoses after ANA testing yielded similar results.

CONCLUSION

A positive ANA test, in addition to known associations with autoimmune diseases, Raynaud's phenomenon, and idiopathic fibrosing alveolitis related disorders, is associated with decreased prevalence of several non-autoimmune diseases.

Comparative physiological anthropogeny: exploring molecular underpinnings of distinctly human phenotypes

Anthropogeny is a classic term encompassing transdisciplinary investigations of the origins of the human species. Comparative anthropogeny is a systematic comparison of humans and other living nonhuman hominids (so-called "great apes"), aiming to identify distinctly human features in health and disease, with the overall goal of explaining human origins. We begin with a historical perspective, briefly describing how the field progressed from the earliest evolutionary insights to the current emphasis on in-depth molecular and genomic investigations of "human-specific" biology and an increased appreciation for cultural impacts on human biology. While many such genetic differences between humans and other hominids have been revealed over the last two decades, this information remains insufficient to explain the most distinctive phenotypic traits distinguishing humans from other living hominids. Here we undertake a complementary approach of "comparative physiological anthropogeny," along the lines of the preclinical medical curriculum, i.e., beginning with anatomy and considering each physiological system and in each case considering genetic and molecular components that are relevant. What is ultimately needed is a systematic comparative approach at all levels from molecular to physiological to sociocultural, building networks of related information, drawing inferences, and generating testable hypotheses. The concluding section will touch on distinctive considerations in the study of human evolution, including the importance of gene-culture interactions.

Serological and clinical associations of autoantibodies in Chinese patients with new-onset systemic lupus erythematosus

To study the clinical significance of autoantibodies in Chinese patients with new-onset systemic lupus erythematosus (SLE), we enrolled 526 new-onset patients who met the 1997 Updated American College of Rheumatology SLE Classification Criteria for a retrospective cohort study. Chi-square test and Wilcoxon rank-sum test were used to detect the relationship of autoantibodies with clinical manifestations and serological results respectively. Our results demonstrated that the positive rate of anti-ribosomal P protein (anti-P) antibody in female patients was higher than that in male patients (41.2% vs. 22%, P = 0.008). Patients with anti-SSB (43.95 ± 73.12 vs. 40.92 ± 75.75, P = 0.004; 63.93 ± 103.56 vs. 55.06 ± 120.84, P = 0.008 respectively) antibodies had higher levels of alanine aminotransferase (ALT) and aspartate transaminase (AST), whereas those with anti-P antibody (28.90 ± 25.70 vs. 50.08 ± 93.00, P = 0.014; 38.51 ± 48.19 vs. 69.95 ± 142.67, P = 0.047, respectively) had lower levels of them. Anti-dsDNA antibody (P = 0.021) was associated with pulmonary arterial hypertension (PAH). The patients with anti-Ro60 (P = 0.044), anti-P (P = 0.012) and anti-dsDNA (P = 0.013) antibodies were less likely to develop Interstitial lung disease. Anti-SmRNP antibody was correlated to lower prevalence of neuropsychiatric symptoms (P = 0.037), and patients with anti-centromere antibody (ACA) were more likely to develop serositis (P = 0.016).We identified five clusters of SLE-related autoantibodies, confirmed previously reported associations of autoantibodies, and discovered new associations.

Doubtful Clinical Value of Subtyping Anti-U1-RNP Antibodies Regarding the RNP-70 kDa Antigen in Sera of Patients with Systemic Lupus Erythematosus

The detection of antinuclear antibodies is central to the diagnosis and prognosis of systemic lupus erythematosus (SLE), primary Sjögren's syndrome (pSS) and mixed connective tissue disease (MCTD). Anti-U1-RNP and anti-RNP70 antibodies were assayed in the sera of patients with SLE (n = 114), pSS (n = 54) and MCTD (n = 12). In the SLE group, 34/114 (30%) were anti-U1-RNP positive, and 21/114 (18%) were both anti-RNP70 positive and anti-U1-RNP positive. In the MCTD group, 10/12 (83%) were anti-U1-RNP positive, and 9/12 (75%) were anti-RNP70 positive. Only one individual with pSS was antibody positive (for both anti-U1-RNP and anti-RNP70). All anti-RNP70-positive samples were also anti-U1-RNP positive. Anti-U1-RNP-positive subjects with SLE were younger (p < 0.0001); showed lower concentrations of complement protein 3 (p = 0.03); had lower eosinophil (p = 0.0005), lymphocyte (p = 0.006) and monocyte (p = 0.03) counts; and had accrued less organ damage (p = 0.006) than the anti-U1-RNP-negative SLE patients. However, we observed no significant clinical or laboratory parameter differences between the anti-U1-RNP-positive individuals with/without anti-RNP70 in the SLE group. In conclusion, anti-RNP70 antibodies are not exclusive to MCTD but are rarely detected in pSS and healthy individuals. In SLE, anti-U1-RNP antibodies are associated with a clinical phenotype that resembles MCTD, with hematologic involvement and less damage accrual. Based on our results, the clinical value of subtyping anti-RNP70 in anti-U1-RNP-positive sera appears to be of limited value.

Impact of Siglecs on autoimmune diseases

Autoimmune diseases affect tens of millions of people just in the United States alone. Most of the available treatment options are aimed at reducing symptoms but do not lead to cures. Individuals affected with autoimmune diseases suffer from the imbalance between tolerogenic and immunogenic functions of their immune system. Often pathogenesis is mediated by autoreactive B and T cells that escape central tolerance and react against self-antigens attacking healthy tissues in the body. In recent years Siglecs, sialic-acid-binding immunoglobulin (Ig)-like lectins, have gained attention as immune checkpoints for therapeutic interventions to dampen excessive immune responses and to restore immune tolerance in autoimmune diseases. Many Siglecs function as inhibitory receptors suppressing activation signals in various immune cells through binding to sialic acid ligands as signatures of self. In this review, we highlight potential of Siglecs in suppressing immune responses causing autoimmune diseases. In particular, we cover the roles of CD22 and Siglec-G/Siglec-10 in regulating autoreactive B cell responses. We discuss several functions of Siglec-10 in the immune modulation of other immune cells, and the potential of therapeutic strategies for restoring immune tolerance by targeting Siglecs and expanding regulatory T cells. Finally, we briefly review efforts evaluating Siglec-based biomarkers to monitor autoimmune diseases.

Cutaneous lupus erythematosus: a review of etiopathogenic, clinical, diagnostic and therapeutic aspects

Cutaneous lupus erythematosus is an autoimmune disease of varied clinical expression, which may present as an exclusively cutaneous disease or be one of the multiple manifestations of systemic lupus erythematosus. Its classification includes acute, subacute, intermittent, chronic and bullous subtypes, which are usually identified based on clinical features and histopathological and laboratory findings. Other non-specific cutaneous manifestations may be associated with systemic lupus erythematosus and are usually related to disease activity. Environmental, genetic and immunological factors play a role in the pathogenesis of skin lesions in lupus erythematosus. Recently, considerable progress has been made in elucidating the mechanisms involved in their development, which allows for foreseeing future targets for more effective treatments. This review proposes to discuss the main etiopathogenic, clinical, diagnostic and therapeutic aspects of cutaneous lupus erythematosus, aiming to update internists and specialists from different areas.

The diagnostic challenge of patients with anti-U1-RNP antibodies

Anti-U1-RNP antibodies are necessary for the diagnosis of mixed connective tissue disease (MCTD), but they are also prevalent in other connective tissue diseases, especially systemic lupus erythematosus (SLE), from which distinction remains challenging. We aimed to describe the presentation and outcome of patients with anti-U1-RNP antibodies and to identify factors to distinguish MCTD from SLE. We retrospectively applied the criteria sets for MCTD, SLE, systemic sclerosis (SSc) and rheumatoid arthritis (RA) to all patients displaying anti-U1-RNP antibodies in the hospital of Caen from 2000 to 2020. Thirty-six patients were included in the analysis. Eighteen patients (50%) satisfied at least one of the MCTD classifications, 11 of whom (61%) also met 2019 ACR/EULAR criteria for SLE. Twelve other patients only met SLE without MCTD criteria, and a total of 23 patients (64%) met SLE criteria. The most frequent manifestations included Raynaud's phenomenon (RP, 91%) and arthralgia (67%). We compared the characteristics of patients meeting only the MCTD (n = 7), SLE (n = 12), or both (n = 11) criteria. Patients meeting the MCTD criteria were more likely to display SSc features, including sclerodactyly (p < 0.01), swollen hands (p < 0.01), RP (p = 0.04) and esophageal reflux (p < 0.01). The presence of scleroderma features (swollen hands, sclerodactyly, gastro-oesophageal reflux), was significantly associated with the diagnosis of MCTD. Conversely, the absence of those manifestations suggested the diagnosis of another definite connective tissue disease, especially SLE.

Significance of anti-transcobalamin receptor antibodies in cutaneous arteritis revealed by proteome-wide autoantibody screening

Cutaneous arteritis (CA) is a single-organ vasculitis that exclusively affects the small to medium-sized arteries of the skin. Diagnosis depends on a histological investigation with skin biopsy, which could be burdensome for both patients and clinicians. Moreover, the pathogenesis of CA remains unstudied, and treatment has not yet been established. Herein, we applied our proteome-wide autoantibody screening method to explore autoantibodies in the serum of CA patients. As a result, anti-transcobalamin receptor (TCblR) antibodies (Abs) were specifically detected in 24% of CA patients. Patients with positive anti-TCblR Abs were spared from peripheral neuropathy compared to those with negative anti-TCblR Abs, showing characteristics as CA confined to the skin. In addition, we revealed that anti-TCblR Abs trigger the autocrine loop of interleukin-6 mediated by tripartite motif-containing protein 21 in human endothelial cells and induce periarterial inflammation in murine skin. Furthermore, we demonstrated that methylcobalamin, a ligand of TCblR, ameliorates inflammation caused by anti-TCblR Abs both in vitro and in vivo. Collectively, our investigation unveils the pathologic significance of anti-TCblR Abs in CA and their potential as a diagnostic marker and a pathophysiology-oriented therapeutic target.

Diagnostic Performance of Anti-Topoisomerase-I, Anti-Th/To Antibody and Anti-Fibrillarin Using Immunoblot Method in Systemic Sclerosis Related Interstitial Lung Disease Patients

Purpose

Systemic Sclerosis related Interstitial Lung Disease (SSc-ILD) is the most common clinical manifestation of SSc with a high morbidity and mortality rate. However, the Thorax High-Resolution Computed Tomography (HCRT) as the gold standard diagnostic tool for SSc-ILD is not widely equipped in health-care facilities. Recently, specific autoantibody examination (anti-topoisomerase-1 (ATA), anti-Th/To antibody, and anti-fibrillarin) has been studied and used for SSc-ILD diagnosis. This study aims to evaluate the diagnostic performance of specific autoantibody examination among SSc-ILD.

Patients and Methods

This retrospective study reviews data from local dedicated SSc database (Sclerosis Systemic Register System Development Electronic Medical Record) which were collected between March 2019 and August 2021. Population of this study include adult inpatients and outpatients at Dr. Hasan Sadikin General Hospital, who have been diagnosed with SSc based on ACR/EULAR 2013 criteria, which met inclusion and exclusion criteria. The SSc patients were grouped into SSc-ILD and SSc non-ILD based on HRCT and tested for SSC-ILD specific autoantibody test (ATA, anti-Th/To antibody, and anti-fibrillarin) to obtain the diagnostic performance (sensitivity, specificity, and positive- and negative-predictive value).

Results

A total of 74 subject grouped into 47 SSc-ILD and 27 SSc-non ILD patients. ATA validity test results showed 85.1% sensitivity, 19.2% specificity, 65.6% PPV, and 41.7% NPV. Anti-Th/To antibody obtained 27.7% sensitivity, 88.9% specificity, 81.3% PPV, and 41.4% NPV. The anti-fibrillarin validity test result showed a 12.8% sensitivity, 96.3% specificity, 85.7% PPV, and 38.8% NPV. The combination of the three parameters had 95.7% sensitivity, 18.5% specificity, 67.1% PPV, and 71.4% NPV.

Conclusion

The combination of the SSc-ILD specific autoantibody test and HCRT is expected to detect all affected patients. Based on these results, SSc-ILD autoantibody-specific test can be used as an alternative examination for screening and diagnosis in health-care facilities that are not equipped with HRCT.

Scleroderma specific autoantibodies in rheumatoid arthritis and Sjögren's syndrome patients with interstitial lung disease: Prevalence and associations

Systemic sclerosis (SSc) has been classically linked to interstitial lung disease (ILD) development, often in association with specific SSc autoantibodies. In the present report, we aimed to estimate the prevalence of SSc autoantibodies in 60 seropositive RA and 41 primary SS patients complicated or not by ILD. SSc autoantibodies were determined in patients' sera by a commercial immunoblot assay. RA ILD patients displayed higher frequency of SSc-specific antibodies at strong titers compared to RA-with no lung involvement (25% vs 3.1%, p = 0.01)[OR 95% CI:10.9 (1.2-94.5)], with no differences detected between primary SS groups. These data indicate that many seropositive RA ILD patients probably represent an overlap RA/SSc entity, requiring tailored diagnostic and therapeutic approach.

ANA-specific antibodies, ANA patterns, anti-ds-DNA results, and clinical diagnosis: a laboratory and clinical audit

The diagnosis of systemic autoimmune diseases (SAID) is challenging, due to overlapping features with other non-immune disorders. Anti-nuclear antibodies (ANA)/anti-cellular antibodies are the sensitive screening tests but anti-double-stranded-deoxyribonucleic acid-antibody (anti-ds-DNA) and ANA-specific antibodies are specific for SAID. We aimed to look at ANA-specific antibodies in our patients and correlated them with ANA patterns, anti-ds-DNA, and clinical diagnosis for proper interpretation and better patient management cost-effectively. A retrospective data analysis of 641 patients was done (1st of February 2019 to 31st of July 2021) who were tested for ANA-specific antibodies at the Immunology Department of Indus Hospital and Health Network. ANA and anti-ds-DNA results and clinical diagnosis were also analyzed for ANA-specific antibody-positive patients. Descriptive data were presented in mean ± standard deviation and frequency percentages whereas inferential data were analyzed with a chi-square test for association between ANA-specific antibodies status, ANA, anti-ds-DNA, and clinical features. ANA-specific antibodies test revealed positivity for at least one autoantibody in 245 (38.2%) patients. Of these, ANA was tested in 206 patients reactive for ANA-specific antibodies and found positive in 195 (95%) as compared to negative (< 0.001). Speckled and homogenous were predominant ANA patterns in ANA-specific antibody-positives (56% and 42% respectively). Multiple ANA patterns were found in 18 patients most commonly with systemic lupus erythematosus (SLE) and mixed connective tissue disorder (MCTD). Anti-SSA were the most common ANA-specific antibodies (50%) and were mostly found in sera with speckled (61/97) and homogenous (38/97) patterns and associated mostly with SLE (48%) and Sjogren's syndrome (86%). Among ANA-negative patients, anti-SSA were the most common antibodies (n = 5). Anti-ds-DNA was found in 66% of SLE patients along with another ANA-specific antibody. This study showed that testing for ANA-specific antibodies cannot be gated on ANA patterns. Also, there is a redundancy of these antibodies with various clinical diagnoses. Moreover, they are useful in making a diagnosis in ANA-negative patients as well with clinical suspicion.

Neonatal lupus erythematosus - prevention is better than cure

Neonatal lupus erythematosus (NLE) is a congenital autoimmune condition in which the transplacental passage of immunoglobulin G (IgG) directed against auto-antigens causes clinical symptoms in the foetus or neonate. Anti-Ro/SS-A, anti-La/SS-B, and to a lesser extent, anti-U1RNP autoantibodies (aAbs) have the strongest association with NLE. However, ~ 50% of affected mothers are asymptomatic despite carrying those aAbs. The clinical picture of the disease is very diverse. Cardiac manifestations are the most severe, including congenital heart block (CHB), with a mortality rate of ~18%. Preventative therapy with hydroxychloroquine (HCQ) reduces the recurrence rate of CHB in subsequent pregnancies by ~50%.

Pulmonary renal syndrome: a clinical review

The term "pulmonary renal syndrome" describes a clinical syndrome which is characterised by the presence of both diffuse alveolar haemorrhage and glomerulonephritis. It encompasses a group of diseases with distinctive clinical and radiological manifestations, as well as different pathophysiological processes. The most common diseases implicated are anti-neutrophil cytoplasm antibodies (ANCA)-positive small vessel vasculitis and anti-glomerular basement membrane (anti-GBM) disease. Prompt recognition is required as respiratory failure and end-stage renal failure can rapidly occur. Treatment includes a combination of glucocorticoids, immunosuppression, plasmapheresis and supportive measures. The use of targeted treatments has significantly reduced mortality. Thus, an understanding of pulmonary renal syndrome is essential for the respiratory physician.

Autoantibodies in Neuropsychiatric Systemic Lupus Erythematosus (NPSLE): Can They Be Used as Biomarkers for the Differential Diagnosis of This Disease?

Systemic lupus erythematosus is a complex immunological disease where both environmental factors and genetic predisposition lead to the dysregulation of important immune mechanisms. Eventually, the combination of these factors leads to the production of self-reactive antibodies that can target any organ or tissue of the human body. Autoantibodies can form immune complexes responsible for both the organ damage and the most severe complications. Involvement of the central nervous system defines a subcategory of the disease, generally known with the denomination of neuropsychiatric systemic lupus erythematosus. Neuropsychiatric symptoms can range from relatively mild manifestations, such as headache, to more severe complications, such as psychosis. The evaluation of the presence of the autoantibodies in the serum of these patients is the most helpful diagnostic tool for the assessment of the disease. The scientific progresses achieved in the last decades helped researchers and physicians to discover some of autoepitopes targeted by the autoantibodies, although the majority of them have not been identified yet. Additionally, the central nervous system is full of epitopes that cannot be found elsewhere in the human body, for this reason, autoantibodies that selectively target these epitopes might be used for the differential diagnosis between patients with and without the neuropsychiatric symptoms. In this review, the most relevant data is reported with regard to mechanisms implicated in the production of autoantibodies and the most important autoantibodies found among patients with systemic lupus erythematosus with and without the neuropsychiatric manifestations.

Autoimmune and immunoserological markers of COVID-19 pneumonia: Can they help in the assessment of disease severity

Background

Immune dysregulation and associated inefficient anti-viral immunity during Coronavirus Disease 2019 (COVID-19) can cause tissue and organ damage which shares many similarities with pathogenetic processes in systemic autoimmune diseases. In this study, we investigate wide range autoimmune and immunoserological markers in hospitalized patients with COVID-19.

Methods

Study included 51 patients with confirmed Severe Acute Respiratory Syndrome Coronavirus 2 infection and hospitalized due to COVID-19 pneumonia. Wide spectrum autoantibodies associated with different autoimmune inflammatory rheumatic diseases were analyzed and correlated with clinical and laboratory features and pneumonia severity.

Results

Antinuclear antibodies (ANA) positivity was found in 19.6%, anti-cardiolipin IgG antibodies (aCL IgG) in 15.7%, and anti-cardiolipin IgM antibodies (aCL IgM) in 7.8% of patients. Positive atypical x anti-neutrophil cytoplasmic antibodies (xANCA) were detected in 10.0% (all negative for Proteinase 3 and Myeloperoxidase) and rheumatoid factor was found in 8.2% of patients. None of tested autoantibodies were associated with disease or pneumonia severity, except for aCL IgG being significantly associated with higher pneumonia severity index (p = 0.036). Patients with reduced total serum IgG were more likely to require non-invasive mechanical ventilation (NIMV) (p < 0.0001). Serum concentrations of IgG (p = 0.003) and IgA (p = 0.032) were significantly lower in this group of patients. Higher total serum IgA (p = 0.009) was associated with mortality, with no difference in serum IgG (p = 0.115) or IgM (p = 0.175). Lethal outcome was associated with lower complement C4 (p = 0.013), while there was no difference in complement C3 concentration (p = 0.135).

Conclusion

Increased autoimmune responses are present in moderate and severe COVID-19. Severe pneumonia is associated with the presence of aCL IgG, suggesting their role in disease pathogenesis. Evaluation of serum immunoglobulins and complement concentration could help assess the risk of non-invasive mechanical ventilation NIMV and poor outcome.

Assessment of Cardiac Risk in Women with Autoimmune Disease

PURPOSE OF REVIEW

The purpose of our review was to evaluate current standards in clinical practice in determining overall cardiac risk in female patients with chronic rheumatologic diseases. We hoped to not only summarize known cardiac manifestations of various chronic rheumatologic diseases but also determine the effectiveness of new risk scores in determining cardiac risk in this patient population.

RECENT FINDINGS

Chronic rheumatologic diseases have been associated with various cardiac manifestations for some time, with initial studies involving risk of coronary artery disease (CAD) in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). However, recent studies have shown numerous other cardiac manifestations associated with these and other chronic rheumatologic diseases. Risk scores have been used for several decades to help determine overall cardiac risk in the general population, but these risk scores have notoriously underestimated the risk of cardiac disease in woman and in patients with chronic rheumatologic diseases. These diseases, often with a female predominance, can impact long-term mortality and have devastating consequences if not monitored and treated appropriately. Thus, new risk scores have been developed over the last several years to help improve detection and awareness of cardiac disease in these patients. Novel modified risk scores have found some success at improving the detection of cardiac disease in patients with chronic rheumatologic diseases. Further studies looking at these risk scores need to determine the accuracy of these scores and where they fall short. With the advent of advanced imaging technologies, future risk scores may involve certain imaging-based markers to help guide accurate risk determination.

Autoantibody Landscape Revealed by Wet Protein Array: Sum of Autoantibody Levels Reflects Disease Status

Autoantibodies are found in various pathological conditions such as autoimmune diseases, infectious diseases, and malignant tumors. However their clinical implications have not yet been fully elucidated. Herein, we conducted proteome-wide autoantibody screening and quantification with wet protein arrays consisting of proteins synthesized from proteome-wide human cDNA library (HuPEX) maintaining their three-dimensional structure. A total of 565 autoantibodies were identified from the sera of three representative inflammatory disorders (systemic sclerosis, psoriasis, and cutaneous arteritis). Each autoantibody level either positively or negatively correlated with serum levels of C-reactive protein, the best-recognized indicator of inflammation. In particular, we discovered total levels of a subset of autoantibodies correlates with the severity of clinical symptoms. From the sera of malignant melanoma, 488 autoantibodies were detected. Notably, patients with metastases had increased overall autoantibody production compared to those with tumors limiting to the primary site. Collectively, proteome-wide screening of autoantibodies using the in vitro proteome can reveal the "autoantibody landscape" of human subjects and may provide novel clinical biomarkers.

A Mechanistic Insight into the Pathogenic Role of Interleukin 17A in Systemic Autoimmune Diseases

Interleukin 17A (IL-17A) has been put forward as a strong ally in our fight against invading pathogens across exposed epithelial surfaces by serving an antimicrobial immunosurveillance role in these tissues to protect the barrier integrity. Amongst other mechanisms that prevent tissue injury mediated by potential microbial threats and promote restoration of epithelial homeostasis, IL-17A attracts effector cells to the site of inflammation and support the host response by driving the development of ectopic lymphoid structures. Accumulating evidence now underscores an integral role of IL-17A in driving the pathophysiology and clinical manifestations in three potentially life-threatening autoimmune diseases, namely, systemic lupus erythematosus, Sjögren’s syndrome, and systemic sclerosis. Available studies provide convincing evidence that the abundance of IL-17A in target tissues and its prime source, which is T helper 17 cells (Th17) and double negative T cells (DNT), is not an innocent bystander but in fact seems to be prerequisite for organ pathology. In this regard, IL-17A has been directly implicated in critical steps of autoimmunity. This review reports on the synergistic interactions of IL-17A with other critical determinants such as B cells, neutrophils, stromal cells, and the vasculature that promote the characteristic immunopathology of these autoimmune diseases. The summary of observations provided by this review may have empowering implications for IL-17A-based strategies to prevent clinical manifestations in a broad spectrum of autoimmune conditions.

LC-MS/MS-Based Serum Protein Profiling for Identification of Candidate Biomarkers in Pakistani Rheumatoid Arthritis Patients

Rheumatoid arthritis is an autoimmune disorder of complex disease etiology. Currently available serological diagnostic markers lack in terms of sensitivity and specificity and thus additional biomarkers are warranted for early disease diagnosis and management. We aimed to screen and compare serum proteome profiles of rheumatoid arthritis serotypes with healthy controls in the Pakistani population for identification of potential disease biomarkers. Serum samples from rheumatoid arthritis patients and healthy controls were enriched for low abundance proteins using ProteoMinerTM columns. Rheumatoid arthritis patients were assigned to one of the four serotypes based on anti-citrullinated peptide antibodies and rheumatoid factor. Serum protein profiles were analyzed via liquid chromatography-tandem mass spectrometry. The changes in the protein abundances were determined using label-free quantification software ProgenesisQITM followed by pathway analysis. Findings were validated in an independent cohort of patients and healthy controls using an enzyme-linked immunosorbent assay. A total of 213 proteins were identified. Comparative analysis of all groups (false discovery rate < 0.05, >2-fold change, and identified with ≥2 unique peptides) identified ten proteins that were differentially expressed between rheumatoid arthritis serotypes and healthy controls including pregnancy zone protein, selenoprotein P, C4b-binding protein beta chain, apolipoprotein M, N-acetylmuramoyl-L-alanine amidase, catalytic chain, oncoprotein-induced transcript 3 protein, Carboxypeptidase N subunit 2, Apolipoprotein C-I and Apolipoprotein C-III. Pathway analysis predicted inhibition of liver X receptor/retinoid X receptor activation pathway and production of nitric oxide and reactive oxygen species pathway in macrophages in all serotypes. A catalogue of potential serum biomarkers for rheumatoid arthritis were identified. These biomarkers can be further evaluated in larger cohorts from different populations for their diagnostic and prognostic potential.

The Past, Present, and Future in Antinuclear Antibodies (ANA)

Autoantibodies are a hallmark of autoimmunity and, specifically, antinuclear antibodies (ANAs) are the most relevant autoantibodies present in systemic autoimmune rheumatic diseases (SARDs). Over the years, different methods from LE cell to HEp-2 indirect immunofluorescence (IIF), solid-phase assays (SPAs), and finally multianalyte technologies have been developed to study ANA-associated SARDs. All of them provide complementary information that is important to provide the most clinically valuable information. The identification of new biomarkers together with multianalyte platforms will help close the so-called "seronegative gap" and to correctly classify and diagnose patients with SARDs. Finally, artificial intelligence and machine learning is an area still to be exploited but in a next future will help to extract patterns within patient data, and exploit these patterns to predict patient outcomes for improved clinical management.

Prevalence of antinuclear antibodies in inflammatory bowel disease and seroconversion after biological therapy

BACKGROUND

Estimates of detectable antinuclear antibodies (ANA) prevalence vary widely, from 6% in healthy populations to 50-80% in patients with autoimmune disease. However, there is a lack of evidence about the overall prevalence in inflammatory bowel disease (IBD) and ANA seroconversion after the beginning of biological therapy.

OBJECTIVES

The aim of the study was to investigate the overall prevalence of ANA in IBD patients, their relationship with different treatments, clinical outcomes and the seroconversion rate of ANA in patients treated with biological therapy.

METHODS

Ambispective observational study including all consecutive IBD patients was carried out. Information about the presence of ANA, disease phenotype, duration, activity, complications, and past and current treatments were transversally collected. Retrospectively, in patients with detectable ANA, data regarding previous ANA detection and the diagnosis of lupus-like syndrome (LLS) was gathered.

RESULTS

A total of 879 IBD patients were included. We observed a detectable ANA prevalence of 13.6%. The presence of ANA was frequently associated with biological therapy (36/118) and decreased when immunomodulators were combined to this therapy (7/32). Of 78 patients with ANA prior to the beginning of biological therapy, a seroconversion rate of 28.8% was observed after a mean of 3.14 years. Only 1 patient suffered LLS.

CONCLUSION

Our study showed a prevalence of detectable ANA higher than the expected in healthy population. The presence of ANA was lower when immunomodulator therapy is associated. The ANA seroconversion rate is relevant after the initiation of biological treatment nevertheless, the risk of LLS appeared to be marginal.

Association of Viral Infection With the Development and Pathogenesis of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that causes multiple organ damage in women of childbearing age and has a relapsing-remitting course. SLE is caused by the interaction between genetic and environmental factors, however, its underlying triggers remain unknown. Among the environmental factors, the involvement of infections as a trigger for SLE, especially those of viral etiology, has been widely reported. Human endogenous retroviruses (HERVs) may put patients at a genetic predisposition to SLE, while the Epstein-Barr virus (EBV) may play a role as an environmental factor that triggers the development of SLE. It has been suggested that EBV-infected B-cells may become resistant to apoptosis, resulting in the activation, proliferation, and antibody production of autoreactive B-cells, which cause tissue damage in SLE. However, the interaction between the virus and immune cells, as well as the impact of the virus on the differentiation and dysfunction of immune cells, remain unclear. In this review, we focus on the relationship between the development and pathogenesis of SLE and viral infections, as well as the mechanism of SLE exacerbation via activation of immune cells, such as B-cells, based on the latest findings.

Autoantibodies in Common Connective Tissue Diseases: A Primer for Laboratory Professionals

Background

Autoimmune connective tissue disorders are a significant health concern throughout the world with an estimated prevalence of 3% to 5%. They are associated with a variety of autoantibodies that play roles in their diagnosis, risk stratification, prognostication, and/or management. While some autoantibodies have been well-characterized for use in clinical laboratories, many more are in the research stage. Rapid transition from research to clinical practice, lack of clinical guidelines, and harmonization across a rapidly growing number of commercially available tests create numerous challenges to clinicians and laboratories.

Content

This article briefly discusses common connective tissue disorders and their association with well-known autoantibodies, describes current methods used in clinical laboratories, and outlines their advantages and limitations in the context of these diseases.

Summary

Understanding the role of specific autoantibodies and various methodologies for autoantibody testing are important for laboratory professionals who may be introducing/repatriating new tests, updating existing tests, or advising clinicians/patients about testing options/results. Collaboration between laboratory professional staff and clinicians, around the advantages and limitations of each methodology, is also important in their appropriate clinical utilization.

Autoantibodies in the disease criteria for systemic sclerosis: The need for specification for optimal application

The ACR/EULAR classification criteria for systemic sclerosis (SSc) entail three autoantibodies: anti-centromere antibodies (ACA), anti-topoisomerase I antibodies (ATA), and anti-RNA-polymerase III antibodies (ARA). The importance of ACA and ATA in the classification criteria is evidence based, but the diagnostic value is overestimated by clinicians. Fortunately, these autoantibodies are characterized by good agreement between different immuno-assays. Inclusion of ARA, however, is based on limited evidence and is related to limited agreement between different immuno-assays. Harmonization of immuno-assays in terms of interpretation based on likelihood ratio's may improve future classification criteria for SSc and this needs to be achieved by close collaboration between clinicians, laboratory specialists and the diagnostic industry.