European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) SLE classification criteria item performance

Classification of systemic lupus erythematosus: From the development of classification criteria to a new taxonomy?

SLE is a highly variable systemic autoimmune disease. Its immunopathological effector phase is partly understood. However, the background of its variability is not. SLE classification criteria have been relying on the clinical manifestations and standard autoimmune serology. This still holds true for the 2019 EULAR/ACR classification criteria. On one hand, this has led to significant precision in defining patients with SLE. On the other hand, the information in the criteria neither helps understanding the individual patient's pathophysiology, nor does it predict the efficacy of the available immunomodulatory therapies. Chances of further improvement of clinical criteria are most likely limited. This is where new multi-omic approaches have started to make an impact. While not yet able to differentiate diseases with the same precision as the classification criteria, the results of these studies go far beyond the scope of the criteria with regard to immune dysregulation. Looking at both sides in detail, we here try to synthesize the available data, aiming at a better understanding of SLE and its immune pathophysiology.

Knowledge of Common Symptoms of Rheumatic Diseases and Causes of Delayed Diagnosis in Saudi Arabia

Purpose

The aim of this study is to determine the general population's knowledge on the different symptoms of rheumatic diseases, the key factors for diagnosis delays from the patient's perspective, the length of delay from the onset of symptoms to the diagnosis, and the effect this holds on the disease activity, response to therapy, and the development of complications and nonreversible deformities in patients diagnosed with rheumatic diseases.

Patients and Methods

This is a cross-sectional study. Our target study population were the residents of Saudi Arabia. Data were collected via an online questionnaire and analyzed with SPSS.

Results

The overall prevalence of rheumatic disease in our cohort was 8.7%. Joint pain (75.7%), joint swelling (47.1%) and morning stiffness (32.9%) were the first and most common presenting symptom. Persistence of symptoms (N=32, 45.7%) and symptom worsening (N=21, 30.0%) was the predominant cause to visit rheumatologist. The duration between first symptom and rheumatic disease diagnosis is significantly longer for patients aged <50 years compared to that of those with ≥50 years of age. Results show that 36.4% of patients aged ≥50 years had delayed diagnosis due to late appointment compared with 5.7% of patients aged <50 years. In addition, patients with longer duration of symptoms were likely to have more visits to the rheumatologist. Most of the participants of <50 years significantly agreed that rheumatologists treat autoimmune diseases, only a few approved that they treat muscle problems.

Conclusion

Most participants in our study have lesser knowledge about their symptoms and they did not know where to consult for the treatment of their disease. This caused unnecessary delays and worsening and aggravation of the symptoms. There is an increased need to organize an awareness campaign in the general population regarding autoimmune and rheumatic diseases.

SLE criteria are by necessity still based on clinical (and immunological) criteria items

INTRODUCTION

The 2019 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria for systemic lupus erythematosus (SLE) rely on clinical and routine immunological items. The criteria have anti-nuclear antibodies (ANA) as an obligatory entry criterion; items are weighted and ordered in domains. While demonstrating good sensitivity and specificity, the lack of a more molecular approach to some came as a disappointment.

AREAS COVERED

Based on a non-systematic literature search, this review covers items investigated in the EULAR/ACR classification criteria project, but not included in the set of criteria. It demonstrates data on the importance of the criteria and analyses implications of multiomics studies started around the same time as the criteria project. We also discuss data on the type-I interferon signature and on other cytokines, as well as on complement proteins and their split products. The final part deals with the variability in disease and the apparently random pattern of autoantibodies and organ manifestations in individual patients.

EXPERT OPINION

We believe that the EULAR/ACR criteria are a relevant step toward the right direction. A more uniform molecular approach will not be feasible as long as the molecular mechanisms underlying the tendency toward producing multiple autoantibodies are not better understood.

Duplex Vertical-Flow Rapid Tests for Point-of-Care Detection of Anti-dsDNA and Anti-Nuclear Autoantibodies

The goal of this study is to develop a rapid diagnostic test for rheumatic disease and systemic lupus erythematosus (SLE) screening. A novel rapid vertical flow assay (VFA) was engineered and used to assay anti-nuclear (ANA) and anti-dsDNA (αDNA) autoantibodies from systemic lupus erythematosus (SLE) patients and healthy controls (HCs). Observer scores and absolute signal intensities from the VFA were validated via ELISA. The rapid point-of-care VFA test that was engineered demonstrated a limit of detection of 0.5 IU/mL for ANA and αDNA autoantibodies in human plasma with an inter-operator CV of 19% for ANA and 12% for αDNA. Storage stability was verified over a three-month period. When testing anti-dsDNA and ANA levels in SLE and HC serum samples, the duplex VFA revealed 95% sensitivity, 72% specificity and an 84% ROC AUC value in discriminating disease groups, comparable to the gold standard, ELISA. The rapid αDNA/ANA duplex VFA can potentially be used in primary care clinics for evaluating patients or at-risk subjects for rheumatic diseases and for planning follow-up testing. Given its low cost, ease, and rapid turnaround, it can also be used to assess SLE prevalence estimates.

[Immunopathogenesis of systemic lupus erythematosus]

Insights into the immunopathogenesis of systemic lupus erythematosus (SLE) help to understand the complex disease patterns and to develop new treatment strategies. The disease manifestations essentially result from autoantibodies, immune complexes and cytokines. Particularly the propensity towards developing various autoantibodies is central to the disease itself; autoantibody specificities lead to highly variable organ manifestations. This review article delineates the clinically relevant state of knowledge on SLE pathogenesis, with the goal to establish a model useful for clinical practice, which also helps to classify the novel therapeutic approaches.

The greatest contribution to medical science is the transformation from studying symptoms to studying their causes-the unrelenting legacy of Robert Koch and Louis Pasteur-and a causality perspective to approach a definition of SLE

The basic initiative related to this study is derived from the fact that systemic lupus erythematosus (SLE) is a unique and fertile system science subject. We are, however, still far from understanding its nature. It may be fair to indicate that we are spending more time and resources on studying the complexity of classified SLE than studying the validity of classification criteria. This study represents a theoretical analysis of current instinctual SLE classification criteria based on "the causality principle." The discussion has its basis on the radical scientific traditions introduced by Robert Koch and Louis Pasteur. They announced significant changes in our thinking of disease etiology through the implementation of the modern version of "the causality principle." They influenced all aspects of today's medical concepts and research: the transformation of medical science from studies of symptoms to study their causes, relevant for monosymptomatic diseases as for syndromes. Their studies focused on bacteria as causes of infectious diseases and on how the immune system adapts to control and prevent contagious spreading. This is the most significant paradigm shift in the modern history of medicine and resulted in radical changes in our view of the immune system. They described acquired post-infection immunity and active immunization by antigen-specific vaccines. The paradigm "transformation" has a great theoretical impact also on current studies of autoimmune diseases like SLE: symptoms and their cause(s). In this study, the evolution of SLE classification and diagnostic criteria is discussed from "the causality principle" perspective, and if contemporary SLE classification criteria are as useful as believed today for SLE research. This skepticism is based on the fact that classification criteria are not selected based on cogent causal strategies. The SLE classification criteria do not harmonize with Koch's and Pasteur's causality principle paradigms and not with Witebsky's Koch-derived postulates for autoimmune and infectious diseases. It is not established whether the classification criteria can separate SLE as a "one disease entity" from "SLE-like non-SLE disorders"-the latter in terms of SLE imitations. This is discussed here in terms of weight, rank, and impact of the classification criteria: Do they all originate from "one basic causal etiology"? Probably not.

Maternal-fetal outcomes in patients with immune-mediated inflammatory diseases, with consideration of comorbidities: a retrospective cohort study in a large U.S. healthcare system

Background

Immune-mediated inflammatory diseases (IMIDs) are likely to complicate maternal health. However, literature on patients with IMIDs undergoing pregnancy is scarce and often overlooks the presence of comorbidities. We aimed to evaluate the impact of IMIDs on adverse pregnancy outcomes after assessing and addressing any discrepancies in the distribution of covariates associated with adverse pregnancy outcomes between patients with and without IMIDs.

Methods

We conducted a retrospective cohort study using data from an integrated U.S. community healthcare system that provides care across Alaska, California, Montana, Oregon, New Mexico, Texas, and Washington. We used a database containing all structured data from electronic health record (EHRs) and analyzed the cohort of pregnant people who had live births from January 1, 2013, through December 31, 2022. We investigated 12 selected IMIDs: psoriasis, inflammatory bowel disease, rheumatoid arthritis, spondyloarthritis, multiple sclerosis, systemic lupus erythematosus, psoriatic arthritis, antiphospholipid syndrome, Sjögren's syndrome, vasculitides, sarcoidosis, and systemic sclerosis. We characterized patients with IMIDs prior to pregnancy (IMIDs group) based on pregnancy/maternal characteristics, comorbidities, and pre-pregnancy/prenatal immunomodulatory medications (IMMs) prescription patterns. We 1:1 propensity score matched the IMIDs cohort with people who had no IMID diagnoses prior to pregnancy (non-IMIDs cohort). Outcome measures were preterm birth (PTB), low birth weight (LBW), small for gestational age (SGA), and caesarean section.

Findings

Our analytic cohort had 365,075 people, of which 5784 were in the IMIDs group and 359,291 were in the non-IMIDs group. The prevalence rate of pregnancy of at least 20 weeks duration in people with a previous IMID diagnosis has doubled in the past ten years. 17% of the IMIDs group had at least one prenatal IMM prescription. Depending on the type of IMM, 48%-70% of the patients taking IMMs before pregnancy continued them throughout pregnancy. Overall, patients with one or more of these 12 IMIDs had increased risk of PTB (Relative risk (RR) = 1.1 [1.0, 1.3]; p = 0.08), LBW (RR = 1.2 [1.0, 1.4]; p = 0.02), SGA (RR = 1.1 [1.0, 1.2]; p = 0.03), and caesarean section (RR = 1.1 [1.1, 1.2], p < 0.0001) compared to a matched cohort of people without IMIDs. When adjusted for comorbidities, patients with rheumatoid arthritis (PTB RR = 1.2, p = 0.5; LBW RR = 1.1, p = 0.6) and/or inflammatory bowel disease (PTB RR = 1.2, p = 0.3; LBW RR = 1.0, p = 0.8) did not have significantly increased risk for PTB and LBW.

Interpretation

For patients who have been pregnant for 20 weeks or greater, the association between IMIDs and adverse pregnancy outcomes depends on both the nature of the IMID and the presence of comorbidities. Because this study was limited to pregnancies resulting in live births, results must be interpreted together with other studies on early pregnancy loss and stillbirth in patient with IMIDs.

Funding

National Institutes of Health.

Systemic Lupus Erythematosus: How Machine Learning Can Help Distinguish between Infections and Flares

Systemic Lupus Erythematosus (SLE) is a multifaceted autoimmune ailment that impacts multiple bodily systems and manifests with varied clinical manifestations. Early detection is considered the most effective way to save patients' lives, but detecting severe SLE activity in its early stages is proving to be a formidable challenge. Consequently, this work advocates the use of Machine Learning (ML) algorithms for the diagnosis of SLE flares in the context of infections. In the pursuit of this research, the Random Forest (RF) method has been employed due to its performance attributes. With RF, our objective is to uncover patterns within the patient data. Multiple ML techniques have been scrutinized within this investigation. The proposed system exhibited around a 7.49% enhancement in accuracy when compared to k-Nearest Neighbors (KNN) algorithm. In contrast, the Support Vector Machine (SVM), Binary Linear Discriminant Analysis (BLDA), Decision Trees (DT) and Linear Regression (LR) methods demonstrated inferior performance, with respective values around 81%, 78%, 84% and 69%. It is noteworthy that the proposed method displayed a superior area under the curve (AUC) and balanced accuracy (both around 94%) in comparison to other ML approaches. These outcomes underscore the feasibility of crafting an automated diagnostic support method for SLE patients grounded in ML systems.

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.

Clinical significance of antinuclear antibodies in primary immune thrombocytopenia

There are discrepancies across guidelines about whether the dosage of antinuclear antibodies (ANAs) is of use at the diagnosis of primary immune thrombocytopenia (ITP). This review describes the current knowledge about ANA prevalence in patients with primary ITP, and their potential usefulness as biomarkers for ITP evolution, response to treatments and increased risk of subsequent development of systemic lupus and thrombosis.

Maternal-fetal outcomes in patients with immune mediated inflammatory diseases, with consideration of comorbidities: a retrospective cohort study in a large U.S. healthcare system

Background

Immune-mediated inflammatory diseases (IMIDs) are likely to complicate maternal health. However, literature data on patients with IMIDs undergoing pregnancy is scarce and often overlooks the impact of comorbidities.

Methods

We investigated 12 selected IMIDs: psoriasis, inflammatory bowel disease, rheumatoid arthritis, spondyloarthritis, multiple sclerosis, systemic lupus erythematosus, psoriatic arthritis, antiphospholipid syndrome, Sjögren's syndrome, vasculitis, sarcoidosis, systemic sclerosis. We characterized patients with IMIDs prior to pregnancy (IMIDs group) based on pregnancy/maternal characteristics, comorbidities, and pre-pregnancy/prenatal immunomodulatory medications (IMMs) prescription patterns. We 1:1 propensity score matched the IMIDs cohort with people who had no IMID diagnoses prior to pregnancy (non-IMIDs cohort). Outcome measures were preterm birth (PTB), low birth weight (LBW), small for gestational age (SGA), and cesarean section.

Findings

The prevalence rate of pregnancy occurring with people with a previous IMID diagnosis has doubled in the past ten years. We identified 5,784 patients with IMIDs. 17% of the IMIDs group had at least one prenatal IMM prescription. Depending on the type of IMM, from 48% to 70% of the patients taking IMMs before pregnancy continued them throughout pregnancy. Patients with IMIDs had similar but slightly increased risks of PTB (Relative risk (RR)=1·1[1·0, 1·3]), LBW (RR=1·2 [1·0,1·4]), SGA (RR=1·1 [1·0,1·2]), and cesarean section (RR=1·1 [1·1,1·2]) compared to a matched cohort of people without IMIDs. Out of the 12 selected IMIDs, three for PTB, one for LBW, two for SGA, and six for cesarean section had results supporting increased risk.

Interpretation

The association between IMIDs and the increased risk of adverse pregnancy outcomes depend on both the nature of the IMID and the presence of comorbidities.

Machine Learning Approach for Predicting Systemic Lupus Erythematosus in an Oman-Based Cohort

Objectives

This study aimed to design a machine learning-based prediction framework to predict the presence or absence of systemic lupus erythematosus (SLE) in a cohort of Omani patients.

Methods

Data of 219 patients from 2006 to 2019 were extracted from Sultan Qaboos University Hospital's electronic records. Among these, 138 patients had SLE, while the remaining 81 had other rheumatologic diseases. Clinical and demographic features were analysed to focus on the early stages of the disease. Recursive feature selection was implemented to choose the most informative features. The CatBoost classification algorithm was utilised to predict SLE, and the SHAP explainer algorithm was applied on top of the CatBoost model to provide individual prediction reasoning, which was then validated by rheumatologists.

Results

CatBoost achieved an area under the receiver operating characteristic curve score of 0.95 and a sensitivity of 92%. The SHAP algorithm identified four clinical features (alopecia, renal disorders, acute cutaneous lupus and haemolytic anaemia) and the patient's age as having the greatest contribution to the prediction.

Conclusion

An explainable framework to predict SLE in patients and provide reasoning for its prediction was designed and validated. This framework enables clinicians to implement early interventions that will lead to positive healthcare outcomes.

Validation of the 2019 EULAR/ACR classification criteria for systemic lupus erythematosus in an academic tertiary care centre

OBJECTIVES

To assess the sensitivity and specificity of the 2019 EULAR/American College of Rheumatology (ACR) classification criteria for systemic lupus erythematosus (SLE) in outpatients at an academic tertiary care centre and to compare them to the 1997 ACR and the 2012 Systemic Lupus International Collaborating Clinics criteria.

METHODS

Prospective and retrospective observational cohort study.

RESULTS

3377 patients were included: 606 with SLE, 1015 with non-SLE autoimmune-mediated rheumatic diseases (ARD) and 1756 with non-ARD diseases (hepatocellular carcinoma, primary biliary cirrhosis, autoimmune hepatitis). The 2019 criteria were more sensitive than the 1997 criteria (87.0% vs 81.8%), but less specific (98.1% vs 99.5% in the entire cohort and 96.5% vs 98.8% in patients with non-SLE ARD), resulting in Youden Indexes for patients with SLE/non-SLE ARD of 0.835 and 0.806, respectively. The most sensitive items were history of antinuclear antibody (ANA) positivity and detection of anti-double-stranded deoxyribonucleic acid (dsDNA) antibodies. These were also the least specific items. The most specific items were class III/IV lupus nephritis and the combination of low C3 and low C4 complement levels, followed by class II/V lupus nephritis, either low C3 or low C4 complement levels, delirium and psychosis, when these were not attributable to non-SLE causes.

CONCLUSIONS

In this cohort from an independent academic medical centre, the sensitivity and specificity of the 2019 lupus classification criteria were confirmed. Overall agreement of the 1997 and the 2019 criteria was very good.

Clinical associations and characteristics of the polyspecific intrathecal immune response in elderly patients with non-multiple sclerosis chronic autoimmune-inflammatory neurological diseases - a retrospective cross-sectional study

Introduction

The polyspecific intrathecal immune response (PSIIR), aka MRZ reaction (M = measles, R = rubella, Z = zoster, optionally Herpes simplex virus, HSV) is defined as intrathecal immunoglobulin synthesis (IIS) for two or more unrelated viruses. Although an established cerebrospinal fluid (CSF) biomarker for multiple sclerosis (MS), a chronic autoimmune-inflammatory neurological disease (CAIND) of the central nervous system (CNS) usually starting in young adulthood, the full spectrum of CAINDs with a positive PSIIR remains ill defined.

Methods

In this retrospective, cross-sectional study, patients with CSF-positive oligoclonal bands (OCB) and - to enrich for non-MS diagnoses - aged ≥50 years were enrolled.

Results

Of 415 with PSIIR testing results (MRZ, HSV optional), 76 were PSIIR-positive. Of these, 25 (33%) did not meet the diagnostic criteria for MS spectrum diseases (MS-S) comprising clinically or radiologically isolated syndrome (CIS/RIS) or MS. PSIIR-positive non-MS-S phenotypes were heterogenous with CNS, peripheral nerve and motor neuron involvement and often defied unequivocal diagnostic classification. A rating by neuroimmunology experts suggested non-MS CAINDs in 16/25 (64%). Long-term follow-up available in 13 always showed a chronically progressive course. Four of five responded to immunotherapy. Compared to MS-S patients, non-MS CAIND patients showed less frequent CNS regions with demyelination (25% vs. 75%) and quantitative IgG IIS (31% vs. 81%). MRZ-specific IIS did not differ between both groups, while additional HSV-specific IIS was characteristic for non-MS CAIND patients.

Discussion

In conclusion, PSIIR positivity occurs frequently in non-MS-S patients ≥50 years. Although sometimes apparently coincidental, the PSIIR seems to represent a suitable biomarker for previously unnoticed chronic neurologic autoimmunities, which require further characterization.

Case report: Unusual patient with dermatomyositis associated with SARS-CoV-2 infection

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak is a major challenge for clinicians. SARS-CoV-2 infection results in coronavirus disease 2019 (COVID-19), and it is best known for its respiratory symptoms. It can also result in several extrapulmonary manifestations such as neurological complications potentially experienced during the course of COVID-19. The association of dermatomyositis (DM) with COVID-19 pathogenesis has not been well-studied. This study aimed to present a previously healthy 37-year-old man, a soldier by profession, with symptoms of DM on the 4th day from the onset of COVID-19. The patient presented DM symptoms with both skin and muscle manifestations. The patient suffered from cough, fever, and fatigue to begin with, and reverse-transcription polymerase chain reaction (RT-PCR) reported positive for SARS-CoV-2 infection. The laboratory findings showed, intra alia, elevated muscle enzymes CK 8253 U/l (N: <145 U/l), a positive test for myositis-specific autoantibodies (anti-Mi-2), electrodiagnostic tests exhibited features of myopathy, with the presence of muscle and skin symptoms. The patient improved with corticosteroids and immunosuppressive agent therapy. In summary, the association between COVID-19 and the development of multi-system autoimmune disorders such as DM remains unclear. Nevertheless, viral infections such as SARS-CoV-2 may likely serve as a trigger.

The increasing prevalence of autoimmunity and autoimmune diseases: an urgent call to action for improved understanding, diagnosis, treatment, and prevention

Autoimmunity is characterized by self-reactive immune components and autoimmune disease by autoimmunity plus pathology. Both autoimmunity and autoimmune diseases are dramatically increasing in many parts of the world, likely as a result of changes in our exposures to environmental factors. Current evidence implicates the momentous alterations in our foods, xenobiotics, air pollution, infections, personal lifestyles, stress, and climate change as causes for these increases. Autoimmune diseases have a major impact on the individuals and families they affect, as well as on our society and healthcare costs, and current projections suggest they may soon take their place among the predominant medical disorders. This necessitates that we increase the scope and scale of our efforts, and coordinate our resources and studies, to understand autoimmune disease risk factors and pathogeneses and improve our diagnostic, therapeutic, and preventive approaches, as the costs of inaction will be profound and far greater without such investments.

Diagnostic accuracy of the European League against rheumatism/American College of Rheumatology-2019 versus the Systemic Lupus International Collaborating Clinics-2012 versus the ACR-1997 classification criteria in adult systemic lupus erythematosus: A systematic review and meta-analysis

Aim

To evaluate the diagnostic performance of the American College of Rheumatology (ACR)-1997, the Systemic Lupus International Collaborating Clinics (SLICC)-2012, and the European League against Rheumatism (EULAR)/ACR-2019 classification criteria in adult patients with systemic lupus erythematosus (SLE).

Methods

PubMed, Embase, Web of Science and Cochrane Library databases were searched for literature comparing the three classification criteria of ACR-1997, SLICC-2012 and EULAR/ACR-2019, which took clinical diagnosis as reference. Meta-analysis was used to evaluate and compare the sensitivity, specificity and diagnostic odds ratio of ACR-1997, SLICC-2012 and EULAR/ACR-2019. To assess the early diagnosis capability of the classification criteria, subgroups of patients with disease duration < 3 years and < 1 year were selected for comparison of sensitivity and specificity based on the inclusion of the original study. The sensitivity and specificity of each item in three sets of classification criteria were evaluated. In addition, the clinical and immunological characteristics of patients who did not meet the three classification criteria were compared.

Results

Nine original studies were included in the analysis, including 6404 SLE patients and 3996 controls. Results showed that the diagnostic odds ratios (95% confidence interval) of the SLICC-2012 [136.35 (114.94, 161.75)] and EULAR/ACR-2019 [187.47 (158.00, 222.42)] were higher than those of the ACR-1997 [67.53 (58.75, 77.63)]. Compared with ACR-1997[(0.86 (0.82, 0.89)], SLICC-2012[(0.96 (0.93, 0.97)] and EULAR/ACR-2019[(0.95 (0.92, 0.97)] had higher sensitivity. The specificity of the three classification criteria was similar: ACR-1997, SLICC-2012, and EULAR/ACR-2019 were 0.93 (0.89, 0.95), 0.86 (0.79, 0.91), and 0.91 (0.85, 0.95), respectively. The sensitivity of SLICC-2012 and EULAR/ACR-2019 were higher than that of ACR-1997 in early-course subgroups. Patients who did not meet ACR-1997 had more hypocomplementemia, patients who did not meet SLICC-2012 had more cutaneous lupus and photosensitivity, and patients who did not meet EULAR/ACR-2019 had more cutaneous lupus and leucopenia.

Conclusions

SLICC-2012 and EULAR/ACR-2019 have better diagnostic ability than the ACR-1997, and the sensitivity of the former two criteria is also higher than that of the latter; Moreover, the SLICC-2012 and EULAR/ACR-2019 for patients in the early stages of disease performed equally excellent.

SLE classification criteria: Science-based icons or algorithmic distractions – an intellectually demanding dilemma

It is, so to say, not a prerogative authority assigned to SLE classification criteria that allow them to declare something definitively important about SLE. This is particularly true as criteria-based classification processes overrule the highly needed evolution of concise diagnostic criteria. It is classification criteria that allocate SLE patients into cohorts intended to describe the nature of their disease. Therefore, all major SLE classification criteria since the 1971 preliminary criteria usurp the role of diagnostic criteria. Today´s practice silently accept that the SLE classification process “diagnose” SLE patients despite the fact that classification criteria are not accepted as diagnostic criteria! This is a central paradox in contemporary SLE research strategies. Contemporary SLE cohorts are designed to investigate SLE´s etiological features. However, each cohort that is categorized by classification criteria has one central inherent problem. From theoretical and practical arguments, they embody multiple distinct clinical phenotypes. This raises the critical and principal question if phenotypically heterogenic SLE cohorts are useful to identify basic SLE-specific etiology(ies) and disease process(es). In times to come, we must prioritize development of firm diagnostic criteria for SLE, as the classification criteria have not contributed to reduce the enigmatic character of the syndrome. No radical improvements are visible in the horizon that may lead to concise investigations of SLE in well-defined homogenous SLE cohorts. We must develop new strategies where studies of phenotypically standardized cohorts of SLE must be central elements. Problems related to contemporary SLE classification criteria are contemplated, analyzed, and critically discussed in this study.

Performances of different classification criteria for systemic lupus erythematosus in a single-center cohort from Turkey

Objective

Sensitivity and specificity of SLE classification criteria may vary in different populations and clinical settings. In this study, we aimed to compare the performances of three criteria sets/rules (1997, 2012, and 2019) in a large cohort of patients and relevant diseased controls.

Methods

The medical records of consecutive SLE patients and diseased controls were reviewed for clinical and laboratory features relevant to all sets of criteria. Criteria sets/rules were analyzed based on sensitivity, positive predictive value, specificity, and negative predictive value, using clinical diagnosis with at least 6 months of follow-up as the gold standard. A subgroup analysis was performed in ANA positive patients.

Results

A total of 393 SLE patients and 308 non-SLE diseased controls were included. Sensitivity was 78.4% for 1997 criteria and was more than 90% for both 2012 (91.9%) and 2019 (94.4%) criteria. Specificity was the highest (95.1%) for 1997 ACR criteria, 91.5% for 2012 SLICC criteria and 91.2% for 2019 EULAR/ACR criteria. When only ANA positive patients were analyzed, sensitivity of each criteria increased by 1%, 0.8%, and 2.2%, respectively. Specificity of 1997 criteria decreased by 2% and specificity of 2012 and 2019 criteria both decreased to less than 90%.

Conclusion

EULAR/ACR criteria were more sensitive than 1997 criteria and had a comparable performance with SLICC criteria. When only ANA positive patients were analyzed, the presence of false positive results (originated from patients with Sjögren’s disease and antiphospholipid syndrome mainly) decreased the specificity of both SLICC and EULAR/ACR criteria.

Longitudinal analysis of ANA in the Systemic Lupus International Collaborating Clinics (SLICC) Inception Cohort

OBJECTIVES

A perception derived from cross-sectional studies of small systemic lupus erythematosus (SLE) cohorts is that there is a marked discrepancy between antinuclear antibody (ANA) assays, which impacts on clinicians' approach to diagnosis and follow-up. We compared three ANA assays in a longitudinal analysis of a large international incident SLE cohort retested regularly and followed for 5 years.

METHODS

Demographic, clinical and serological data was from 805 SLE patients at enrolment, year 3 and 5. Two HEp-2 indirect immunofluorescence assays (IFA1, IFA2), an ANA ELISA, and SLE-related autoantibodies were performed in one laboratory. Frequencies of positivity, titres or absorbance units (AU), and IFA patterns were compared using McNemar, Wilcoxon and kappa statistics, respectively.

RESULTS

At enrolment, ANA positivity (≥1:80) was 96.1% by IFA1 (median titre 1:1280 (IQR 1:640-1:5120)), 98.3% by IFA2 (1:2560 (IQR 1:640-1:5120)) and 96.6% by ELISA (176.3 AU (IQR 106.4 AU-203.5 AU)). At least one ANA assay was positive for 99.6% of patients at enrolment. At year 5, ANA positivity by IFAs (IFA1 95.2%; IFA2 98.9%) remained high, while there was a decrease in ELISA positivity (91.3%, p<0.001). Overall, there was >91% agreement in ANA positivity at all time points and ≥71% agreement in IFA patterns between IFA1 and IFA2.

CONCLUSION

In recent-onset SLE, three ANA assays demonstrated commutability with a high proportion of positivity and titres or AU. However, over 5 years follow-up, there was modest variation in ANA assay performance. In clinical situations where the SLE diagnosis is being considered, a negative test by either the ELISA or HEp-2 IFA may require reflex testing.

Seropositive Neuromyelitis Optica in a Case of Undiagnosed Ankylosing Spondylitis: A Neuro-Rheumatological Conundrum

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune astrocytopathy against foot processes of aquaporin-4 (AQP4) water channels. Patients with NMOSD tend to have other coexisting autoimmune/connective tissue diseases. However, AQP-4-antibody-positive NMOSD coexisting with ankylosing spondylitis (AS) is rare. AS is an immune-mediated disorder, a subset of axial spondyloarthropathies, which commonly manifests as chronic inflammatory back pain in young people, and it has a strong association with HLA-B27. In this study, a 35-year-old Indian man with an undiagnosed progressive axial spondyloarthropathy (i.e., AS) is reported presenting with acute-onset longitudinally extensive transverse myelitis, a clinical subset of NMOSD. Neuromyelitis optica spectrum disorder (NMOSD), a primary demyelinating disorder of the central nervous system (CNS), is an autoimmune astrocytopathy against foot processes of aquaporin-4 (AQP4) water channels, which manifests with optic neuritis, longitudinally extensive transverse myelitis (LETM), area-postrema syndrome, brainstem syndrome diencephalic syndrome, and cerebral syndrome.^1-4 Ankylosing spondylitis (AS) is an immune-mediated disorder, a subset of axial spondyloarthropathies, which commonly manifests as chronic inflammatory back pain in young people, and it has a strong association with HLA-B27.^5,6 AS characteristically targets the axial skeleton, peripheral joints, entheses (connective tissues between tendons/ligaments and bones), and gut.^5,6 Patients with NMOSD tend to have other coexisting autoimmune/connective tissue diseases.⁷ For example, cases with NMOSD and multiple sclerosis, which are other autoimmune primary demyelinating disorders of the CNS, have been reported.^8,9 However, concurrent existence of AS and NMOSD in the same patient even over years of disease course is rare.^10,11 In addition, studies describing neurological manifestations of AS are limited,¹² and they focus on joint inflammation and long-standing bony pathology (ankylosis) related to compressive myelopathy, myelo-radiculopathy, and cauda equina syndromes.^12,13 The authors present a case of a young Indian man with an undiagnosed progressive AS (misdiagnosed and mismanaged by an indigenous medical practitioner) presenting with acute-onset LETM variant of AQP4-positive NMOSD. A 35-year-old healthy, non-comorbid man from rural India came to the outpatient department with complaints of persistent tingling, numbness, and weakness of both lower limbs (right more than left) for 10 days. The clinical picture showed acute-onset urinary retention, which was relieved by urinary catheterization. An indigenous medical practitioner had prescribed drugs to treat a urinary tract infection. His weakness gradually progressed over the following week, causing him to become bedridden. During the removal of the catheter, he felt urgency, increased frequency of micturition, and overt urinary incontinence. He gave no history suggestive of any girdle-like sensations, root/radicular/tract pain, vertebral pain, trauma, recent vaccination, and diarrheal or febrile illness. For the last 8 months, he had a complaint of an insidious-onset, persistent, bilateral, dull aching pain in the gluteal region accompanied by low-back pain and morning stiffness up to 1 h, which markedly improved with activity and reoccurred following long periods of inactivity. He sometimes had to rise in the middle of the night because of excruciating pain, which could be relieved after moving around the room and corridors for half an hour. He was taking over-the-counter diclofenac tablets for pain relief prescribed by some indigenous medical practitioners who told him that it was due to overwork in agricultural fields, that is, mechanical back pain. He also had a normal X-ray of the lumbosacral spine. He had no addiction liabilities, and none of the family members had ever suffered from a similar kind of illness. He had never consulted any trained medical practitioner, as his previous back-pain-related symptoms responded well to the tablets prescribed by the indigenous medical practitioner(s). During examination, he was found to have recent-onset, asymmetric spastic paraparesis (right more than left) with upper motor neuron-type urinary bladder symptoms. Cognitive assessment (assessed by the Montreal cognitive assessment test) was normal, and posterior column sensations were preserved. Sensory system examination revealed no definite sensory level. Except for the paretic lower limbs, cerebellar functions were normal in other regions. Neuro-ophthalmological examinations were also normal, and no signs of meningeal irritation were observed. The history and course of the disease and clinical examinations were analyzed. Selective tractopathy (early and predominant motor and autonomic tract affection) was suggested for an intramedullary demyelinating pathology affecting the anterior central cord. This case was initially classified as acute-onset non-compressive myelopathy at the lower cervical/upper dorsal region level in a patient with a pre-existing axial spondyloarthropathy. Complete blood cell count; liver, kidney, and thyroid function tests; and plasma glucose and electrolytes were normal, except for an increased erythrocyte sedimentation rate (66 mm in the first hour). Magnetic resonance imaging (MRI) of the spinal cord revealed a demyelinating LETM from C5 to D4 level (Figure 1). Meanwhile, an MRI of the sacroiliac joints revealed bilateral sacroiliitis. Brain and orbital MRIs were devoid of any lesions. Anti-aquaporin 4 (AQP-4) antibodies were tested by cell-based assay in serum and cerebrospinal fluid (CSF), and both were positive. CSF further revealed lymphocytic pleocytosis and increased intrathecal protein production. Visually evoked potential recordings were also normal. In addition, anti-myelin oligodendrocyte glycoprotein antibodies were negative. Anti-nuclear antibody (ANA), ANA-profile, autoimmune vasculitis profile (c-ANCA, p-ANCA), neurovirus panel (i.e., polymerase chain reaction for adenovirus, Epstein-Barr virus, herpes simplex viruses 1 and 2, human herpesviruses 6 and 7, cytomegalovirus, enteroviruses, varicella-zoster virus, Japanese encephalitis, and dengue virus), CSF-polymerase chain reaction for Mycobacterium tuberculosis, angiotensin-converting enzyme, anti-phospholipid, and anti-thyroid antibodies were negative. Anti-CCP-antibody and rheumatoid factor were also negative, including creatine phosphokinase level and serum vitamin B12. Moreover, serologies for hepatitis B, C, human immunodeficiency virus, and scrub typhus were negative. However, HLA-B27 assay was positive. The final diagnosis was AQP4-positive NMOSD associated with AS. He was placed on pulse intravenous methylprednisolone (1 g/day for 5 days). Consequently, his lower limb power improved remarkably. Cyclical rituximab therapy was initiated to prevent relapses. At 3-month follow-up, he had no residual neurological deficit except for persistence of paresthesias. Neuroimaging and visually evoked potential studies revealed no active or new lesions. After 6 months of therapy, a subjective and objective improvement was observed in disease severity based on the Ankylosing Spondylitis Disease Activity Score. Our patient satisfied the new Assessment of SpondyloArthritis International Society diagnostic/classification criteria for AS and the Wingerchuk criteria for NMOSD,^4,14 an association that has been rarely reported.^10,11 Amid the extra-articular complications of long-standing AS, neurological manifestations are considered infrequent.¹⁵ However, subclinical neurological complications may be frequent in AS.¹² Common neurological manifestations result from bony (vertebral) ankylosis, subluxation of joints, ossification of anterior and posterior longitudinal ligaments, secondary spinal canal stenosis, bony (vertebral) fractures, and subsequent compressions over nerve radicles/roots/cauda equina, and inflammation-related (entrapment) peripheral neuropathies.^12,16,17 Acute transverse myelitis can occur as a subset of several primary demyelinating disorders of the CNS (i.e., multiple sclerosis, NMOSD, myelin oligodendrocyte glycoprotein antibody disease, and acute disseminated encephalomyelitis) and various systemic autoimmune connective tissue disorders (i.e., systemic lupus erythematosus, mixed connective tissue disease, Sjögren syndrome, inflammatory bowel disease, and neurosarcoidosis).¹⁸ Acute transverse myelitis (short or long segment) is an infrequent extra-articular complication of AS.¹⁸ It has been reported to evolve either as a distinct neurological complication of AS, or it may develop secondary to TNF-alpha-inhibitor therapy for the treatment of AS.^18,19 AS is a heritable inflammatory spondyloarthropathy that primarily affects the axial skeleton, which is mediated by T-cells; B-cells only play a minor role.⁵ On the contrary, the key for the pathogenesis of NMOSD is the production of autoantibodies against AQP-4 channels expressed on astrocytes, leading to complement-mediated damage, with ensuing demyelination. Myelitis usually shows high signal intensity on the tbl2-weighted image and contrast enhancement in the spinal cord.^1-4 Despite the difference in molecular mechanisms, the diagnosis of these diseases in the same individual may not be coincidental. Recent evidence has shown T-cell-mediated inflammatory responses in cases of NMOSD.²⁰ In particular, Th17 and Th2-related cytokines are elevated in the CSF of NMO patients.²⁰ Environmental factors such as Escherichia coli have also been proven to aggravate autoimmunity in AS and NMOSD (however, body fluid cultures for Escherichia coli, performed in our patient, showed similar association, and they were found negative two times).^21,22 Although large-scale epidemiological studies investigating the underlying pathogenesis related to these diseases are lacking, studies have demonstrated an increased incidence of optic neuritis among patients with AS.²³ Systemic sclerosis and mixed and undifferentiated connective tissue diseases were excluded after expert opinions (from two board-certified rheumatologists and two dermatologists) because of the lack of suggestive clinical findings (e.g., absence of skin thickening, salt-and-pepper appearance, nail changes, Mauskopf facies, sclerodactyly, calcinosis cutis, Raynaud's phenomenon, other cutaneous manifestations, pulmonary arterial hypertension/interstitial lung disease, dysphagia, muscular pain/weakness renal impairments, absence of ANA, anti-centromere antibodies, anti-Scl-70, PM-Scl antibodies, anti-ds DNA, PCNA, CENP-B, anti-nucleosomes, anti-Smith, anti-U1-RNP, anti-Jo1, anti-Mi2, anti-Ro52, anti-La antibodies, and normal C3 and C4 complement levels) (The European League Against Rheumatism and the American College of Rheumatology classification criteria 2019).²⁴ Finally, our patient was treated with intravenous steroids followed by rituximab infusions, a monoclonal anti-CD20 antibody directed against B-cells. In particular, this patient clinically and radiologically responded to immunomodulatory drugs, which might support a possible common pathogenic basis of the two processes. TNF-alpha inhibitors are commonly used as novel therapeutics in AS; however, they can potentially result in serious complications, that is, secondary demyelinating disorders.²⁵ However, such inhibitors in this patient were not used. When used in cases of AS, they show satisfactory results.^25,26 Therefore, it was decided to treat him with rituximab only without adding any second immunomodulatory. Other possible therapeutic options include cyclophosphamide and mycophenolate mofetil, but they were not used because of their low efficacy-safety balance. Moreover, plasmapheresis was not available in our specific setting, despite solid evidence that early treatment with therapeutic strategy (5-7 courses) provides good long-term outcomes in patients with NMOSD.²⁷ Therefore, when dealing with a case of acute non-compressive myelopathy, history and clinical examination are important to determine the potential underlying etiology and identify an undermined systemic disorder with apparently unrelated non-specific features. Connective tissue disorders should always be considered as a differential diagnosis and be ruled out in all cases of either seropositive or seronegative NMOSD. A diagnosis of AS should be considered in relevant circumstances when dealing with a case of isolated seronegative LETM. Moreover, early diagnosis and treatment of AS are quintessential to prevent lifelong distressing disabilities. However, whether patients with AS have any extra predilection to develop NMOSD throughout their life requires further studies.

Advances in SLE classification criteria

This year, the American College of Rheumatology (ACR) 1982 classification criteria for systemic lupus erythematosus (SLE) celebrate their 40th anniversary. From this start, the quest for optimal SLE criteria has led to the 1997 ACR update, the 2012 publication of the Systemic Lupus International Collaborating Clinics (SLICC) criteria, and, in 2019, the European League Against Rheumatism (EULAR)/ACR classification criteria. The latter have since been externally validated in more than two dozen studies and have become the gold standard inclusion criterion of SLE clinical trials. This comprehensive review attempts to follow the evolving success story of SLE classification, highlighting relevant decisions and their rationale, and discussing consequences for the way SLE is defined and managed.

A glimpse into the future of systemic lupus erythematosus

This viewpoint article on a forecast of clinically meaningful changes in the management of systemic lupus erythematosus (SLE) in the next 10 years is based on a review of the current state of the art. The groundwork has been laid by a robust series of classification criteria and treatment recommendations that have all been published since 2019. Building on this strong foundation, SLE management predictably will take significant steps forward. Assessment for lupus arthritis will presumably include musculoskeletal sonography. Large-scale polyomics studies are likely to unravel more of the central immune mechanisms of the disease. Biomarkers predictive of therapeutic success may enter the field; the type I interferon signature, as a companion for use of anifrolumab, an antibody against the common type I interferon receptor, is one serious candidate. Besides anifrolumab for nonrenal SLE and the new calcineurin inhibitor voclosporin in lupus nephritis, both of which are already approved in the United States and likely to become available in the European Union in 2022, several other approaches are in advanced clinical trials. These include advanced B cell depletion, inhibition of costimulation via CD40 and CD40 ligand (CD40L), and Janus kinase 1 (Jak1) and Tyrosine kinase 2 (Tyk2) inhibition. At the same time, essentially all of our conventional therapeutic armamentarium will continue to be used. The ability of patients to have successful SLE pregnancies, which has become much better in the last decades, should further improve, with approaches including tumor necrosis factor blockade and self-monitoring of fetal heart rates. While we hope that the COVID-19 pandemic will soon be controlled, it has highlighted the risk of severe viral infections in SLE, with increased risk tied to certain therapies. Although there are some data that a cure might be achievable, this likely will remain a challenge beyond 10 years from now.

Exploring the Differences in Molecular Mechanisms and Key Biomarkers Between Membranous Nephropathy and Lupus Nephritis Using Integrated Bioinformatics Analysis

Background: Both membranous nephropathy (MN) and lupus nephritis (LN) are autoimmune kidney disease. In recent years, with the deepening of research, some similarities have been found in the pathogenesis of these two diseases. However, the mechanism of their interrelationship is not clear. The purpose of this study was to investigate the differences in molecular mechanisms and key biomarkers between MN and LN. Method: The expression profiles of GSE99325, GSE99339, GSE104948 and GSE104954 were downloaded from GEO database, and the differentially expressed genes (DEGs) of MN and LN samples were obtained. We used Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) for enrichment analysis of DEGs. A protein-protein interaction (PPI) network of DEGs was constructed using Metascape. We filtered DEGs with NetworkAnalyst. Finally, we used receiver operating characteristic (ROC) analysis to identify the most significant DEGs for MN and LN. Result: Compared with LN in the glomerulus, 14 DEGs were up-regulated and 77 DEGs were down-regulated in MN. Compared with LN in renal tubules, 21 DEGs were down-regulated, but no up-regulated genes were found in MN. According to the result of GO and KEGG enrichment, PPI network and Networkanalyst, we screened out six genes (IFI6, MX1, XAF1, HERC6, IFI44L, IFI44). Interestingly, among PLA2R, THSD7A and NELL1, which are the target antigens of podocyte in MN, the expression level of NELL1 in MN glomerulus is significantly higher than that of LN, while there is no significant difference in the expression level of PLA2R and THSD7A. Conclusion: Our study provides new insights into the pathogenesis of MN and LN by analyzing the differences in gene expression levels between MN and LN kidney samples, and is expected to be used to prepare an animal model of MN that is more similar to human.

Anti-dsDNA antibodies in the classification criteria of systemic lupus erythematosus

Anti-double stranded DNA (dsDNA) antibodies play an important role in the diagnosis, classification and management of systemic lupus erythematosus (SLE), an autoimmune disease characterized by heterogeneous clinical manifestations and a wide range of autoantibodies, which makes the diagnosis quite challenging. In the absence of diagnostic criteria, classification criteria have been used for many decades. The first classification criteria for SLE were formulated in 1971 by the American College of Rheumatology (ACR), followed by two revisions in 1982 and 1997. In order to improve their clinical performance and to reflect new knowledge on autoantibodies, new classification criteria for SLE were issued in 2012 by the Systemic Lupus International Collaborating Clinics (SLICC). These criteria proposed to classify only patients that have at least one immunologic criterion, overcoming SLE classification based solely on clinical manifestations. In 2019, the European League Against Rheumatism (EULAR)/ACR proposed new criteria that aimed to maintain the high specificity of the ACR criteria with a sensitivity close to the SLICC 2012 criteria. These 2019 criteria reinforced the importance of autoantibodies in SLE diagnosis, assigning the highest score (6 points) to anti-dsDNA antibodies in the fully weighted scoring of the disease. The current criteria require the use of an anti-dsDNA assay with at least 90% specificity, such as the Crithidia luciliae immunofluorescence test (CLIFT) or FARR assay. However, the criteria do not comment on all the tests currently widely used in clinical laboratories. Neither do they consider the technological evolutions, nor standardization issues. Since strict adherence to any of the classification criteria, including the serological items, could lead to possible misclassification of SLE and/or delayed diagnosis, test characteristics of the distinct immunoassays should be taken into consideration.

Classification of systemic lupus erythematosus in children and adults

Systemic Lupus Erythematosus (SLE) is an autoimmune multisystem disease with a variable clinical phenotype and no single clinical, laboratory or pathological feature that can be used as a gold standard for disease classification or diagnosis. Classification criteria have been developed in an attempt to define homogenous groups of SLE patients for clinical research. They have been mainly validated in adult cohorts, given the much lower prevalence of SLE before puberty. The three commonly used sets of current classification criteria and their validation studies to date are described in this review. Challenges relating to classification of SLE patients, including important differences across age-groups and ethnicities, are explored along with future directions in the classification of SLE.