Specific antinuclear antibodies are associated with clinical features in systemic lupus erythematosus

Clinical characteristics and prognostic value of autoantibody profile in children with monogenic lupus

Objective

To report the frequency of selected autoantibodies and their associations with clinical features in Arab children with monogenic lupus.

Methods

This study was retrospective single-center study of genetically confirmed monogenic lupus cases at childhood lupus clinic at King Faisal Specialist Hospital and Research Center, from June 1997 to July 2022. We excluded familial lupus without genetic testing and patients with insufficient data. Collected data comprised clinical and laboratory findings, including the autoantibody profile, which included the anti-double-stranded DNA (anti-dsDNA), anti-Smith, anti-Sjögren's-syndrome-related antigen A (anti-SSA), anti-Sjögren's-syndrome-related antigen B (anti-SSB), and antiphospholipid (APL) antibodies. Also, disease activity and accrual disease damage were collected at the last follow-up visit.

Results

This study enrolled 27 Arab patients (14 males) with a median age of 11 years (interquartile range 8.0~16 years), with 63% having early-onset disease. The consanguinity rate and family history of lupus were high (74.1% and 55.6%, respectively). The most frequent clinical features were hematological (96.3%), fever (81.5%), mucocutaneous lesions (85.2%), and renal (66.7%). The frequency of the APL antibodies was 59.3%, anti-dsDNA was 55.6%, and anti-Smith and anti-SSA were 48.2% and 44.4%, respectively. Moreover, dsDNA antibodies were significantly associated with musculoskeletal complaints (p<0.05). Likewise, both anti-Smith and anti-SSA antibodies were linked to failure to thrive and recurrent infections in the univariate analysis (p<0.05).

Conclusion

Our study reveals autoantibody frequencies and their association with clinical and prognostic in a substantial monogenic lupus cohort. Distinct clinical manifestations and prognosis association with certain autoantibodies support the idea that monogenic lupus is a distinctive form of lupus. Larger studies needed to validate these findings.

[Fever in rheumatological diseases]

Fever is a frequent and important symptom in patients with rheumatological diseases and can be an expression of activity of the underlying rheumatological disease. There is great variability in the incidence of fever as a symptom of the disease between individual diseases. The growing understanding of the molecular signatures of the diseases can help to explain these discrepancies: A genetic overactivation of potently pyrogenic cytokines is the reason why fever is nearly always present in autoinflammatory syndromes. In contrast, fever is less common in polyarthritis and myositis and mostly limited to severe courses of disease. In the diagnostic work-up of fever, frequent differential diagnoses, such as infections, malignancies, side effects of drugs and hypersensitivity reactions should be considered. This article provides an overview of the physiology of the development of fever, describes the relevance of fever in individual rheumatological diseases and proposes a workflow for the clinical clarification of rheumatological patients who present with fever.

Prevalence of concomitant rheumatologic diseases and autoantibody specificities among racial and ethnic groups in SLE patients

Objective

Leveraging the Manhattan Lupus Surveillance Program (MLSP), a population-based registry of cases of systemic lupus erythematosus (SLE) and related diseases, we investigated the proportion of SLE with concomitant rheumatic diseases, including Sjögren's disease (SjD), antiphospholipid syndrome (APLS), and fibromyalgia (FM), as well as the prevalence of autoantibodies in SLE by sex and race/ethnicity.

Methods

Prevalent SLE cases fulfilled one of three sets of classification criteria. Additional rheumatic diseases were defined using modified criteria based on data available in the MLSP: SjD (anti-SSA/Ro positive and evidence of keratoconjunctivitis sicca and/or xerostomia), APLS (antiphospholipid antibody positive and evidence of a blood clot), and FM (diagnosis in the chart).

Results

1,342 patients fulfilled SLE classification criteria. Of these, SjD was identified in 147 (11.0%, 95% CI 9.2-12.7%) patients with women and non-Latino Asian patients being the most highly represented. APLS was diagnosed in 119 (8.9%, 95% CI 7.3-10.5%) patients with the highest frequency in Latino patients. FM was present in 120 (8.9%, 95% CI 7.3-10.5) patients with non-Latino White and Latino patients having the highest frequency. Anti-dsDNA antibodies were most prevalent in non-Latino Asian, Black, and Latino patients while anti-Sm antibodies showed the highest proportion in non-Latino Black and Asian patients. Anti-SSA/Ro and anti-SSB/La antibodies were most prevalent in non-Latino Asian patients and least prevalent in non-Latino White patients. Men were more likely to be anti-Sm positive.

Conclusion

Data from the MLSP revealed differences among patients classified as SLE in the prevalence of concomitant rheumatic diseases and autoantibody profiles by sex and race/ethnicity underscoring comorbidities associated with SLE.

Clusters based on demography, disease phenotype, and autoantibody status predicts mortality in lupus: data from Indian lupus cohort (INSPIRE)

OBJECTIVES

SLE is associated with significant mortality, and data from South Asia is limited. Thus, we analysed the causes and predictors of mortality and hierarchical cluster-based survival in the Indian SLE Inception cohort for Research (INSPIRE).

METHODS

Data for patients with SLE was extracted from the INSPIRE database. Univariate analyses of associations between mortality and a number of disease variables were conducted. Agglomerative unsupervised hierarchical cluster analysis was undertaken using 25 variables defining the SLE phenotype. Survival rates across clusters were assessed using non-adjusted and adjusted Cox proportional-hazards models.

RESULTS

Among 2072 patients (with a median follow-up of 18 months), there were 170 deaths (49.2 deaths per 1000 patient-years) of which cause could be determined in 155 patients. 47.1% occurred in the first 6 months. Most of the mortality (n = 87) were due to SLE disease activity followed by coexisting disease activity and infection (n = 24), infections (n = 23), and 21 to other causes. Among the deaths in which infection played a role, 24 had pneumonia. Clustering identified four clusters, and the mean survival estimates were 39.26, 39.78, 37.69 and 35.86 months in clusters 1, 2, 3 and 4, respectively (P < 0.001). The adjusted hazard ratios (HRs) (95% CI) were significant for cluster 4 [2.19 (1.44, 3.31)], low socio-economic-status [1.69 (1.22, 2.35)], number of BILAG-A [1.5 (1.29, 1.73)] and BILAG-B [1.15 (1.01, 1.3)], and need for haemodialysis [4.63 (1.87,11.48)].

CONCLUSION

SLE in India has high early mortality, and the majority of deaths occur outside the health-care setting. Clustering using the clinically relevant variables at baseline may help identify individuals at high risk of mortality in SLE, even after adjusting for high disease activity.

Ro52/TRIM21 - From host defense to autoimmunity

Ro52 (TRIM21) belongs to the ubiquitin ligase family. This protein plays a crucial role in many immunological processes, including antibody-dependent intracellular neutralization, synergy with the complement system, antiviral response, death mediation, oxidative stress response, and protein ubiquitination. Abnormal expression of TRIM21 can break immunological tolerance and lead to the production of autoantibodies against TRIM21. Antibodies against TRIM21 are detected in various autoimmune diseases, including Sjögren's syndrome (SS), systemic lupus erythematosus (SLE), or myositis. However, anti-TRIM21 presence is not limited to autoimmune connective tissue disorders. It was observed in patients with malignancies, various cancerous processes, infectious diseases, and idiopathic interstitial pneumonia. The occurrence of TRIM21 autoantibodies is also associated with clinical features, such as the prevalence of interstitial lung diseases and cardiac or haematological involvement in connective tissue disorders. The purpose of this review was to summarize current knowledge of the immunological functions of TRIM21 and analyze the clinical implications of anti-TRIM21 antibodies in the disease course.

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.

Genetic susceptibility for autoimmune diseases and white blood cell count

Some autoimmune (AI) conditions affect white blood cell (WBC) counts. Whether a genetic predisposition to AI disease associates with WBC counts in populations expected to have low numbers of AI cases is not known. We developed genetic instruments for 7 AI diseases using genome-wide association study summary statistics. Two-sample inverse variance weighted regression (IVWR) was used to determine associations between each instrument and WBC counts. Effect size represents change in transformed WBC counts per change in log odds-ratio of the disease. For AI diseases with significant associations by IVWR, polygenic risk scores (PRS) were used to test for associations with measured WBC counts in individuals of European ancestry in a community-based (ARIC, n = 8926), and a medical-center derived cohort (BioVU, n = 40,461). The IVWR analyses revealed significant associations between 3 AI diseases and WBC counts: systemic lupus erythematous (Beta = - 0.05 [95% CI, - 0.06, - 0.03]), multiple sclerosis (Beta =  - 0.06 [- 0.10, - 0.03]), and rheumatoid arthritis (Beta = 0.02 [0.01, 0.03]). PRS for these diseases showed associations with measured WBC counts in ARIC and BioVU. Effect sizes tended to be larger among females, consistent with the known higher prevalence of these diseases among this group. This study shows that genetic predisposition to systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis was associated with WBC counts, even in populations expected to have very low numbers of disease cases.

The Role of LFA-1 for the Differentiation and Function of Regulatory T Cells—Lessons Learned from Different Transgenic Mouse Models

Regulatory T cells (Treg) are essential for the maintenance of peripheral tolerance. Treg dysfunction results in diverse inflammatory and autoimmune diseases with life-threatening consequences. β2-integrins (CD11a-d/CD18) play important roles in the migration of leukocytes into inflamed tissues and cell signaling. Of all β2-integrins, T cells, including Treg, only express CD11a/CD18, termed lymphocyte function-associated antigen 1 (LFA-1), on their surface. In humans, loss-of-function mutations in the common subunit CD18 result in leukocyte adhesion deficiency type-1 (LAD-1). Clinical symptoms vary depending on the extent of residual β2-integrin function, and patients may experience leukocytosis and recurrent infections. Some patients can develop autoimmune diseases, but the immune processes underlying the paradoxical situation of immune deficiency and autoimmunity have been scarcely investigated. To understand this complex phenotype, different transgenic mouse strains with a constitutive knockout of β2-integrins have been established. However, since a constitutive knockout affects all leukocytes and may limit the validity of studies focusing on their cell type-specific role, we established a Treg-specific CD18-floxed mouse strain. This mini-review aims to delineate the role of LFA-1 for the induction, maintenance, and regulatory function of Treg in vitro and in vivo as deduced from observations using the various β2-integrin-deficient mouse models.

[Autoimmune diagnostics in nephrology and rheumatology]

Autoimmune diagnostics plays a central role in the detection of various acute and/or chronic diseases in both nephrology and rheumatology, which are associated with high morbidity and mortality if left untreated or not detected in time. Patients are threatened with significant limitations in everyday skills and quality of life due to loss of kidney function and dialysis, immobilizing and destructive joint processes or also significant damage of organ systems. In all of these autoimmune diseases, early diagnosis and treatment is of central importance for the further course and prognosis of disease.Antibodies play an essential role in the pathogenesis of autoimmune diseases. Antibodies are either directed against organ or tissue-specific antigens, such as in primary membranous glomerulonephritis or Goodpasture's syndrome, or they lead to a systemic disease such as systemic lupus erythematosus (SLE) or rheumatoid arthritis.Knowledge of the sensitivity and specificity of antibodies is crucial for the interpretation of antibody diagnostics results. Antibody detection can precede the clinical onset of the disease, and antibody titers often reflect disease activity. However, there are also false positive results. Detection of antibodies in the absence of disease symptoms often leads to uncertainty and unnecessary further diagnostics. Therefore, an unfounded "antibody screening" is not recommended.A rational antibody diagnostics is an integral part of the diagnostics and during treatment of nephrological and rheumatological diseases like glomerulonephrititis, pulmorenal syndrome, SLE and other collagenosis, thrombotic microangiopathy (HUS/TTP) and rheumatoid arthritis.

Risk of systemic lupus erythematosus flares according to autoantibody positivity at the time of diagnosis

To estimate the risk of systemic lupus erythematosus (SLE) flares based on the autoantibody positivity at the time of SLE diagnosis. This retrospective cohort study included 228 patients with newly diagnosed SLE. Clinical characteristics including autoantibody positivity at the time of diagnosis of SLE were reviewed. Flares were defined as a new British Isles Lupus Assessment Group (BILAG) A score or BILAG B score for at least one organ system. Multivariable Cox regression analyses were performed to estimate the risk of flares according to autoantibody positivity. Anti-dsDNA, anti-Sm, anti-U1RNP, anti-Ro, and anti-La antibodies (Abs) were positive in 50.0%, 30.7%, 42.5%, 54.8%, and 22.4% of the patients, respectively. The incidence rate of flares was 28.2/100 person-years. Multivariable Cox regression analysis, adjusted for potential confounders, revealed that anti-dsDNA Ab positivity (adjusted hazard ratio [HR]: 1.46, p = 0.037) and anti-Sm Ab positivity (adjusted HR: 1.81, p = 0.004) at the time of diagnosis of SLE were associated with higher risk of flares. To better delineate the flare risk, patients were categorized as double-negative, single-positive, double-positive for anti-dsDNA and anti-Sm Abs. Compared with double-negativity, double-positivity (adjusted HR: 3.34, p < 0.001) was associated with higher risk of flares, while anti-dsDNA Ab single-positivity (adjusted HR: 1.11, p = 0.620) or anti-Sm Ab single-positivity (adjusted HR: 1.32, p = 0.270) was not associated with higher risk of flares. Patients who are double-positive for anti-dsDNA and anti-Sm Abs at the time of the diagnosis of SLE are at higher risk of flares and may benefit from stringent monitoring and early preventive treatment.

Impaired Treg-DC interactions contribute to autoimmunity in leukocyte adhesion deficiency type 1

Leukocyte adhesion deficiency type 1 (LAD-1) is a rare disease resulting from mutations in the gene encoding for the common β-chain of the β2-integrin family (CD18). The most prominent clinical symptoms are profound leukocytosis and high susceptibility to infections. Patients with LAD-1 are prone to develop autoimmune diseases, but the molecular and cellular mechanisms that result in coexisting immunodeficiency and autoimmunity are still unresolved. CD4+FOXP3+ Treg are known for their essential role in preventing autoimmunity. To understand the role of Treg in LAD-1 development and manifestation of autoimmunity, we generated mice specifically lacking CD18 on Treg (CD18Foxp3), resulting in defective LFA-1 expression. Here, we demonstrate a crucial role of LFA-1 on Treg to maintain immune homeostasis by modifying T cell-DC interactions and CD4+ T cell activation. Treg-specific CD18 deletion did not impair Treg migration into extralymphatic organs, but it resulted in shorter interactions of Treg with DC. In vivo, CD18Foxp3 mice developed spontaneous hyperplasia in lymphatic organs and diffuse inflammation of the skin and in multiple internal organs. Thus, LFA-1 on Treg is required for the maintenance of immune homeostasis.

Lupus nephritis: A focus on the United Arab Emirates and the potential role of genetics

Lupus nephritis (LN) is a severe manifestation of systemic lupus erythematosus (SLE), characterized by chronic and progressive inflammation of the kidneys. As with many other autoimmune diseases, LN is a multifactorial disease caused by genetic and environmental factors. Globally, LN can affect around 60% of SLE patients, and it was observed to be less frequent and severe in Caucasian patients compared to other ethnic groups, including Arabs. Data on LN in the United Arab Emirates (UAE) are scattered and scarce in literature. Nevertheless, LN is common, occurring in around 43%-55% of SLE patients in the UAE. Anecdotally, the demographics and clinical features of SLE in the UAE have been distinct. However, the paucity of supporting literature makes it difficult to draw meaningful conclusions. Over the past two decades, there have been improvements in understanding the pathogenesis of LN; however, many cellular and molecular mechanisms which are implicated in the disease development and progression remain ambiguous. Investigating the clinical, pathological, and genetic characteristics of LN in different cohorts of patients is of importance for a better understanding of its pathogenesis, and thus improving its outcome. As a result, we acknowledge the need for large-scale epidemiological, clinical, and genetic investigation of LN cohorts in the UAE and surrounding regions.

Predictive model of risk and severity of enteritis in systemic lupus erythematosus

INTRODUCTION

To describe the clinical and laboratory features of systemic lupus erythematosus (SLE) enteritis and to establish a predictive model of risk and severity of lupus enteritis (LE).

METHODS

Records of patients with SLE complaining about acute digestive symptoms were reviewed. The predictive nomogram for the diagnosis of LE was constructed by using R. The accuracy of the model was tested with correction curves. The receiver operating characteristic curve (ROC curve) program and a Decision curve analysis (DCA) were used for the verification of LE model. Receiver operating characteristic curve was also employed for evaluation of factors in the prediction of severity of LE.

RESULTS

During the eight year period, 46 patients were in the LE group, while 32 were in the non-LE group. Abdominal pain, emesis, D-dimer >5 μg/mL, hypo-C3, and anti-SSA positive remained statistically significant and were included into the prediction model. Area under the curve (AUC) of ROC curve in this model was 0.909. Correction curve indicated consistency between the predicted rate and actual diagnostic rates. The DCA showed that the LE model was of benefit. Forty-four patients were included in developing the prediction model of LE severity. Infection, SLE disease activity index (SLEDAI), CT score, and new CT score were validated as risk factors for LE severity. The AUC of the combined SLEDAI, infection and new CT score were 0.870.

CONCLUSION

The LE model exhibits good predictive ability to assess LE risk in SLE patients with acute digestive symptoms. The combination of SLEDAI, infection, and new CT score could improve the assessment of LE severity.

Predictive factors for concomitant pulmonary arterial hypertension at diagnosis of systemic lupus erythematosus in a Chinese population

AIM

To investigate the predictive factors of pulmonary arterial hypertension (PAH) in systemic lupus erythematosus (SLE) patients.

METHOD

This chart review study included 408 SLE patients. We defined PAH as 2 consecutive systolic pulmonary arterial pressure (PAP) values ≥40 mm Hg by echocardiography. Demographic characteristics, clinical symptoms, autoantibodies, and laboratory tests were studied.

RESULTS

Thirty-four patients in the SLE/PAH+ group and 374 patients in the SLE/PAH- group were analyzed. The prevalence of PAH in SLE is 8.3% in this study. The occurrences of interstitial pneumonitis, polyserositis and myocardial damage were higher in the SLE/PAH+ group (P = .001, P = .033 and P < .001, respectively). The occurrence of anti-double-stranded DNA and anti-ribosomal RNA protein (anti-rRNP) antibodies were lower in the SLE/PAH+ group (P = .003, .010). Positive rates of anti-Sjögren's syndrome antigen A (anti-SSA)/Ro52 antibodies and anti-SSB antibodies were higher in the SLE/PAH+ group (P = .046, .021). C-reactive protein and immunoglobin G (IgG) were higher in the SLE/PAH+ group (P = .009, .005). Ejection fraction and SLE disease activity index between the 2 groups had no differences. Multivariable logistic regression indicated that interstitial pneumonitis, myocardial damage and high IgG are predictive factors for SLE-associated PAH patients.

CONCLUSION

From this study, we found that interstitial pneumonitis, myocardial damage, and high IgG were predictive factors of PAH in SLE patients.

Antibody-Mediated Rejection and Recurrent Primary Disease: Two Main Obstacles in Abdominal Kidney, Liver, and Pancreas Transplants

The advances in acute phase care have firmly established the practice of organ transplantation in the last several decades. Then, the next issues that loom large in the field of transplantation include antibody-mediated rejection (ABMR) and recurrent primary disease. Acute ABMR is a daunting hurdle in the performance of organ transplantation. The recent progress in desensitization and preoperative monitoring of donor-specific antibodies enables us to increase positive outcomes. However, chronic active ABMR is one of the most significant problems we currently face. On the other hand, recurrent primary disease is problematic for many recipients. Notably, some recipients, unfortunately, lost their vital organs due to this recurrence. Although some progress has been achieved in these two areas, many other factors remain largely obscure. In this review, these two topics will be discussed in light of recent discoveries.

How to report the antinuclear antibodies (anti-cell antibodies) test on HEp-2 cells: guidelines from the ICAP initiative

Results of the anti-nuclear antibodies-indirect immunofluorescence assay (anti-cell antibodies test) on HEp-2 cell substrates should be communicated to clinicians in a standardized way, adding value to laboratory findings and helping with critical clinical decisions. This paper proposes a test report based on the practices informed by 118 laboratories in 68 countries, with recommendations from the International Consensus on ANA Patterns (ICAP) group. Major focus is placed on the report format containing endpoint titers, immunofluorescence patterns together with anti-cell (AC) nomenclature, remarks on follow-up or reflex testing, and possible other autoantibody associations. ISO 15,189 directives were integrated into the test report. Special situations addressed include serum screening dilutions and endpoint titers, relevance of immunofluorescence patterns with special attention to cytoplasmic patterns, mixed and compound patterns, and how to report different titers corresponding to multiple patterns or autoantibodies in the same sample. This paper suggests a subtitle for the HEp-2-IIFA, namely anti-cell antibodies test, which could gradually substitute the original outdated ANA nomenclature. This ICAP pro forma report represents a further step in harmonizing the way relevant clinical information could be provided by laboratories.

Autoantibody Profile of Egyptian Juvenile Systemic Lupus Erythematosus Patients and Its Association with Clinical Characteristics and Disease Activity

OBJECTIVE

This study was conducted to estimate the frequency of anti-nuclear antibodies (ANAs), anti-dsDNA, and anti-extractable nuclear antigen (ENA) antibodies in juvenile systemic lupus erythematosus (JSLE) patients and their association with different clinical manifestations and disease activity.

PATIENTS AND METHODS

A cross-sectional study that includes 100 JSLE patients from Ain Shams University Hospital was conducted. All subjects underwent history taking, clinical examination, assessment of disease activity based on the SLE disease activity index (SLEDAI), laboratory investigations, and tests for autoantibodies, namely ANA, anti-dsDNA, and anti-ENA antibodies, including anti-Ro (SSA), anti-La (SSB), anti-Smith (Sm), and anti-U1-ribonucleoprotein (U1-RNP).

RESULTS

The most common clinical features were polyarthralgia (71%), haematological manifestations (65%), malar rash (54%), and nephritis (51%), respectively. All patients had positive ANA (100%), while anti-dsDNA frequency was 83%. The most common anti-ENA antibodies were anti-RNP (41%), anti-Sm (31%), anti-SSA (27%), and anti-SSB (20%), respectively. Anti-RNP had a clinical association with oral ulcer, Raynaud' phenomena, haematological, neuropsychiatric and thromboembolic manifestations. Meanwhile, anti-Sm had a significant association with serositis, mucocutaneous, constitutional, and neuropsychiatric manifestations. Anti-SSA was associated with mucocutaneous, musculoskeletal, Raynaud' phenomena, renal, haematological and cardiac manifestations, while anti-SSB was significantly associated with malar rash, serositis, thromboembolic, musculoskeletal, and neuropsychiatric manifestations. Concerning SLEADI score, anti-dsDNA antibody was significantly associated with moderate disease activity score (p=0.032) while anti-SSA significantly associated with high disease activity (p=0.045). Both anti-SSB and anti-Sm were significantly associated with both moderate and high disease activities, meanwhile anti-U1-RNP was associated with moderate disease activity (p=0.014).

CONCLUSION

Anti-dsDNA and anti-ENAs antibodies were frequently found in JSLE patients (83%, 63%), respectively. They were significantly associated with variable clinical manifestations and could be used as predictors for assessment of disease activity.

Nailfold capillaroscopy changes associated with anti-RNP antibodies in systemic lupus erythematosus

Anti-U1RNP antibody is associated with distinct organ involvement in patients with systemic lupus erythematosus (SLE). Nailfold capillaroscopy (NFC) allows non-invasive assessment of microvascular abnormalities in several connective tissue diseases. The objective of this study is to determine the association of anti-U1RNP antibody with microvascular changes by NFC in RNP-positive SLE patients in comparison with RNP-negative SLE patients (negative disease controls) and mixed connective tissue disease (MCTD) cases (positive disease controls). NFC examination was performed in consecutive patients with SLE with or without anti-U1RNP positivity. MCTD patients were recruited as disease controls. Abnormalities noted in the three groups were compared using non-parametric tests. Ordinal logistic or linear regression was used wherever applicable. 81 patients were studied, of whom 28 were diagnosed as RNP-positive SLE (age 30.0 ± 10.37; 26 females), 26 were RNP-negative SLE (age 29.42 ± 9.20; 25 females) and 27 had MCTD (age36.5 ± 9.70; 25 females). RNP-positive SLE patients had more frequent giant capillaries, enlarged capillaries and ramified capillaries as compared to RNP-negative SLE (p = 0.05, < 0.01 and 0.03, respectively). The capillary density was lower in patients with MCTD as compared with patients with RNP-positive SLE (5.11 ± 1.69/mm vs 7.25 ± 1.38/ mm, p < 0.01) and RNP-negative SLE (8.92 ± 1.13/mm, p < 0.01). The reduction in capillary density was less severe in patients with RNP-negative SLE as compared with RNP-positive SLE (OR = 0.1058 [95% CI = 0.02-0.546], p < 0.01) which was independent of the presence of Raynaud's phenomenon, interstitial lung disease and disease duration. Presence of anti-U1RNP antibody is associated with notable patterns of microvascular abnormalities in SLE. These NFC abnormalities are noted more profoundly in patients with MCTD and are less marked in RNP-negative SLE patients.

A nomogram to predict the risk of lupus enteritis in systemic lupus erythematosus patients with gastroinctestinal involvement

BACKGROUND

Lupus enteritis (LE), a main cause of acute abdominal pain in systemic lupus erythematosus (SLE) patients, is a serious and potentially fatal complication. This study aimed to identify clinical serological indicators to establish a nomogram to assess LE in SLE patients with gastrointestinal manifestations.

METHODS

The clinical and laboratory data of SLE patients with gastrointestinal manifestations that were hospitalized in the West China Hospital from January 2010 to January 2020 were retrospectively analyzed. The least absolute shrinkage and selection operator logistic regression model was used to select potentially relevant features. Subsequently, a nomogram was developed using multivariable logistic analysis. The performance of the nomogram was evaluated using a receiver operating characteristic curve, a calibration curve, and decision curve analysis (DCA).

FINDINGS

We included a total of 8,505 SLE patients, of which 251 had experienced gastrointestinal manifestations. The patients were randomly divided into training (n = 176) and validation (n = 75) groups. The LRA (LE Risk Assessment) model consisted of 11 significantly associated variables, which included complement 4, antineutrophil cytoplasmic antibody, albumin, anion gap, age, d-dimer, platelet, serum chlorine, anti-Sjögren's-syndrome-related antigen A, anti-ribosomal P protein, and anti-ribonucleoprotein. In the training and validation cohorts, the areas under the curve were 0.919 (95% confidence interval [CI]: 0.876-0.962) and 0.870 (95% CI: 0.775-0.964), respectively. The nomogram demonstrated excellent performance in the calibration curve and DCA.

INTERPRETATION

The LRA model exhibits good predictive ability in assessing LE risk in SLE patients with gastrointestinal manifestations.

Autoantibodies Targeting Intracellular and Extracellular Proteins in Autoimmunity

Detecting autoantibodies provides foundational information for the diagnosis of most autoimmune diseases. An important pathophysiological distinction is whether autoantibodies are directed against extracellular or intracellular proteins. Autoantibodies targeting extracellular domains of proteins, such as membrane receptors, channels or secreted molecules are often directly pathogenic, whereby autoantibody binding to the autoantigen disrupts the normal function of a critical protein or pathway, and/or triggers antibody-dependent cell surface complement killing. By comparison, autoantibodies directed against intracellular proteins are recognized as useful diagnostic biomarkers of abnormal autoimmune activity, but the link between antigenicity and pathogenicity is less straightforward. Because intracellular autoantigens are generally inaccessible to autoantibody binding, for the most part, they do not directly contribute to pathogenesis. In a few diseases, autoantibodies to intracellular targets cause damage indirectly by immune complex formation, immune activation, and other processes. In this review, the general features of and differences between autoimmune diseases segregated on the basis of intracellular or extracellular autoantigens are explored using over twenty examples. Expression profiles of autoantigens in relation to the tissues targeted by autoimmune disease and the temporal appearance of autoantibodies before clinical diagnosis often correlate with whether the respective autoantibodies mostly recognize either intracellular or extracellular autoantigens. In addition, current therapeutic strategies are discussed from this vantage point. One drug, rituximab, depletes CD20+ B-cells and is highly effective for autoimmune disorders associated with autoantibodies against extracellular autoantigens. In contrast, diseases associated with autoantibodies directed predominately against intracellular autoantigens show much more complex immune cell involvement, such as T-cell mediated tissue damage, and require different strategies for optimal therapeutic benefit. Understanding the clinical ramifications of autoimmunity derived by autoantibodies against either intracellular or extracellular autoantigens, or a spectrum of both, has practical implications for guiding drug development, generating monitoring tools, stratification of patient interventions, and designing trials based on predictive autoantibody profiles for autoimmune diseases.

Performance of Anti-Topoisomerase I Antibody Testing by Multiple-Bead, Enzyme-Linked Immunosorbent Assay and Immunodiffusion in a University Setting

BACKGROUND/OBJECTIVE

The criterion standard for anti-topoisomerase I antibody (anti-topo I antibody) testing in systemic sclerosis (SSc) uses immunodiffusion (ID) techniques, but enzyme-linked immunosorbent assay (ELISA) and multiple-bead technology are often used in current settings to save time and cost. Our aim was to assess the performance of the multiple-bead assay, ELISA, and ID testing methods.

METHODS

We conducted a retrospective study of patients at the University of Michigan whose extractable nuclear antigen 10 autoantibody panel tested positive for the anti-topo I antibody by multiple-bead technology during a 1-year period. All samples positive by multiple-bead assay were sent to the RDL Laboratories and reflexed for ELISA, and all anti-topo I antibodies positive by ELISA were further tested by ID. Clinical data were reviewed by a rheumatologist and assessed for presence of SSc. Data were analyzed via frequency tables.

RESULTS

Approximately 9500 extractable nuclear antigen 10 panels were ordered by physicians at the University of Michigan. Of these, 129 patients were positive for the anti-topo I antibody by multiple-bead assay, 51 were positive by multiple-bead assay and ELISA, and 21 were positive by multiple-bead assay, ELISA, and ID. We found that 26.4% of patients positive by multiple-bead assay, 47.1% positive by multiple-bead assay and ELISA, and 95.2% positive by multiple-bead assay, ELISA, and ID had SSc.

CONCLUSIONS

Multiple-bead assays have a high rate of false-positive results for the anti-topo I antibody in patients without clinical evidence of SSc. A stepwise approach of confirmation of positive multiple-bead assay results using both ELISA and ID improves the predictive value of antibody testing for the diagnosis of SSc.

Analysis of trends and causes of death in SLE patients over a 40-years period in a cohort of patients in the United Kingdom

BACKGROUND

Systemic Lupus Erythematosus (SLE) an autoimmune rheumatic disease with a complex pathogenesis, remains potentially life-threatening. SLE patients have increased morbidity and premature mortality compared to non-SLE patients. The five-year survival rate has improved from <50% in the 1950s to >90% in the 1980s. Lupus patients still have a mortality risk three times that of the general population.

OBJECTIVES

To provide a detailed analysis of the causes of death, main characteristics and trends in the management of the deceased SLE patients from the lupus clinic at the University College London Hospital (UCLH); during the past four decades.

METHODS

This was a non-interventional, retrospective study based on historical real-world data from paper and electronic records of patients followed up at UCLH. The analysis focused on data collected between 1st January 1978 and 31th December 2018. We collected the: causes of death, duration of disease, key laboratory and clinical parameters and the treatment received. We compared the results from the four decades to ascertain trends in the causes of mortality. All statistical analyses were performed using the Statistical Package for Social Sciences (SPSS), version 22.0. The 95% confidence intervals for the means of data were calculated.

RESULTS

111 SLE patients (15%), died during follow-up. Their median age was 51 years (interquartile range (IQR) = 38-63 years) and the median duration of disease, 15 years (IQR = 8.5-24 years). The main causes of death in the past 40 years were infection (31.7%), cancer (26.7%) and cardiovascular disease (CVD) (21.8%). 93.6% of these patients were immunosupressed. During the 40-year period, there were several therapeutic developments notably the introduction of mycophenolate mofetil (MMF) and rituximab; the latter initially only given to patients when more conventional inmunosupressants had failed, but more recently offered to patients at diagnosis. There was a statistically significant increase in the use of hydroxycloroquine (HCQ), MMF and rituximab. In contrast, the use of Azathioprine (AZA) and steroids, hardly changed over time.

CONCLUSIONS

This retrospective review shows how epidemiological factors, causes of death and treatment of SLE patients have changed during the last 40 years in the UCLH cohort.

Analysis of gene expression from systemic lupus erythematosus synovium reveals myeloid cell-driven pathogenesis of lupus arthritis

Arthritis is a common manifestation of systemic lupus erythematosus (SLE) yet understanding of the underlying pathogenic mechanisms remains incomplete. We, therefore, interrogated gene expression profiles of SLE synovium to gain insight into the nature of lupus arthritis (LA), using osteoarthritis (OA) and rheumatoid arthritis (RA) as comparators. Knee synovia from SLE, OA, and RA patients were analyzed for differentially expressed genes (DEGs) and also by Weighted Gene Co-expression Network Analysis (WGCNA) to identify modules of highly co-expressed genes. Genes upregulated and/or co-expressed in LA revealed numerous immune/inflammatory cells dominated by a myeloid phenotype, in which pathogenic macrophages, myeloid-lineage cells, and their secreted products perpetuate inflammation, whereas OA was characterized by fibroblasts and RA of lymphocytes. Genes governing trafficking of immune cells into the synovium by chemokines were identified, but not in situ generation of germinal centers (GCs). Gene Set Variation Analysis (GSVA) confirmed activation of specific immune cell types in LA. Numerous therapies were predicted to target LA, including TNF, NFκB, MAPK, and CDK inhibitors. Detailed gene expression analysis identified a unique pattern of cellular components and physiologic pathways operative in LA, as well as drugs potentially able to target this common manifestation of SLE.

Clusters in Pediatric Rheumatic Diseases

PURPOSE OF THE REVIEW

Rheumatic diseases usually have very diverse and complex pathophysiology resulting in different clinical phenotypes. Some certain phenotypes cluster together with a common presentation, course, and outcome. Our primary aim is to review the known disease clusters in certain rheumatological conditions.

RECENT FINDINGS

Cluster analysis has been reported in several rheumatic diseases, Behcet disease being the most common. Five individual clusters together with some clinical associations have been reported in Behcet patients. Certain antibody-phenotype associations and damage clusters have been reported in systemic lupus erythematosus (SLE) patients as well. Although there is no proper cluster analysis, two distinct phenotypes are evident in deficiency of ADA2 (DADA2): those with a polyarteritis nodosa-like vasculopathy and hematological involvement with pure red cell aplasia or bone marrow failure. The variants are claimed to be different regions of this gene for these 2 phenotypes. Lastly, there is a recent paper grouping ANCA-associated vasculitis according to disease phenotype and antibody associations. There are distinct clusters in certain rheumatic diseases which might help us to predict comorbidities, disease course, and treatment response.

Anti-vimentin antibodies: a unique antibody class associated with therapy-resistant lupus nephritis

Background

Tubulointerstitial inflammation (TII) in lupus nephritis is associated with a worse prognosis. Vimentin, a filamental antigen, is commonly targeted by in situ activated B-cells in TII. The prognostic importance of high serum anti-vimentin antibodies (AVAs) in lupus nephritis and their relationship with common lupus autoantibody specificities is unknown. Herein we investigated associations between AVA isotypes, other autoantibodies, and response to mycophenolate mofetil (MMF) in the presence or absence of rituximab.

Methods

The Translational Research Initiative in the Department of Medicine (TRIDOM) cross-sectional cohort of 99 lupus patients was assayed for IgG-, IgA- and IgM- AVAs, lupus-associated and rheumatoid arthritis-associated antibodies, and hierarchically clustered. Serum from baseline, 26 and 52 weeks from 132 Lupus Nephritis Assessment with Rituximab (LUNAR) trial enrolled lupus nephritis patients was also analysed and correlated with renal function up to week 78.

Results

In TRIDOM, AVAs, especially IgM AVAs, clustered with IgG anti-dsDNA and away from anti-Sm and -RNP and rheumatoid arthritis-associated antibodies. In LUNAR at baseline, AVAs correlated weakly with anti-dsDNA and more strongly with anticardiolipin titers. Regardless of treatment, IgG-, but not IgM- or IgA-, AVAs were higher at week 52 than at baseline. In contrast, anti-dsDNA titers declined, regardless of therapeutic regime. High IgG AVA titers at entry predicted less response to therapy.

Conclusion

AVAs, especially IgG AVAs, are unique in distribution and response to therapy compared with other commonly measured autoantibody specificities. Furthermore, high-titer IgG AVAs identify lupus nephritis patients resistant to conventional therapies. These data suggest that AVAs represent an independent class of prognostic autoantibodies.

A review and meta-analysis of anti-ribosomal P autoantibodies in systemic lupus erythematosus

The discovery of autoantibodies to ribosomal proteins (anti-RibP) dates back more than fifty years when antibodies to ribosomes were identified in systemic lupus erythematosus (SLE) sera. Over the years, anti-RibP autoantibodies have been the subject of extensive study and became known as a highly specific biomarker for the diagnosis of SLE and were associated with neuropsychiatric SLE (NPSLE), lupus nephritis (LN) and hepatitis (LH). As demonstrated by studies on cultured human cells and of murine models, there is evidence to suggest that anti-RibP may have a pathogenic role in LN and NPSLE. Despite a wealth of evidence, in comparison to other SLE autoantibodies such as anti-Sm and anti-dsDNA, anti-RibP has not been included in classification criteria for SLE. A significant challenge is the variability of assays used to detect anti-RibP, including the antigens and diagnostic platforms employed. This may account for the marked variation in frequencies (10-47%) in SLE and its association with clinical and demographic features reported in SLE cohorts. We performed a systematic literature review and meta-analysis to help clarify its prevalence, various clinical and serological associations in SLE based on the different RibP antigens and assay platforms used.

Longitudinal anti-nuclear antibody (ANA) seroconversion in systemic lupus erythematosus: a prospective study of Swedish cases with recent-onset disease

Serum immunoglobulin (Ig)G anti-nuclear antibodies (ANA) detected by indirect immunofluorescence (IF) microscopy remains a hallmark of systemic lupus erythematosus (SLE). Whether or not IF-ANA status varies over time is controversial. We therefore designed a prospective study with longitudinal follow-up of patients with recent-onset SLE. The study population consisted of 54 recently diagnosed SLE cases, all meeting the 1982 American College of Rheumatology (ACR) and/or the 2012 Systemic Lupus International Collaborating Clinics (SLICC) criteria. Clinical follow-up data, including disease activity, organ damage and sera, were collected from clinical onset of SLE and onwards, in most cases yearly (0-96 months). IF-ANA was analysed on human epithelial cells-2 (HEp-2) cells and categorized regarding staining patterns. Using an addressable laser bead assay (FIDIS™ Connective profile), we measured IgG-ANA fine specificities against Ro52/SSA, Ro60/SSA, Sjögren's syndrome type B antigen (La/SSB), Smith antigen (Sm), Smith antigen/ribonucleoprotein (Sm/RNP), U1 RNP (U1RNP), dsDNA, ribosomal-P protein and histone. At baseline, all patients were judged ANA-positive at an abnormal titre corresponding to the 95th percentile of healthy blood donors, but seven of 54 patients (13%) lost ANA-positivity over time. Homogeneous (AC-1; 46%) and speckled (AC-4 or 5; 31%) were the most frequently observed patterns at inclusion, whereas 7% switched pattern at least once during follow-up. Established associations between ANA fine specificities and clinical data were confirmed. Levels of anti-Sm/RNP, but not of anti-dsDNA, correlated with clinical disease activity [modified SLE disease activity 2000 (mSLEDAI-2K)]. Our data indicate that a considerable proportion of Swedish patients with SLE lose ANA-positivity over time, whereas consistent staining patterns were frequent. The clinical and mechanistic relevance of ANA seroconversion remains uncertain. Further prospective evaluations in larger SLE populations with more diverse ethnicities are warranted.

When Chest Pain Reveals More: A Case of Hydrochlorothiazide-Induced Systemic Lupus Erythematosus

BACKGROUND Drug induced lupus erythematosus is considered an autoimmune entity which is precipitated by medications. Hydrochlorothiazide has been recognized to cause subacute cutaneous lupus erythematosus, but very few cases of systemic drug induced lupus systemic erythematosus have been reported. CASE REPORT A 57-year-old Caucasian male with a past medical history of hypertension and hyperlipidemia presented with recurrent fevers, chest pain, and dyspnea. Initial evaluation revealed diffuse ST elevations, small pericardial effusion, anemia, and leukopenia. He was initially treated with nonsteroidal anti-inflammatory drugs and prednisone for pericarditis. Six months later, he reported fatigue, arthralgias, morning stiffness, weight loss, fevers, and night sweats. Laboratory tests revealed persistent anemia and leukopenia. Extensive workup, including bone marrow biopsy and infectious evaluations, was negative. Autoimmune workup, however, revealed positive antihistone and antichromatin antibodies despite negative antinuclear antibody. A diagnosis of drug induced lupus secondary to hydrochlorothiazide was made. The medication was stopped, and prednisone was initiated resulting in marked improvement in his symptoms and hematologic abnormalities. CONCLUSIONS This report is one of the few known cases of systemic lupus erythematosus most likely induced by hydrochlorothiazide. Based on our finding, hydrochlorothiazide should be considered a possible offending agent when a patient presents with symptoms suspicious of drug induced lupus.

Phenome-wide association study identifies dsDNA as a driver of major organ involvement in systemic lupus erythematosus

In systemic lupus erythematosus (SLE), dsDNA antibodies are associated with renal disease. Less is known about comorbidities in patients without dsDNA or other autoantibodies. Using an electronic health record (EHR) SLE cohort, we employed a phenome-wide association study (PheWAS) that scans across billing codes to compare comorbidities in SLE patients with and without autoantibodies. We used our validated algorithm to identify SLE subjects. Autoantibody status was defined as ever positive for dsDNA, RNP, Smith, SSA and SSB. PheWAS was performed in antibody positive vs. negative SLE patients adjusting for age and race and using a false discovery rate of 0.05. We identified 1097 SLE subjects. In the PheWAS of dsDNA positive vs. negative subjects, dsDNA positive subjects were more likely to have nephritis ( p = 2.33 × 10^-9) and renal failure ( p = 1.85 × 10^-5). After adjusting for sex, race, age and other autoantibodies, dsDNA was independently associated with nephritis and chronic kidney disease. Those patients negative for dsDNA, RNP, SSA and SSB negative subjects were all more likely to have billing codes for sleep, pain and mood disorders. PheWAS uncovered a hierarchy within SLE-specific autoantibodies with dsDNA having the greatest impact on major organ involvement.

A rare regulatory variant in the MEF2D gene affects gene regulation and splicing and is associated with a SLE sub-phenotype in Swedish cohorts

Systemic lupus erythematosus (SLE) is an autoimmune disorder with heterogeneous clinical presentation and complex etiology involving the interplay between genetic, epigenetic, environmental and hormonal factors. Many common SNPs identified by genome wide-association studies (GWAS) explain only a small part of the disease heritability suggesting the contribution from rare genetic variants, undetectable in GWAS, and complex epistatic interactions. Using targeted re-sequencing of coding and conserved regulatory regions within and around 215 candidate genes selected on the basis of their known role in autoimmunity and genes associated with canine immune-mediated diseases, we identified a rare regulatory variant rs200395694:G > T located in intron 4 of the MEF2D gene encoding the myocyte-specific enhancer factor 2D transcription factor and associated with SLE in Swedish cohorts (504 SLE patients and 839 healthy controls, p = 0.014, CI = 1.1–10). Fisher’s exact test revealed an association between the genetic variant and a triad of disease manifestations including Raynaud, anti-U1-ribonucleoprotein (anti-RNP), and anti-Smith (anti-Sm) antibodies (p = 0.00037) among the patients. The DNA-binding activity of the allele was further studied by EMSA, reporter assays, and minigenes. The region has properties of an active cell-specific enhancer, differentially affected by the alleles of rs200395694:G > T. In addition, the risk allele exerts an inhibitory effect on the splicing of the alternative tissue-specific isoform, and thus may modify the target gene set regulated by this isoform. These findings emphasize the potential of dissecting traits of complex diseases and correlating them with rare risk alleles with strong biological effects.

Clinical & immunological characteristics in systemic lupus erythematosus patients

Background & objectives:

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease which affects females more than males. Gender affects the manifestations of SLE and men with lupus show more severe symptoms and worse prognosis. This study was aimed to compare clinical and immunological features in female and male lupus patients in Iran.

Methods:

Demographic, clinical and laboratory data from 78 women and 20 men with lupus were collected. Autoantibodies (against nRNP, Sm, SSA, SSB, Ro-52, CENP, Jo-1, Scl-70, nucleosome, anti-dsDNA, histone and Rib-p protein) were determined using immunoblotting technique.

Results:

Men with lupus had less anti-SSA (21.1 vs 48.1%) and anti-Ro52 (10.5 vs 44.3%) antibodies when compared to women and none of the male patients had anti-SSB antibodies. Kidney damage was more frequent in men (68.4% in men vs 36.7% in women). In men with kidney involvement, anti-dsDNA increased significantly (84.6 vs 20.0%) in comparison to males without nephritis. Anti-SSA (7.7 vs 50.0%) and anti-nRNP (0.0 vs 33.8%) on the other hand, decreased. Women with renal involvement had no anti-SSB antibodies.

Interpretation & conclusions:

In male patients, SLE appeared with more severe features, and kidney damage was more frequent in males. The frequency of some autoantibodies was different between females and males. In males with kidney damage anti-dsDNA increased significantly, while anti-SSA and anti-nRNP decreased. Anti-SSB was not detected in males and females with nephritis.

An electrochemical biosensor for rapid detection of anti-dsDNA antibodies in absolute scale

The authors report an electrochemical biosensor enabling fast (30 min) detection of anti-DNA antibodies in serum with reduced manipulation steps.

Cytokine and autoantibody clusters interaction in systemic lupus erythematosus

Background

Evidence supports the existence of different subphenotypes in systemic lupus erythematosus (SLE) and the pivotal role of cytokines and autoantibodies, which interact in a highly complex network. Thus, understanding how these complex nonlinear processes are connected and observed in real-life settings is a major challenge. Cluster approaches may assist in the identification of these subphenotypes, which represent such a phenomenon, and may contribute to the development of personalized medicine. Therefore, the relationship between autoantibody and cytokine clusters in SLE was analyzed.

Methods

This was an exploratory study in which 67 consecutive women with established SLE were assessed. Clinical characteristics including disease activity, a 14-autoantibody profile, and a panel of 15 serum cytokines were measured simultaneously. Mixed-cluster methodology and bivariate analyses were used to define autoantibody and cytokine clusters and to identify associations between them and related variables.

Results

First, three clusters of autoantibodies were defined: (1) neutral, (2) antiphospholipid antibodies (APLA)-dominant, and (3) anti-dsDNA/ENA-dominant. Second, eight cytokines showed levels above the threshold thus making possible to find 4 clusters: (1) neutral, (2) chemotactic, (3) G-CSF dominant, and (4) IFNα/Pro-inflammatory. Furthermore, the disease activity was associated with cytokine clusters, which, in turn, were associated with autoantibody clusters. Finally, when all biomarkers were included, three clusters were found: (1) neutral, (2) chemotactic/APLA, and (3) IFN/dsDNA, which were also associated with disease activity.

Conclusion

These results support the existence of three SLE cytokine-autoantibody driven subphenotypes. They encourage the practice of personalized medicine, and support proof-of-concept studies.

Electronic supplementary material

The online version of this article (10.1186/s12967-017-1345-y) contains supplementary material, which is available to authorized users.

Next-Generation Autoantibody Testing by Combination of Screening and Confirmation-the CytoBead® Technology

Occurrence of autoantibodies (autoAbs) is a hallmark of autoimmune diseases, and the analysis thereof is an essential part in the diagnosis of organ-specific autoimmune and systemic autoimmune rheumatic diseases (SARD), especially connective tissue diseases (CTDs). Due to the appearance of autoAb profiles in SARD patients and the complexity of the corresponding serological diagnosis, different diagnostic strategies have been suggested for appropriate autoAb testing. Thus, evolving assay techniques and the continuous discovery of novel autoantigens have greatly influenced the development of these strategies. Antinuclear antibody (ANA) analysis by indirect immunofluorescence (IIF) on tissue and later cellular substrates was one of the first tests introduced into clinical routine and is still an indispensable tool for CTD serology. Thus, screening for ANA by IIF is recommended to be followed by confirmatory testing of positive findings employing different assay techniques. Given the continuous growth in the demand for autoAb testing, IIF has been challenged as the standard method for ANA and other autoAb analyses due to lacking automation, standardization, modern data management, and human bias in IIF pattern interpretation. To address these limitations of autoAb testing, the CytoBead® technique has been introduced recently which enables automated interpretation of cell-based IIF and quantitative autoAb multiplexing by addressable microbead immunoassays in one reaction environment. Thus, autoAb screening and confirmatory testing can be combined for the first time. The present review discusses the history of autoAb assay techniques in this context and gives an overview and outlook of the recent progress in emerging technologies.

Ribosomal P antibody: 30 years on the road

The identity of the protein antigens targeted by anti-cytoplasmic antibodies in lupus was discovered 30 years ago. These antigens are three acidic ribosomal phosphoproteins, P0, P1, and P2. Precise identification of the shared epitope on these three proteins enabled sensitive and specific immunoassays to be developed. Anti-P antibodies are highly specific for systemic lupus erythematosus (SLE) and occur in 15%–35% of patients, depending on ethnicity as well as the age of onset. Increased frequencies of detection of anti-P have been reported in childhood SLE as well as in neuropsychiatric, renal, and hepatic disease. While longitudinal studies by the Systemic Lupus International Collaborating Clinics (SLICC) consortium supported the association of anti-P with neuropsychiatric lupus, the predictive value of antibody determination remains controversial. This is likely explained by the heterogeneity of neuropsychiatric lupus as well as by the different methodologies used for assay. A number of experimental studies have suggested a direct pathogenic role for anti-P antibodies in brain disease. Findings include cross reactivity between anti-P and a neuronal surface antigen, which was detected in areas of the brain involved in memory, cognition, and emotion. Direct injection of anti-P antibodies into the brains of rodents was also associated with abnormal electrical activity and behavioral disturbances. Taken together, research over the last 30 years has established anti-P antibodies as a useful diagnostic marker of SLE and at least a subset of patients with neuropsychiatric disease. Further research is required to fine tune the association of anti-P with clinical manifestations and establish beyond high probability a pathophysiologic role for the antibodies.

A Child's HLA-DRB1 genotype increases maternal risk of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) disproportionately affects women of reproductive age. During pregnancy, women are exposed to various sources of fetal material possibly constituting a significant immunologic exposure relevant to the development of SLE. The objective of this study was to investigate whether having any children who carry DRB1 alleles associated with SLE increase the risk of maternal SLE. This case-control study is based on the University of California, San Francisco Mother-Child Immunogenetic Study and from studies at the Inova Translational Medicine Institute. Analyses were conducted using data for 1304 mothers (219 cases/1085 controls) and their respective 1664 children. We selected alleles based on their known association with risk of SLE (DRB1*03:01, *15:01, or *08:01) or Epstein-Barr virus (EBV) glycoproteins (*04:01) due to the established EBV association with SLE risk. We used logistic regression models to estimate odds ratios (OR) and 95% confidence intervals (CI) for each allele of interest, taking into account maternal genotype and number of live births. We found an increase in risk of maternal SLE associated with exposure to children who inherited DRB1*04:01 from their father (OR 1.9; 95% CI, 1.1-3.2), among *04:01 allele-negative mothers. Increased risk was only present among mothers who were positive for one or more SLE risk-associated alleles (*03:01, *15:01 and/or *08:01). We did not find increased risk of maternal SLE associated with any other tested allele. These findings support the hypothesis that a child's alleles inherited from the father influence a mother's subsequent risk of SLE.

Autoantibody Detection Using Multiplex Technologies

Measurement of multiple antibodies has been possible for years using labor-intensive methods such as counterimmunoelectrophoresis and radioimmunoprecipitation. Recently, simpler methods that are more practical for routine analysis, often described as multiplex technologies, have been introduced. One common technique, the line assay, uses nitrocellulose strips that are precoated at different locations with more than a dozen recombinant proteins or peptides. Detection of results may be performed visually or with scanning instrumentation. A second technique uses families of polystyrene beads that are dyed to establish a unique identity; each bead type is then coated with a specific affinity-purified or recombinant protein. Detection is performed by flow cytometry. There have been multiple descriptions of the use of these techniques for measuring antibodies associated with the antinuclear antibody screen. More recent reports describe applications to antibodies associated with hypothyroidism, ANCA, anti-phospholipid syndrome, and celiac disease. This review summarizes the work that has been performed to date and examines the potential benefits of multiplexing to both the laboratory and the physician.

Raynaud's phenomenon

Raynaud's phenomenon (RP) is a major cause of pain and disability in patients with autoimmune connective tissue diseases (CTDs), particularly systemic sclerosis (SSc). The clinician must perform a comprehensive clinical assessment in patients with RP to differentiate between primary (idiopathic) and secondary RP, in particular (for rheumatologists), secondary to an autoimmune CTD, as both the prognosis and treatment may differ significantly. Key investigations are nailfold capillaroscopy and testing for autoantibodies (in particular, those associated with SSc). Patients with RP and either abnormal nailfold capillaroscopy or an SSc-specific antibody (and especially with both) have a high risk of transitioning to an autoimmune CTD. Both nailfold capillaroscopy and autoantibody specificity may help the clinician in predicting organ-based complications. The management of CTD-associated RP requires a multifaceted approach to treatment, including patient education and conservative ('non-drug') measures. Patients with CTD-associated RP often require pharmacological treatment, which in the first instance is usually a calcium channel blocker, although other agents can be used. There is an increasing tendency to use phosphodiesterase type 5 inhibitors early in the treatment of CTD-associated RP. Oral therapies are commonly associated with side effects (often due to systemic vasodilation) that may result in failure of dose escalation and/or permanent discontinuation. Intravenous prostanoid therapy and surgery (e.g., botulinum toxin injection and digital sympathectomy) can be considered in severe RP. Patients with CTD-associated RP can develop a number of ischaemic digital complications (primarily ulcers and critical ischaemia), which may be associated with significant tissue loss. Future research is required to increase the understanding of the pathogenesis and natural history of RP (to drive therapeutic advances), and to explore/develop drug therapies, including those that target the mechanisms mediating cold-induced vasoconstriction, and locally acting therapies free of systemic side effects.

Characterization of Patients With Lupus Nephritis Included in a Large Cohort From the Spanish Society of Rheumatology Registry of Patients With Systemic Lupus Erythematosus (RELESSER)

The aim of the study was to profile those patients included in the RELESSER registry with histologically proven renal involvement in order to better understand the current state of lupus nephritis (LN) in Spain. RELESSER-TRANS is a multicenter cross-sectional registry with an analytical component. Information was collected from the medical records of patients with systemic lupus erythematosus who were followed at participating rheumatology units. A total of 359 variables including demographic data, clinical manifestations, disease activity, severity, comorbidities, LN outcome, treatments, and mortality were recorded. Only patients with a histological confirmation of LN were included. We performed a descriptive analysis, chi-square or Student's t tests according to the type of variable and its relationship with LN. Odds ratio and confidence intervals were calculated by using simple logistic regression. LN was histologically confirmed in 1092/3575 patients (30.5%). Most patients were female (85.7%), Caucasian (90.2%), and the mean age at LN diagnosis was 28.4 ± 12.7 years. The risk for LN development was higher in men (M/F:47.85/30.91%, P < 0.001), in younger individuals (P < 0.001), and in Hispanics (P = 0.03). Complete response to treatment was achieved in 68.3% of patients; 10.35% developed ESRD, which required a kidney transplant in 45% of such cases. The older the patient, the greater was the likelihood of complete response (P < 0.001). Recurrences were associated with persistent lupus activity at the time of the last visit (P < 0.001) and with ESRD (P < 0.001). Thrombotic microangiopathy was a risk factor for ESRD (P = 0.04), as for the necessity of dialysis (P = 0.01) or renal transplantation (P = 0.03). LN itself was a poor prognostic risk factor of mortality (OR 2.4 [1.81-3.22], P < 0.001). Patients receiving antimalarials had a significantly lower risk of developing LN (P < 0.001) and ESRD (P < 0.001), and responded better to specific treatments for LN (P = 0.014). More than two-thirds of the patients with LN from a wide European cohort achieved a complete response to treatment. The presence of positive anti-Sm antibodies was associated with a higher frequency of LN and a decreased rate of complete response to treatment. The use of antimalarials reduced both the risk of developing renal disease and its severity, and contributed to attaining a complete renal response.

Systemic lupus erythematosus and Raynaud's phenomenon

BACKGROUND

Patients with systemic lupus erythematosus seem to belong to different serological and clinical subgroups of the disease. Genetic background can cause the appearance of these subgroups.

OBJECTIVE

To determine whether Brazilian patients who have systemic lupus erythematosus and Raynaud's phenomenon differ from those who do not.

METHODS

Retrospective analysis of 373 medical records of systemic lupus erythematosus patients studied for demographic, clinical and serological data. A comparative analysis was performed of individuals with and without RP.

RESULTS

There was a positive association between Raynaud's phenomenon and age at diagnosis (p=0.02), presence of anti-Sm (p=0.01) antibodies and anti-RNP (p<0.0001). Furthermore, a negative association was found between Raynaud's phenomenon and hemolysis (p=0.01), serositis (p=0.01), glomerulonephritis (p=0.0004) and IgM aCL (p=0.004) antibodies.

CONCLUSION

Raynaud's phenomenon patients appear to belong to a systemic lupus erythematosus subset with a spectrum of clinical manifestations located in a more benign pole of the disease.

The Ro60 autoantigen binds endogenous retroelements and regulates inflammatory gene expression

Autoantibodies target the RNA binding protein Ro60 in systemic lupus erythematosus (SLE) and Sjögren's syndrome. However, it is unclear whether Ro60 and its associated RNAs contribute to disease pathogenesis. We catalogued the Ro60-associated RNAs in human cell lines and found that among other RNAs, Ro60 bound an RNA motif derived from endogenous Alu retroelements. Alu transcripts were induced by type I interferon and stimulated proinflammatory cytokine secretion by human peripheral blood cells. Ro60 deletion resulted in enhanced expression of Alu RNAs and interferon-regulated genes. Anti-Ro60-positive SLE immune complexes contained Alu RNAs, and Alu transcripts were up-regulated in SLE whole blood samples relative to controls. These findings establish a link among the lupus autoantigen Ro60, Alu retroelements, and type I interferon.

Clinical associations of anti-Smith antibodies in PROFILE: a multi-ethnic lupus cohort

The aim of this study was to determine the association of anti-Sm antibodies with clinical manifestations, comorbidities, and disease damage in a large multi-ethnic SLE cohort. SLE patients (per American College of Rheumatology criteria), age ≥16 years, disease duration ≤10 years at enrollment, and defined ethnicity (African American, Hispanic or Caucasian), from a longitudinal US cohort were studied. Socioeconomic-demographic features, cumulative clinical manifestations, comorbidities, and disease damage (as per the Systemic Lupus International Collaborating Clinics Damage Index [SDI]) were determined. The association of anti-Sm antibodies with clinical features was examined using multivariable logistic regression analyses adjusting for age, gender, ethnicity, disease duration, level of education, health insurance, and smoking. A total of 2322 SLE patients were studied. The mean (standard deviation, SD) age at diagnosis was 34.4 (12.8) years and the mean (SD) disease duration was 9.0 (7.9) years; 2127 (91.6%) were women. Anti-Sm antibodies were present in 579 (24.9%) patients. In the multivariable analysis, anti-Sm antibodies were significantly associated with serositis, renal involvement, psychosis, vasculitis, Raynaud's phenomenon, hemolytic anemia, leukopenia, lymphopenia, and arterial hypertension. No significant association was found for damage accrual. In this cohort of SLE patients, anti-Sm antibodies were associated with several clinical features including serious manifestations such as renal, neurologic, and hematologic disorders as well as vasculitis.

Autoantigen microarrays reveal autoantibodies associated with proliferative nephritis and active disease in pediatric systemic lupus erythematosus

Introduction

Pediatric systemic lupus erythematosus (pSLE) patients often initially present with more active and severe disease than adults, including a higher frequency of lupus nephritis. Specific autoantibodies, including anti-C1q, anti-DNA and anti-alpha-actinin, have been associated with kidney involvement in SLE, and DNA antibodies are capable of initiating early-stage lupus nephritis in severe combined immunodeficiency (SCID) mice. Over 100 different autoantibodies have been described in SLE patients, highlighting the need for comprehensive autoantibody profiling. Knowledge of the antibodies associated with pSLE and proliferative nephritis will increase the understanding of SLE pathogenesis, and may aid in monitoring patients for renal flare.

Methods

We used autoantigen microarrays composed of 140 recombinant or purified antigens to compare the serum autoantibody profiles of new-onset pSLE patients (n = 45) to healthy controls (n = 17). We also compared pSLE patients with biopsy-confirmed class III or IV proliferative nephritis (n = 23) and without significant renal involvement (n = 18). We performed ELISA with selected autoantigens to validate the microarray findings. We created a multiple logistic regression model, based on the ELISA and clinical information, to predict whether a patient had proliferative nephritis, and used a validation cohort (n = 23) and longitudinal samples (88 patient visits) to test its accuracy.

Results

Fifty autoantibodies were at significantly higher levels in the sera of pSLE patients compared to healthy controls, including anti-B cell-activating factor (BAFF). High levels of anti-BAFF were associated with active disease. Thirteen serum autoantibodies were present at significantly higher levels in pSLE patients with proliferative nephritis than those without, and we confirmed five autoantigens (dsDNA, C1q, collagens IV and X and aggrecan) by ELISA. Our model, based on ELISA measurements and clinical variables, correctly identified patients with proliferative nephritis with 91 % accuracy.

Conclusions

Autoantigen microarrays are an ideal platform for identifying autoantibodies associated with both pSLE and specific clinical manifestations of pSLE. Using multiple regression analysis to integrate autoantibody and clinical data permits accurate prediction of clinical manifestations with complex etiologies in pSLE.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0682-6) contains supplementary material, which is available to authorized users.

The ying and yang of fever in rheumatic disease

Fevers are relatively common in rheumatic disease, largely due to the fact that the inflammatory process is driven by inflammatory mediators that function as endogenous pyrogens. Since the immune system's sensors cannot accurately distinguish between endogenous and exogenous (pathogen-derived) pyrogens a major challenge for physicians and rheumatologists has been to decipher patterns of clinical signs and symptoms to inform clinical decision making. Here we describe some of the common pitfalls and clinical challenges, and highlight the importance of a systematic approach to investigating the rheumatic disease patient presenting with fever.

Role of autoantibody testing

Autoantibodies are the serological hallmark of autoimmune disease. Though their pathogenic role is debatable, they play an important role in the management of a patient with rheumatic disease. However, due to their presence in the general population as well as in multiple autoimmune diseases, the presence of an autoantibody alone does not make a diagnosis; the result has to be interpreted along with clinical findings. Similarly, the absence of autoantibody does not exclude a disease. The common autoantibodies used in clinical practice include rheumatoid factor, anti-CCP antibodies, antinuclear antibodies (ANAs), anti-neutrophil cytoplasmic antibodies (ANCA) and anti-phospholipid antibodies. Once an autoantibody to a broad antigen is detected in a patient, sub-specificity analysis can improve the utility of the antibody. Autoantibodies are detected in the serum using different assays and results of which can vary; thus, it is important for a clinician to know the method used, its sensitivity and specificity to help in the proper interpretation of the laboratory results. This review will address these issues.