Anti-dsDNA Testing Specificity for Systemic Lupus Erythematosus: A Systematic Review

The added value of coupling anti-dsDNA and anti-chromatin antibodies in follow-up monitoring of systemic lupus erythematosus patients

Objective

The autoimmune response to chromatin (Chr) or one of the nucleosome components (double stranded (ds)DNA and histones) is typically associated with the development of systemic lupus erythematosus (SLE). Related autoantibodies (Ab) are heterogeneous and, among them, anti-dsDNA Ab are part of the classification criteria and recommended for monitoring SLE with regards to lupus flares and therapy responses. However, anti-dsDNA Ab biomarker performances are weak; therefore, coupling anti-dsDNA with anti-Chr Ab can be proposed, which is the aim of this study.

Methods

In this single center study from 2009 to 2024, 269 SLE patients with follow-up information were retrospectively selected from a population of 646 individuals, including 325 SLE patients, who tested positive for anti-dsDNA and/or anti-Chr Ab (Bioplex 2200™). Bio-clinical information during follow-up were assessed at several time points through medical records in order to explore associations between the anti-dsDNA/Chr Ab profile with disease presentation, and anti-dsDNA/Chr Ab fluctuations with disease activity using clinical SLEDAI-2K, flares requiring specific treatment, and the therapeutic response.

Results

At inclusion in the follow-up analysis, corresponding to diagnosis (116/269, 43.1 %) or flare (153/269, 56.9 %), SLE patients were subdivided into three serological groups: the double positive dsDNA/Chr group (DP+, 190/269: 70.6 %), followed by the single positive Chr group (SP-C+, 42/269: 15.6 %), and the single positive dsDNA group (SP-D+, 37/269: 13.8 %). The DP + group, which presented important anti-dsDNA/Ab variations during follow-up, was at risk to develop lupus nephritis (56.8 % versus 2.4 % in SP-C+ and 29.7 % in SP-D+ groups, p < 0.04) and serositis (30 % versus 9.5 % in SP-C+ group, p = 0.006). During follow-up, anti-dsDNA and Chr Ab levels in the SP-C+ and SP-D+ groups remained stable over time irrespective of disease activity, flares, and therapeutic response. Regarding the DP + group, disease activity was correlated with both anti-dsDNA (RmCorr = 0.46, p = 1.6x110-91) and anti-Chr (RmCorr = 0.38, p = 2.8x10-60) Ab levels, which can be used to predict flares. Following therapy introduction, Ab reduction occurred in all patients from the DP + group with a more pronounced effect reported in complete responders.

Conclusion

coupling anti-dsDNA with anti-Chr Ab detection at disease initiation/flare allows definition of endotypes, which is useful to follow disease activity, predict lupus nephritis/serositis, and anticipate therapeutic response in the DP + group.

A retrospective study on the correlation between antibody levels and endothelial function in SLE patients: An analysis based on ultrasound and serum biomarkers

BACKGROUND

Systemic lupus erythematosus (SLE) was a complex autoimmune disease characterized by a spectrum of clinical and immunological manifestations, with cardiovascular disease (CVD) being a leading cause of morbidity and mortality. Endothelial dysfunction was critical in the pathogenesis of atherosclerosis and other cardiovascular complications in SLE. This study aimed to investigate the correlation between autoantibody levels and endothelial function in SLE patients using ultrasound and serum biomarkers.

METHODS

A retrospective case-control study was conducted with 317 SLE patients treated from December 2021 to December 2023. Patients were categorized based on Flow-Mediated Dilation (FMD) values into an abnormal endothelial function group (n = 191) and a normal function group (n = 126). Serum biomarkers, including soluble thrombomodulin (sTM), von Willebrand factor (vWF), and soluble vascular cell adhesion molecule-1 (sVCAM-1), were assessed. Autoantibody levels were measured using enzyme-linked immunosorbent assays for anti-double stranded DNA (anti-dsDNA), anti-Smith, and anticardiolipin antibodies levels. Statistical analyses, including correlation and logistic regression, were performed to determine associations between antibody levels and endothelial function.

RESULTS

Higher levels of Anti-Smith were significantly associated with poorer endothelial function, while higher Anti-dsDNA levels were positive correlated with endothelial function (Anti-Smith: coefficient = -0.168, Std_Error = 0.027, t_value = -6.228, P < 0.001; Anti-dsDNA: coefficient = 0.140, Std_Error = 0.022, t_value = 6.345, P < 0.001). These results underscore the importance of antibody levels in assessing endothelial health.

CONCLUSION

This study highlights the intricate relationship between specific autoantibodies and endothelial dysfunction in SLE patients. Elevated sVCAM-1 and Anti-Smith levels were associated with a higher risk of endothelial impairment, whereas Anti-dsDNA antibodies showed a positively correlated better endothelial function.

Coexistence of antinucleosome and anti-double-stranded DNA antibodies is associated with severe systemic lupus erythematosus in Tunisian patients

INTRODUCTION

We sought to compare clinical features among distinct antibody profiles defined by the presence or absence of antinucleosome (anti-NCS) and anti-double-stranded DNA (anti-dsDNA) antibodies in Tunisian patients with systemic lupus erythematosus (SLE).

METHODS

The study enrolled 131 patients with SLE meeting at least 4 American College of Rheumatology or SLICC criteria. Participants were recruited from the Department of Internal Medicine and Rheumatology at the university teaching hospital of Monastir between January 2000 and December 2022. The patients were divided into 4 groups: Group 1 with neither anti-dsDNA nor anti-NCS; Group 2 with anti-dsDNA and no anti-NCS; Group 3 with anti-NCS lacking anti-dsDNA; and Group 4 with both anti-NCS and anti-dsDNA.

RESULTS

The mean (SD) age at the time of diagnosis for the 131 participants with SLE was 38.7 (15.1) years; the ratio of female to male individuals was 7.2. Thirty-four (26%) patients were positive for anti-NCS and anti-dsDNA (group 4: antinuclear antibody pattern AC-1, 72%; pattern AC-5, 16%), and 30 (22.9%) were positive for anti-NCS and negative for anti-dsDNA (group3: pattern AC-1, 53.6%; pattern AC-5, 32.1%). The group 3 patients showed higher peripheral neuropsychiatric SLE (P =.034) and lower rates of disease activity (P =.01). The comparison between the 4 groups showed that group 4 patients had the highest frequency of lupus nephritis (P ≤.001) and the highest rate disease activity (P =.013).

DISCUSSION

Patients with both anti-NCS and anti-dsDNA at the time of diagnosis are likely to have severe SLE, while anti-NCS was associated with nonsevere disease in patients with SLE who lack anti-dsDNA.

Isolated anti-ribosomal P antibodies are associated with reduced risk of renal and articular involvement in systemic lupus erythematosus patients. An observational study from one center

Introduction

The aim of the study was to compare the specific clinical manifestations of systemic lupus erythematosus (SLE) or laboratory findings between patients with and without anti-ribosomal P (anti-P) antibodies and to investigate possible associations between isolated anti-P antibodies and these features.

Material and methods

Seventy-five SLE patients were enrolled in this study. They were recruited from the Department of Internal Medicine and Department of Rheumatology at the University Hospital of Monastir, Tunisia (January 2008 - December 2022). All patients met at least four American College of Rheumatology criteria or Systemic Lupus Erythematosus International Collaborating Clinics criteria at the time of disease diagnosis. Antibody typing was performed using a commercial line blot technique. Statistical analysis was performed using the χ2 test, Fisher's test when appropriate, Student's t-test, or Mann-Whitney U test according to normality of the data distribution.

Results

Thirty patients (40%) were positive for anti-P (anti-P+). The anti-P+ had higher frequency of skin features (26/49 [53.1%] vs. 4/26 [15.4%], p = 0.003) and central nervous system (CNS) involvement (10/15 [66.7%] vs. 20/60 [33.3%], p = 0.018) than patients without anti-P. Interestingly, anti-P+ showed a lower frequency of SLE/rheumatoid arthritis overlap syndrome (1/11 [9.1%] vs. 29/64 [45.3%], p = 0.042). The comparison between groups of patients according to the presence of anti-P, anti-dsDNA, and anti-Sm showed that the group with anti-P lacking anti-dsDNA and anti-Sm had the highest frequency of neuropsychiatric SLE (75%, p = 0.034), and the lowest frequency of lupus nephritis (0%, p = 0.029) and arthritis (12.5%, p = 0.039).

Conclusions

This study supports the association of anti-P antibodies with CNS and cutaneous manifestations. To the best of our knowledge, this is the first study to report a negative association between isolated anti-P antibodies and renal and articular involvement in SLE.

Cutting edge confusion about cut-off settings in autoimmune diagnostics

In autoimmune diagnostics results are interpreted in relation to a single or multiple cut-off value(s) in order to decide if the test is negative, weak positive, positive, or even strong positive. The way a cut-off is established appears to be very heterogeneous and this hampers harmonization of test results obtained in assays, either established in-house or obtained from different companies. In this context it is surprising that in diagnostic and classification criteria for distinct autoimmune diseases referral is made to cut-off values with the intention of harmonization. In this review article distinct ways to establish cut-off values will be described and discussed in relation to some disease criteria in order to increase the awareness of the confusion matrix of cut-off values and, as a consequence, the implications for test result interpretation.

Impact of serological activity on flare following clinically inactive disease and remission in childhood-onset systemic lupus erythematosus

OBJECTIVES

The objectives of this study were to assess the association between serological activity (SA) and clinical inactivity in SLE and to investigate whether SA predicts flare after the attainment of clinically inactive disease (CID) and remission.

METHODS

The longitudinal data of children from three paediatric rheumatology referral centres were retrospectively reviewed. CID was interpreted as the beginning of a transitional phase of clinical inactivity on a moderate glucocorticoid dose during which tapering was expected and defined as the absence of disease activity in clinical domains of SLEDAI, without haemolytic anaemia or gastrointestinal activity, in patients using <15 mg/day prednisolone treatment. Modified DORIS remission on treatment criteria were used to determine remission.

RESULTS

Of the 124 patients included, 89.5% displayed SA at onset. Through follow-up, the rate of SA decreased to 43.3% at first CID and 12.1% at remission. Among the patients with CID, 24 (20.7%) experienced a moderate-to-severe flare before the attainment of remission. While previous proliferative LN [odds ratio (OR): 10.2, P: 0.01) and autoimmune haemolytic anaemia (OR: 6.4, P: 0.02) were significantly associated with increased odds of flare after CID, SA at CID was not associated with flare. In contrast, 21 (19.6%) patients experienced flare in a median of 18 months after remission. Hypocomplementemia (OR: 9.8, P: 0.02) and a daily HCQ dose of <5 mg/kg (OR: 5.8, P: 0.02) during remission significantly increased the odds of flare.

CONCLUSION

SA during remission increases the odds of flare, but SA at CID does not. Suboptimal dosing of HCQ should be avoided, especially in children with SA in remission, to lower the risk of flares.

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.

Comparative analysis of contemporary anti-double stranded DNA antibody assays for systemic lupus erythematosus

Objective

Elevated double-stranded DNA (dsDNA) antibody levels in blood serum are considered a disease-specific marker in systemic lupus erythematosus (SLE), correlate with disease activity and the incidence of lupus nephritis, and can be detected in up to 86% of all SLE cases. Despite the high clinical relevance, the variety of dsDNA antibody testing methods with heterogenous performance in clinical use remains challenging. This study is the first to prospectively investigate the performance of two of today's most commonly applied anti-dsDNA testing methods head-to-head under real-world conditions, as well as their correlation with other clinical and serological disease parameters in SLE patients.

Methods

In this prospective study, all SLE patients undergoing treatment at the Department of Rheumatology at the University Hospital Bonn within a 13-months period (n=41) and control patients without connective-tissue disease (n=51) were consecutively enrolled and examined. For all study participants' serum samples both anti-dsDNA-NcX enzyme-linked immunoassay testing EUROIMMUN, Luebeck, Germany) and the fluorescence immunoassay ELiA dsDNA (Thermo Fisher Scientific, Waltham, USA) were performed. In addition, demographic data, further laboratory values and disease activity parameters were recorded. Clinical disease activity was assessed by SLEDAI-2K.

Results

Both assays showed high specificity (anti-dsDNA-NcX ELISA: 0.9, ELiA dsDNA: 0.959), but there were notable differences in sensitivity (anti-dsDNA-NcX ELISA: 0.51, ELiA dsDNA: 0.38). Pearsons's correlation yielded a positive correlation between anti-dsDNA concentrations and CRP concentrations for the anti-dsDNA-NcX ELISA (R=0.22; p=0.038) and a mild-to-moderate inverse correlation between concentrations of anti-dsDNA and complement C4 for the ELiA dsDNA test (R=-0.22; p=0.045) when SLE and control patients were considered together. Other than, no significant correlation between anti-dsDNA concentrations and clinical or laboratory findings was found for either test procedure.

Conclusion

Both anti-dsDNA antibody assays represent reliable examination methods with high specificity for the diagnosis of SLE that fulfill EULAR/ACR requirements. However, the anti-dsDNA-NcX ELISA showed superior sensitivity and significant correlation with disease activity (as measured by CRP concentrations).

Longitudinal study of patients with discrepant results in CLIFT and a solid-phase dsDNA antibody assay: does a gold standard dsDNA assay exist?

OBJECTIVE

Antidouble-stranded DNA (dsDNA) antibodies are essential for diagnosis and follow-up of systemic lupus erythematous (SLE). To ensure the best diagnostic approach, most healthcare laboratories opt for a combination of highly sensitive methods, such as solid-phase immunoassays, and highly specific methods, such as the Crithidia luciliae indirect immunofluorescence test (CLIFT). Even so, discordant results are common, thus hindering the diagnostic process. Therefore, this study aimed to characterise a cohort of patients with discrepant results for a dsDNA fluorescence enzyme immunoassay (FEIA) and CLIFT during 2016-2018 and to follow patients up until December 2021.

METHODS

We performed an observational, longitudinal and retrospective study on 417 samples from 257 patients who had been referred for suspected connective tissue diseases or followed up after diagnosis. All of them were positive for antinuclear antibodies (ANAs) using an indirect immunofluorescence assay (IFA) on Hep-2 cells, the entry criterion in our laboratory, and positive for FEIA dsDNA. Samples were then tested with CLIFT according to our routine protocol, which includes CLIFT testing after FEIA dsDNA results ≥10 UI/ml. After the assessment of data quality, the final analysis was based on 222 patients.

RESULTS

Eighty-three patients (37.4%) had positive results in both tests and met the diagnostic criteria for SLE. However, 139 patients (62.6%) had discrepant results (FEIA+, CLIFT-). Of these, 58 patients (41.7%) had a diagnosis of SLE, with 47 (33.8%) having been previously diagnosed and under treatment. The remaining 11 patients (7.9%) had a new diagnosis of SLE, which was made up within 4 years of the initial screening. A total of 81 of the 139 patients (57.5%) with discrepant results did not meet lupus criteria during the follow-up period.

CONCLUSIONS

The study showed that CLIFT could be negative in both treated and newly diagnosed SLE, thus underlining the importance of follow-up of dsDNA-positive results using solid-phase tests. Therefore, quantitative tests such as FEIA could add value to the diagnosis and management of patients with suspected SLE.

Diagnostic Performance of Anti-dsDNA Tests by Indirect Immunofluorescence and Enzyme-linked Immunosorbent Assay in Patients with Systemic Lupus Erythematosus

BACKGROUND

Several laboratory techniques for anti double-stranded (ds) DNA detection in systemic lupus erythematosus (SLE) are available, with variable diagnostic performance. We aimed to evaluate anti-dsDNA's diagnostic performance by indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (EIA).

METHODS

We conducted a single-center retrospective (2015 to 2020) study. Patients with anti-dsDNA tests by IIF and EIA were included. We evaluated the indications, applications, concordance, positive predictive value (PPV) of anti-dsDNA to confirm SLE diagnosis or flares, and associations of disease manifestations with positivity with each technique.

RESULTS

A total of 1368 reports of anti-dsDNA tests by IIF and EIA and the corresponding medical records of the patients were analyzed. The main indication for anti-dsDNA testing was to help in the diagnosis of SLE in 890 (65%) of the samples, and the main application after obtaining the results was SLE exclusion in 782 (57.2%) cases. The combination with the highest frequency was the negativity result by both techniques in 801 (58.5%) cases (Cohen kappa 0.57). Both methods were positive in 300 patients with SLE (Cohen kappa 0.42). The PPVs of anti-dsDNA tests to confirm diagnosis/flare was 79.64% (95% CI, 75.35-83.35) by EIA, 78.75% (95% CI, 74.27-82.62) by IIF, and 82% (95% CI, 77.26-85.93) when both were positive.

CONCLUSIONS

Anti-dsDNA detection by IIF and EIA are complementary and may indicate different clinical patterns in patients with SLE. The detection of anti-dsDNA antibodies by both techniques has a higher PPV than either separately for confirming SLE diagnosis or flares. These results highlight the need for evaluating both methods in clinical practice.

A Rare Case of Antinuclear Antibody (ANA)-Negative Lupus Nephritis

Because most patients with lupus nephritis have a positive antinuclear antibody (ANA), ANA-negative lupus nephritis is a rare complication of systemic lupus erythematosus (SLE). In the 2019 European Alliance of Associations for Rheumatology/American College of Rheumatology (EULAR/ACR) classification criteria for SLE, a negative ANA precludes further work-up of SLE. The following case discusses a patient with multiple negative ANA titers but was diagnosed with SLE based on the findings of the kidney biopsy showing lupus nephritis. Though ANA was negative, anti-double-stranded DNA (anti-dsDNA) and anti-Sjogren's syndrome-A (anti-SS-A) antibodies were high. This case highlights the nuances of SLE and further illustrates the challenges in making a diagnosis of SLE when serology alone is relied on for screening.

Autoantibodies to dsDNA in the diagnosis, classification and follow-up of patients with systemic lupus erythematosus

Autoantibodies, in particular anti-dsDNA antibodies, are increasingly used for diagnosis, classification and follow-up of patients with SLE. Since standardization of autoantibody assays is a major challenge, more attention should be paid to harmonization initiatives and better definition of required test characteristics in classification criteria. For diagnosis and follow-up separate multi-center studies are required to establish test characteristics of distinct immuno-assays for both purposes. Finally, such studies should consider not to evaluate SLE as a single disease, but as a disease with distinct subtypes.