Anti-Nuclear Antibodies Patterns in Patients With Systemic Lupus Erythematosus and Their Correlation With Other Diagnostic Immunological Parameters

Comprehensive Exploration of Antinuclear Antibodies (ANAs): Unveiling Clinical Significance, Associations with Cancer, and the Nuances of Differential Diagnosis in Positive ANA Patients

This comprehensive review delves into the complex realm of antinuclear antibodies (ANAs), expanding beyond their traditional involvement in autoimmune rheumatic disorders. By digging into historical changes, diagnostic complexity, and clinical significance, the debate reveals the shifting relationships between ANAs, particularly with cancer. Specialized studies provide practical insights on ANA testing processes, standardization, and upcoming challenges. Examining prevalence trends in the United States provides a time dimension to ANA dynamics, linking autoimmune and oncological considerations. The debate delves into the complexity of lupus erythematosus, emphasizing ANAs' diverse presentations and their potential as flexible diagnostic and prognostic indicators. The complex relationship between ANAs and cancer is highlighted, demonstrating their potential as early markers or indicators of malignancies. Looking ahead, this synthesis anticipates advances in personalized medicine and collaborative research, putting ANAs at the forefront of advanced diagnostics and treatments for autoimmune disorders and cancer. This synthesis envisions a future for ANA research in which these antibodies play a critical role in promoting personalized treatment, enhancing diagnostics, and fostering collaborative initiatives that cross traditional boundaries. As ANAs grow more prominent at the junction of autoimmune illnesses and cancer, this synthesis lays the path for further research and novel advances in understanding, diagnosing, and treating complicated medical conditions.

Validation of a murine proteome-wide phage display library for identification of autoantibody specificities

Autoimmunity is characterized by loss of tolerance to tissue-specific as well as systemic antigens, resulting in complex autoantibody landscapes. Here, we introduce and extensively validate the performance characteristics of a murine proteome-wide library for phage display immunoprecipitation and sequencing (PhIP-seq) in profiling mouse autoantibodies. This library was validated using 7 genetically distinct mouse lines across a spectrum of autoreactivity. Mice deficient in antibody production (Rag2-/- and μMT) were used to model nonspecific peptide enrichments, while cross-reactivity was evaluated using anti-ovalbumin B cell receptor-restricted OB1 mice as a proof of principle. The PhIP-seq approach was then utilized to interrogate 3 distinct autoimmune disease models. First, serum from Lyn-/- IgD+/- mice with lupus-like disease was used to identify nuclear and apoptotic bleb reactivities. Second, serum from nonobese diabetic (NOD) mice, a polygenic model of pancreas-specific autoimmunity, was enriched in peptides derived from both insulin and predicted pancreatic proteins. Lastly, Aire-/- mouse sera were used to identify numerous autoantigens, many of which were also observed in previous studies of humans with autoimmune polyendocrinopathy syndrome type 1 carrying recessive mutations in AIRE. These experiments support the use of murine proteome-wide PhIP-seq for antigenic profiling and autoantibody discovery, which may be employed to study a range of immune perturbations in mouse models of autoimmunity profiling.

A Retrospective Study on Antinuclear Antibody Patterns in Systemic Lupus Erythematosus Patients and Its Correlation With Serological Markers

INTRODUCTION

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease. Detection of antinuclear antibodies (ANAs) aids in the diagnosis of SLE. The indirect immunofluorescence (IIF) assay is often used a routine screening test for the detection of ANA. The pathogenic role and significance of various patterns produced in IIF is yet to be explored.

AIM

This study aimed to detect ANA patterns generated by IIF and correlate these patterns with specific antibodies detected by line immunoassay. We also investigated the significance of each ANA pattern and its association with specific serological SLE markers, such as complement molecules, anti-dsDNA, antiphospholipid antibody, and C-reactive protein (CRP), along with associations with direct Coombs test (DCT).

MATERIALS AND METHODS

We conducted a retrospective study that included 204 patients newly diagnosed with SLE according to the European Alliance of Associations for Rheumatology/American College of Rheumatology (EULAR/ACR) criteria. The detection and pattern determination of ANA was performed by IIF using HEp-20-10. Furthermore, line immunoassay was performed, and the antibody profile of each sample was obtained. Other immunodiagnostic markers were analyzed, including C3, C4, anti-dsDNA, antiphospholipid antibodies (anti-cardiolipin antibodies, anti-beta-2-glycoprotein I, and lupus anticoagulant), CRP, and DCT.

RESULTS

Of the 204 samples, the most frequent ANA pattern observed was nucleus speckled (52.9%), followed by nucleus homogenous (27.5%), mixed (13.7%), and cytoplasm speckled (5.9%). The nucleus homogenous pattern showed the most pathogenic immune profile due to its close association with markers of disease activity, namely, high anti-dsDNA titer, low C3 level, and DCT positivity.  Conclusion: This study showed that the most common pattern associated with SLE is nucleus speckled, followed by the nucleus homogenous pattern. Based on associations with specific serological markers, the nucleus homogenous pattern may be linked to a high disease activity in SLE.

Discriminating between Homogeneous (AC-1) and Dense Fine Speckled (AC-2) Antinuclear Antibody Patterns: Re-Evaluation of Immunofluorescence Imaging

Antinuclear antibodies (ANAs) are essential diagnostic markers in systemic autoimmune rheumatic diseases. Among the 30 ANA patterns, homogeneous (AC-1) and dense fine speckled (AC-2) should be focused on owing to their somewhat indistinct presentation in immunofluorescence imaging and distinct correlation with clinical conditions. This study aimed to develop a flowchart to guide discrimination between AC-1 and AC-2 patterns and to re-evaluate ANA samples according to this flowchart to verify its detection ability. We re-evaluated immunofluorescence imaging of 62 ANA blood samples simultaneously subjected to solid-phase assays for autoantibodies against dsDNA, nucleosomes, histones, and DFS70. The results showed statistically significant odd ratios (ORs) of detection of anti-DFS70 using AC-2 after re-evaluation of total samples (OR 101.9, 95% CI 11.7-886.4, p-value < 0.001) and subgroup analysis of patients' samples (OR 53.8, 95% CI 5.9-493.6, p-value < 0.001). The OR of anti-nucleosome/histone/dsDNA detection using AC-1 in re-evaluated data increased to 5.43 (95% CI 1.00-29.61, p-value = 0.05). In the analysis of specific autoantibodies, more than half of the samples with an AC-2 pattern (54.2%) had specific autoantibodies other than anti-DFS70. We conclude that the flowchart for discriminating between AC-1 and AC-2 ANA patterns in this study is a viable practical guide for other laboratories when encountering equivocal ANA results.

The Immunodiagnostic Utility of Antinuclear Antibody Patterns: A Prediction for Renal Involvement in Systemic Lupus Erythematosus Patients in the Western Region of Saudi Arabia

Objectives Previous studies have noted associations between the immunofluorescence patterns of antinuclear autoantibodies (ANA) and the autoimmune responses seen in systemic lupus erythematosus (SLE). In this study, the authors tested the hypothesis of whether ANA patterns predict renal involvement in SLE patients. Method A retrospective study was carried out on consecutive SLE patients who had ANA staining pattern data and who were screened for renal involvement defined as all-stage proteinuria or chronic kidney disease (CKD) at a referral tertiary center in western Saudi Arabia from December 2021 to February 2022. Demographic data and levels of lupus immune markers including ANA titers, anti-double-stranded deoxyribonucleic acid antibodies (anti-dsDNA), complements C3 and C4, anticardiolipin (aCL) immunoglobulin (Ig) G and IgM, anti-β2 glycoprotein (β2-IgM and β2-IgG), and lupus anticoagulant (LA) antibodies were collected. Result Among 243 patients included, 25.1% had renal involvement (95% confidence interval {CI}=19.8-31.0). A mixed ANA pattern was associated with a higher prevalence of renal involvement (46.2%), followed by homogenous (26.5%) and speckled (25.6%) patterns, compared with 4.5% for the other patterns (p=0.044). No further association of renal involvement was observed with other biological markers. Adjusted logistic regression showed age (odds ratio {OR}=0.95; 95% CI=0.92-0.97) and mixed ANA pattern (OR=26.66; 95% CI=2.53-281.11) to be independently associated with renal involvement, explaining 12.6% of the variance. Conclusion A mixed homogenous/speckled ANA staining pattern is associated with an increased risk of renal involvement, independent of ANA titer or other lupus immune markers. The potential clinical applications of the ANA staining pattern in SLE should be explored in various subtypes of SLE and patient groups.

Validation of a murine proteome-wide phage display library for the identification of autoantibody specificities

Autoimmunity is characterized by loss of tolerance to tissue-specific as well as systemic antigens, resulting in complex autoantibody landscapes. Here, we introduce and extensively validate the performance characteristics of a murine proteome-wide library for phage display immunoprecipitation and sequencing (PhIP-seq), to profile mouse autoantibodies. This system and library were validated using seven genetic mouse models across a spectrum of autoreactivity. Mice deficient in antibody production (Rag2-/- and μMT) were used to model non-specific peptide enrichments, while cross-reactivity was evaluated using anti-ovalbumin B cell receptor (BCR)-restricted OB1 mice as a proof of principle. The PhIP-seq approach was then utilized to interrogate three distinct autoimmune disease models. First, serum from Lyn-/- IgD+/- mice with lupus-like disease was used to identify nuclear and apoptotic bleb reactivities, lending support to the hypothesis that apoptosis is a shared origin of these antigens. Second, serum from non-obese diabetic (NOD) mice, a polygenic model of pancreas-specific autoimmunity, enriched peptides derived from both insulin and predicted pancreatic proteins. Lastly, Aire-/- mouse sera were used to identify numerous auto-antigens, many of which were also observed in previous studies of humans with autoimmune polyendocrinopathy syndrome type 1 (APS1) carrying recessive mutations in AIRE. Among these were peptides derived from Perilipin-1, a validated autoimmune biomarker of generalized acquired lipodystrophy in humans. Autoreactivity to Perilipin-1 correlated with lymphocyte infiltration in adipose tissue and underscores the approach in revealing previously unknown specificities. These experiments support the use of murine proteome-wide PhIP-seq for antigenic profiling and autoantibody discovery, which may be employed to study a range of immune perturbations in mouse models of autoimmunity.

Autoantibody-based subgroups and longitudinal seroconversion in juvenile-onset systemic lupus erythematosus

OBJECTIVE

To explore the clinical value of autoantibody-based subgroup framework and the trend of autoantibody fluctuation in juvenile-onset SLE (JSLE).

METHODS

Eighty-seven patients with JSLE were retrospectively collected and divided into subgroups via a two-step cluster based on the status of nine autoantibodies (double-stranded-DNA (dsDNA), nucleosome, histone, ribosomal P protein, Smith (Sm), u1-ribonucleoprotein (RNP), Sjögren's syndrome antigen A (SSA)/Ro52, SSA/Ro60, Sjögren's syndrome antigen B (SSB)/La). The final model selected in this study was based on adequate goodness of fit of the Silhouette coefficient and clinical interpretability. Clinical manifestations, organ involvements and disease activity were compared among the subgroups. Fluctuation in autoantibody status was also collected and analysed. Flare-free survival rates of the patients with positive/negative seroconversion and patients without seroconversion were studied by the Kaplan-Meier method and compared using a log-rank test.

RESULTS

Two clusters were identified: subgroup 1 (positive anti-Sm/RNP group) and subgroup 2 (negative anti-Sm/RNP group). There were more lupus nephritis (LN) and neuropsychiatric SLE (NPSLE) cases in subgroup 1 than in subgroup 2. Patients in subgroup 1 exhibited higher SLE Disease Activity Index scores compared with those in subgroup 2. Furthermore, anti-ribosomal P protein (61.1%), anti-nucleosome (58.3%) and anti-dsDNA (54%) were most commonly positive autoantibodies. A progressive decrease in the frequency of patients with positive results was demonstrated during the follow-up years. The decrease was notable for anti-dsDNA, anti-nucleosome and anti-ribosomal P protein (remaining 27.27%, 38.89% and 45.00% positive in the fifth year, respectively). While for those negative at baseline diagnosis, the decrease in the frequency of negative results was progressive but modest. Kaplan-Meier curve showed that the flare-free survival of patients with positive seroconversion was significantly lower than those without seroconversion and those with negative seroconversion (p<0.001).

CONCLUSIONS

In children with SLE, subgroups based on autoantibody profile can be applied to differentiate phenotypes and disease activity. Two important organ involvements, LN and NPSLE, are more common in patients with positive anti-Sm/RNP autoantibodies. Positive seroconversion may provide a valuable perspective for assessing flare, and it is worthwhile to retest the array of autoantibodies during follow-up.

Presence of anti-nuclear antibody associated with worse clinical outcomes of anti-NMDAR encephalitis

Purpose

Systemic autoantibodies are important for the diagnosis of autoimmune diseases, but their roles in anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis are unknown. The purpose of our study is to investigate the characteristics and a prognosis of anti-NMDAR encephalitis with the prevalence of autoantibodies.

Methods

Systemic autoantibodies were evaluated in 64 patients with anti-NMDAR encephalitis and 14 patients with autoimmune encephalitis with other forms. Then, according to systemic autoantibodies, patients with anti-NMDAR encephalitis were divided into an anti-nuclear antibody (ANA) positive group and an ANA negative group. The clinical outcome was assessed by a modified Rankin score at 12 months after the disease onset.

Results

A total of 64 patients with anti-NMDAR encephalitis were enrolled, of which 28.13% (18/64) were positive for ANA. The titers of a positive anti-NMDAR antibody in CSF (p = 0.041) and serum (p = 0.031) in the ANA-positive group were significantly higher than the ANA-negative group. Patients with ANA positive than those with ANA negative showed lower rates of headache (p = 0.047) and speech disorder (p = 0.049). The presence of ANA was associated with a worse clinical outcome at 12 months (p = 0.043).

Conclusion

ANA was prevalent in patients with anti-NMDAR encephalitis, and associated with a worse prognosis and impaired neurological recovery.