Antinuclear Antibody Tests

Application of the Monoclonal Autoantibody and Its Target Protein Derived from the Peripheral Blood of SLE Patients in Serological Diagnosis and Differential Diagnosis of SLE

INTRODUCTION

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder with limited reliable diagnostic biomarkers. This study evaluates the utility of DEAD-box helicase 5 (DDX5) as a diagnostic and differential marker for SLE and assesses the performance of a capture bead-based flow cytometry (CBFCM) method for detecting serum proteins.

METHOD

Serum samples were collected from 52 patients with SLE, 38 patients with rheumatoid arthritis (RA), 49 patients with lung cancer (LC), and 50 healthy controls (HCs). Levels of DDX5, anti-DDX5, anti-dsDNA, and anti-Sm were quantified using enzyme-linked immunosorbent assay (ELISA) and CBFCM.

RESULTS

Serum DDX5 levels were significantly elevated in patients with SLE compared to patients with RA and HCs, correlating with the SLE activity. DDX5 demonstrated strong discriminatory power between SLE and RA. Combining DDX5, anti-dsDNA, and anti-Sm as biomarkers yielded an area under the curve (AUC) of 0.976 for SLE diagnosis. Decision curve analysis indicated a high clinical benefit from the combined biomarkers. The sensitivity and specificity of DDX5 were 66.11% and 88.89% for ELISA, and 72% and 91.3% for CBFCM.

DISCUSSION

DDX5 shows promise as a novel serological biomarker for SLE diagnosis and differential diagnosis. Additionally, CBFCM outperforms ELISA in detecting soluble serum proteins.

Targeted isolation of diketopiperazines from a deep-sea derived fungus with anti-neuroinflammatory effects

Prenylated indole diketopiperazines represent a diverse array of alkaloids with complex chemical scaffolds and with a wide range of biological activities. Aiming to discover bioactive metabolites with structural novelty, genomic annotation in association with the MS/MS-based molecular networking demonstrated a deep-sea derived fungus Aspergillus puulaauensis F77 containing a profile of diketopiperazines. Targeted separation of the cultured fungus led to the isolation of 19 undescribed austamide-type diketopiperazines namely versicoines A-S. Their structures were elucidated by the 2D NMR data, in association with Snatzke'method, ECD calculations, and single-crystal X-ray diffraction data for configurational assignments. Versicoine N-S represent a unique class of austamide-type alkaloids with a spirocenter at C-3. Bioassay results demonstrated versicoine N and relevant analogs possessing inhibitory effects against NO production in LPS-stimulated BV-2 cells. Further mechanistic investigation demonstrated the significant inhibition of versicoine N against p65 expression and its nuclear translocation, along with the inhibition toward phosphorylation of IKK/IκB in NF-κB signaling pathway. In addition, versicoine N also inhibited NLRP3 inflammasome activation and its related proteins, including caspase 1, pro-caspase1, IL-1β and pro-IL-1β. This study largely extends the chemical diversity of austamide-type alkaloids, and provides promising lead compounds for anti-neuroinflammation.

Detection of anti-calreticulin antibody in the sera of Chinese patients with primary Sjögren syndrome

BACKGROUND

Primary Sjögren syndrome (pSjS) is one of the most prevalent systemic autoimmune diseases and characterized with hyperactivation of B cell and the abundant presence of autoantibodies in sera. The salivary gland epithelial cells (SGECs) release autoantigens to evoke autoimmunity through releasing elevated apoptosis or secreting autoantigen-containing exosomes, thus identifying autoantibodies directly to SGECs might provide insights into disease related biomarkers as well as further elucidating pathogenesis mechanisms. The present study was undertaken to identify autoantibodies to SGECs and to evaluate its clinical values in Chinese pSjS.

METHODS

Cell-based indirect immunofluorescence and immunostaining, two-dimensional electrophoresis and liquid chromatograph-tandem mass spectrometry were conducted to identify the autoantibodies to human salivary gland cell line A253 in pSjS sera. Enzyme-linked immunosorbent assay (ELISA) was applied to identify autoantibody titer in pSjS cohort and healthy controls. The prevalence and clinical significance of the identified autoantibodies was further assessed in pSjS population.

RESULTS

Anti-calreticulin (CALR) antibody was identified as a new autoantibody directly to SGECs in sera from pSjS patients. Anti-CALR antibody were detected in 37 of 120 pSjS patients (30.83 %) and 1 of 54 healthy controls (1.85 %). It was found in 40.85 % pSjS with anti-SSA positive, 53.85 % with anti-SSB positive, and 14.7 % in sero-negative pSjS. Anti-CALR antibody was associated with clinical manifestations including weight loss(p = 0.045), vasculitis (p = 0.031), and laboratory parameters including erythrocyte sedimentation rate (ESR) (r = 0.056, p = 0.021), Krebs von den Lungen-6 (KL-6) (r = 0.121, p = 0.035), IgG (r = 0.097, p < 0.001), IgG2 (r = 0.142, p = 0.022), IgG3 (r = 0.287, p < 0.001), fibrinogen (r = 0.084, p = 0.016), D-Dimer (r = 0.086, p = 0.012) and fibrinogen degradation production (r = 0.150, p = 0.002). The expression of CALR in salivary glands was related to lymphocytes infiltration into salivary glands in pSjS patients (r = 0.7076, p = 0.0034).

CONCLUSION

To our knowledge, this was the first study to investigate the prevalence and clinical significance of anti-CALR antibody in Chinses pSjS patients. The present study identified an autoimmune antibody, anti-CALR antibody, as a good autoimmune biomarker for sero-negative pSjS.

Reconstruction of Sjögren's syndrome-like sialadenitis by a defined disease specific gut-reactive single TCR and an autoantibody

Lymphocytes such as CD4+ T cells and B cells mainly infiltrate the salivary glands; however, the precise roles and targets of autoreactive T cells and autoantibodies in the pathogenesis of Sjögren's Syndrome (SS) remain unclear. This study was designed to clarify the role of autoreactive T cells and autoantibodies at the single-cell level involved in the development of sialadenitis. Infiltrated CD4+ T and B cells in the salivary glands of a mouse model resembling SS were single-cell-sorted, and their T cell receptor (TCR) and B cell receptor (BCR) sequences were analyzed. The predominant TCR and BCR clonotypes were reconstituted in vitro, and their pathogenicity was evaluated by transferring reconstituted TCR-expressing CD4+ T cells into Rag2-/- mice and administering recombinant IgG in vivo. The reconstitution of Th17 cells expressing TCR (#G) in Rag2-/- mice resulted in the infiltration of T cells into the salivary glands and development of sialadenitis, while an autoantibody (IgGr22) was observed to promote the proliferation of pathogenic T cells. IgGr22 specifically recognizes double-stranded RNA (dsRNA) and induces the activation of dendritic cells, thereby enhancing the expression of IFN signature and inflammatory genes. TCR#G recognizes antigens related to the gut microbiota. Antibiotic treatment severely reduces the activation of TCR#G-expressing Th17 cells and suppresses sialadenitis development. These data suggest that the anti-dsRNA antibodies and, TCR recognizing the gut microbiota involved in the development of sialadenitis like SS. Thus, our model provides a novel strategy for defining the roles of autoreactive TCR and autoantibodies in the development and pathogenesis of SS.

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.

Clinical value of chemiluminescence method for detection of antinuclear antibody profiles

BACKGROUND

Antinuclear antibodies (ANAs) are crucial in diagnosing autoimmune diseases, mainly systemic lupus erythematosus (SLE). This study aimed to compare the performance of chemiluminescence assay (CLIA) and line immunoassay (LIA) in detecting ANAs in patients with autoimmune diseases, evaluate their diagnostic accuracy for SLE, and develop a novel diagnostic model using CLIA-detected antibodies for SLE. Specimens from patients with autoimmune diseases and physical examination specimens were collected to parallel detect specific antibodies. Individual antibodies' diagnostic performance and a model combining multiple antibodies were assessed. The findings provide valuable insights into improving the diagnosis of SLE through innovative approaches.

AIM

To compare the performance of CLIA and LIA in detecting ANAs in patients with autoimmune diseases, assess their accuracy for SLE, and develop a novel diagnostic model using CLIA-detected antibodies for SLE.

METHODS

Specimens have been obtained from 270 patients with clinically diagnosed autoimmune disorders, as well as 130 physical examination specimens. After that, parallel detection of anti-double-stranded DNA (dsDNA) antibody, anti-histone (Histone) antibody, anti-nucleosome (Nuc) antibody, anti-Smith (Sm) antibody, anti-ribosomal P protein (Rib-P) antibody, anti-sicca syndrome A (Ro60) antibody, anti-sicca syndrome A (Ro52) antibody, anti-sicca syndrome (SSB) antibody, anti-centromere protein B (Cenp-B) antibody, anti-DNA topoisomerase 1 (Scl-70) antibody, anti-histidyl tRNA synthetase (Jo-1) antibody, and anti-mitochondrial M2 (AMA-M2) antibody was performed using CLIA and LIA. The detection rates, compliance rates, and diagnostic performance for SLE were compared between the two methodologies, followed by developing a novel diagnostic model for SLE.

RESULTS

CLIA and LIA exhibited essentially comparable detection rates for anti-dsDNA antibody, anti-Histone antibody, anti-Nuc antibody, anti-Sm antibody, anti-Rib-P antibody, anti-Ro60 antibody, anti-Ro52 antibody, anti-SSB antibody, anti-Cenp-B antibody, anti-DNAScl-70 antibody, anti-Jo-1 antibody and anti-AMA-M2 antibody (P > 0.05). The two methods displayed identical results for the detection of anti-dsDNA antibody, anti-Histone antibody, anti-Nuc antibody, anti-Sm antibody, anti-Ro60 antibody, anti-Ro52 antibody, anti-SSB antibody, anti-Cenp-B antibody, anti-Scl-70 antibody, and anti-AMA-M2 antibody (Kappa > 0.7, P < 0.05), but showed a moderate agreement for the detection of anti-Rib-P antibody and anti-Jo-1 antibody (Kappa = 0.671 and 0.665; P < 0.05). In addition, the diagnostic performance of these antibodies detected by both methods was similar for SLE. The diagnostic model's area under the curve values, sensitivity, and specificity, including an anti-dsDNA antibody and an anti-Ro60 antibody detected by CLIA, were 0.997, 0.962, and 0.978, respectively. These values were higher than the diagnostic performance of individual antibodies.

CONCLUSION

CLIA and LIA demonstrated excellent overall consistency in detecting ANA profiles. A diagnostic model based on CLIA-detected antibodies can successfully contribute to developing a novel technique for detecting SLE.

Detection of antinuclear antibodies: recommendations from EFLM, EASI and ICAP

OBJECTIVES

Antinuclear antibodies (ANA) are important for the diagnosis of various autoimmune diseases. ANA are usually detected by indirect immunofluorescence assay (IFA) using HEp-2 cells (HEp-2 IFA). There are many variables influencing HEp-2 IFA results, such as subjective visual reading, serum screening dilution, substrate manufacturing, microscope components and conjugate. Newer developments on ANA testing that offer novel features adopted by some clinical laboratories include automated computer-assisted diagnosis (CAD) systems and solid phase assays (SPA).

METHODS

A group of experts reviewed current literature and established recommendations on methodological aspects of ANA testing. This process was supported by a two round Delphi exercise. International expert groups that participated in this initiative included (i) the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group "Autoimmunity Testing"; (ii) the European Autoimmune Standardization Initiative (EASI); and (iii) the International Consensus on ANA Patterns (ICAP).

RESULTS

In total, 35 recommendations/statements related to (i) ANA testing and reporting by HEp-2 IFA; (ii) HEp-2 IFA methodological aspects including substrate/conjugate selection and the application of CAD systems; (iii) quality assurance; (iv) HEp-2 IFA validation/verification approaches and (v) SPA were formulated. Globally, 95% of all submitted scores in the final Delphi round were above 6 (moderately agree, agree or strongly agree) and 85% above 7 (agree and strongly agree), indicating strong international support for the proposed recommendations.

CONCLUSIONS

These recommendations are an important step to achieve high quality ANA testing.

Clinical usefulness of anti-nuclear antibody in childhood: real-world experience at a tertiary care center : Usefulness of ANA in pediatric autoimmune diseases

We evaluated the reasons for requesting anti-nuclear antibody (ANA) analysis in clinical practice at a tertiary center and the performance of ANA in pediatric autoimmune diseases. Patients under 18 years of age who underwent ANA testing for various symptoms between 2013 and 2017 were included. We retrieved data from medical records, including demographic and clinical characteristics, diagnoses, ANA results, titers, and staining patterns. The performance assessment tools were calculated according to the ANA titer for autoimmune diseases. Risk factors for autoimmune diseases in ANA-positive patients were evaluated using logistic regression analysis. Changes in ANA titer and seroconversion were evaluated using repeated ANA analyses. A total of 3812 patients underwent ANA. Medical records of 3320 patients were obtained. The rate of ANA positivity was 27.4%. ANA was requested most frequently because of musculoskeletal findings in 1355 patients (40.8%). Juvenile idiopathic arthritis (n = 174, 20.2%) was the most common diagnosis in ANA-positive patients, followed by systemic lupus erythematosus (n = 52, 6%). For autoimmune diseases, a titer of ≥ 1:100, a sensitivity of 40.1%, and a specificity of 77.1% were observed. At a titer ≥ 1:1000, the sensitivity and specificity were 24.1% and 89%, respectively. Homogeneous staining was an additional risk factor for autoimmune diseases in ANA-positive patients by multivariate logistic regression analysis (OR [95% CI]: 4.562 [3.076-6.766], p < 0.001).    Conclusion: Our results revealed that the performance of the ANA test in diagnosing autoimmune diseases in pediatric clinical practice was poor. Therefore, clinical findings should be carefully evaluated before ANA testing is performed. What is Known: • ANA can be detected in systemic autoimmune rheumatic diseases. • The diagnostic role of ANA is controversial, especially in childhood. What is New: • One in four patients who requested the ANA test had an autoimmune disease. • Less than half of patients with an autoimmune disease had ANA positivity.

Differential immune response to xenobiotic-modified self-molecule in simple and connective tissue disease-associated primary biliary cholangitis

BACKGROUND AND AIMS

Our previous studies demonstrated that 2-octynoic acid (2OA) might alter the conformational structure of the inner lipoic acid (LA) binding domain (ILD) in the E2 subunit of pyruvate dehydrogenase complex (PDC-E2), leading to the loss of immune tolerance in simple primary biliary cholangitis (S-PBC). Here, we further explore if this etiological mechanism also accounts for connective tissue disease-associated PBC (CTD-PBC).

METHODS

Intein-mediated protein ligation was used to prepare ILD, LA-ILD and 2OA-ILD, and their reactivity with serum samples from 124 S-PBC and 132 CTD-PBC patients was examined. The antibodies to LA, 2OA, LA-ILD and 2OA-ILD, the isotypes of antibodies to LA, 2OA and ILD, were comparatively detected between the two patient groups by enzyme-linked immunosorbent assay and immunoblotting.

RESULTS

Both the percentage and reactivity of antibody to 2OA in S-PBC were significantly higher than in CTD-PBC. Antibodies to 2OA and to LA between the two groups separately shared the same characteristics. Remarkably, coexistence of the antibodies to LA-ILD and to 2OA, and coexistence of the antibodies to LA and to 2OA in S-PBC were both significantly more frequent than in CTD-PBC, whereas the percentage of anti-LA antibody without anti-2OA antibody in S-PBC was markedly lower than in CTD-PBC. Moreover, the isotype of antibody to LA was predominantly IgG in CTD-PBC, whilst this isotype was mainly IgM in S-PBC.

CONCLUSION

Xenobiotic 2OA might play less important pathogenic role in CTD-PBC than in S-PBC, suggesting that different underlying mechanisms are involved in their immune intolerance to PDC-E2.

Safety and Efficacy of PD-1/PD-L1 Inhibitors in Cancer Patients With Preexisting Autoantibodies

Background

Programmed cell death protein-1/programmed cell death ligand-1 (PD-1/PD-L1) inhibitors therapy is now a routine scheme in cancers. However, the effect of preexisting autoantibodies on the safety and efficacy of PD-1/PD-L1 inhibitors in cancer patients is not well understood.

Methods

The present retrospective cohort study evaluated the safety and efficacy of PD-1/PD-L1 inhibitors in patients with preexisting autoantibodies. Patients who received PD-1/PD-L1 inhibitors in the Department of Medical Oncology, Peking Union Medical College Hospital between November 2017 and August 2021 were reviewed.

Results

67 (37.9%) of the 177 patients, 27 (20.3%) of the 133 patients, and 16 (11.0%) of 146 patients who received PD-1/PD-L1 inhibitors were positive for ANA, anti-Ro52, and antithyroid antibodies, respectively. Preexisting ANA and anti-Ro52 antibody were not associated with the increased risk of immune-related adverse events (irAEs), while thyroid dysfunction was more frequent in patients with positive antithyroid antibody (75.0% versus 13.8%, p < 0.001). The median progression-free survival (PFS, 13.1 versus 7.0 months, p = 0.015) was significantly longer in the ANA-positive patients, while the median overall survival (OS, 14.5 versus 21.8 months, p = 0.67) did not differ significantly between the ANA-positive and ANA-negative groups. Moreover, the preexisting anti-Ro52 and antithyroid antibodies were not significantly associated with PFS and OS.

Conclusions

The presence of ANA and anti-Ro52 antibody were not associated with a higher risk of irAEs, whereas patients positive for antithyroid antibody should monitor closely immune-related thyroid dysfunction. Preexisting ANA might be a predictor of longer PFS, while anti-Ro52 and antithyroid antibodies had no significant effect on survival outcomes in patients receiving PD-1/PD-L1 inhibitors therapy.