Levels of anti-topoisomerase I antibody correlated with short onset of cardiopulmonary involvement in Thai systemic sclerosis patients.

Anti-topoisomerase-I antibody (ATA) is associated with disease severity and internal organ involvement in patients with systemic sclerosis (SSc). The correlation between ATA levels and the clinical course of SSc is unclear. We aimed to determine the correlation between ATA level and survival time and the onset of internal organ fibrosis in SSc patients. This historical cohort study was conducted in adult SSc patients with quantitative tests of ATA between January 2019 and December 2022. Patients with overlap syndrome and no quantitative ATA test were excluded. According to the sample size calculation, and 10% compensated for missing data, a total of 153 patients were needed. The respective mean age on the study date and median ATA level was 59.9 ± 11.3 years and 370 U/mL (range 195-652). Most cases (107 cases; 69.9%) were the diffuse cutaneous SSc subset. According to a multivariable analysis, the ATA titer had a negative correlation with the onset of cardiac involvement (Rho - 0.47, p = 0.01), and had a positive correlation with skin thickness progression (Rho 0.39, p = 0.04). Eleven cases exhibited ATA levels < 7 U/mL and outlier ATA levels were excluded, 142 cases were included in the sensitivity analysis, and multivariable analysis showed the correlation between early onset of ILD and cardiac involvement (Rho - 0.43, p = 0.03 and Rho - 0.51, p = 0.01, respectively). The ATA level was correlated with neither the survival time nor the onset of renal crisis in both analyses. High ATA levels were correlated with a short onset of ILD and cardiac involvement and the presence of extensive skin tightness. Quantitative tests of ATA could serve as an effective tool for identifying patients at risk of an unfavorable prognosis.

Nuclear-penetrating scleroderma autoantibody inhibits topoisomerase 1 cleavage complex formation.

The contributions of anti-Topoisomerase 1 (Top1) autoantibodies to the pathophysiology of diffuse cutaneous systemic sclerosis (dcSSc), the most aggressive scleroderma subtype, are unknown. Top1 catalyzes DNA relaxation and unwinding in cell nuclei, a site previously considered inaccessible to antibodies. The discovery of autoantibodies in systemic lupus erythematosus that penetrate nuclei and inhibit DNA repair raised the possibility that nuclear-penetrating autoantibodies contribute to mechanisms of autoimmunity. Here we show that an anti-Top1 autoantibody produced by a single B cell clone from a patient with dcSSc penetrates live cells and localizes into nuclei. Functionally, the autoantibody inhibits formation of the Top1 cleavage complex necessary for DNA nicking, which distinguishes it from cytotoxic camptothecin Top1 inhibitors used in cancer therapy that trap the cleavage complex rather than preventing its formation. Discovery of a patient-derived cell-penetrating scleroderma anti-Top1 autoantibody that inhibits Top1 cleavage complex formation supports the hypothesis that anti-Top1 autoantibodies contribute to cellular dysfunction in dcSSc and offers a valuable antibody reagent resource for future studies on anti-Top1 autoantibody contributions to scleroderma pathophysiology.

Clinical significance of the anti-Nucleolar Organizer Region 90 antibodies (NOR90) in systemic sclerosis: Analysis of the European Scleroderma Trials and Research (EUSTAR) cohort and a systematic literature review.

BACKGROUND: The anti-Nucleolar Organizer Region 90 antibodies (NOR90) are rare antinuclear antibodies (ANA) reported in systemic sclerosis (SSc). Especially due to low prevalence, the clinical relevance of NOR90 in SSc remains uncertain. OBJECTIVES: To analyze the clinical associations of NOR90 in patients with SSc in a multicentric cohort. METHODS: Post-hoc, cross-sectional study of prospectively collected data from the European Scleroderma Trials and Research (EUSTAR) database, with additional information on NOR90. Further, we performed a systematic literature search, using the terms "systemic sclerosis" and "NOR90" across three databases: Medline via PubMed, Scopus, and Thomson Reuters' Web of Science Core Collection, from inception to November 1st, 2023. RESULTS: Overall, 1318 patients with SSc were included (mean age 58.3 ± 13.7 years, 81.3 % female), of whom 44 (3.3 %) were positive for NOR90. Of these, 32 were also positive for one of the SSc-criteria antibodies: 9/44 (20.5 %) for anti-topoisomerase I, 18/42 (42.9 %) for anti-centromere, and 5/40 (12.5 %) for anti-RNA polymerase III. NOR90-positive patients were more frequently female, had lower modified Rodnan skin score (mRSS), and lower prevalence of upper and lower gastrointestinal (GI) symptoms compared to NOR90-negative patients. In multivariable analysis, NOR90 remained significantly associated with lower mRSS and less frequent GI symptoms. The literature search identified 17 articles, including a total number of 87 NOR90-positive out of 3357 SSc patients, corresponding to an overall prevalence of 2.6 %. CONCLUSION: To our best knowledge, this is the largest SSc cohort tested for NOR90 to date, confirming the NOR90 prevalence in SSc patients is around 3 %.

Detection of IgE-autoantibodies to nuclear antigens in patients with systemic sclerosis and analysis of their clinical relevance.

OBJECTIVES: Antinuclear antibodies (ANA) of the IgE-type have been described in several connective tissue disorders (CTD) but not yet in systemic sclerosis (SSc). Aim of the study was, therefore, to establish an ELISA for the demonstration of IgE-autoantibodies to topoisomerase-I (topo-I) and the centromeric proteins A and B (CENP-A/B), to assess their prevalence and reactivity in SSc and to analyse their clinical relevance. METHODS: One hundred fifty-one patients with SSc and 88 with CREST-syndrome, 291 patients with other CTD, and 23 patients with fibromyalgia syndrome (FM) as a control collective were included into the study. Patients' sera were analysed by an in-house-ELISA for IgE autoantibodies against topo-I and CENP-A/B using recombinant antigens. Patients were assessed for median Rodnan skin score(mRSS), different organ and cutaneous manifestations. RESULTS: Of the patients with CREST syndrome, 67% had IgE-anti-CENP-A- and 77% IgE-anti-CENP-B-antibodies. IgE-anti-topo-I antibodies were found in 56% of patients with SSc. Prevalence and reactivity were significantly higher in CREST and SSc, respectively, than in other CTD or FM. IgE-reactivity strongly correlated with IgG-antibody reactivity. In CRESTsyndrome, IgE-anti-CENP-A (but not CENP-B)-antibodies were significantly higher and more prevalent in patients with skin ulcers, high mRSS, and more than four organ manifestations. They did not correlate with blood eosinophil counts. In contrast, for IgE-anti-topo-I antibodies no correlation with clinical manifestations was observed. CONCLUSIONS: IgE-autoantibodies against CENP-A/B and topo-I occur in SSc underlining the concept that SSc may be a T helper cell type 2 mediated disease. IgE-anti-CENP-A-antibodies correlated with disease activity, but this has to be confirmed in larger studies.