{
  "abstract": "Introduction Although classical systemic sclerosis (SSc)-specific autoantibodies—anticentromere (ACA), anti-topoisomerase I (ATA), and anti-RNA polymerase III (ARA)—define major disease subsets and play a pivotal role in clinical stratification, up to one-third of patients may lack these specificities; hence the need to identify novel biomarkers with diagnostic and pathogenetic relevance. Protein arginine methyltransferase 5 (PRMT5), which plays a pivotal role in epigenetic regulation, fibroblast activation, and immune signalling, has recently been identified as a potential novel autoantigen in SSc. Our study aims to determine the prevalence of anti-PRMT5 antibodies in a monocentric cohort of Caucasian SSc patients and to explore their association with disease manifestations and serological subsets.Material and Methods A cross-sectional study was conducted in adult patients fulfilling ACR/EULAR 2013 criteria for SSc. Clinical, laboratory, and serological data were collected systematically. Serum levels of anti-PRMT5 were assessed by enzyme-linked immunosorbent assays in sera from unselected patients with SSc and compared with patients with rheumatoid arthritis (RA, n = 109) and healthy controls (n = 71). Optical density (OD) cut-off for positive anti-PRMT5 antibodies was determined by ROC curve analysis and set as 0.155.Results A total of 114 patients were enrolled. The median disease duration was 35 months (IQR 34–192), and the median age was 58 years (IQR 48–68). Most patients had limited cutaneous ssc (57%) and were positive for ata (37%) ( table 1). Anti-prmt5 antibodies were detected in 23.7% of ssc patients, being significantly higher than in ra (p <0.001) or healthy controls (p <0.001) (figure 1). PRMT5-positive patients more frequently displayed ATA seropositivity (57% vs. 33%, p = 0.026) and showed a lower prevalence of gastro-oesophageal involvement (64% vs. 84%, p = 0.036). In the multivariate analysis, both pulmonary arterial hypertension (PAH) (OR 9.38, 95% CI 1.29–68.0, p = 0.027) and ATA subset (OR 3.23, 95% CI 1.23–8.48, p = 0.017) independently predicted anti-PRMT5 seropositivity. An additional multivariate model, adjusted for age and sex, showed that anti-PRMT5 positivity was not independently associated with the diagnosis of PAH (OR 4.8, 95% CI 0.7–33.5, p = 0.12).Conclusions Our study confirms the presence of anti-PRMT5 antibodies and their association with SSc in an independent cohort of Caucasian patients. Anti-PRMT5 positivity appears to be associated with distinctive SSc features—namely ATA-positivity and vascular manifestations, particularly PAH—suggesting a potential role for these autoantibodies in the stratification of scleroderma patients. Further longitudinal studies are warranted to clarify their potential contribution to disease pathogenesis and prognostic value.Abstract P.037 Figure 1Abstract P.037 Table 1Demographic, clinical, and serological characteristics in the overall SSc cohort and according to anti-PRMT5 status",
  "authors": [
    {
      "affiliations": [
        "Rheumatology Unit, Department of Medicine-DIMED, Padova University Hospital, Padova, Italy"
      ],
      "name": "Marco Binda"
    },
    {
      "affiliations": [
        "Rheumatology Unit, Department of Medicine-DIMED, Padova University Hospital, Padova, Italy"
      ],
      "name": "Anna Ghirardello"
    },
    {
      "affiliations": [
        "Rheumatology Unit, Department of Medicine-DIMED, Padova University Hospital, Padova, Italy"
      ],
      "name": "Beatrice Moccaldi"
    },
    {
      "affiliations": [
        "Rheumatology Unit, Department of Medicine-DIMED, Padova University Hospital, Padova, Italy"
      ],
      "name": "Anna Cuberli"
    },
    {
      "affiliations": [
        "Rheumatology Unit, Department of Medicine-DIMED, Padova University Hospital, Padova, Italy"
      ],
      "name": "Andrea Benini"
    },
    {
      "affiliations": [
        "Rheumatology Unit, Department of Medicine-DIMED, Padova University Hospital, Padova, Italy"
      ],
      "name": "Marta Tonello"
    },
    {
      "affiliations": [
        "Rheumatology Unit, Department of Medicine-DIMED, Padova University Hospital, Padova, Italy"
      ],
      "name": "Roberta Ramonda"
    },
    {
      "affiliations": [
        "Rheumatology Unit, Department of Medicine-DIMED, Padova University Hospital, Padova, Italy"
      ],
      "name": "Elisabetta Zanatta"
    }
  ],
  "title": "P.037 Anti-protein arginine methyltransferase 5 (PRMT5) antibodies in the assessment of patients with systemic sclerosis",
  "uid": "d366f1ac-809e-59a1-be04-052ee608a91b"
}