AB0727 Antibody profile and systemic sclerosis clinical features – myth or reality?
Authors: A.C. Duarte, A. Cordeiro, M.J. Santos, J. Canas da Silva
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Antinuclear antibodies(ANA) occur in 80%–98% of systemic sclerosis(SSc) patients (pts), with different specificities. Anticentromere antibody(ACA), antitopoisomerase I(anti-Scl70) and anti-RNA polymerase III are the commonest and are included in the new SSc ACR/EULAR classification criteria. According to literature, ANA specificities are associated with clinical features of the disease. <h3>Objectives</h3> Evaluate the relationship between antibody profile and clinical manifestations in a cohort of SSc pts. <h3>Methods</h3> We conducted a retrospective analysis of SSc pts followed in our department. Demographic data, disease duration, ANA specificities and clinical manifestations were collected. Mann-Whitney U test and Chi-square were used for comparisons between pts who tested positive or negative for different ANA specificities. <h3>Results</h3> In total, 117 pts were included, 91.5% female with mean age of 60.7±15.2 years and mean disease duration of 11.9±10.7 years. Seventy-five pts (64.1%) had limited cutaneous SSc(lcSSC), 26 (22.2%) diffuse cutaneous SSc(dcSSc), 8 (6.8%) very early diagnosis SSc, 7 (6%) overlap syndromes and 1 (0.9%) SSc sine scleroderma. Most (92.3%) were ANA positive, with 53.8% having ACA, 26.5% anti-Scl70, 3.4% anti-U3 RNP, 2.6% anti-U1 RNP, 1.7% anti-PM/Scl and 0.9% anti-RNA polymerase III and 0.9% anti-Th/To. Positivity for ACA was significantly associated with female gender (OR: 1.18 95% CI 1.04–1.34) and lcSSc phenotype (OR: 9.43 95% CI 3.86–23.03). ACA was also associated with older age at disease onset (p=0.008). Vascular involvement, defined by current/previous digital ulcers and/or telangiectasias, was also more prevalent in this group (OR: 5.59 95% CI 2.47–12.66). Pulmonary arterial hypertension (group 1 ERS/<sup>ECS 2013</sup> classification) was present in 6.3% of pts with ACA. Oesophageal involvement was the second commonest manifestation and occurred in 57.1% of pts with ACA, although this association was not statistically significant. ACA seemed to have a protective effect for interstitial lung disease (ILD) (OR: 0.027 95% CI 0.004–0.213). Anti-Scl70 positivity was associated with dcSSc phenotype (OR: 9.29 95% CI 3.26–26.5) and ILD (OR: 10.39 95% CI 3.86–27.92). From the 4 pts with anti-U3 RNP, 3 had dcSSC subtype. The only patient with renal manifestations was anti-U3 RNP positive and had rapidly progressive cutaneous involvement. Legend: ACA – anticentromere antibody; anti-ScI70 – antitopoisomerase I; lcSSc – limited cutaneous systemic sclerosis; dcSSc – diffuse cutaneous systemic sclerosis; PAH – pulmonary arterial hypertension; GI – gastro-intestinal; MS – muscle-skeletal Anti-U1RNP was associated with muscle-skeletal manifestations (OR: 10.7 95% CI 0.92–20.44) and with overlap syndromes (OR: 15.2 95% CI 4.7–29.1). Pts with anti-Th/To and anti-RNA-polymerase III had lcSSc subtype. Vascular manifestations, oesophageal involvement and calcinosis cutis were the main manifestations, respectively. Table 1 shows detailed clinical manifestations and antibody profile. <h3>Conclusions</h3> In our cohort, ACA and anti-Scl70 were the commonest antibodies and were associated with lcSSC and dsSSc phenotype, respectively. ACA positivity conferred a higher risk of vascular disease and had a protective effect for ILD, while anti-Scl70 was associated with ILD. Pts with anti-U1 RNP and anti-PM/Scl had mainly muscle-skeletal manifestations. This study confirms an association between immunological profile and clinical manifestations, reinforcing the importance of antibody profile and raising awareness for possible disease complications. Larger national studies would be desirable, specially for a better understanding of major organ involvement associated with least common antibodies. <h3>Disclosure of Interest</h3> None declared