Clinical features of systemic sclerosis patients with anti-RNA polymerase III antibody in a single centre in Spain.

Objective. To evaluate the clinical features and survival of patients with positive anti-RNA polymerase III (anti-RNAP III) in a Spanish single centre. Methods. We analysed 221 patients with SSc according to LeRoy and Medsger criteria. Twenty-six patients with positivity for anti-RNAP III antibodies were compared with 195 negative patients. Epidemiological, clinical, immunological features and survival were analysed. Results. In patients with anti-RNAP III positivity diffuse cutaneous SSc (dcSSc) subset was the most prevalent (20, 76.9% vs. 35, 17.9%, p<0.001), with shorter diagnosis delay (4.11 +/- 7.34 years vs. 6.77 +/- 9.22 years, p=0.005). Patients with anti-RNAP III antibodies had higher frequency of arterial hypertension (13, 50% vs. 55, 28.2%, p=0.024), scleroderma renal crisis (SRC) (3, 11.5% vs. 3, 1.5%, p=0.023), arthritis (9, 34.6% vs. 35, 17.9%, p=0.046), tendon friction rubs (4, 15.4% vs. 1, 0.5%, p=0.001) and contractures (5, 19.2% vs. 10, 5.1%, p=0.02). There were no differences found in the presence of cancer or in global survival. In the multivariate survival analysis, severe interstitial lung disease (ILD) (HR: 8.61, 95%CI 3.40-21.81), pulmonary arterial hypertension (PAH) (HR: 4.05, 95%CI 1.4211.61) and SRC (HR: 17.27, 95%CI 3.36-88.97) were the only factors associated with poor prognosis. Conclusion. In this cohort anti-RNAP III antibodies are related with dcSSc subset, shorter diagnostic delay and higher prevalence of musculoskeletal involvement, arterial hypertension and SRC. ILD, PAH and SRC were independent prognostic factors.