Objective: To analyze clinical and serological characteristics of subjects with scleroderma renal crisis (SRC) in Italian patients with systemic sclerosis (SSc).
Methods: A retrospective analysis of medical records from 9 Italian rheumatologic referral centers was carried out. All patients with SRC and an available serum sample at the time of crisis were included. Antinuclear antibodies (ANA) by indirect immunofluorescence, anti-topoisomerase (topo) I by enzyme-linked assay (ELISA), anti-RNA polymerases (RNAP) by ELISA for the subunit III, and immunoprecipitation (IP) were performed.
Results: Forty-six cases (38 female; 40 diffuse cutaneous SSc) were identified. Mean age at SSc and SRC onset was 52.8 years +/- 13.2 and 55.4 years +/- 11.8, respectively. ANA were present in 44 patients (96%). Anti-topo I antibodies were detected in 30 (65%), anti-RNAP I-III in 7 (15%). No differences emerged between these 2 groups for their main clinical characteristics. The proportion of patients in the anti-RNAP I-III group developing SRC early (< 18 mo) in the course of SSc was significantly higher (p = 0.03). Cumulative survival rates were 64%, 53%, and 35% at 1, 2, and 10 years of followup, respectively. Survival rates of SSc patients significantly differed according to their autoantibody profile, being lower in the anti-topo I than in the anti-RNAP I-III group (p = 0.034).
Conclusion: SRC is a rare manifestation of SSc in Italy but it is still associated with severe prognosis. Anti-topo I reactivity was more frequent than anti-RNAP I-III in our patients with SRC and was associated with delayed onset and high mortality rates.