Undifferentiated connective tissue disease with antibodies to Ro/SSa: clinical features and follow-up of 148 patients.

OBJECTIVE To evaluate the clinical and serologic profile, the rate of progression to well defined CTD and the possible predictors of disease evolution in patients affected by UCTD with antibodies anti-RoISSA. METHODS 148 patients diagnosed as UCTD were retrospectively evaluated. Antibodies to SSA/Ro were determined by counter-immunoelectrophoresis and ELISA. RESULTS Thirty-six patients (24.3%) developed a well-defined CTD after a mean follow-up of 4.5 years. Most patients developed primary Sjögren's syndrome (SS) (50%) or systemic lupus erythematosus (SLE) (30.5%). Leukopenia and xerophthalmia developed more frequently in the group of patients evolving to defined CTDs (p < 0.0032 and p < 0.0063). Leukopenia independently predicted the evolution in CTD by multivariate regression analysis (p < 0.019). Anti-dsDNA predicted the evolution in SLE (p < 0.0207), while the presence of additional anti-ENA specificity to anti-Ro/SSA was not associated with the outcome. CONCLUSION 24.3% of patients with UCTD and antibodies to Ro/SSA can progress in a relatively short period of time to well-defined CTDs. The development of primary SS could be predicted by xerophthalmia and SLE by the appearance of anti-dsDNA antibodies.