Five-year follow-up of 165 Italian patients with undifferentiated connective tissue diseases.

OBJECTIVE: To study those conditions with a proven or hypothesised immunologic pathogenesis and denominated under a working definition of undifferentiated connective tissue diseases (UCTD).

METHODS: A multicentre prospective study was organised involving 10 tertiary referral centers of internal medicine in Italy, with the aim of describing the natural history of UCTD and the prevalence of its different clinical and immunological manifestations.

RESULTS: After a five-year follow-up period, data on 165 patients were available for analysis. UCTDs occur mainly in females in their fourth decade of life. Articular and mucocutaneous features and Raynaud's phenomenon represent the most common findings. Nevertheless, we also detected a relatively high incidence of permanent major organ damage. Regarding the immunologic parameters, we documented some conflicting results in the correlation between serologic abnormalities and clinical features. In 10 patients UCTD evolved to a major disease, generally systemic lupus erythematosus or Sjögren's syndrome.

CONCLUSION: A low rate of evolution to a defined autoimmune disease, the limited use of steroid or immunosuppressive therapy, and a favourable course in the majority of cases are the main characteristics of patients with UCTDs.