The aim of the present study was to assess the
autoantibody profile, dominant clinical symptoms and cluster characteristics of different
mixed connective tissue disease (
MCTD phenotypes. Two-hundred-and-one patients with
MCTD were followed-up longitudinally. Five clinical parameters, Raynaud's phenomenon, pulmonary artery
hypertension (PAH),
myositis,
interstitial lung disease (ILD), erosive
arthritis and five auto-
antibodies besides anti-U1RNP, antiendothelial cell
antibodies (
AECA),
anti-CCP, anti-
cardiolipin (anti-CL), anti-SSA/SSB and
IgM rheumatoid factor (RF) were selected for cluster analysis. The mean age of patients was 52.9 ± 12.4 years and the mean follow-up of the disease was 12.5 ± 7.2 years. Patients were classified into three cluster groups. Cluster 1 with 77 patients, cluster 2 with 79 patients and cluster 3 with 45 patients. In cluster 1 the prevalence of PAH (55.8%; p < 0.001), Raynaud's phenomenon (92.2%; p < 0.001) and
livedo reticularis (24.6%, p < 0.001) was significantly greater than in cluster 2 and 3. In cluster 2, the incidence of ILD (98.7%; p < 0.001),
myositis (77.2%; p < 0.001), and
esophageal dysmotility (89.8%; p < 0.001) was significantly greater than that in cluster 1 and 3. In cluster 3,
anti-CCP antibodies were present in 31 of 45 patients (68.8%) with erosions.
Anti-CCP antibodies were present in 37 of 42 patients (88.0%) with erosions. PAH, angina,
venous thrombosis was observed in cluster 1 and
pulmonary fibrosis in cluster 2, musculosceletal damage, gastrointestinal symptoms and
osteoporotic fractures were most frequent in cluster 3. Cumulative survival assessment indicated cluster 1 patients having the worst prognosis. Cluster analysis is valuable to differentiate among various subsets of
MCTD and useful prognostic factor regarding the disease course.