Serum levels of tissue inhibitor of metalloproteinases in patients with mixed connective tissue disease

Objective. To determine serum tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 levels in patients with mixed connective tissue disease (MCTD) and investigate whether these levels were correlated with the clinical or serological features of this disease. Methods. Serum TIMP-1 and TIMP-2 levels were measured with specific enzyme-linked immunosorbent assays. Serum samples from 26 patients with MCTD and 18 healthy individuals were examined. Results. Serum levels of TIMP-1 were significantly higher in patients with MCTD than those in healthy individuals (mean ± SD: 218.9 ± 50.8 ng/ml versus 160.0 ± 38.7 ng/ml, P < 0.0001). MCTD patients with elevated TIMP-1 had esophageal involvement at a significantly higher incidence than those without (77.8% versus 35.3%, p < 0.05). There was no difference in serum TIMP-2 levels between patients with MCTD and healthy controls (75.6 ± 11.9 ng/ml versus 77.3 ± 10.7 ng/ml). Conclusion. These results suggest that TIMP-1 is involved in the pathogenesis of MCTD, and that TIMP-1 may be a serological marker for the presence of esophageal involvement in these patients.