Concentration of fibronectin and granulocyte elastase in plasma of patients with systemic connective-tissue diseases.

The concentration of granulocyte elastase-alpha-1-protease inhibitor (E-AT) complex in plasma is enhanced in inflammatory processes, e.g. in septicaemia and rheumatoid arthritis, being an expression of granulocyte activation during inflammatory response. In the present study we measured E-AT and fibronectin in the plasma of 46 patients with various connective-tissue diseases in relation to the course of the disease. In about 50% of the cases, E-AT was found to be elevated to 2-3 times the normal concentrations, in relation to increasing serum content of C-reactive protein. In follow-ups over 2 years, an elevation of E-AT and a decreasing fibronectin in plasma was found in patients with activated disease. Without relation to other parameters used in connective-tissue diseases, fibronectin was found to be diminished below the normal range in 7 patients with systemic lupus erythematodes and 1 patient with overlapping syndrome. Our results indicate that the concentration of E-AT and fibronectin in plasma may be helpful parameters for judging the activity of connective-tissue diseases.