The motivation for a study by Gruber et al. (A-55) was a desire to find a potentially useful serum marker in rheumatoid arthritis (RA) that reflects underlying pathogenic mechanisms. They measured, among other variables, the circulating levels of gelatinase B in the serum and synovial fluid

(SF) of patients with RA and of control subjects. The results were as follows:

Serum Synovial Fluid Serum Synovial Fluid RA Control RA Control RA Control RA Control 26.8 23.4 71.8 3.0 36.7 19.1 30.5 29.4 4.0 57.2 249.6 10.3 185.0 3.9 71.3 53.6 8.0 114.0 6.9 25.2 66.1 7.3 69.6 9.6 46.7 52.6 10.1 52.3 22.1 30.9 14.5 17.3 113.1 13.4 27.5 22.7 24.4 104.7 13.3 17.2 43.5 19.7 60.7 10.3 25.4 8.4 116.8 7.5 29.8 20.4 84.9 31.6 27.6 16.3 215.4 30.0 106.1 16.5 33.6 42.0 76.5 22.2 158.3 20.3 Source: Data provided courtesy of Dr. Darius Sorbi.