INCREASED LEVELS OF MATRIX METALLOPROTEINASE-3 IN SERA FROM PATIENTS WITH ACTIVE LUPUS NEPHRITIS

Objective To determine the matrix metalloproteinase-3 (MMP-3) levels i n sera from patients with systemic lupus erythematosus (SLE) and to an alyse the relationships between MMP-3 and clinical and laboratory feat ures. Methods Serum MMP-3 levels were measured by an enzyme immunoassa y in 124 patients with SLE and 237 patients with other systemic rheuma tic diseases. Results The frequencies of patients with high MMP-3 leve ls were 76% in SLE and 82% in rheumatoid arthritis (RA). The level of MMP-3 in the SLE patients was 193.0 +/- 171.5 ng/ml (mean SD) and was almost equal to the level in the RA patients (259.5 +/- 255.6 ng/ml). The MMP-3 levels were significantly higher in SLE patients who had a h istory of the following abnormalities: persistent proteinuria, cellula r casts, anti-double stranded DNA antibodies, decreased C3, decreased creatinine clearance (p < 0.001), circulating immune complex (p < 0.01 ), malar rash, hypoalbuminemia, or decreased C4 (p < 005). The serum M MP-3 level in patients with SLE at admission showed direct correlation s with serum uric acid, total cholesterol (p < 0.001), triglyceride, t he white blood cell count, and the neutrophil count (p < 0.05), as wel l as inverse correlations with the total protein (p < 0.01), and Ige ( p < 0.05). In SLE patients with active renal disease, the median MMP-3 level at admission and that at 6 months after admission were signific antly higher than that at 6 months before admission. Conclusions The i ncreased level of serum MMP-3 in SLE is closely associated with clinic al features relevant to lupus nephritis, suggesting that it plays a ro le in the pathogenesis of this condition.