Significantly decreased serum levels of MDC and MMP-9 was found in SLE patients as compared to those in controls, 450.95±76.76 pg/ml vs 606.23±23.71 pg/ml (P<0.001) and 108.52±113.23 ng/ml vs 352.25±155.01ng/ml (P<0.001) respectively. This evidence concerns the gene MMP9 and systemic lupus erythematosus.