MMP9 and systemic lupus erythematosus: The increased serum level of MDC remains to be studied, but the increased serum level of MMP-9 may explain that glucocortisone influenced the release of MMP-9 from blood circulation.11 It is thought that the increased serum level of MDC and MMP-9 may demonstrate the lupus improvement, so the serum levels of MDC and MMP-9 may serve as markers for the determination of disease progression or improvement.