Expression of tumor necrosis factor alpha and matrix metalloproteinase-9 in surgically induced necrotizing scleritis

Background: Surgically induced necrotizing scleritis is primarily managed with immunosuppressive regimens. Such treatments can alter inflammatory cytokines and products such as tumor necrosis factor-α (TNF-α) and matrix metalloproteinase-9 (MMP-9), which are an important proinflammatory cytokine and a tissue-degrading protease involved in necrosis of some ocular tissues. Object: To evaluate TNF-α and MMP-9 in the tear or sclera of surgically induced necrotizing scleritis. Methods: After tear collection from healthy and diseased eyes of 2 patients, immunoblot analysis using monoclonal antibody specific for human TNF-α and MMP-9 was performed. In another patient, scleral tissues were obtained during scleral allograft surgery, and the same immunoblot analysis was done. Results: The level of TNF-α and MMP-9 was increased in tear fluid from patients compared to that of control volunteers and returned to the control level after treatment. The diseased sclera showed an increased expression of MMP-9 compared to that of the normal donor sclera. Conclusions: TNF-α and MMP-9 may suggest disease activity of surgically induced necrotizing scleritis and can be altered by proper immunosuppressive treatment.