MMP9 and inclusion conjunctivitis: These studies have shown an increase in pro-inflammatory and matrix factors (IL1B (interleukin 1 beta), TNF (tumor necrosis factor), S100A7 (psoriasin), IL17A, IFNG (interferon gamma), perforin, IL12, IL10, CXCL5, CTGF (connective tissue growth factor) and MMP9 (matrix metalloproteinase 9) in individuals with active trachoma and/or chlamydial infection, indicating the involvement of a type 1 T helper (Th1) cell response, NK cell cytotoxicity and potentially Th17 cells.