MMP9 and inclusion conjunctivitis: IL-17A, CXCL5, PDGF, MMP7 and MMP9 have previously been associated with various stages of trachoma (trachomatous inflammation–follicular [10,11,44,45], TS [1,6,7] and TT [8,9]) at mRNA and protein expression levels, however they were not demonstrably up-regulated in TT cases in the present study.