MMP9 and keratoconus: Moreover, we explored the different expression levels of cytokines and MMPs, which revealed decreased expression levels of IL-1B, IL-6, LIF, TNF, CRP, TGFB1, VCAM1, SELL, GZMB, FASLG, TLR4, MMP-1, MMP-2, MMP-3, MMP-9, MMP-10, MMP-11, MMP-12, and MMP-13 and upregulated expression levels of IL-5 and MMP-7 in KC patients compared with healthy controls (Figure 4G).