Soluble cell adhesion molecules and soluble receptors: Significantly higher levels of soluble vascular cell adhesion molecule (sVCAM) and soluble P-selectin were observed in grade-3/4 KC (Fig. 6), along with a significant increase in soluble tumour necrosis factor receptor 1 (sTNFRI) in FFKC compared to controls (Fig. 6). Here, SELP is linked to keratoconus.