Vaginal and uterine colonization models with CEACAM1-binding N. gonorrhoeae showed that the expression of human CEACAM1 is fundamental for pathogen adhesion and tissue penetration in mucosae of the female reproductive organs, but the vaginal mucosa did not produce KC (Li et al., 2011; Islam et al., 2018). Here, CEACAM1 is linked to keratoconus.