Immunohistochemical expression of epithelial cell markers in corneas with congenital aniridia and ocular cicatrizing pemphigoid.

PURPOSE: We investigated the immunohistochemical characteristics of corneal specimens in congenital aniridia and pemphigoid using various corneal markers to determine the status of the corneal epithelium.
METHODS: Conjunctivalization was clinically suspected in all corneas. Ten aniridia and seven pemphigoid paraffin-embedded corneal specimens were stained with periodic Schiff reagent (PAS) and antibodies against CK3/12, CK12, CK19, breast cancer resistance protein 1 (BCRP) and p63.
RESULTS: Aniridia: six cases contained goblet cells, four were negative. Both groups had cases with (three of six; one of four) and without CK19 positivity and cases with (two of six; three of four) and without p63 positivity. All aniridia cases except two in the goblet cell group were CK3/12- and CK12-positive and BCRP-negative. Pemphigoid: only one of the seven cases contained goblet cells. This case stained positively for CK19, 3/12, 12 and p63 and negatively for BCRP. The other six cases were positive for CK3/12, five of which were positive for CK12; only one case was CK19-positive. Three cases were p63-positive and two BCRP-positive. The CK12 staining was heterogenous in most cases and was often found in the superficial layer.
CONCLUSION: Three different stages of epithelial characteristics were found in congenital aniridia and pemphigoid: (i) CK19-negative and inhomogenous CK12-positive cases indicating epithelium mainly from (partly) CK12-deficient limbal stem cells; (ii) CK19- and/or goblet cell-positive and CK12-positive cases with their epithelia originating from CK12-deficient limbal stem cells and from incursing conjunctival cells; and (iii) CK19-positive and CK12-negative cases consisting of conjunctival cells alone.