Expression of stem cell factor in pterygium.

PURPOSE To investigate the possible role of stem cell factor (SCF) in the pathogenesis of pterygium. METHODS The localization of SCF was examined immunohistochemically in excised tissue from 4 primary pterygia and 5 normal conjunctival specimens. RESULTS Three of the four pterygia showed strong immunoreactivity of SCF in the subepithelial connective tissue at the cap area. This immunoreactivity was completely blocked by using a primary antibody preincubated with recombinant SCF. The SCF-positive cells were identified as a population of fibroblasts by immunostaining for vimentin and prolyl 4-hydroxylase in adjacent sections. No apparent immunoreactivity of SCF was observed in the subepithelial connective tissues in the head and body of the pterygia and in the normal conjunctiva. CONCLUSION Stem cell factor is overexpressed in fibroblasts at the cap area of most pterygia.