Immunohistochemical detection of beta IG-H3 in scarring human corneas

Background: beta IG-H3 is a recently described extracellular matrix protein that is present in various organs. In rabbit corneas, increased PIG (the r abbit form of beta IG-H3) mRNA levels were shown during corneal development and wound healing. In this study, we investigated the localization of beta IG-H3 protein in scarring human corneas. Methods: Corneal buttons obtained during keratoplasty were examined. Immunohistological detection using a po lyclonal antipeptide antibody against the beta IG-H3 protein was performed on 24 pathological corneas (9 ulcerations, 8 alkali bums, 2 perforating inj uries, 5 bullous keratopathy) and 2 normal corneas. Results: In normal corn eas, strong staining was present in the basal layer of the epithelium and i n the endothelium; the stromal fibers showed faint, uniform immunoreactivit y. In all scarring corneas, the epithelium was usually thickened and all of its layers were reactive with the beta IG-H3 antibody. The cytoplasm of th e stromal fibroblasts, as well as the stromal fibers around them also showe d staining with the antibody. These changes were present in all scarring co rneas, irrespective of the pathological process leading to scar formation. Conclusion: These results prove, at the protein level, the presence of incr eased amounts of beta IG-H3 at the sites of scarring in human corneas.