EXPRESSION OF BLOOD-GROUP ANTIGEN-A AND OR ANTIGEN-B IN DISEASED CORNEAS/

Purpose. Only epithelial cells are thought to express blood group anti gens (bga) A and/or B in normal corneas, and ABO blood group (bg) matc hing seems to reduce immune rejection in high risk transplantations. T his study attempts for the first time to investigate to what extent th e bga A and/or B are expressed in diseased corneas. Methods. Thirty-ni ne diseased corneal buttons of 39 patients were examined. Immunohistoc hemical staining of paraffin-embedded sections was performed with mono clonal mouse anti human blood groups A and B antibodies using the Stre ptavidin-Biotin-peroxidase complex technique (LSAB Kit, Dako). Results . The expression of blood group antigens A and/or B on the cornea was found to correlate directly with the blood group of the patients in al l cases. The corneal epithelium of all 18 patients with blood groups A and/or B could be stained with antibodies to bga A and/or B. However, neither bga A nor bga B could be detected in any corneal cells of pat ients with the blood group O (21 patients). In addition to the epithel ium, the stromal keratinocytes as well as the endothelium contained im munohistochemically detectable bga A and/or B in cases of keratitis or keratoconus, but not in stromal and/or endothelial cells of corneas w ith pseudophakic bullous keratopathy and Fuchs' dystrophy tall patient s with the bgs A and/or B). Conclusion. These findings show that an up -regulation of bga A and/or B in corneal stromal and endothelial cells is possible in diseased corneas. This phenomenon might play an import ant role in graft rejection after corneal transplantation.