Effect of ABO blood group mismatching on corneal epithelial cells: an in vitro study

Aim-To determine, in vitro, the effects of blood group ABO mismatching on c orneal epithelial cells. Methods-Corneal epithelial cell cultures were established from 32 human cad aver donor eyes. Epithelial cells (100 mul of 4 X 10(2) cells per pl) were incubated for 4 hours with antibodies against blood group antigens A, B, an d AB, with and without complement. Cell lysis was assayed by a chemilumines cent assay using Cytolite reagent. Live cells, remaining after incubation, were counted in a scintillation counter. The blood group of the donors was determined retrospectively, in a blinded manner. Results-Retrospective tracing of donor blood groups was possible for 20 don ors. In all cases the blood group corresponded with that suggested by the c ell lysis assay. Significant cell lysis was observed when known A group cel ls were incubated with anti-A and anti-AB antibody, B group cells were incu bated with anti-B and AB antibody, and AB group cells were incubated with a nti-AB antibody. Lysis occurred only in the presence of complement. No lysi s of O group cells was observed with any of the antibodies. In all cases, l ysis was observed only with neat (serum) antibody concentrations. Conclusions-Blood group ABO mismatching results in significant lysis of cor neal epithelial cells. The antibody concentration required for lysis equals that found in serum. Such levels of antibody are unlikely to be achieved i n tears and/or aqueous. This may offer an explanation for the conflicting r eports of the studies on the effect of blood group matching on corneal graf ts. The variability in the outcome may reflect the levels of antibodies gai ning access to the corneal cells and not the mismatching alone.