Background: Penetrating keratoplasty in infants has a very poor outcome compared to adults. It is of intrinsic interest to gain insight into the still unknown immunological mechanisms of graft failure because any form of uncorrected corneal opacity leads to amblyopia.
Methods: Allogeneic keratoplasty was performed between Lewis and Fisher rats. The recipients’ ages were 10 and 3 weeks, respectively. All experiments were controlled syngeneically. Survival rates were calculated and cellular infiltrates analyzed histologically.
Results: Median graft survival times were 15 days in old recipients and 9 days in young recipients (p<0.01). We noted fewer infiltrating cells in the younger rats than in the older ones on the day of rejection. Despite the fact that T cells dominated we detected significantly more NK in young recipients at all time points after transplantation when compared to old recipients.
Conclusions: We established an animal model that shows similar rejection kinetics as in children, i.e. corneal graft failure occurs sooner in young rats. Already little infiltration was sufficient to reject a corneal allograft. The dominance of infiltrating NK cells and the vigorous rejection process suggest an involvement of the innate immune system in this process.