Acute and chronic immune reactions after penetrating keratoplasty with normal immune risk

Background For diagnostic and therapeutic reasons it is important to differentiate between acute and chronic immune reactions. Up to now in the literature as well as in clinical follow-up such a differentiation has been performed only very insufficiently. We analysed retrospectively frequency and type of immune reactions after penetrating keratoplasties with normal immune risk in order to have a data basis for comparison with the corresponding data from our high risk keratoplasties. Patients and methods The clinical courses of 646 penetrating keratoplasties with good prognosis performed between 11/1986 and 6/1994 were analysed. The mean patient age was 58 (12-89) years. Only endothelial and stromal immune reactions were recorded. Results 18% of the grafts suffered from at least one immune reaction during the first 3 postoperative years (Kaplan Meier value). 94% of the grafts without immune reactions remained clear in contrast to 45% of the grafts with immune reactions during this period of time (Kaplan Meier values, Log Rank Test: p<0.001). 81 immune reactions were observed after 62 keratoplasties. 45 immune reactions (56%) had an acute course (43 endothelial, 2 stromal), 36 (44%) were chronic (31 endothelial, 5 stromal). 93.7% of the grafts without clinical signs of immune reactions, 100.0% of the grafts with only chronic immune reactions and 38.7% of the grafts with only acute immune reactions were clear 3 years postoperatively (Kaplan Meier values). No graft with a combination of acute and chronic immune reactions was clear 3 years postoperatively. 56% of all acute immune reactions occurred during the first postoperative year, 82% during the first 2 and 91% during the first 3 postoperative years. For chronic immune reactions the corresponding values reached 51%, 94% and 100%. Conclusions After penetrating normal-risk keratoplasty acute immune reactions occur more often than chronic immune reactions, but the latter are in fact far more frequent than anticipated. If they are diagnosed in time and treated correctly they do not lead to graft failure in the mean run. Both types occur predominantly during the first 3 postoperative years and only rarely thereafter.