Background: HLA matching in penetrating keratoplasty is still neglected in most eye clinics. This is due to contradictory results of studies performed in the past. Different surgical techniques in multicenter studies, missing risk differentiation in high-risk situations and faulty HLA typing can be identified as the main reasons for these contradictory results. In this monocenter study, the value of HLA class I and II matching (A, B, DR loci) was examined in a homogenous group of 398 normal-risk keratoplasty patients using modern typing techniques.
Methods: Penetrating normal-risk keratoplasty was performed in two groups of patients (group I with 0-2, group II with 3-6 mismatches in the A/B/DR loci). Surgery was done by 3 experienced surgeons according to a standardized scheme. Also, postoperative therapy and controls were standardized. There were no statistically significant differences between the two study groups as regards number of AB0 or H-Y compatibilities, patient age, patient gender, ratio of previous intraocular surgery, ratio of triple procedures, indication for surgery, follow-up period, donor age, donor gender, post-mortem time of the graft and endothelial cell density of the graft at the end of organ culture. HLA typing was performed in a quality-controlled laboratory, serologically for HLA class I (A and B loci) and moleculargenetically for HLA class II (DR locus).
Results: Four years postoperatively, the ratio of clear and rejection-free graft survival was 91% in group I and 67% in group II (Kaplan-Meier estimation, log rank test, p = 0.03). Monovariate analysis in the Cox model gave no influence of solitary HLA class I or II matching, but only an influence of combined HLA class I and II matching (p = 0.03).
Conclusions: In this monocenter study with proper typing techniques the beneficial effect of HLA class I plus II matching on clear and rejection-free graft survival could be demonstrated in a homogenous group of normal-risk keratoplasty patients.