Appearance, recurrence and prognosis of immunological graft rejection after penetrating keratoplasty

Abstract

The aim of this study was to examine the patterns of immunological graft rejection reactions (IAR) after penetrating keratoplasty (KPL) and to assess the prognosis for preservation of transparency of the corneal graft. In the period from 2006 to 2015 a total of 190 IAR, which occurred in 120 eyes of 119 patients, were retrospectively analyzed. The underlying disease, number of previous KPL and IAR and measures of best corrected visual acuity (BCVA, logMAR) and pachymetry at the time points T1 = postoperatively, T2 = acute IAR, T3 = follow-up at 6 weeks and T4 = follow-up at 3-12months were recorded. Asuccessful treatment was defined as alack of early recurrence (6-12weeks after treatment) or the necessity for repeating the KPL. Data were compared using the χ2-test and Wilcoxon-Mann-Whitney U‑test with asignificance level of 5%. The Kaplan-Meier procedure was used to define the rejection-free interval after KPL. The temporal analysis showed amedian rejection-free interval of 19.3months after the previous KPL (95% confidence interval, CI 14.7-26.6 months). In 138 out of 190 cases (72.6%) the IAR could be successfully treated, 12(6.3%) suffered an early recurrence and 40(21%) were irreversible. Despite asignificant decrease of BCVA at T2 from 0.5 ± 0.4 at T1 to 0.7 ± 0.5 at T2 (p < 0.001), the comparison with the follow-up at 3-12months (T1 vs. T4) showed no significant differences. The pachymetry at the thinnest point showed significant changes from T1 (535.4 ± 64.1 µm) to T2 (636.1 ± 102.1 µm; p < 0.001). Despite asignificant reduction in thickness at T3 (607.3 ± 114.0 µm, p = 0.03), the corneal grafts were still significantly thicker in the follow-up at 3-12months (591.8 ± 116.8 µm; p < 0.001; T1 vs. T4). With closely monitored aftercare following surgery IAR after KPL is rare. In most cases IAR typically occurs in the second postoperative year after KPL and under adequate treatment is reversible in approximately 75% of the cases. While BCVA showed agood recovery until the end of the follow-up period, the corneal grafts were still significantly thicker in the long-term after IAR (7.7-9.7%).