[Significance of cyclosporin A absorption for effective immunomodulatory therapy after high-risk keratoplasty].

AIM: Cyclosporin A (CsA) is applied as an immune modulator in transplantation medicine, including high-risk keratoplasty. We examined the C(0) and C(2)-CsA serum levels after high-risk keratoplasty. The rate of so-called low absorbers was determined, and the importance of low absorption for the survival and rejection freedom of corneal grafts was examined.
METHODS: Follow-up of 89 high-risk cornea grafts in the patient group (n=32) ranged from 1 to 72 months postoperatively. The evaluation included data about serum levels of CsA C(0) (24 h after oral CsA application) and C(2) (2 h after oral CsA application) and clinical follow-ups. Using statistical methods, CsA C(0) and C(2) levels and clinical data were examined. Low absorbers did not reach the target C(2) levels by CsA dose adjustment. OUTCOMES: High intraindividual and interindividual variance of CsA C(0) and C(2) values was observed in the examined group of patients. A rate of up to 34.4% (n=11) represented the low absorbers. There was no significance of the low-absorption factor for clear graft survival, rejection freedom, or the rate of side effects observed. An acute endothelial rejection was observed in 23% of grafts and caused 37% of graft failures. In the patients without rheumatic corneal ulcers (n=27), 89% of the corneal grafts remained clear after 12 months, and 52% remained clear after 36 months.
CONCLUSIONS: In our study, with a low number of patients and multiple cofactors, the influence of low-absorption CsA on the clear corneal graft survival and rejection rates could not be proved statistically. Due to the specific immune status of the cornea, the influence of low absorption may be lower than in organs such as the kidney and liver. In our study, the C(2) serum level of CsA after high-risk keratoplasty did not provide any helpful information about the prognosis of the corneal grafts or CsA treatment monitoring.