Background: Plasma level of plasminogen activator inhibitor (PAI)-1 is genetically determined by a polymorphism in the promoter region, involving two alleles, 4G and 5G. Plasma PAI-1 concentrations are higher in subjects homozygous for the 4G allele than other genotypes (5G/5G and 4G/5G). Such genetic variation in fibrinolytic system may affect the long-term renal transplant outcome.
Methods: We determined PAI-1 4G/5G-promoter genotype polymorphism among our renal transplant recipients between 1985 and 2001. Primary event was defined as doubling of baseline serum-creatinine level.
Results: Over a median period of 79 months, 130 patients with 132 kidney grafts were assessed. Baseline clinical variables were comparable among three genotype groups. There was no association between primary event and PAI-1 genotype among the entire cohort. However, among subjects with prior acute rejection episodes, those homozygous for 4G had significantly higher risk of serum creatinine doubling than the other two genotypes (relative risk 2.45, 95% confidence interval 1.19-5.04). PAI-1 genotype does not predict primary events in patients without rejection (relative risk 0.57, 95% confidence interval 0.07-4.17).
Conclusions: PAI-1 4G/5G-promoter polymorphism modulates the risk of renal transplant outcomes after acute rejection(s). Recipients homozygous for PAI-1 4G allele have a higher risk of progressive renal damage after acute rejection episode(s). PAI-1 promoter polymorphisms are potentially important determinants of renal response to rejection.