Transforming growth factor-beta1 gene polymorphism in renal transplant recipients

BACKGROUND: Cytokine transforming growth factor (TGF) is involved in regulation of tissue repair after injury. More recently, TGF-beta1 codon 10 gene polymorphism has been shown to be associated with circulating TGF-beta levels. We tested whether TGF-beta1 genotype polymorphism was predictive of renal allograft function decline. PATIENTS AND METHODS: The study population consisted of 129 consecutive cadaveric or living related renal transplant recipients at our center between 1985 and 2001. The recipient TGF-beta1 genotype polymorphism was determined from peripheral blood leucocytes DNA. The primary endpoint was rate of glomerular filtration rate decline between the first year and the third year of transplant. RESULTS: Baseline glomerular filtration rate as estimated by MDRD study equation at 1 year measured 50+/-17 mL/min/1.73 m2. At the end of the 3-year follow-up period, 52 patients (40%) experienced biopsy-confirmed acute rejections. Frequency and severity of allograft rejection did not differ with TGF-beta genotypes. However, the decline in glomerular filtration rate was significantly greater in Leu/Leu (TT) than Leu/Pro (CT) recipients, 6.3+/-16.9 mL/min/1.73 m2 versus 0.1+/-10.2 mL/min/1.73 m2, p=0.04. CONCLUSION: Our results demonstrate that recipient TGF-beta1 codon 10 Leu/Leu homozygosity is a potential risk factor of kidney allograft function decline.