PARVG gene polymorphism and operational renal allograft tolerance

A unique blood transcriptional profile of 49 genes has been previously highlighted that may be used to distinguish drug-free operationally tolerant kidney recipients (TOL) from other kidney recipients with contrasted clinical situations and healthy volunteers. The aim of this study was to investigate whether the pattern of these 49 genes could be influenced by genetic polymorphisms located in the corresponding genomic sequences and whether some of these single nucleotide polymorphisms (SNPs) could be associated with clinical status of kidney transplant recipients. In this study, 1152 candidate tag SNPs spanning these genes were genotyped using a Golden Gate Illlumina assay in a sample of 164 kidney transplant recipients, including 11 operationally tolerant patients, 134 patients with stable graft function, 19 with proven signs of chronic rejection, and 27 healthy volunteers. The gene expression and clinical status were studied according to the different SNPs. Among the genes demonstrating expression difference between TOL compared with CR&STA patients, PARVG, which is a member of a family of actin-binding proteins associated with focal contacts, stands out with 2 SNPs, (rs139144 and rs5764592) explaining about 20% of the gene expression variability. Linkage disequilibrium analysis of these 2 SNPs showed the rs139144GG genotype was associated with decreased PARVG expression and was numerically more frequent in TOL (60%) than in CR&STA (28%) patients (P = .068). These preliminary results, which should be confirmed in a larger population, open new perspective of regulation pathways and hypothesis in operational tolerance mechanism.