Impact of HLA-G 14 bp polymorphism and soluble HLA-G level on kidney graft outcome

Abstract

Human leukocyte antigen G (HLA-G) is a non-classical HLA class I protein with various immunosuppressive functions. Besides its profound effect to induce fetal tolerance, HLA-G has been also found to enhance graft acceptance. The aim of the study was to analyse the association between HLA-G 14 bp insertion/deletion polymorphism, soluble HLA-G level and kidney graft outcome in the Slovak population. We investigated 69 kidney transplant recipients aged 27-65 years. Out of this group, 37 recipients developed acute rejection, confirmed by biopsy, and 32 patients had stable allograft function. Plasma was obtained from recipients at 1 day before transplantation and analyzed by ELISA. Genotyping of HLA-G polymorphism was performed by PCR. Significantly higher pre-transplantation levels of sHLA-G were found in the group with stable allograft function in comparison to group with acute rejection (P = 0.0409). In the homozygous -14/-14 recipients with stable allograft function, significantly higher values of sHLA-G were determined in comparison to the recipients with acute rejection (P = 0.0052). The study revealed an association between 14 bp deletion polymorphism and soluble HLA-G level that is proportional to kidney graft acceptance. It is suggested that pre-transplantation levels of soluble HLA-G should be monitored as additional marker to predict kidney graft outcome.