Background: Efficient T cell-APC interaction requires the participation of primary and co-stimulatory signals. The main co-stimulatory pathway involves the interaction of CD80 and CD86, expressed on the APCs, with their T cell counter-receptor, CD28 and CTLA-4. Recently, a G to A transition has been described at position +1057 of the CD86 gene, located in their cytoplasmic tail.
Methods: CD86 polymorphism was analyzed by sequence based typing in DNA samples obtained from 205 liver transplant recipients. Acute rejection and chronic rejection were diagnosed based upon conventional clinical, biochemical and histological criteria.
Results: The study of CD86 +1057 (G/A) polymorphism revealed that recipients bearing the A allele or the AA genotype have a reduced risk of acute rejection. In fact, the AA genotype was absent in the group of patients showing acute rejection episodes, whereas its frequency in those patients without acute rejection episodes was 8.8% (P=0.009, OR=0.07). This polymorphism did not reveal any association with the incidence of chronic rejection, but patients bearing the AA genotype showed a higher graft survival rate (83.3%) than those bearing the GA genotype (49.3%) or GG genotype (56.5%).
Conclusions: The results of the present report suggest that the CD86 AA genotype at +1057 position could be involved in liver transplant acceptance, given that its presence is related to a decrease of acute rejection frequency and to a graft survival increase.