Functional Genetic Variants Affecting Tacrolimus Trough Levels and Side Effects in Chinese Renal Transplantation.

Tacrolimus is an effective immunosuppressive drug widely used in solid organ transplantation to prevent rejection. It is characterized by a narrow therapeutic range and large inter- and intra- individual variability in its pharmacokinetics. Many factors are associated with the variability. Of these factors, genetic factor play an important role. Full understanding of this mechanism is important for the personalized use of tacrolimus and reducing the risk of side effects.The CYP3A5*3 (A6986G) resulting in a splicing defect and the absence of protein activity, was identified as a functional variant (Kuehl P.2001). The CYP3A4*1G was also reported as a functional variant (Richards-Waugh LL. 2014). In addition, other functional variants will also be identified and analyzed in our project.

Our project has two parts:first, retrospective study, 839 renal transplant recipients using tacrolimus as immunosuppressive drug were recruited from Nanfang Hospital. Fifty-eight SNPs from GWAS, GTEx and promoter region of CYP3A gene were genotyped. The association of 58 SNPs on the dose corrected tacrolimus trough levels and side effects (acute rejection, nephrotoxicity and neurotoxicity) were analyzed. Luciferase reporter gene assay were used to identify the functional variants. Second, in this part, there is another renal transplantation cohort. For this cohort, it was a retrospective cohort. All the patients will be stratified to different groups according to the different genotypes. The side effects (acute rejection, nephrotoxicity and neurotoxicity) will be observed.During the study period, all the therapeutic procedures of the patients are as usual.

This will be the largest cohort of this kind of study in Chinese population. The findings will be useful for the patients to improve the therapeutic efficacy and reduce the side effects.