title: Do drug transporter (ABCB1) SNPs influence cyclosporine and tacrolimus dose requirements and renal allograft outcome in the posttransplantation period?
abstract: Polymorphisms in the drug transporter gene (ABCB1) may play a significant role in individualizing cyclosporine (CsA) and tacrolimus (Tac) dosage and subsequently the allograft outcome in renal transplant recipients. In total, 225 recipients on CsA and 75 on Tac-based immunosuppression regimen were recruited, and 6 common polymorphic sites in the ABCB1 gene were analyzed for association with dose-adjusted levels of CsA/Tac. Furthermore, association of ABCB1 single-nucleotide polymorphisms (SNPs) with allograft outcome was examined. GG and CC genotype patients at ABCB1 2677G>T and ABCB1 3435C>T were associated with lower dose-adjusted levels of CsA and Tac at 1 month (P = .057, P = .034), 3 months (P = .001, P = .015), and 6 months (P = .043) posttransplantation. Wild-type patients at 1236C>T (log P = .025) and 2677G>T (log P = .002) in CsA and 2677G>T (log P = .008) and 3435C>T (log P = .015) in Tac therapy patients demonstrated lower mean time to allograft rejection. No influence of ABCB1 haplotypes on CsA/Tac dose-adjusted levels was observed. Wild-type patients at ABCB1 2677G>T and 3435C>T were associated with lower dose-adjusted levels and thereby were at increased risk of allograft rejection because of under-immunosuppression in the early part of posttransplantation. Thus, genetic evaluation may be helpful to identify patients at risk for allograft rejection and also to individualize immunosuppressant dosing.
authors.affiliation: Department of Urology and Renal Transplantation, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Uttar Pradesh, India.
authors.forename: Ranjana
authors.initials: R
authors.lastname: Singh
authors.forename: Aneesh
authors.initials: A
authors.lastname: Srivastava
authors.forename: Rakesh
authors.initials: R
authors.lastname: Kapoor
authors.forename: Rama Devi
authors.initials: RD
authors.lastname: Mittal
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics*; D000328:Adult; D016572:Cyclosporine / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006084:Graft Rejection / Q000235:genetics; D006239:Haplotypes; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D016030:Kidney Transplantation; D008297:Male; D020641:Polymorphism, Single Nucleotide; D012189:Retrospective Studies; D016559:Tacrolimus / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D014184:Transplantation, Homologous; D016896:Treatment Outcome
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D007166:Immunosuppressive Agents; D016572:Cyclosporine; D016559:Tacrolimus