Background The intrapatient variability (IPV) of tacrolimus (Tac) is associated with the long‐term outcome of kidney transplantation. The CYP3A single‐nucleotide polymorphism (SNP) may affect the IPV of Tac. We investigated the impact of IPV and genetic polymorphism in pediatric patients who received kidney transplantation. Methods A total of 202 pediatric renal transplant recipients from 2000 to 2016 were analyzed retrospectively. The IPV was calculated between 6 and 12 months after surgery. Among these patients, CYP3A5 polymorphism was analyzed in 67 patients. Results The group with high IPV had a significantly higher rate of de novo donor‐specific human leukocyte antigen antibodies (dnDSA) development (35.7% vs. 16.7%, p = .003). The high IPV group also had a higher incidence of T‐cell‐mediated rejection (TCMR; p < .001). The high IPV had no significant influence on Epstein–Barr virus, cytomegalovirus, and BK virus viremia but was associated with the incidence of posttransplant lymphoproliferative disorders (p = .003). Overall, the graft survival rate was inferior in the high IPV group (p < .001). The CYP3A5 SNPs did not significantly affect the IPV of Tac. In the CYP3A5 expressor group, however, the IPV was significantly associated with the TCMR‐free survival rate (p < .001). Conclusion The IPV of Tac had a significant impact on dnDSA development, occurrence of acute TCMR, and graft failure in pediatric patients who received renal transplantation. CYP3A5 expressors with high IPV of Tac showed worse outcomes, while the CYP3A5 polymorphism had no impact on IPV of Tac.

Background:The effects of renal transplantation in patients with augmentation cystoplasty are still controversial. We retrospectively analyzed nine patients who underwent renal transplantation after augmentation cystoplasty. Methods: A total of nine patients who underwent augmentation cystoplasty prior to renal transplantation between January 1990 and May 2020 were reviewed. Basic information on augmentation cystoplasty, transplant procedures, and long-term outcomes of renal transplantation were analyzed. Results: The bowel segments utilized for augmentation cystoplasty were the stomach in two patients (one patient needed revision using the ileum), the ileum in four patients, the ileocolic pouch in one patient, the sigmoid in one patient, and the ureter in one patient. All the cystoplasties were performed prior to renal transplantation. The mean follow-up period after transplantation was 161 months (range, 2-341 months). Two patients had an episode of acute rejection each; however, their graft functions were well-maintained. Five patients had recurrent urinary tract infections, and three of these patients progressed to allograft failure. One patient died from bladder cancer with a functioning graft. Five of nine patients showed well-maintained graft function. Conclusions: Renal transplantation after bladder augmentation surgery is a major operation requiring a high level of surgical skill. Based on our long-term experiences, we recommend diligent postoperative monitoring for urinary tract infections, optimal catheter use, and use of appropriate antibiotic prophylaxis to avoid severe complications.