Introduction: IgA nephropathy (IgAN) is characterized by a highly variable course with risk for post-transplant recurrence. Data are limited on the transplant outcomes among pediatric and young adults with IgAN. 
Methods: Retrospective cohort study including patients aged 0 to 25 years from the Scientific Registry of Transplant Recipients between 10/1/1987 and 6/31/2021 who received a primary kidney transplant for IgA nephropathy or renal dysplasia. Primary outcomes included: 1) incidence of graft loss attributable to recurrence of IgAN and 2) the association between peri-transplant management and graft survival.
Results: 5475 transplant recipients were identified, including 1915 patients with IgAN and 3560 patients with renal dysplasia. In a multivariable Cox proportional hazards model, IgAN was associated with a higher risk of graft loss (aHR 1.35, 95%CI 1.21-1.50, p<0.001) compared to renal dysplasia (Table 1). Prednisone maintenance immunosuppression was not associated with superior graft survival (p=0.2). Graft loss due to recurrent disease was reported among 5.4% of patients with IgAN. In a multivariable competing risks analysis, IgAN patients receiving a parental living donor kidney were more likely to report graft loss from recurrent disease compared to those recipients of a living donor kidney from a nonparental relative (aHR 0.52 95%CI 0.31-0.91) p=0.02) (Table 2) . In analysis restricted to donor-recipient pairs matched at 3-6 HLA loci, incidence of graft loss due to recurrent disease was significantly higher among parental living donors (9.3%) compared to nonparental living related donors (5.1%), unrelated living donors (2.4%) or deceased donors (4.5%) (p=0.02). Overall graft survival remained higher among those with a 4-6 loci HLA matched kidney (aHR for graft failure 0.78 (95%CI 0.65-0.93) p=0.005) compared to those matched at 0-2 or 3 HLA loci, regardless of donor type. 
Conclusion: In IgAN, utilization of a parental living donor is associated with a higher risk of graft loss due to recurrent disease.  Despite this, overall graft survival remains higher with increased HLA matching. Individuals receiving a parental living donor allograft should have increased monitoring for recurrent disease, but maintenance prednisone immunosuppression does not improve graft survival.