Kidney Transplantation in Childhood-Onset ANCA-Associated Vasculitis

Key Points . Among 72 patients with childhood-onset ANCA-associated vasculitis, kidney transplant survival was good (86%). . ANCA-associated vasculitis relapse occurred in 8 patients (11%), a median of 71 months after transplantation and resulted in graft failure in only one case. . Positive ANCA at the time of transplantation did not predict graft failure but was associated with a higher risk of relapse and worse graft function. Background ANCA-associated vasculitis (AAV) is rare in children, and results in kidney failure in up to one third of cases. There is very limited knowledge on kidney transplantation in childhood-onset AAV. We assessed kidney transplantation outcomes and prognostic factors in a multicenter cohort of patients with childhood-onset AAV. Methods Patients diagnosed with AAV during childhood (<= 18 years) who received a kidney transplant were included in this retrospective study. We determined patient and graft survival, rates of chronic graft dysfunction (defined as eGFR <60 ml/min per 1.73 m(2) for >= 3 months) and AAV relapse, and assessed determinants of outcome with logistic regression models. Patients were matched 1:2 for age, sex, and era of transplantation with non-AAV recipients from the Hospital for Sick Children in Toronto, Canada, and their graft survival was compared. Results We included 72 patients, of whom 53 (74%) had microscopic polyangiitis and 19 (26%) granulomatosis with polyangiitis. Their median age (interquartile range at the time of diagnosis and transplantation was 12 (9-14) and 14 (12-16) years, respectively. After a median post-transplant follow-up of 53 months (interquartile range, 25-97), 70 patients (97%) were alive, 62 (86%) had a functioning graft, 28 (39%) had developed chronic graft dysfunction, and 8 (11%) had experienced AAV relapse. Graft survival was comparable between AAV and non-AAV recipients. Acute rejection was the only independent predictor of graft failure (hazard ratio [HR], 12.11; 95% confidence interval [CI], 1.19 to 122.49). Positive ANCA at the time of transplantation was significantly associated with a chronic graft dysfunction (HR, 4.16; 95% CI, 1.71 to 10.13) and AAV relapse (HR, 23.1; 95% CI, 2.67 to 200.28). Conclusions Patients with childhood-onset AAV show good overall and graft survival after kidney transplantation and a low rate of post-transplant relapse. Further studies are warranted to confirm whether positive ANCA at the time of transplantation is associated with poorer graft outcomes.