Background/Objectives: Kidney transplantation is the treatment of choice for children with end-stage renal disease (ESRD), but its outcome can be affected by urological complications, with incidence rates of 2.5–25%. The aim of this study was to evaluate the occurrence of urological complications and their management in a cohort of pediatric kidney transplant recipients. Materials and Methods: A retrospective analysis on 178 patients who received a renal transplant at our Pediatric Kidney Transplant Center between 2011 and 2023 was conducted. Demographic and clinical data were analyzed. Urological complications were categorized as early, intermediate, or late based on their onset time. Results: Out of 178 patients, 28 (15.7%) experienced urological complications. Most patients (61%) had a pre-existing uropathy. Early complications (7–30 days) were all obstructive, namely, ureterovesical junction obstruction and perirenal collections. Intermediate complications (1–3 months) comprised ureteral stenosis, symptomatic vesicoureteral reflux (VUR), and obstructive lymphocele. Late complications (>3 months) included symptomatic VUR and ureteral stenosis, with one case leading to ureteral rupture. Early complications were often detected due to acute graft dysfunction, while late ones were mainly identified during routine clinical, laboratory, or ultrasound follow-up. Urological complications requiring surgical or endoscopic therapy were 13.4%. Most ureteral stenoses were treated with initial endoscopic stents, followed by definitive surgery. VUR was treated with endoscopic correction with a high success rate (75%), while open surgery was reserved for cases where initial treatments failed or complications recurred. No clear correlations were found between patient characteristics and risk of urological complication. Urological complications required multiple diagnostic procedures and therapeutic interventions (+2.5 admissions in mean and approximately +EUR 24,000) compared to an uncomplicated post-transplant course. However, they did not significantly impact transplant outcomes, with a graft survival rate comparable to that of the control group. Conclusions: Regular post-transplant follow-up is crucial, especially for patients with known risk factors, to allow for timely detection and treatment of urological complications, avoiding detrimental effects on graft function and improving transplantation outcomes.

Background and Objectives: Kidney transplantation is the preferred treatment for children with end-stage renal disease (ESRD), but its outcome can be affected by urological complications, with incidence rates of 1%-27%. The aim of this study was to evaluate the occurrence of urological complications and their management in a cohort of pediatric kidney transplant recipients. Materials and Methods: A retrospective analysis on 178 patients undergone to renal transplantation at our Pediatric Kidney Transplant Center between 2011 and 2023 was conducted. Demographic and clinical data were analyzed. Urological complications were categorized as early, intermediate, or late based on their onset time. Results: Out of 178 patients, 28 (15.7%) experienced urological complications. Most patients (61%) had a pre-existing uropathy. Early complications (7-30 days) were all obstructive, namely ureterovesical junction obstruction and perirenal collections. Intermediate complications (1-3 months) comprised ureteral stenosis, symptomatic vesicoureteral reflux (VUR), and obstructive lymphocele. Late complications (>3 months) included symptomatic VUR and ureteral stenosis, with one case leading to ureteral rupture. Early complications were often detected due to acute graft dysfunction, while late ones were mainly identified during routine clinical, laboratory, or ultrasound follow-up. Urological complications requiring surgical or endoscopic therapy were 13.4%. Most ureteral stenoses were treated with initial endoscopic stents, followed by definitive surgery. VUR was treated with endoscopic correction with a high success rate (75%), while open surgery was reserved for cases where initial treatments failed, or complications recurred. No clear correlations were found between patient characteristics and risk of urological complication. Urological complications required multiple diagnostic procedures and therapeutic interventions (+2.5 admissions in mean and approximately +24,000 euros) compared to an uncomplicated post-transplant course. However, they did not significantly impact transplant outcomes, with a graft survival rate comparable to the control group. Conclusions: Regular post-transplant follow-up is crucial, especially for patients with known risk factors, to allow timely detection and treatment of urological complications, avoiding detrimental effects on graft function and improving transplantation outcomes.

Background: Kidney transplantation is the treatment of choice for pediatric patients with end-stage kidney disease. However, transplantation in children weighing < 15 kg remains challenging due to limited donor availability and higher surgical and medical risks. We report our 35-year single-center experience in this population, focusing on perioperative and long-term outcomes. Methods: We retrospectively analyzed kidney transplants performed from 1987 to 2023 in children weighing < 15 kg. Data on demographics, donor type, complications, immunosuppression, and outcomes at 2, 5, and 10 years (including survival, graft function, rejection, infections, and urological issues) were collected. Outcomes were compared between deceased and living donors and between recipients weighing < 10 kg and ≥10 kg. Results: Ninety-six transplants were included (mean age 3.3 years; mean weight 11.1 kg), 80 from deceased and 16 from living donors. Most patients (69.8%) had been treated with peritoneal dialysis. Median follow-up was 120 months. Patient survival was 95.8%; graft survival was 78.1%. Eight grafts (8.3%) were lost to renal vein thrombosis, all in deceased-donor recipients (p = 0.60). Preserved renal function (eGFR > 60 mL/min/1.73 m²) declined from 80.4% at 2 years to 66.0% at 5 years and 18.0% at 10 years. Graft survival at 10 years was significantly lower in children < 10 kg vs. ≥10 kg (49.6% vs. 80.3%, p = 0.003). CAKUT was associated with higher urological complication rates (p = 0.017). No significant differences emerged between living and deceased donor groups. Conclusions: Transplantation in children < 15 kg is feasible with good outcomes, but those <10 kg present lower graft survival at 10 years. Multidisciplinary assessment and center experience are key to optimizing results.

While the pathogenic role of donor-specific anti-HLA antibodies (DSAs) in long-term immune-mediated injury after kidney transplantation is well established, the clinical relevance of non-donor-specific antibodies (nDSAs), also detected in transplant recipients, remains a subject of debate. This retrospective study evaluated the prognostic value of nDSAs in 92 pediatric kidney transplant recipients (89.1%, 9.8%, and 1.1% for first, second, and third transplants, respectively) at the University Hospital of Padua between January 2015 and December 2022, investigating the association between antibody development and clinical outcomes, including graft function, rejection episodes, and viral infections. Clinical, immunological, virological, and histopathological data were collected at 6, 12, and 24 months post-transplant. Antibody prevalence increased over time, with nDSAs being more frequent than DSAs at all timepoints. The combined presence of DSAs and nDSAs significantly increased the risk of ABMR (HR = 45.10; p < 0.001). Isolated nDSAs and DSAs were also associated with an increased risk of ABMR (HR = 6.43 and 12.10, respectively), suggesting a synergistic alloimmune effect. Viral infections also emerged as relevant cofactors in humoral alloimmunity. EBV viremia and intrarenal Parvovirus B19 (PVB19) infection were significantly associated with ABMR, with PVB19 also correlating with nDSA formation. In conclusion, integrated immunological and virological monitoring may support risk stratification and guide individualized post-transplant management. Larger multicenter studies are warranted to define the long-term impact of nDSAs in pediatric kidney transplantation.

Background: Renal allograft biopsy is essential in the follow-up of pediatric kidney transplant recipients, but the optimal sedation strategy remains uncertain. Methods: We retrospectively reviewed 711 ultrasound-guided biopsies in 251 children and adolescents (2009–2024), comparing oral conscious sedation with midazolam to deep intravenous (IV) sedation with propofol, midazolam, and ketamine. Outcomes included tissue yield, diagnostic success, complications, and cost-effectiveness. Results: IV sedation was used in 77.1% of procedures and was associated with longer cortical cores (median 1.8 vs. 1.5 cm, p < 0.001) and more glomeruli (16 vs. 8, p < 0.001), improving tissue yield and consequently increasing diagnostic success from 75% to 88.5% (p < 0.001; OR 2.6). Biopsy-related complications occurred in 12.9% of cases, with no difference between groups. Sedation-related complications, all mild or moderate, occurred only with IV sedation (4.9%). The improved tissue yield reduced the cost per successful diagnosis (EUR 1243 vs. EUR 1467), making IV sedation the dominant strategy. Conclusions: IV sedation enhances the diagnostic quality and cost-effectiveness of pediatric kidney allograft biopsies without increasing overall risk, though prospective studies should also assess patient anxiety and comfort.

Background and Objectives: Primary Epstein–Barr virus (EBV) infection in pediatric kidney transplant recipients with donor/recipient mismatch (D+/R−) carries the highest risk of post-transplant lymphoproliferative disorder (PTLD). Current prophylactic strategies are not standardized. Intravenous immunoglobulins (IVIG), containing anti-EBV antibodies, have been proposed as a potential preventive option, but evidence is lacking. This single-center retrospective case–control study evaluated the efficacy of serial IVIG administration in preventing primary EBV infection and promoting long-term immunity in this high-risk population. Materials and Methods: We retrospectively analyzed 26 pediatric kidney transplant recipients (age 1–18 years) with EBV D+/R− mismatch and a median follow-up of 7.5 years. Fourteen patients received scheduled IVIG infusions (200 mg/kg monthly for six months post-transplantation), while twelve received no EBV-directed prophylaxis. The primary endpoint was the cumulative incidence of primary EBV infection, defined as EBV-DNA > 1000 copies/mL in peripheral blood. The secondary endpoint was Epstein–Barr Nuclear Antigen-Immunoglobulin G (EBNA-IgG) seroconversion. Results: Patients receiving IVIG were significantly younger than controls (median age 4.2 vs. 10.8 years, p = 0.01). No significant variations were observed between groups in renal function or immunosuppressive levels during follow-up. IVIG prophylaxis was unexpectedly linked to a higher cumulative incidence of EBV infection compared with controls (64% vs. 25%, p = 0.047). Time-to-event analysis confirmed an increased, although not statistically significant, risk of EBV acquisition in the IVIG group (Hazard Ratio [HR] 3.24, 95% Confidence Interval [CI] 0.87–12.01; p = 0.079). EBV-specific immunity, assessed by EBNA-IgG seroconversion, was comparable between groups (HR 1.78; p = 0.45), confirming no immunological advantage of IVIG. One IVIG-treated patient (7.1%) developed PTLD, while none did in the control group. Conclusions: Scheduled IVIG administration during the first six months after transplantation does not constitute an effective strategy to prevent primary EBV infection or to enhance long-term immunity in high-risk EBV D+/R− pediatric kidney recipients and may even increase susceptibility to viral acquisition. These findings argue against the use of IVIG as EBV prophylaxis in this population.