Pediatric Donor Glomerulopathy Is a Possible Cause of Abnormal Urinalysis in Adults Receiving Small Pediatric Donor Kidneys

Abstract

Background. Reports about prognosis of adults receiving small pediatric-donor kidneys (PDK) as compared to those receiving elder pediatric or adult donor kidneys (ADKs) are controversial. This study aimed to examine the outcomes of adults receiving small PDK and possible prognostic factors. Methods. The records of adults who received kidneys from donors < 10 years old at our center from July 1, 2011 to June 30, 2018 were reviewed. Results. A total of 121 adults were small PDK recipients. Twenty-three patients received 29 biopsies or nephrectomy between 6 and 896 days posttransplantation days. Seven patients (30.4%) had pediatric donor glomerulopathy (PDG), which developed from 113 to 615 days posttransplantation. The incidence of proteinuria and hematuria was significantly higher in the PDG group. The characteristic pathological finding in PDG was irregular lamination and splintering of the glomerular basement membrane (GBM). Donor age, donor weight, and donor kidney volume were significantly less in PDG cases compared with the non-PDG cases. For the risk factors of PDG, increasing urinary RBC count during follow-up was an independent predictor, while increasing donor age and body weight were protective factors. PDG was not a significant risk factor for Scr increasing of PDKs. Conclusions. PDG is a potential cause of abnormal urinalysis in adults receiving small PDKs. The pathological characteristic change of PDG is splitting and lamination of GBM. Persistent hematuria after transplantation in recipients of PDK is a predictor of PDG development.

Small donors for small recipients – excellent growth and long‐term function of single kidney grafts

“…Donor−recipient size mismatch is controversially discussed regarding its predictive value for graft function in children and adults. Cardiovascular complications, abdominal compartment [14], or downregulation of filtration without the ability to adapt function later in case of large‐for‐size organs contrast concerns regarding hyperfiltration injury or graft thrombosis reported for small donor‐size [6,10,24]. Although a significant proportion of patients in our study had a mismatch of D/R (<0.75/>1.25), multivariate analysis revealed no significant impact of this parameter on graft survival.…”

“…Jiang et al . [10] reported adult SDK‐recipients presenting with proteinuria and Alport‐like splitting and lamination of the glomerular basement membrane (GBM). Histological findings were detected within 4–18 months after transplantation.…”

“…Superior graft survival was associated with donor weight >10–15 kg, higher donor/recipient weight ratio (D/R), en bloc versus single grafts, and a high level of experience at the transplant centre [4–8]. In contrast, lower donor‐to‐recipient size was shown to result in higher graft loss [9] possibly related to hyperfiltration‐induced kidney injury [10]. Moreover, recent registry data reported the highest risk of graft failure for young recipients of grafts from young donors (<5 years of age) [11].…”

De novo Glomerular Disease and the Significance of Electron Microscopy in Renal Transplantation

“…The development of "size mismatch glomerulopathy (SMG)" which affects <10% of adult recipients, is defined by the process of hyperfiltration injury and adaptation secondary to higher recipient blood pressure and blood flow within the glomeruli in pediatric donor allografts of <3 years of age [18]. Since the glomerular size in the pediatric donors is smaller and often immature, DOI: 10.1159/000517124 with extremely thin glomerular capillary basement membranes, exposure to the direct mechanical adultlevel hemodynamic forces appears to stress and injure the glomerular epithelial cells, resulting in this unique lesion [19].…”

“…At 5 years posttransplantation, there is >50% graft survival. A recent study showed that a higher donor age, donor weight, or donor kidney volume may be protective and may not tend to develop SMG in the recipient [ 18 , 19 ].…”