Comparative long-term outcomes of kidney transplantation from donors with isolated microscopic hematuria and thin basement membrane disease versus donors with isolated microscopic hematuria and normal histology: the largest cohort analysis to date

BackgroundThin basement membrane disease (TBMD) represents a frequent etiology of isolated microscopic hematuria (IMH) and is often identified during the evaluation of living kidney donor candidates. Although typically regarded as a benign condition, its genotypic overlap with Alport spectrum disorders has raised concerns regarding potential post-transplant implications. This study aimed to compare long-term graft and recipient outcomes following kidney transplantation from donors with biopsy-confirmed TBMD versus donors exhibiting IMH with normal histopathological findings.MethodsA retrospective cohort analysis was conducted including 93 living donor–recipient pairs: 39 donors (41.9%) with TBMD and 54 donors (58.1%) with normal biopsy results despite IMH. Donor and recipient demographic, clinical, and immunologic parameters were examined. Primary outcomes encompassed renal function, persistence of hematuria, proteinuria, arterial blood pressure, biopsy-proven rejection episodes, and both patient and graft survival. Follow-up duration extended up to 9 years (median 3 years).ResultsBaseline demographic and clinical characteristics were comparable between the two groups. At 12 months post-transplant, mean serum creatinine levels did not differ significantly between recipients of TBMD donor kidneys and those of normal biopsy donors (95 µmol/L vs. 88.5 µmol/L; p = 0.579). Renal function and graft survival remained stable over the follow-up period. The incidences of delayed graft function and biopsy-confirmed acute rejection were low and similar between groups. Persistent microscopic hematuria was observed in 87.2% of recipients from TBMD donors and 73.1% of those from normal biopsy donors; however, none developed albuminuria. One-year graft survival was excellent and sustained at the latest follow-up (97.4% vs. 98.1%).ConclusionsKidney allografts from donors with TBMD demonstrate long-term graft function and survival outcomes equivalent to those from donors with IMH and normal histology, supporting the overall safety of the allograft after kidney transplantation from TBMD donors. Although persistent microscopic hematuria was common, it did not adversely affect graft outcomes. Further large-scale, prospective, and genetically stratified studies including both recipients and donors are warranted to confirm long-term allograft safety and to refine donor selection criteria.