Introduction: The role of proteinuria in determining the suitability of living kidney donors has been a subject of significant debate. Even at low levels, individuals with proteinuria are quickly ruled out as potential kidney donors without undergoing a renal biopsy. Our study examined 70 renal donor candidates with proteinuria, focusing on evaluating light microscopy (LM) and electron microscopy (EM) findings. We aimed to assess the correlation between proteinuria levels and histopathological findings, utilizing a scoring system for both LM and EM criteria.
Material and Methods: LM and EM findings were assessed and scored in 70 renal donor candidates with proteinuria. Donors with insignificant biopsy findings were categorized into two groups based on proteinuria levels: Group 1 had proteinuria <300 mg/day and Group 2 had proteinuria ≥300 mg/day. Renal allograft survival data were collected from the records of patients who underwent kidney transplants from donors with insignificant biopsy findings.
Results: Among the cases with proteinuria, 35 (50%) exhibited glomerulonephritis (GN), and 2 (2.8%) showed tubulointerstitial nephritis (TIN). The remaining 33 donors had biopsy findings classified as insignificant. Proteinuria levels were significantly higher in donors with GN and TIN (557±363 mg/day) than those with insignificant biopsy findings 304±105 mg/day (p<0.001). LM and EM findings demonstrated a notable correlation with proteinuria levels. The incidence of specific histopathological and ultrastructural features, including GBM and mesangium thickness, interstitial inflammation, interstitial fibrosis, higher glomerular magnitude, higher glomerular proliferation, subendothelial widening, endothelial swelling, foot process effacement, and GBM lamellation was elevated in Group 2 donors (p<0.05 for all). LM and EM scores were 2±1.3 and 1.9±1.3 in Group 1, respectively, and 6±2.3 and 5±1.8 in Group 2, respectively (p<0.001 for all). Among the 33 donors, 21 had the opportunity to donate their kidneys to their relatives, while the remaining 12 were removed from the donor list. Overall, 5- and 10-year graft survival rates were 90% and 80%, respectively.
Conclusion: Our study underscores the significance of proteinuria as a reliable marker of glomerular pathology and renal disease. While kidneys with low LM and EM scores were deemed suitable for donation, we advocate caution with donors exhibiting proteinuria greater than 300 mg. We propose incorporating renal biopsy into the assessment protocol for every donor with proteinuria to ensure a meticulous evaluation of potential risks and enhance the overall success of kidney transplantation.