Background: The aim of the present study was to describe the histologic features disclosed by protocol kidney transplant biopsies in patients who experienced neither acute rejection nor acute renal failure during the 2 years after transplantation.
Methods: We studied 10 recipients of HLA-identical kidneys from living-related donors and 31 recipients of cadaveric kidneys. They were selected because, during the 2 years after transplantation, they did not experience clinical acute or chronic rejection, their renal function was normal and stable, and they underwent a protocol kidney biopsy at 3 months and at 2 years after transplantation.
Results: Histologic chronic allograft nephropathy was present in 25% of patients at 3 months and in 50% at 2 years, but was absent in the recipients of HLA-identical kidneys. Histologic worsening was associated with increased donor age, the presence of asymptomatic grade I acute rejection at 3 months, and an increased cyclosporine trough level.
Conclusions: Protocol biopsies contribute important information that could be used to improve the prophylaxis of chronic allograft nephropathy.