Course of renal allograft histopathology after transplantation in early childhood

Background. We report a long-term prospective follow-up of renal allograft histology in children <5 years of age at transplantation (Tx). Methods. Fifty-one kidney allograft recipients were prospectively followed for renal allograft histology and function up to 7 years after Tx. Twenty p atients were recipients of kidneys from living related donors, and 31 were cadaveric kidney recipients. All patients received triple immunosuppression . Biopsies were analyzed according to the Banff classification and scored s emiquantitatively. The "chronic allograft damage index" (CADI) was calculat ed. Results. Five of seven grafts were lost because of nephrosis in patients wi th congenital nephrotic syndrome of the Finnish type. Most of the biopsies (52-69%) were considered normal (Banff classification), and the proportion with chronic allograft nephropathy did not increase with time. The median C ADI score was 2.5 (scale: 0-36) at 1.5 years and 3.5 at 7 years. Recipients with an acute rejection episode had higher CADI scores than recipients wit hout acute rejection episode. Patients with a high CADI score at 3 years ha d inferior graft function at 5 years. Recipients <2 years of age had CADI s cores and numbers of acute rejection episode similar to recipients between 2 and 5 years of age. However, in contrast to the older recipients, the you nger recipients did not improve their absolute glomerular filtration rate w ith time. Conclusions. The long-term histopathological findings were mostly mild and stable with time. Acute rejection episode had an impact on these changes an d CADI predicted later graft function. Nonimmunological risk factors seem t o be more important in the youngest recipients.