Graft volume as the surrogate marker for nephron number affects the outcomes of living-donor kidney transplantation.

Post-transplant outcome of kidney allografts depends on various factors, one of which may be the compatibility in volume between graft and recipient. However, previous studies adjusted the graft volume only for recipient's size. As the adjusted graft volume for donor's size would be substituted of nephron number more accurately, we adjusted the graft volume for both recipient's and donor's sizes. In 351 cases of living-donor kidney transplantation, we found that the adjusted graft volume for both recipient's and donor's body surface areas (BSAs) yielded larger area under the curves for the transplant outcomes than looking only at the adjusted volume for the recipient's BSA. The recipients were separated into two groups according to the low and high adjusted graft volumes. During the follow-up period (mean 55.6 months), the low-graft-volume group conferred greater risk of rejection, chronic change, glomerulonephritis, and graft loss than the high-graft-volume group (all p's < 0.05). However, the frequency of T-cell infiltration, as evaluated in protocol biopsy, was not different between the two adjusted graft volume groups. In conclusion, the graft volume as the surrogate marker for nephron number should be considered in kidney transplantation, especially in otherwise similar donor conditions.