The Effect of Donor and Recipient Gender On Graft Survival and Function After Kidney Transplantation.

Abstract

Previous studies have shown inferior outcome when female kidneys are transplanted into male patients. A finding that might be explained by nephron-underdosing theory. More recently however, two large multicenter studies demonstrated that female recipients of male donor kidneys had the worst graft survival after the first year and up to ten years post transplant, which suggests an “ H-Y effect” in which the female immune system attacks H-Y antigens presented by male kidney cells. Study goal: The primary goal is to assess the outcome of renal graft function, graft and patient survival after kidney transplantation in the different donor/recipient gender combinations. The secondary goal is to find if there is an H-Y effect in our patient population as previously reported. Patients and Methods: We performed a cohort-retrospective study using data on kidney transplantation done between 1995 and 2005 at our center representing Israel largest transplantation experience. Donor and recipient demographics and clinical data including graft and patient survivals and renal function were collected to database and statistically analyzed on SPSS 21 software. Results: For female recipients, grafts from female versus male donor had superior long-term graft survival (HR 0.52, p=0.048). For male recipients, grafts from male versus female donor had superior long-term graft survival )HR 1.35, p=0.04). Female donor to male recipient had inferior long term graft survival compared to other groups (HR 2.25, p=0.02). Likewise, male donor to female recipient had increased risk for graft failure compared to other groups (HR 2.09, p=0.047) and an increased graft failure rate due to chronic rejection (HR 1.46, p=0.041). Comparing GFR means, grafts from male donor has better function than grafts from female donor, irrespective of whether the recipient was male or female. Conclusions: The results presented confirm the known so far for the hypothesis of nephron-underdosing and for the H-Y antigen in kidney transplantation. Male recipients could probably profit from male kidneys, with their higher nephron doses. Female recipients, however, might not need the same number of nephrons as men, and could profit from the lower likelihood of rejection associated with a sex-matched donor kidney.