Angiotensin-converting-enzyme insertion/deletion genotype and long-term renal allograft survival

Increased activity of the renin-angiotensin system has been implicated in decreased long-term survival of renal allografts. Recent studies suggest that a deletion variant of the angiotensin-converting enzyme, associated with increased humoral and tissue activity of this enzyme, may be a risk factor for the development of diabetic nephropathy and the progression of IgA nephropathy. The present study was conducted to determine whether the deletion variant of the angiotensin-converting-enzyme gene influences the long-term outcome in renal-transplant recipients.

We examined the relationship between recipient angiotensin-converting-enzyme genotype and clinical outcome in patients with a surviving allograft of at least 10 years (median survival 156 months, n= 86). Patients with an allograft survival of less than 3 years served as controls (median survival 10.4 months, n=87).

Genotype distribution in long-term renal allograft survivors (II, 18; ID, 41; DD, 27; qD, 0.55) was similar to that in the control group (II, 12; ID, 53; DD, 22; qD, 0.56), and there were no significant differences between the genotypic groups in either cases or controls. Long-term survivors were more often female (58 vs 38%) and less often hypertensive (67 vs 77%). Both recipient and donor age were markedly lower in the long-term survivor group, whereas number of HLA mismatches and cold ischaemia time were comparable between cases and controls.

This study does not support the hypothesis that the angiotensin-converting-enzyme insertion/deletion polymorphism is an important determinant of long-term transplant survival in Caucasian patients undergoing renal transplantation.