Angiotensin converting enzyme gene polymorphism and development of post-transplant erythrocytosis

BACKGROUND: An increased activation of the renin-angiotensin system probably plays a major role in the development of post-transplant erythrocytosis (PTE). It is known that deletion type polymorphism (DD) in the angiotensin converting enzyme (ACE) gene is associated with higher circulating angiotensin II (AII) levels. The aim of this study was to investigate the effect of ACE gene polymorphism on development of PTE. METHODS: 86 PTE patients (male/female: 68/18, mean age: 32 +/- 10 years) and 68 consecutively transplanted non- PTE patients (male/female: 38/30, mean age: 31 +/- 10 years) were included; 140 patients (91%) had been transplanted from living donors; 92 patients (60%) had hypertension. ACE gene polymorphism was determined by polymerase chain reaction (PCR). RESULTS: The mean time to appearance of PTE was 8.8 +/- 7.9 (range of 1-53) months. DD genotype was detected in 65 patients. PTE patients had a higher prevalence of hypertension (70% vs. 46%, p=0.003) and a lower frequency of DD genotype (34% vs. 54%, p=0.014) as compared to non-PTE patients [OR: 2.2 (1.14-4.25, 95% CI)]. PTE developed more frequently in male patients (68/106: 64%) than females (18/48: 38%) (p=0.002). Patients with DD genotype had a significantly longer leading time to PTE in Kaplan-Meier survival analysis with log-rank (136 +/- 15 vs. 92 +/- 13 months, p=0.015). In Cox regression analysis, hypertension (p=0.002) and recipient ACE genotype (p=0.013) were retained as independent variables for predicting PTE development. CONCLUSIONS: PTE develops more frequently in male, hypertensive renal transplant recipients with good allograft function. DD-type ACE gene polymorphism seems to protect against PTE development.