Post-kidney transplantation erythrocytosis and its relationship to renal artery stenosis, IGF-1, and its binding protein 3 (IGFBP-3)

Abstract

BACKGROUND: Erythrocytosis is relatively common following kidney transplantation. It increases the risk of thromboembolism. Insulin-like growth factor-1 (IG-1) and its binding protein 3 (IGFBP-3) may play a role in its pathogenesis. PATIENTS AND METHODS: A total of 120 consecutive kidney-transplanted patients with at least 3 month graft function were studied. Forty-five kidney transplant patients were then selected and divided into 2 groups: 15 patients with post-transplant erythrocytosis (PTE; group I), 30 without erythrocytosis (group II), and 15 healthy subjects matched with the cases as a control group (group III). Full medical history, clinical examination, hematological parameters, routine biochemical tests, IGF-1, and IGFBP-3 were measured in all subjects. Duplex ultrasonography for diagnosis of renal artery stenosis was done. RESULTS: Post-transplant erythrocytosis developed with an incidence rate of 23.3%.The serum of IGF-1 was signifi cantly higher in the renal transplant recipients with and without erythrocytosis (309.4 ± 72.9, 301.6 ± 67.5 ng/mL, respectively) compared to controls (232.5 ± 95.3 ng/mL, p < 0.01), although there was no statistical difference between the first 2 groups. However, the serum of IGFBP-3 was significantly higher in the renal transplant recipients with erythrocytosis than those without erythrocytosis and normal individuals (p < 0.001). Graft function and incidence of acute and chronic rejection were similar between the 2 groups. CONCLUSION: Post-transplant erythrocytosis represents an anomaly of IGF-1 and its major binding proteins in which they may alter erythropoietin homeostatic mechanisms in the denervated transplant kidney which may be superimposed on a setting of multiple risk factors and leads to a state of erythrocytosis that is seen after kidney transplantation.