HIGH-RATE OF ACUTE REJECTIONS IN RENAL-ALLOGRAFT RECIPIENTS WITH THROMBOPHILIC RISK-FACTORS

Inherited and acquired thrombophilic disorders predispose patients for thromboembolic and probably other occlusive vascular events that occu r when additional risk factors play in concert. Because acute rejectio ns in renal transplant recipients may reflect vascular events, and an impairment of the fibrinolytic system in immunosuppressed patients has been previously described, the implications of genetic or acquired ri sk factors of thrombophilia for the occurrence of early acute rejectio ns after kidney transplantation were evaluated. The following risk fac tors of thrombophilia were determined in 97 patients after cadaveric k idney transplantation: factor V Leiden mutation, protein S, protein C, and antithrombin deficiency. In a retrospective analysis, the prevale nce of acute rejections, the histologic classification when rejection episodes had been confirmed by biopsy, and other vascular complication s were evaluated. In 21 of the 97 patients, an inherited or acquired r isk factor of thrombophilia was detected. Prevalence of acute rejectio ns was 71% in the first 6 mo after transplantation in patients with a thrombophilic disorder and significantly higher compared with patients without thrombophilia (41%; P = 0.017). The distribution of classic r isk factors associated with acute rejections, such as number of human leukocyte antigen mismatches or percentage of panel-reactive antibodie s, was similar in patients with and without thrombophilia. In the eigh t patients with thrombophilia and histologically proven acute rejectio n, four patients had an acute vascular rejection, and in two patients a vascular involvement was suspected. Furthermore, prevalence of cereb ral or coronary vascular disease, or venous thromboembolic complicatio ns, was significantly higher in patients with a thrombophilic clotting defect (67%) compared with patients with normal hemostasis parameters (28%; P < 0.002). It is concluded that renal allograft recipients wit h thrombophilia are at risk of developing an acute rejection or other vascular event. Although the determination of thrombotic risk factors was performed at least 3 mo after an acute rejection episode, it can b e presumed that acute rejection episodes are associated with subsequen t coagulatory abnormalities with further consequences for transplant s urvival. Thus, pretransplant evaluation of genetic and acquired risk f actors of thrombophilia is recommended.