Uric Acid Handling, Pregnancy and Ciclosporin in Renal Transplant Women

J.M. Morales, Nephrology Department, Hospital ‘12 de Octubre’, E-28041 Madrid (Spain) Dear Sir, Pregnant renal transplant women under azathioprine immunosuppression show a normal physiologic increment in uric acid clearance [1]. Because ciclosporin can induce hyperuricemia [2], contrary the effect of pregnancy on uric acid handling, we studied the changes on urate clearance in our pregnant transplant women. Seven pregnancies in 6 women (X age 30 years, range 21–36) were studied. All had received kidney grafts from cadaveric donors between 7 and 27 months before. Previous creatinine clearance was 76.6 ml/min (X, range 60.8–90). Four women with 5 pregnancies, were on ciclosporin with a dose of 4.3 mg/kg daily (X), and the other 2 received azathioprine with a dose of 1.5 mg/kg daily (X). Also, all were taking prednisone 10 mg daily (X). In 3 women, 2 under ciclosporin and 1 under azathioprine treatment, therapeutic abortions were performed because of pregnancies in the early posttransplant period, severe liver disease and hereditary disease. At the 6th month of pregnancy, 1 women treated with ciclosporin with previous arterial hypertension suffered fetal death. The remaining pregnancies were uncomplicated, and 4 babies, 1 pair of twins in a ciclosporin patient [3], were delivered. In all patients in the first trimester, an increase in creatinine clearance to 106 ml/min (X), range 68–175) was observed. Changes in uric acid handling are showed in figure 1. Urate clearance increased only in 4 cases, in the 2 women treated with azathioprine and in the single patient under ciclosporin immunosuppression, with two pregnancies. By contrast, the other 3 ciclosporin patients failed to improve urate clearance in spite of renal function improvement: previous creatinine clearance was 65.8 ml/min (X, range 60.8–71), and in the 2nd month of pregnancy it was 80 ml/min (X, range 79–93). While the first ciclosporin patient never suffered nephrotoxicity, the other patients showed frequent episodes of cicloπ–i–i–i–i–ι–ι–ι–i 1 a 3 0J i 1–i–i–i–i–i–i–i–i 1 b B 1 3 5 7 9 PP Months Fig. 1. Uric acid handling in our renal transplant patients. ■ = Azathioprine patients; O = ciclosporin patients; = fetal death; = abortion; PP = postpartum. a Uric acid concentration.