TRIIODOTHYRONINE (T3) REFLECTS RENAL GRAFT FUNCTION AFTER RENAL-TRANSPLANTATION

OBJECTIVE Abnormalities in thyroid function are observed in patients w ith end stage renal disease. However, there are no data available eval uating sequential changes of thyroid function after renal transplantat ion. Therefore, we have studied thyroid hormone function in the immedi ate post-operative period after renal transplantation in order to dete rmine the relationship between improving renal function and changes in thyroid hormone economy. DESIGN AND PATIENTS Thyroid function was eva luated in 22 patients before and on days 1, 3, 7 and 15 after renal tr ansplantation. All patients received prednisone and cyclosporin as imm unosuppressive therapy. Twelve patients with normal renal function und ergoing comparable surgical procedures served as a control group. MEAS UREMENTS Serum creatinine and thyroid hormone parameters (total T4, to tal T3, free T4, free T3, Thyroxin binding globulin (TBG), reverse T3, T3 sulphate and TSH) were measured. RESULTS According to past-operati ve kidney function after renal transplantation, patients could be subd ivided into three groups: five patients had primary graft function (gr oup I); seven patients had delayed graft function because of acute ren al failure (group II); 10 patients had delayed graft function requirin g high doses of prednisone and some also of OKT3 because of acute reje ction (group III). There was a significant fall in T3 and T4 concentra tions with a concomitant rise in reverse T3 in all patients up to 3 da ys after renal transplantation. However, only patients in group I reac hed pre-operative values on day 15 after renal transplantation (serum creatinine 167 +/- 52 mu M), whereas patients in group II (creatinine 609 +/- 118 mu M) and group ill (creatinine 839 +/- 71 mu M) continued to have T3 concentrations well in the hypothyroid range (group I, 1.6 8 +/- 0.28 nM) vs 0.87 +/- 0.09 nM in group II and 0.76 +/- 0.10 nM in group III; P < 0.01). Serum T4 concentrations were also tow in group III (47.7 nM vs 100.2 nM in group I; P < 0.05) 15 days after renal tra nsplantation. These changes were accompanied by a concomitant fall in T3/TBG ratio and in free T3. Elevated reverse T3 returned to normal va lues in all groups on the 15th day after renal transplantation. TSH fe ll significantly on the first postoperative day, but did not return to pre-operative Values in renal transplantation patients. In the contro l group, TSH did not change during the study period. T3 sulphate, know n to be elevated in chronic renal failure, remained above normal in al l patients irrespective of graft function during this study period. CO NCLUSIONS T3 concentrations reflect renal graft function after renal t ransplantation. T3 is below normal in patients with delayed graft func tion (acute renal failure or acute rejection). The post-operative peri od (up to 3 days after renal transplantation) is associated with a low T3 syndrome. TSH does not return to preoperative values even in patie nts with primary graft function. This might be due to the administrati on of prednisone. T3-sulphate is elevated before and after renal trans plantation irrespective of graft function.