Who should be converted from cyclosporine to conventional immunosuppression in kidney transplantation, and why.

Twenty-three cadaveric renal allograft recipients with stable but compromised kidney function were electively converted from cyclosporine to azathioprine one year after transplantation. Within a few weeks glomerular filtration rate (GFR) rose by 40% and serum creatinine fell from 171 +/- 12 (mean +/- SEM) to 129 +/- 7 mumol/L. The increase in GFR was due to an increase in effective renal plasma flow of 21%. This suggests that one year of continuous cyclosporine (CsA) therapy does not result in irreversible structural renal damage. Although antihypertensive treatment was not changed, blood pressure fell from 142 +/- 4/90 +/- 3 to 123 +/- 3/77 +/- 2 mmHg. In addition a significant drop in serum cholesterol and triglycerides and an improvement in glucose tolerance were found. The beneficial effects on renal function, blood pressure, and metabolic indices were, however, outweighed by a high incidence of postconversion rejection in recipients of a second allograft. For these patients conversion from CsA to azathioprine seems therefore contraindicated. Recipients of a first kidney allograft can be converted safely, as long-term CsA administration in these patients induced a solid engraftment. The sequelae of the mode of treatment--impaired renal function, hypertension, and metabolic disturbances--are reversible even after late conversion.