Influence of immunosuppressive therapy on lipoprotein(a) and other lipoproteins following renal transplantation

Coronary heart disease (CHD) is more common in patients with chronic renal failure and is a major cause of death after renal transplantation. Elevated serum levels of lipoprotein(a) (Lp(a)) are a known risk factor for CHD in the general population and levels have been reported to be increased in renal transplant recipients. It has been suggested that cyclosporin may elevate Lp(a) levels. We therefore measured the serum concentration of Lp(a) in 50 renal transplant recipients who were receiving cyclosporin alone as immunosuppressive therapy and 50 who were treated with azathioprine and prednisolone, but not cyclosporin. The patients attended two renal transplant centres, one where cyclosporin alone was used as immunosuppressive treatment when possible and another where many patients commenced on azathioprine and prednisolone remain on this medication rather than cyclosporin. Patients in each group were matched for age and sex, but the time since transplantation was greater in those not receiving cyclosporin. Transplant function, obesity and the underlying cause of renal disease were similar in both groups of patients. Median Lp(a) concentration in the cyclosporin monotherapy group was 32.0 (range <0.8-140.3) mg/dl and was significantly (p <0.05) greater than that of the azathioprine and prednisolone group which was 18.3 (range <0.8-167.7) mg/dl. The serum high-density lipoprotein (HDL) cholesterol concentration, which was 1.24 ± 0.39 mmol/l (mean ± SD) in patients receiving cyclosporin, was significantly (p <0.05) less than that of those treated with azathioprine and prednisolone in whom it was 1.41 ± 0.40 mmol/l. The lower level in those on cyclosporin was due to a decrease in the HDL2 subfraction. Serum lipid and lipoprotein concentrations were otherwise similar in the two groups of patients. The serum level of Lp(a) after renal transplantation may be influenced by the choice of immunosuppressive therapy.