Cyclosporine A-induced side effects related to a low total serum cholesterol level: An indication for a free cyclosporine A assay?

In blood approximately 40% of CsA is bound to erythrocytes and between 50% and 60% to cholesterol- and triglyceride-containing lipoproteins. Considering several possibilities, we hypothesized that low total serum cholesterol levels lead to increased unbound or free CsA levels. If this hypothesis is true, then normal therapeutic whole blood CsA levels with concomitant low cholesterol levels could predispose patients to not only CNS toxicity, but also nephrotoxicity, hypertension, hepatotoxicity, and opportunistic infections. Therefore, we retrospectively analyzed our liver transplantation data to determine whether the development of nephrotoxicity and hypertension was related to total serum cholesterol levels.