1. ¹Assistance Publique–Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Biochimie, Paris, France
2. ²INSERM UMR-S 747, Centre Universitaire des Saints-Pères, Paris, France
3. ³AP-HP, Hôpital Henri Mondor, Service de Pharmacologie Clinique, Créteil, France
4. ⁴AP-HP, Hôpital Henri Mondor, Unité de Recherche Clinique, Créteil, France
5. ⁵AP-HP, Hôpital Necker, Service de Transplantation Rénale, Paris, France
6. ⁶AP-HP, Hôpital Henri Mondor, Service de Néphrologie, Créteil, France

Correspondence: S Sanquer, (sylvia.sanquer@gmail.com)

Received 29 January 2007; Accepted 13 June 2007; Published online 22 August 2007.

Abstract

The objective of the study was to evaluate the effect of mycophenolate mofetil (MMF) on the regulation of inosine monophosphate dehydrogenase (IMPDH) during the first 2 years after renal transplantation. Twelve patients were enrolled, and 10-h time-course evaluations of the effects of MMF were regularly performed during the study. IMPDH activity and gene expression were measured in whole blood and in mononuclear cells, respectively. Type I IMPDH (IMPDH-I) mRNA was increased during the first 3 months following transplantation and reached its maximal level during acute rejection episodes, whereas type II IMPDH mRNA was stable. Furthermore, although no alteration in the predose samples was observed, patients with prolonged MMF treatment exhibited an increase in the induction potency of both IMPDH activity and gene expression. In vitro experiments confirmed that IMPDH-I is inducible, but preferentially in monocytes than in lymphocytes. This finding suggests that the measurement of IMPDH mRNAs may provide reliable information to predict acute rejection.