Neutrophil dysplasia caused by mycophenolate mofetil.

Two transplant recipients developed striking morphological abnormalities in their circulating neutrophils while receiving mycophenolate. The changes included nuclear hypolobulation and abnormal clumping of nuclear chromatin and were presumably related to inhibition of guanosine nucleoside synthesis. In both cases the neutrophil abnormalities preceded the development of neutropenia and were thus a sign of impending hematological toxicity. The hematological changes resolved after the drug was discontinued.