We describe a case of idiopathic myelofibrosis with total neutrophil m
yeloperoxidase deficiency. The combination of this enzymatic defect wi
th myelofibrotic changes in the nuclear shape of neutrophils confers a
peculiar appearance on leukograms produced by a Technicon H1. The cl
inical course of the disease was shortened by recurrent infections tha
t may be ascribed, at least in part, to reduced leukocyte microbicidal
ability. (C) 1997, Ferrata Storti Formulation.