The marrow is normo- or hypercellular with increased myelopoiesis, where neutrophils predominate. Myelopoietic precursors mature, often there is a left shift, however the number of myeloblasts is normal. Myeloid hyperplasia may sometimes be so extensive that it resembles hemoblastosis (leukemic reaction). Other lineages are either normal or also display reactive changes (for example an increased number of megakaryocytes caused by an inflammation).