Neutrophils
A polynuclear neutrophil (neutro) is a plurilobular nucleus bearing cell with a slightly granulated cytoplasm. Neutros have two types of granulations (lysozome) named azurophilic and specific. Neutros lysozomes havediverse enzyme activities, some being specific like the peroxydase. Neutrophils also possess a heterogenic group of hydrolase gathered under the term esterase. One of these esterases, the Naphtyl AS-D Chloroacetate esterase, seems to be specific for the polynuclear lineage. This activity is shared with the mastocytes and some macrophages (some think that this activity is due to phagocyted neutros). Since mastocytes are not seen in urine, and that the macrophage size and aspect is quite different from leukocytes, this activity is used in a specific staining procedure for leukocytes.
Because of a pycnotic nucleus or of an unfavorable refractive index of the urine, the plurilobulated nucleus are not always obvious. Acidification of the sediment, with one drop of 2% acetic acid enhances the contrast of the preparation.