Few facts in medicine are as well established as the increase in leukocytes and neutrophils that characterizes certain infectious processes, although the information to be gained from a study of the morphologic characteristics of the leukocytes responsible for this increase has not received due consideration. In the development of an adult polymorphonuclear neutrophil, the young cell passes through a series of well defined stages, with gradually increasing condensation and segmentation of the nuclear chromatin and the appearance of granules and neutrophilic staining properties in the cytoplasm, until the mature neutrophil is formed. The observation that there is an increase in the number of the less mature polymorphonuclear neutrophils in certain acute infections is the basis for the various methods of classification of these cells which have appeared from time to time during the past thirty years.
Arneth1 is credited with the pioneer work on the changes in nuclear structure
MILLS SD. FILAMENTED-NONFILAMENTED CELL COUNT IN APPENDICITIS IN CHILDREN. Am J Dis Child. 1935;50(1):36-48. doi:10.1001/archpedi.1935.01970070045004