ABSTRACT
Neutrophils are an important first line of defense against bacterial pathogens. Formed in the bone marrow from myeloid precursors, mature neutrophils are released into the blood on a regular basis. The neutrophil is responsive to several chemotactic factors that are released from epithelial and other cells after contact with damage-associated molecular patterns (DAMPs) and/or pathogen-associated molecular patterns (PAMPs). This chapter examines neutrophils that are incapable of leaving the blood vascular space in response to chemotactic stimuli, and explores neutrophils that are unable to ingest and kill. Cyclic episodes of neutropenia occur in a regular pattern in dogs affected with this condition, leading to episodes of infection when peripheral neutrophil counts fall to less than 1000/μL. The history of recurrent infection and the breed and coat color of the dog strongly suggested cyclic neutropenia. The cycle occurs at approximately 10- to 12-day intervals, with periods of neutropenia often followed by a brief neutrophilia.
