When a person has an acute bacterial infection, which type of leukocyte increases in number?

In the case of an acute bacterial infection, neutrophils are the primary type of leukocytes that respond and increase in number. These cells are a type of white blood cell that plays a critical role in the immune response. They are the first line of defense during an infection, particularly bacterial, as they can quickly move to the site of infection to engulf and destroy pathogens through phagocytosis. Neutrophils are known for their ability to rapidly respond to infection, and their elevation can be observed in blood tests during such an event, indicating an ongoing immune response.

In contrast, eosinophils typically increase in response to parasitic infections and allergic reactions rather than bacterial infections. Lymphocytes, which include T cells and B cells, are more involved in the adaptive immune response and would not be the primary responders in the acute phase of a bacterial infection. Monocytes, while they do participate in the immune response, primarily differentiate into macrophages and dendritic cells and usually increase later in the immune response rather than at the onset of an acute bacterial infection. This highlights why neutrophils are particularly significant in the context of acute bacterial infections.