Final answer:
Basophils and neutrophils are types of leukocytes that release chemicals promoting inflammation, such as histamine and cytokines, respectively, aiding in the body's immune response.
Step-by-step explanation:
A leukocyte that releases chemicals which promote inflammation is known as a basophil. Basophils are involved in inflammatory reactions, particularly those that cause allergic symptoms. They release histamine, a key mediator of inflammation that dilates blood vessels and makes vessel walls permeable, allowing other immune cells to engage in the inflammatory response. Furthermore, another type of leukocyte called a neutrophil also participates in the promotion of inflammation. Neutrophils release cytokines, such as leukotrienes and various other substances which attract other neutrophils and amplify the inflammatory response.