ABSTRACT
Inflammation is a complex interaction between chemical mediators and cells that occurs when tissue is injured. Inflammatory reactions are designed to eliminate the cause of the injury and repair the damaged tissue. Inflammation is initiated when mechanical barriers are damaged by trauma or infection. The chapter reviews important diagnostic information that is provided by cytologic evaluation of inflammatory lesions. Endogenous proinflammatory molecules, including cytokines and danger-associated molecular patterns that are released from dying cells, can stimulate inflammation. Kinins are potent, slow-acting vasodilators that increase capillary permeability. They mediate pain and produce sustained rubor, calor, and dolor associated with inflammation. Prostaglandin Es are key mediators of inflammation and are produced by macrophages, platelets, and several other cell types. Lymph nodes are key sites for formation of an adaptive immune response to eliminate the agent causing inflammation. Suppurative inflammation is predominated by neutrophils.
