Abstract
Cellular blood components include leukocytes, erythrocytes, and platelets. Leukocyte subtypes are neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Red blood cell components include mature erythrocytes and reticulocytes. Increases or decreases in cell counts/concentrations for each of these blood components may occur in response to many stimuli or pathologic conditions, including stress, inflammation, infectious agents, neoplasia, and the toxic effects of endogenous, environmental, or pharmaceutical compounds. Changes may be limited to a few blood components or may be observed in all blood components depending on the stimulus. Morphologic alterations in blood components may also be observed in conjunction with alterations in blood cell counts. Specific examples of conditions that cause alterations in blood components are described, as well as the mechanisms by which many of these specific alterations occur. Many xenobiotics are able to cause similar alterations in blood components through the same or comparable mechanisms, and examples of xenobiotic-induced alterations in blood components are provided.