Pathologic states associated with activation of eosinophils and with eosinophilia

Eosinophils are involved in cytotoxicity against helminths and tumor cells and effect both tissue damage and tissue protection in hypersensitivity reactions. Their migratory patterns and oxidative mechanisms are most similar to those of neutrophils, but their tissue longevity and functional variation are more similar to those of monocytes and macrophages. Their enzyme components and behaviors are only now beginning to be defined, and their biologic functions in pathologic states remain a topic of considerable discussion.