Eosinophils are circulating granulocytes involved in pathogenesis of
asthma. A cascade of processes directed by Th2
cytokine producing T-cells influence the recruitment of eosinophils into the lungs. Furthermore, multiple elements including
interleukin (IL)-5,
IL-13,
chemoattractants such as eotaxin, Clara cells, and
CC chemokine receptor (CCR)3 are already directly involved in recruiting eosinophils to the lung during allergic
inflammation. Once recruited, eosinophils participate in the modulation of immune response, induction of
airway hyperresponsiveness and remodeling, characteristic features of
asthma. Various types of promising treatments for reducing asthmatic response are related to reduction in eosinophil counts both in human and experimental models of pulmonary allergic
inflammation, showing that the recruitment of these cells really plays an important role in the pathophysiology of allergic diseases such
asthma.