CCL11 and eosinophilic pneumonia: Lesser known mechanisms proposed involved the immune system [6, 10, 26, 36, 41, 43], cytochrome metabolism system [47], inflammatory pathways [15, 41], an eotaxin (i.e., a chemoattractant for eosinophils) and serotonin eosinophilic-specific chemo-attracting action leading to eosinophilic pneumonia [49].