When eosinophils encounter adhesion molecules expressed on the endothelial cells of post capillary venule wall, the cells adhere and emigrate through the cell layer [47] . Local signals do however drive a low level influx of eosinophils in specific tissues at homeostasis. Eosinophils are present in almost all mucosal associated tissues, nasal mucosa [48] (Figure 3B ), lungs [49] ( Figure 4B ), gastrointestinal mucosa [50] , the reproductive tract, the uterus [51] , breast mucosa of mice [52] and skin [53] . The chemokine eotaxin is responsible for homeostatic eosinophil influx in the gastrointestinal tract in mice [54] whereas the mechanism of influx in other organs remains unknown. In addition, lymphocyte-associated tissue: lymph nodes [50] , thymus [55] and spleen [50] will have some cells stained red by eosin (see Figure 5 ).