It has long been known that asthma is a disease linked to the activation of helper Th2-lymphocytes (whose key cytokines are mainly IL-2, IL-3, IL-4, IL-5, IL-9, IL-13 and GM-CSF) with a concomitant lack of inhibition by Treg lymphocytes for defective production of IL-10 [25, 26]. Here, IL5 is linked to asthma.