IL10 and asthma: Foxp3 expression is reduced and CD25(hi) Treg-suppressive function is deficient in asthma. Corticosteroids and allergen immunotherapy act on Tregs, in part to increase IL-10 production, while vitamin D3 and long-acting beta-agonists enhance Tr1 cell function [57]. Heligmosomoides polygyrus infection is associated with elevated numbers of Tregs in airway challenged mice [60], efficiently protects mice from asthma by induction of accumulation of highly suppressive Tregs in the lungs [61].