Seasonal variation in circulating group 2 innate lymphoid cells in mugwort-allergic asthmatics during and outside pollen season

Background Group 2 innate lymphoid cells (ILC2s) are a newly identified cell population with the potent capability to produce Th2-type cytokines in a non-antigen specific manner. Previous study demonstrated that enhanced circulating ILC2s in cat-allergic patient after experimental allergen challenge, whereas the effects of natural allergen exposure on peripheral ILC2s are still unclear. We therefore examined the variations in circulating ILC2s among asthmatic patients sensitized to different allergens in- and outside- pollen season.