CD40LG and allergic disease: In allergic asthma, platelets can not only facilitate leukocytes to migrate into the lung, but also polarize adaptive immune response through a variety of possible ways: they promote differentiation and activation of Th2 and ILC2s, promote IgM to IgE switch, inhibit apoptosis of eosinophils in the lung, and induce allergy to innocuous allergens in the environment.