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. The gene discussed is CD40LG; the disease is Allergy.