There are two phases of asthma exacerbation: the early and late phase. The early phase: IgE antibodies are sensitized nad released by plasma cells. The IgE antibodies can be triggered by certain risk factors of the environment. The antibodies bind to mast cells and basophils which cause a release in cytokines and de-granulation. Histamine, grostaglandins, and leukotrienes are then relasesd from the mast cells and cause the smooth muscle to contract and the airway to restrict. Th2 lymphocytes produce the series of interleukins: IL-4, IL-5, IL-13, and GM-CSF, which aid in sustaining the inflammation. IL-3 and IL-5 aid in the survival of eosinophils and basophils. Then IL-13 is involved with remodeling, fibrosis, and hyperplasia. The late phase: this phase happens a few hours after the early phase. This phase is when eosinophils, basophils,neutrophils, and help and memory T-cells are in the lungs and cause bronchoconstriction and inflammation.