Which cytokines are primarily responsible for promoting eosinophilia?

The correct answer highlights key cytokines that play a significant role in promoting eosinophilia, a condition characterized by an elevated number of eosinophils, which are a type of white blood cell involved in the body’s immune response, especially in allergic reactions and asthma.

IL-5 is the most critical cytokine for the survival and activation of eosinophils. It promotes their differentiation, proliferation, and survival in the bone marrow and tissues, directly leading to increased eosinophil numbers in the bloodstream and tissues.

CCL11, also known as eotaxin-1, is another pivotal chemokine that specifically attracts eosinophils to sites of inflammation. It binds to the eosinophil chemokine receptor CCR3, thereby enhancing eosinophil recruitment when allergies or parasitic infections occur.

TSLP (Thymic Stromal Lymphopoietin) and IL-25 are involved in the activation of type 2 helper T cells (Th2 cells), which play a crucial role in eosinophilic inflammation. These cytokines help initiate and amplify the Th2 response, leading to the production of IL-5 and CCL11, thus further promoting eosinophilia.

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