Basophils are granulocytes that are morphologically similar to eosinophils. and whose granules absorb methylene blue These cells express high-affinity surface receptors for IgE which allow them to launch very sensitive responses, especially in the case of helminths (parasitic worms). This response includes the release of histamine, immunological mediators, and lipid derivatives that are pro-inflammatory, edema, and smooth muscle contraction. Because they release the cytokine IL-4, they play an important role in allergic responses.