basophilswhich

Basophilswhich is not a standard term in immunology. It is likely a misspelling or concatenation of basophils. This article uses basophils as the intended concept.

Basophils are a type of circulating white blood cell and one of the granulocytes. They comprise about 0.5–1% of peripheral leukocytes and develop in the bone marrow from myeloid precursors under the influence of cytokines such as IL-3 and GM-CSF. They contain large granules that stain with basic dyes and hold mediators including histamine, heparin, and proteases.

Functionally, basophils participate in inflammatory and allergic responses. They express high-affinity receptors for IgE (FcεRI); when allergens cross-link bound IgE on basophil surfaces, the cells degranulate and release histamine and other mediators, contributing to vasodilation, increased vascular permeability, and smooth muscle effects. In addition to histamine, basophils produce lipid mediators such as leukotrienes and prostaglandins and secrete cytokines like IL-4 and IL-13, which promote Th2 responses and B-cell class switching to IgE. Basophils are circulating counterparts to tissue-resident mast cells, sharing some mediators but differing in location and development.

Clinical relevance includes basophilia or basopenia, which can appear in certain allergic or hematologic conditions, infections, or during corticosteroid therapy. Basophil activation tests (BAT) can help evaluate allergic reactions by measuring activation markers (e.g., CD63, CD203c) after allergen exposure. Basophils constitute a small but notable component of the immune response, particularly in allergic disease and parasitic infections.