Le polynucléaire basophile: nouveautés en physiopathologie et implications diagnostiques

Basophils represent a rare cell population belonging to the myeloid cell lineage. They account for less than 1 % of total peripheral blood leukocytes. During several decades and due to the difficulties to clearly identify these cells, basophils were though to display similar functionalities than tissue mast cells. However, recent development of novel analytic tools allowed highlighting previously unrecognized roles of basophils, and appreciating the distinct functions of basophils and mast cells in immune responses. Different subsets of basophils with complementary functions were identified. To our current knowledge, basophils are involved in the modulation of innate and adaptive immune responses, and play an important role in protective immunity against parasites. Additionally, basophils could have deleterious effects during development and maintenance of immune disorders, like auto-immune diseases or allergy. However, despite their multiple functions, basophils are essentially useful for the biologic diagnosis of allergy, by histamine release assays or basophils activation tests realized in vitro.