Basophils are not the key antigen‐presenting cells in allergic patients

Background Recent data obtained in mouse models have initiated a controversy whether basophils are the key antigen‐presenting cells ( APC s) in allergy. Here, we investigate whether basophils are of importance for the presentation of allergen and the induction of T cell proliferation in allergic patients. Methods T cells, basophils, and APC s depleted of basophils were purified from allergic patients. Co‐culture systems based on purified major allergens were established to study allergen‐specific T cell responses using proliferation assays. Results Only co‐cultures of T cells with APC s depleted of basophils but not with basophils proliferated in response to allergen. Even addition of IL ‐3 to T cell–basophil co‐cultures failed to induce allergen‐specific T cell proliferation. Conclusions Our data demonstrate by classical in vitro proliferation assays that basophils are not key antigen‐presenting cells that promote T cell proliferation in secondary immune responses to allergen in allergic patients.