The response of basophils of allergic patients to allergen has been reported to be greater than that to anti-IgE or anti-FcεRI.27,28 In a previous study of children with cow's milk allergy,28 the ratio between the percentage of CD63 basophils in response to cow's milk and to anti-FcεRI was higher in patients with persistent cow's milk allergy compared with that in patients who outgrew their allergy and was correlated with the severity of the reactions during challenges. The gene discussed is CD63; the disease is allergic disease.