Patients with AD have activated circulating basophils and increased basophil and neutrophil releasability of LT-C4 compared with healthy subjects [10, 11], while urinary levels of LT-E4, a stable metabolite of LT-C4 and LT-D4, has been showed high levels in children affected by severe atopic eczema, but not in healthy normal subjects or in patients with mild or moderate atopic eczema [12]. The gene discussed is C4A; the disease is atopic eczema.