Further evidence of the strict relationship between HE and Th2 cytokine production is given by the few patients with ALL-associated HE in whom genetic abnormalities, such as t (5; 14) (q31; q32) and del (5) (q15q33), induce IL-3 gene activation and relevant production of this eosinophilopoietic cytokine [8,9,10]. Here, IL3 is linked to hereditary elliptocytosis.