Xue JM, et al. - Given the critical role played by the biased T helper 2 (Th2) responses in the pathogenesis of allergy and that survivin can regulate multiple cellular activities, researchers examined how survivin influence the development and maintenance of Th2 polarization. They isolated CD4+ T cells from blood samples collected from patients with allergic asthma (AS) and HS control (HS) subjects. They employed mice carrying CD4+ T cells with survivin knockout (KO mice) to test the role of survivin in the development of the biased Th2 responses. Airway allergy was not induced in KO mice. Furthermore, in the AS group, peripheral CD4+ T cells expressed higher survivin than in the HS group. Findings thus suggest the facilitatory role of survivin in the development of biased Th2 polarization; it promotes expression of interleukin 4 (IL-4) and impairs the activation-induced cell death (AICD) machinery of CD4+ T cells. Modulation of the expression of survivin in CD4+ T cells seems to have the translational potential in the treatment of allergic diseases.