Helminth infection induces type 2 immune responses characterized by upregulation of specific cytokines including IL-4, IL-5, IL-9, and IL-13.24 These cytokines polarize different immune cells such as CD4+ T helper 2 (TH2) cells and alternatively activated macrophages (AAMs) or M2 macrophages.24 Although CD8+ T cells are not directly involved in anti-helminth immunity, type 2 cytokines elicited during helminth infection can cause bystander activation of naïve CD8+ T cells. This evidence concerns the gene IL9 and helminthiasis.