In recent years, the IL-21/IL-21R signaling axis has been implicated in the regulation of immunity and the pathogenesis in several bacterial, viral, fungal, and parasitic infections (Moretto and Khan, 2016; Solaymani-Mohammadi and Berzofsky, 2019; Spolski et al., 2019). This evidence concerns the gene IL21R and parasitic infectious disease.