Arg1 activity was of particular interest because prior studies showed that Arg1-expressing macrophages play a critical host protective role in schistosomiasis by suppressing the pro-inflammatory activity of IL-12/IL-23 during the acute phase and by slowing the progression of IL-13-driven fibrosis in the chronic phase of schistosomiasis [8], [31]. This evidence concerns the gene IL13 and schistosomiasis.