ARG1 and helminthiasis: Upon helminth infection, macrophages adopt an “alternatively activated” macrophage phenotype (M2-like), which involves the production of various effector molecules including Arginase-1 (Arg1) and Resistin-like protein alpha/beta (Relmα/β), which both have been shown to have an elementary role in regulating Th2 response but also in limiting type-2 immunopathology (5).