HAVCR2 and helminthiasis: Helminth infection modulates host T cell function through multiple factors including induction of Tregs, IL-10/TGF-β regulatory cytokines (23, 64), PD-1/PD-L, and other co-inhibitory molecules such as LAG-3, BTLA-4, CTLA-4, Tim-3, etc. (9, 65).