IL4R and helminthiasis: In addition to failing to regulate histological GVHD in IL-4Rα−/− or CKO mice undergoing BMT, helminth infection offered no survival advantage in the same circumstances (WT C57BL/6→IL-4Rα−/− BMT or WT C57BL/6→CKO BMT), although it promoted the survival of some WT BALB/c recipients (Fig. 3), as was shown previously (14, 17, 18).