Infections of IL-4-/-, IL-13-/-, IL-4Rα-/- and Stat 6-/- mice with the nematodes Trichuris muris, Heligmosomoides polygyrus and Nippostrongylus brasiliensis have demonstrated a positive relationship between polarisation to a TH2 immune response, goblet cell hyperplasia and worm expulsion [14-19]. The gene discussed is IL4R; the disease is infection.