Intravenous injection of H-IPSE induces IL-4 expression by basophils. A) A higher proportion of basophils from the peripheral blood of H-IPSE-injected mice were IL-4+ compared with PBS-injected mice. After ifosfamide (Ifos) injection, this cell population was similar in both H-IPSE and PBS groups. B) There was no significant difference in IL-4+ peripheral blood mast cells between H-IPSE and PBS groups before and after ifosfamide injection. C) IL-4-expressing basophils were present at higher numbers in the bladders of both H-IPSE and PBS groups after ifosfamide injection. D) There was no difference in IL-4-positive bladder mast cells, with or without ifosfamide, between the H-IPSE and PBS groups. Consistently, BALB/c mice did not express GFP (IL-4), as expected. Plotted data are pooled from 2 repeat experiments (n = 3–7). Horizontal bars represent means. *P < 0.05, **P < 0.01, ***P < 0.001.