IL-33–induced peritoneal neutrophil influx is mast cell–dependent. (A) Flow cytometry plots of c-Kit⁺ mast cells and Ly-6G⁺ neutrophils in peritoneal fluid from wild-type mice, W^sh/W^sh-mice, W^sh/W^sh mice reconstituted with wild-type BMMCs and W^sh/W^sh mice reconstituted with T1/ST2^−/− BMMCs and injected intraperitoneally with 0.1 μg IL-33. Representative plots are shown. (B) Quantification of panel A (n = 4-5). (C) Percentage of mast cells in the peritoneum of wild-type, W^sh/W^sh-mice, and W^sh/W^sh mice reconstituted with wild-type or T1/ST2−/− BMMCs (n = 5-11). Values are presented as mean ± SEM, *P < .05, ns = not significant.