Reduced lung inflammation in TSLPR^−/− mice in response to HDM. The formalin-fixed lung sections were stained with periodic acid Schiff reagent (PAS) to visualize mucus (a). Magnification ×20. Representative sections from WT saline control, HDM treated WT, and TSLPR^−/− mice are shown. A semi-quantitative histological assessment of cell infiltration and mucus hypersecretion was performed by two independent observers (b). A scale from 0 to 3 is given on the axis. These experiments were performed twice ( mice per group). One representative experiment is shown. Values are the mean SEM of 8 mice per group.