CXCR2 and Pruritus: In cheek itch models, we revealed that the CXCR2 shRNA virus caused a significant reduction in itching responses induced by CQ (107 ± 17 versus 38 ± 7, p < 0.01) and histamine (115 ± 7 versus 72 ± 11, p < 0.01) (Figure 4I).