However, immunological staining showed that hindlimb ischemia caused increases of leukocyte infiltration inside myocytes and in the interstitial space in both WT and PD-1-/- mice, and the leukocyte infiltration increased 2.04-fold in PD-1-/- mice as compared with corresponding WT mice (Figures 2A, B). The gene discussed is PDCD1; the disease is ischemia.