Although CD62P/P-selectin and CD54/ICAM-1 are required for leukocyte infiltration of liver, kidney, lung, brain, or peritoneum (50, 51), these molecules are dispensable for immune cell trafficking under specific inflammatory conditions such experimental autoimmune encephalomyelitis or lymphocyte transmigration into secondary lymphoid organs (15, 52). This evidence concerns the gene ICAM1 and experimental autoimmune encephalomyelitis.