In brain ischemia/reperfusion experiments on mice with a null mutation in the LFA-1 and Mac-1 genes, no effect on the adhesion process of leukocytes 4 hours after reperfusion was shown, while such an effect appeared after 24 hours, which correlated with the time of ICAM-1 peak density at the cell membranes of endothelial cells (92, 118). The gene discussed is ICAM1; the disease is brain ischemia.