The α4 integrin chain was also expressed on a proportion of peripheral neutrophils in 3xTg-AD mice at 6 and 9 months of age, but we observed no difference in α4 expression on circulating neutrophils in the brains of 3xTg-AD and wild-type mice, suggesting that VLA-4 is not required for neutrophil trafficking in the AD brain. This evidence concerns the gene APP and Alzheimer disease.