ITGA1 and viral infectious disease: However, other studies have found evidence of functional and potentially resident CD49a+CD103+CD69+ NK subgroups in human lung explants, which are present in the parenchyma and degranulate upon viral infection.[51] However, researchers have found that there are resident NK subsets with the CD49a+CD103+CD69+ phenotype in the parenchyma of human lungs that degranulate during viral infection.