Aselizumab (HuDreg-55) is a humanized IgG4 monoclonal antibody that targets L-selectin (CD62L), a cell adhesion molecule found on circulating neutrophils. L-selectin plays a crucial role in directing cell migration through chemotaxis to injury sites. Aselizumab has been associated with an increased incidence of infections and leukopenia, particularly following trauma, suggesting potential safety concerns that need further investigation in clinical contexts.