CD43, also known as leukosialin and sialophorin, is a type I transmembrane sialylated, negatively charged mucin that is expressed on the surface of most hematopoietic cells. CD43 plays an important role in T lymphocyte function by negatively regulating antigen-specific T cell activation and interfering with cellular adhesion and proliferation. It also has been reported that CD43 is involved in viral clearance. Aberrant expression of CD43 is associated with several diseases, such as Wiskott-Aldrich syndrome and acute leukemia.