There is evidence to suggest that carbohydrate antigens restricted to neutrophils and monocytes among human blood cells, but distributed widely in epithelial tissues and secretions, are ligands for cell-cell adhesion molecules that are transiently expressed on endothelia and platelets at sites of inflammation. If these combining specificities are confirmed, it means that biological specificities may arise through regulated focal expression of proteins that recognize oligosaccharides that are not necessarily unique.