The role of lactadherin in the phagocytosis of phosphatidylserine-expressing sickle red blood cells by macrophages.

Lactadherin is a phosphatidylserine-binding glycoprotein secreted by macrophages. Less than 0.5% of normal circulating red cells showed any binding to lactadherin. However, the red cells from patients with sickle cell disease showed 2 to 10-fold increases in lactadherin binding. Further, lactadherin stimulated the phagocytosis of sickle red blood cells by macrophages suggesting a potential role in sickle red cell clearance.