CD10 also known as common acute lymphoblastic leukemia antigen (CALLA), is a 100 kD protein having neutral metalloendopeptidase activity and inactivates a variety of biologically active peptides. CD10 is a type II cell surface glycoprotein typically expressed on acute lymphoblastic leukemias (ALL). In normal healthy volunteers expression of CD10 is detected on the precursors of B and T cells and also on granulocytes. CD10 plays important role in the development process of B cell in germinal centers.