CD5/CD20

CD5 is expressed in some B- cell derived lymphoproliferative disorders, notably chronic lymphocytic leukaemia (CLL) (> 90%) (1, 2), and centrocytic leukaemia.CD20 can be considered a pan- B cell antigen, as it is expressed on the surface of all mature B lymphocytes but not in secreting plasma cells. CD20 is expressed early during pre- B cell development, presumably just before the expression of cytoplasmic µ- chains, and it persists until plasma cell differentiation. A small subset of T cells expresses low levels of CD20. CD20 is expressed in acute lymphoblastic leukaemia, B- cell chronic lymphocyticleukaemia, hairy cell leukaemia and Burkitt’s lymphoma.