CD20

Summary

CD20 is a component of the B-cell receptor and is therefore expressed by mature B-lymphocytes. In many ways its expression is similar to that of CD19; however CD20 expression is acquired slightly later in B cell development and may be retained by some plasma cells.

Background

CD20 is expressed by B-cells at late developmental stages including expression by some plasma cells.

Diagnostic Use

• CD20 is regarded as a pan-B-cell marker and may be useful in the diagnosis of mature B-cell types if other patterns are atypical
• Low levels of CD20 expression may be helpful in the recognition of CLL (similar to CD19, CD79b and light-chains)
• CD20 is the target of rituximab and other therapeutic antibodies so expression may be absent from neoplastic cells relapsing after treatment with these antibodies

---