Table 3.

Comparison of immunophenotypic features between normal and abnormal plasma cells

	Normal Plasma Cell	Abnormal Plasma Cell	Comments
CD19	Positive (>70%)	Negative (95%)	Present on all B-cells and most normal plasma cells. Clonal plasma cells have dim or no expression.
CD2070	Negative	Positive (30%)	Typically seen during the maturation process of B-cells and absent from plasma cells. CD20 expression is seen on a subset of clonal plasma cells.
CD2732,71,72	Positive (100%)	Negative/weak (15–45%)	This molecule is involved in the differentiation of mature B cells into plasma cells. Weakly or not expressed in myeloma.
CD2873,74	Negative (<15%)	Positive (45%)	CD28 is involved in T-cell activation. Expression on plasma cells in myeloma correlates with aggressive disease.
CD3377,78	Negative	Positive in a small subset of patients	This myeloid-lineage affiliated antigen may be present aberrantly in a subset of myeloma patients.
CD5661,96	Negative (< 15%)	Positive (75%)	The neural-cell adhesion molecule, typically present on NK-cells. Almost invariably present on neoplastic plasma cells, but expression may be low or lost in cells in circulation and in extramedullary disease.
CD81	Positive (100%)	Negative/weak	Member of CD19/CD21/Leu-13 signal transduction complex. Functions of this and other members of the tetraspan family are as yet poorly understood.
CD11728,97	Negative	Positive	Typically seen on progenitors of myeloid and megakaryocytic lineage. Adapted from: Paiva et al, Clinical Cytometry, 12 Feb 2010

Adapted from: Paiva et al, Clinical Cytometry 12 Feb 2010