[Phenotypic analysis of myeloma cells].

Recent 2-color phenotypic analysis using anti-CD38 antibody reveals that plasma cells alone locate at CD38strong positive (CD38++) fraction and expression of adhesion molecules such as VLA-5 and MPC-1 can define VLA-5-MPC-1- immature, VLA-5-MPC-1+ intermediate and VLA-5+ MPC-1+ mature plasma (myeloma) cells. Furthermore, phenotypic analysis of plasma cells with anti-CD19 and -CD56 antibodies can distinguish normal (polyclonal) plasma cells from malignant (monoclonal) plasma cells; normal plasma cells from various tissues are all CD19+ CD56-, while malignant plasma cells are mostly CD19- CD56+. Therefore, this 2-color phenotypic analysis is very useful for differential diagnosis of bone marrow plasmacytosis, that is, myeloma, benign monoclonal gammopathy or polyclonal gammopathy, and furthermore contributes to understanding of differentiated stages of myeloma cells (immature, intermediate or mature myeloma cells).