CELL-SURFACE MARKERS IN MULTIPLE-MYELOMA

Objective: To describe the immunophenotype of normal and myelomatous p lasma cells (PCs) and the changes in immunoregulatory nonmyelomatous c ells in multiple myeloma (MM). Design: The cell surface markers (antig ens) associated with this common cancer were reviewed. Material and Me thods: Immunophenotypic characterization of both normal PCs and their counterpart malignant hematopoietic cells can be achieved by using mon oclonal antibodies and either flow cytometry or immunocytochemical tec hniques. Results: Normal PCs are heterogeneous and express, in additio n to cytoplasmic immunoglobulins, the antigens CD9, CD10, CD13, CD19, CD20, CD33, CD38, and D-related human leukocyte antigen (HLA-DR). This heterogeneity also occurs in malignant PCs. Myelomatous PCs may expre ss, in addition to CD38 (the most typical PC marker), the antigens CD9 , CD10, HLA-DR, and CD20. Other non-B-cell lineage markers such as mye loid (CD13, CD14, CD15, CD33, CD41, and glycophorin A), T-cell (CD2 an d CD4), and natural killer-associated (CD56) antigens, as well as CD23 , CD24, CD25, CD37, CD39, CDw40, CD45R, CD71, and certain unclustered antigens (R1-3, PCA-1, PCA-2, PC1, 62B1, 8A, 8F6, and MM4), have been noted in myelomatous PCs. The presence of these antigens in the myelom a cells may have a prognostic value-for example, the expression of CD2 0 and of myelomonocytic antigens (CD11b, CD13, CD14, CD15, and CD33) m ay be related to a poor prognosis. The adverse prognostic implication of the expression of CD10 initially described in MM has not been subse quently confirmed. Patients with MM may have mononuclear cells in thei r peripheral blood that express the same antigens as those expressed b y the myeloma cells in their bone marrow. The presence of such cells o r their therapy-associated decrease or disappearance may be related to the prognosis of patients with MM. Conclusion: The presence of cell s urface markers on PCs and their prognostic significance in patients wi th MM warrant further investigation.