[Immunophenotype in multiple myeloma cells detected by multiparameter flow cytometry]

This study was purposed to investigate the immunophenotypic characteristics in multiple myeloma (MM) cells and their significance. Thirty three cases of MM and 12 cases of reactive plasmacytosis (as control group) were enrolled in the study. The expressions of surface antigens in MM cells were detected with flow cytometry by using direct immunofluorescent technique and gating method of CD38/SSC and were confirmed with morphologic observation of myeloma cells. The results indicated that the proportion of myeloma cells detected by morphologic examination was 6.0% - 76.0%. With CD38/SSC gating method, a cluster of CD38 bright positive cells could be detected in their scatter plot, the proportion ranged from 0.99% to 57.54%. Most phenotype of MM was 38(st+)CD138(+)CD19(-)CD56(+) (78.8%). While the expressions of CD20, CD33, CD117, HLA-DR were seen in some MM patients, the positive rates were 12.1%, 15.2%, 30.3%, 9.1%, respectively; the expression of other antigens was negative. cκ or cλ monoclonal restriction was detected in 27 cases (81.8%) of MM, both cκ and cλ in the remaining cases of MM was negative. It is concluded that detecting the immunophenotype of MM patients by flow cytometry with CD38/SSC gating method and basing on the heterogeneity of cell antigens can discriminate myeloma cells from normal plasma cells, which provides evidence for targeted therapy and prognosis evaluation.