Characteristics and significance of atypical flow cytometric immunophenotype in plasma cell myeloma

Abstract

Objective To investigate the characteristics and significance of atypical flow cytometric immunophenotype in plasma cell myeloma. Methods Using case-control study, 48 cases with atypical immunophenotype of plasma cell myeloma and 42 cases as control group were studied by flow cytometry, the former cases were classified into three groups according to the expression of CD38, CD138, CD19, CD56 : CD38+/CD138+/CD19+/CD56+ , CD38+/CD138+/CD19+/CD56- , CD38+/CD138+/CD19-/CD56-. And compare the three groups with intracellular immunoglobulin light chain (cKappa, cLambda) , bone marrow morphology and immunofixation. The positive rate was compared with chi-square test. Results Bone marrow plasma cells showed expression of particular antigens in the following proportion of the 48 cases: CD45 29.17%, CD38 100%, CD138 100%, CD19 95.83%, CD56 43.75%, cKappa 43.75% and cLambda 56.25%. And in the three groups, the expression of monoclonal immunoglobulin were 43.75%, 52.08% and 4.17%, which bone marrow morphology and immunofixation were 57.14%,80%,100% and 71.43%,88%,100%. The positive rate of flow cytometry, bone marrow morphology and serum immunofixation electrophoresis were 100%, 70.83% and 81.25%.While the expression of particular antigens in the control group were: CD45 47.62%, CD38 100%, CD138 100%, CD19 100%, CD56 0%, cKappa 100% and cLambda 100%. And no abnormalities were detected in bone marrow morphology and immunofixation. Conclusions Compared with the bone marrow morphology and immunofixation，multiparameter flow cytometry has more helpful to find out atypical immune phenotype of plasma cell myeloma, and differentiate malignant and benign plasma cell, contributes to the diagnosis of clinical plasma cell myeloma, prognosis and treatment monitoring.（Chin J Lab Med,2014,37:687-690） Key words: Multiple myeloma; Immunophenotyping; Flow cytometry