Applicated value of multi-parameter flow cytometry and Ig gene rearrangement in early diagnosis of multiple myeloma

Abstract

Objective To explore the clinical value of multi-parameter flow cytometry and Ig gene rearrangement in early diagnosis of multiple myeloma. Methods 19 cases of multiple myeloma were detected and analyzed by BD flow cytometry and Ig gene rearrangement, the multi-parameter analysis of tumor cell markers were CD45, CD138, CD10, CD19, CD20, CD22, CD13, CD33, CD117, CD56, CD38, cell oar kappa light chain(cκ), cell plasma lambda light chain(cλ). Results Abnormal plasma cells ratio was 1.40% ~32.8% detected by flow cytometry, which gate using CD45 and CD138; the proportions of antigen positive expression were CD138: 100.0%, CD38: 100.0%, CD56: 63.1%, CD117: 42.1%, CD13: 0.0%, CD33: 26.3%, CD20: 5.2%, CD22: 0.0%, CD10: 0.0%, CD19: 0.0%, respectively. The naive and mature plasma cell ratio was 2.5%~75.5% detected by bone marrow morphology. The both methodologies above had a correlation(r=0.702, P<0.01). The restricted expression of immunoglobulin cytoplasm in MM patients, 9 cases of cκ(9/19), 10 cases of cλ(10/19). The subtypes were 4 cases IgG+ κ, 2 cases IgA+ κ, 4 cases IgG+ λ, 1 case IgA+ λ, 3 cases κ and 5 cases λ detected by immunofixation electrophoresis; Ig gene rearrangement shown 8 cases of IGH FR1-JH rearrangement, 11 cases of IGH FR2-JH rearrangement, 2 cases of IgH DH-JH rearrangement, 11 cases of IGK Vk-Jk rearrangement, 8 cases of IGK Vk-Kde and intron-Kde rearrangement; combined with IgH and IgK gene rearrangement, the positive rate of early MM was 89.5%(17/19). Conclusion Multi-parameter flow cytometry can be more accurate to set the required analysis of abnormal plasma cell population, abnormal plasma cells most of the expressions of CD138, CD38, CD56 antigen, while does not express CD19, CD10, CD13, CD22.The diagnostic value of Ig in the diagnosis of MM is the combination of cell morphology examination and immunohistochemistry electrophoresis and the application of BIOMED 2 gene rearrangement technique. Key words: Multiple myeloma; Flow cytometry; Gene rearrangement; Diagnosis