The Importance Of Multiparametric Flow Cytometric In The Detecting Of Multiple Myeloma Minimal Residual Disease And Its Relationship With Bone Marrow Morphologic Findings And Serology

Objective: To investigate the detectable significance of multiparameter flow cytometry(MFC) in the diagnosis of multiple myeloma(MM) minimal residual disease(MRD) and compare MFC with bone marrow smear findings in the same patient, at last we try to find is there any correlation between the ratio of cyto-kappa and cyto-lambda in MFC and the level of serological M-protein,?2-MG or Albumin.Methods: MFC was used to identify the plasma cells by the expression of CD38 or CD138 antigen in 24 healthy control and 123 patients with multiple myeloma,the aberrant myeloma cells were differentiated from normal plasma cells by combining surface antigen like CD19,CD20,CD45,CD56 and the cytoplasm kappa and lambda light chain.Besides,we compare this method with the classical four color single tube strategy(a backbone of CD38,CD138 and CD45 associated with differentiating surface antigen or cytoplasmic light chains as clone marker) in sensitivity.Meanwhile,bone marrow smears were contrasted with MFC results,at last we try to find the relationship between he ratio of cyto-kappa and cyto-lambda in MFC and the level of serological M-protein,?2-MG or Albumin.Results:Bone marrow samples of 24 cases of healthy donor and 123 patients of multiple myeloma were collected with the consent of all experimental target.The method of classical four color multi-tube flow cytometry and the updated eight color single-tube flow cytometry were used to analysis every sample in the meantime,19/123 MRD are missed intraditional 4-color MFC but can be figured out in our 8-color single tube MFC for the cytoplasm light chain restricted. The ratio of kappa and lambda is 0.35-3.49, which are identified as negative for MRD. The majority of the missed MRD are mixted subset with the light chain restrited subset account for less than 50% of total plasma cells in the bone marrow. There is a good overlap between 4-color panel and 8-color panel when MRD is negative or the light chain restricted subset is more than 50% of PCs. The detection by adopting a single tube eight-colors MFC strategy including cytoplasm immunoglobulin light chains can imprve the accuracy in MRD detection especially when the MRD are doubtful and the abnormal PC subset account for less than 50% of total PCs in the bone marrow.Retrospective analysis indicated that 16/123 doubtful multiple myeloma patients which were diagnosed by classical bone marrow morphology was conformed by our eight color single tube flow cytometry strategy combined with other clinical or experimental information.The united of bone marrow morphology and multiple parameter flow cytometry in the same sample can improve the diagnostic accuracy of multiple myeloma.The relevant research was done between the ratio of cytoplasm kappa and lambda in MFC and the level of serological M-protein, ? 2-MG or Albumin in some patients,conclusions may be made such as more deviation from the normal range of cyto-kappa and cyto-lambda ratio,the larger tumor burden loads maybe seen for the higher level of serological M-protein or ? 2-MG.while no obvious relationships was found between the ratio of cytoplasm kappa and lambda in MFC and the level of serological albumin. For the limited number of patients in our experiment,the larger sample and more rational test may be preferred to confer some conclusions of our analysis.Conclusion:The multiparametric flow cytometry has important significance in the diagnosis of MM MRD,our method(eight color single tube) show higher sensitivity than the classical four color single tube strategy. United with bone marrow morphology can improve the accuracy in the diagnosis of MM, also some relationships between the ratio ofcyto-kappa and cyto-lambda in MFC and the level of serological M-protein, ?2-MG or Albumin was found in some patients.