Abstract: ｂｊｅｃｔｉｖｅ：To investigate the number and immunophenotypic characteristics of malignant plasma cells in bone marrow and their relationship with disease risk stratification in patients with primary systemic light chain amyloidosis (AL).
Ｍｅｔｈｏｄｏｌｏｇｙ：Using multiparametric flow cytometry (MFC) to measure the expression of CD19,CD38,CD138,CD56,CD117 and κ/λ light chain restriction of plasma cells.The patients with monoclonal gammopathy of renal significance(MGRS) and multiple myloma(MM) were selected as control groups.Laboratory examination results were collected to observe the clinical characteristics of AL patients.
Ｒｅｓｕｌｔｓ：A total of 119 AL patients and a control group consist of 49 patients with nonAL MGRS (27 cases of Proliferative glomerulonephritis with monoclonal Ig deposits,16 cases of monoclonal immunoglobulin deposition disease,3 cases of light chain deposition disease,2 cases of heavy chain deposition disease,one case of heavy and light chains amyloidosis) and 19 patients with MM were enrolled in this study.96(807%) AL patients  cases were found out light chain restriction,the positive expression rate of CD19,CD56,and CD117 on plasma cell surface was 104% 719% and 469%,respectively.The number of bone marrow plasma cells in AL patients was higher than that in  MGRS patients(P<0001) and lower than that in MM patients(P<0001), compared with the latter two,the positive rate of CD117 of monoclonal plasma cells in AL patients was higher (P=0001,P<0001).The number of plasma cells in AL patients with CD19 negative on monoclonal plasma cells surface was higher than that in patients with CD19positive monoclonal plasma cells(P=0013).Furthermore,based on Mayo staging system,the highest proportion of monoclonal plasma cells in AL patients was 098% (06%,137%) in stage Ⅳ,and the lowest was 053% (029%,103%) in stage Ⅱ.The difference between the two groups was statistically significant (P=0033).The positive rate of CD117 was higher in stage Ⅳ patients than in stage Ⅱ and Ⅲ patients (P=0032,P=0021).
Ｃｏｎｃｌｕｓｉｏｎ：The number and immunophenotypic characteristics of monoclonal plasma cells in AL patients are different with those in  MGRS and MM patients.Besides,AL patients with higher Mayo stage  have higher clonal plasma cell load and CD117 positive rate.Altogether,using MFC to detect the number of bone marrow plasma cells and their immunophenotypic characteristics can help diagnosis and risk assessment of AL.