OBJECTIVETo explore the expression of CD27 antigen in patients with multiple myeloma(MM), and its clinical diagnostic value, as well as the correlation of CD27 with clinical features and genetic abnormalities.

METHODSUsing 8 color flow cytometry, the immunophenotype of 123 MM patients' marrow cells was examined, while 51 cases of normal plasma cell reactive prolieration were used as control. Antibodies are as follows:ckappa-FITC/clambda-PE/ CD38-ECD/CD45-PERCP/CD19-PC7/ CD27-APC/CD138-BV421/ CD56-BV510. For differentiation of abnormal plasma cells from normal or reactive plasma cells, FS INT /FS PEAK with CD138/CD38 gating strategy was used to measure cell markers CD138,CD38, CD56, CD19, ckappa, clambda and CD45, then the expression rate of CD27 and mean fluorescence intensity(MFI) were analyzed for its diagnostic value in MM. At the same time, the laboratory data of 107 cases of MM patients were analyzed and the fluorescence in situ hybridization (FISH) was used to detecte 1q21 amplification, 13q14 deletion, p53 deletion and IGH rearrangement in 34 cases, then the clinical features and genetic abnormalities were compared between CD27and CD27MM patients.

RESULTSThe CD27 positive rate of abnormal plasma cells in MM patients was 48% (59/123) (percentage ≥20% as positive criterion), MFI was 31.3±35.6; while the positive rate of normal or reactive plasma cells were 100% (51/51), the MFI was 93.7±6.3. The positive rate and MFI of CD27 in MM patients were significantly lower than that in normal or reactive plasma cells (P<0.01). Laboratory examination of 58 cases of CD27 negative and 49 cases of CD27 positive MM patients indicated that no significant differences were shown on disease progress parameter, such as hemoglobin, albumin, serum calcium, serum creatinine,and no notable differences were involved in the analysis of prognostic factors between the 2 groups, such as β2-MG microglobulin and LDH levels (P<0.05). The 1q21 amplification, 13q14 deletion, p53 deletion, and IGH rearrangement results all were not significantly different between 17 cases of CD27 negative and 17 cases of CD27 positive MM patients(P<0.05).

CONCLUSIONCD27 has a unique expression profile, and its negative or weak expression is highly suggestive for MM. The 8 color flow cytometry can be used to analyze the expression of multiple antigens, which can provide a reliable evidence for the diagnosis and differential diagnosis of MM disease.