[Application of BIOMED- 2 standardized Ig gene rearrangement system in multiple myeloma]

To explore the application of BIOMED- 2 standardized immunoglobulin (Ig) gene rearrangement system in the diagnosis of multiple myeloma (MM), and the significance of clonality analysis by multiplex-PCR amplifications.

A total of 167 cases of MM bone marrow samples from 2009 to 2013, and 20 cases of reactive plasmacytosis used as the controls were included in this study. Multiplex-PCR amplifications were performed and the Ig gene rearrangements were analyzed using BIOMED-2 standardized clonality analysis system.

① Of 167 MM cases, 107 showed IgH VH-JH rearrangement, 33 showed IgH DH-JH rearrangement, and 30% showed IgH DH-JH rearrangement in 60 IgH VH-JH rearrangement negative MM cases. The difference was statistically significant between IgH VH-JH rearrangement positive and negative cases (14.0% vs 30.0%, P=0.032). The total positive rate of IgH VH-JH, IgH DH-JH and IgK was 94.6%. The 20 reactive plasmacytosis (RP) cases showed negative Ig gene rearrangement. 2 of 167 MM cases, 9 (5.4%) showed clonal IgH rearrangement by agarose electrophoresis were confirmed as polyclonality by capillary electrophoresis. ③ Of 53 MM cases who have been detected by Ig gene rearrangement system and fluorescence in situ hybridization (FISH) for IgH simultaneously, 36 showed IgH rearrangement, 26 showed FISH IgH positive, and the difference was statistically significant (67.9% vs 49.1%, P=0.049).

Combined detection of IgH VH- JH, IgH DH- JH and IgK could improve the positive rate of MM clonality dramatically, and measurement of IgH DH-JH rearrangement was more important in the IgH VH- JH negative cases. Ig gene rearrangement system was a faster and more sensitive method than FISH IgH. Application of BIOMED- 2 standardized immunoglobulin (Ig) gene rearrangement system is of significance for MM diagnosis.