Characteristics of immunoglobulin gene rearrangements in vietnamese newly diagnosed multiple myeloma patients

Abstract

Background

The immunoglobulin (IG) gene rearrangements provide valuable markers in monitoring minimal residual disease (MRD) after treatment in multiple myeloma (MM) patients. Methods: We conducted an observational study from June 2019 to June 2023. Bone marrow samples from newly diagnosed MM patients at Blood Transfusion Hematology Hospital were collected and analyzed for IG gene rearrangements. Clonal IG gene rearrangement samples were analyzed for the repertoire of rearrangements.

Results

111 newly diagnosed MM patients were collected. Bone lesions and anemia were found in 100% and 77.5% of patients, respectively. According to rISS classification, 91.9% of patients were diagnosed at an advanced stage. Cytogenetic analysis showed that 28.8% of patients expressed at least one high-risk abnormality. The most common immunophenotype of malignant plasma cells was CD38⁺CD138⁺CD19^–CD56⁺. Noteworthily, 104 patients (93.7%) expressed at least one clonal IG gene rearrangement, while 69.4% and 18.9% of patients expressed double and triple IG gene rearrangements, respectively. V_H3 and V_H4 were the two most frequent among V_H segments, while D_H3 and J_H4 were the most common among D_H and J_H segments, and V_K1 and J_K4 were the most popular repertoires in IGK gene rearrangements. KDE rearrangements were detected in 42.5% patients, and V_L1 and J_L3 were the most common segments in IGL gene rearrangements. Notably, the rate of clonal IGH gene rearrangements was significantly different between heavy-chain and light-chain only MM groups.

Conclusion

This is the first study in Vietnamese MM patients to comprehensively describe the characteristics of IG gene rearrangements.