Targeted NGS of heavy-chain Ig repertoires from peripheral B-lineage cells of myeloma patients. (A) Clonotypic rearrangements in the peripheral blood of the myeloma patient cohort. Panel A shows patients MM001 and MM020, who were negative for the clonotypic rearrangement by a qualitative PCR approach. In patients MM021, MM024, MM031, MM034, MM048, and MM081, the clonotypic rearrangement was qualitatively detectable by PCR. For NGS, Ig transcripts were amplified with isotype-specific primers and multiplex sequenced on a MiSeq Illumina sequencer. Data were plotted using ggplot2 for R statistical software assigning a position to each potential V-D-J rearrangement. In patient MM020, a small clone was plotted at the expected site of the clonotypic rearrangement. However, this rearrangement was different from the clonotypic rearrangement (HCDR3 sequence and somatic hypermutation pattern). (B) Absence of clonotypic rearrangements in posttreatment follow-up samples of patients MM024 and MM031. Only IgG repertoires are shown. allo-HSCT, allogeneic hematopoietic stem cell transplant; auto-HSCT, melphalane high-dose chemotherapy followed by autologous stem cell transplant.