Fig. 3

Strategy of the IG-based NGS method. A Pairs of primers for IGH and IGK sequencing. The forward primers target FR1, FR2 and FR3, while the inverse primer targets the JH region in IGH. 3 pairs of primers were designed for IGK sequencing, including the forward primer targeting Vκ or introns and the inverse primers targeting Jκ or Kde. B The workflow of NGS MRD monitoring. After diagnosis by the gold-standard, the samples of patients are collected (BM or PB) and sequenced to identify index clones. Information acquired during sequencing can also be used in risk stratification and prediction of prognosis. By tracking the index clone, the MRD level is measured continuously during and after the treatment. The major clones in samples from patients who experience relapse are compared with the index clone at diagnosis to study clonal evolution