LymphoTrack Is Equally Sensitive as PCR GeneScan and Sanger Sequencing for Detection of Clonal Rearrangements in ALL Patients

Monoclonal rearrangements of immunoglobulin (Ig) genes and T-cell receptor (TCR) genes are used for minimal measurable disease in acute lymphoblastic leukemia (ALL). The golden standard for screening of gene rearrangements in ALL has been PCR GeneScan and Sanger sequencing, which are laborsome and time-consuming methods. More rapid next-generation sequencing methods, such as LymphoTrack could possibly replace PCR GeneScan and Sanger sequencing for clonality assessment. Our aim was to evaluate to what extent LymphoTrack can replace PCR GeneScan and Sanger sequencing concerning sensitivity and quantifiability in clonality assessment in 78 ALL samples. With LymphoTrack, clonality assessment was based on the %Total reads, where ≥10% was used as cut off for clonal rearrangements. The patients displayed 0 to 4 clonal rearrangements per assay. The detection rate (rearrangements detected with PCR GeneScan and/or Sanger sequencing, also detected with LymphoTrack) was 85/85 (100%) for IGH, 64/67 (96%) for IGK, 91/93 (98%) for TCRG and 34/35 (97%) for TCRB. Our findings demonstrate that LymphoTrack was equally sensitive in detecting clonal rearrangements as PCR GeneScan and Sanger Sequencing. The LymphoTrack assay is reliable and therefore applicable for clonal assessment in ALL patients in clinical laboratories.