Improving efficiency and sensitivity: European Research Initiative in CLL (ERIC) update on the international harmonised approach for flow cytometric residual disease monitoring in CLL

Leukemia. 2013 Jan;27(1):142-9. doi: 10.1038/leu.2012.216. Epub 2012 Jul 31.


Detection of minimal residual disease (MRD) in chronic lymphocytic leukaemia (CLL) is becoming increasingly important as treatments improve. An internationally harmonised four-colour (CLR) flow cytometry MRD assay is widely used but has limitations. The aim of this study was to improve MRD analysis by identifying situations where a less time-consuming CD19/CD5/κ/λ analysis would be sufficient for detecting residual CLL, and develop a six-CLR antibody panel that is more efficient for cases requiring full MRD analysis. In 784 samples from CLL patients after treatment, it was possible to determine CD19/CD5/κ/λ thresholds that identified cases with detectable MRD with 100% positive predictive value (PPV). However, CD19/CD5/κ/λ analysis was unsuitable for predicting iwCLL/NCI response status or identifying cases with no detectable MRD. For the latter cases requiring a full MRD assessment, a six-CLR assay was designed comprising CD19/CD5/CD20 with (1) CD3/CD38/CD79b and (2) CD81/CD22/CD43. There was good correlation between four-CLR and six-CLR panels in dilution studies and clinical samples, with 100% concordance for detection of residual disease at the 0.01% (10(-4)) level (n=59) and good linearity even at the 0.001-0.01% (10(-5)-10(-4)) level. A six-CLR panel therefore provides equivalent results to the four-CLR panel but it requires fewer reagents, fewer cells and a much simpler analysis approach.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, CD / analysis
  • Biomarkers, Tumor / analysis*
  • Europe
  • Flow Cytometry / standards*
  • Humans
  • Immunoglobulin Light Chains / immunology
  • Immunoglobulin kappa-Chains / immunology
  • Immunoglobulin lambda-Chains / immunology
  • Immunophenotyping
  • Leukemia, Lymphocytic, Chronic, B-Cell / immunology
  • Leukemia, Lymphocytic, Chronic, B-Cell / pathology*
  • Neoplasm Staging
  • Neoplasm, Residual / diagnosis*
  • Neoplasm, Residual / immunology
  • Prognosis
  • Sensitivity and Specificity


  • Antigens, CD
  • Biomarkers, Tumor
  • Immunoglobulin Light Chains
  • Immunoglobulin kappa-Chains
  • Immunoglobulin lambda-Chains