title: Improving efficiency and sensitivity: European Research Initiative in CLL (ERIC) update on the international harmonised approach for flow cytometric residual disease monitoring in CLL.
abstract: 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.
authors.affiliation: HMDS, St James's Institute of Oncology, Leeds Teaching Hospitals, Leeds, UK. andy.rawstron@hmds.org.uk
authors.forename: A C
authors.initials: AC
authors.lastname: Rawstron
authors.forename: S
authors.initials: S
authors.lastname: Böttcher
authors.forename: R
authors.initials: R
authors.lastname: Letestu
authors.forename: N
authors.initials: N
authors.lastname: Villamor
authors.forename: C
authors.initials: C
authors.lastname: Fazi
authors.forename: H
authors.initials: H
authors.lastname: Kartsios
authors.forename: R M
authors.initials: RM
authors.lastname: de Tute
authors.forename: J
authors.initials: J
authors.lastname: Shingles
authors.forename: M
authors.initials: M
authors.lastname: Ritgen
authors.forename: C
authors.initials: C
authors.lastname: Moreno
authors.forename: K
authors.initials: K
authors.lastname: Lin
authors.forename: A R
authors.initials: AR
authors.lastname: Pettitt
authors.forename: M
authors.initials: M
authors.lastname: Kneba
authors.forename: E
authors.initials: E
authors.lastname: Montserrat
authors.forename: F
authors.initials: F
authors.lastname: Cymbalista
authors.forename: M
authors.initials: M
authors.lastname: Hallek
authors.forename: P
authors.initials: P
authors.lastname: Hillmen
authors.forename: P
authors.initials: P
authors.lastname: Ghia
mesh_terms: D015703:Antigens, CD / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis*; D005060:Europe; D005434:Flow Cytometry / Q000592:standards*; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000276:immunology; D007145:Immunoglobulin kappa-Chains / Q000276:immunology; D007146:Immunoglobulin lambda-Chains / Q000276:immunology; D016130:Immunophenotyping; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000276:immunology / Q000473:pathology*; D009367:Neoplasm Staging; D018365:Neoplasm, Residual / Q000175:diagnosis* / Q000276:immunology; D011379:Prognosis; D012680:Sensitivity and Specificity
chemical_list: D015703:Antigens, CD; D014408:Biomarkers, Tumor; D007147:Immunoglobulin Light Chains; D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains