title: Minimal residual disease monitoring in chronic lymphocytic leukaemia patients. A comparative analysis of flow cytometry and ASO IgH RQ-PCR.
abstract: Minimal residual disease (MRD) is becoming increasingly important in chronic lymphocytic leukaemia (CLL) as treatment strategies are progressively improving. The primary objective of this study was to compare the applicability of three different flow cytometric approaches: basic 4-colour analysis, European Research Initiative in CLL (ERIC) consensus method and 8-colour analysis. Secondly, we investigated the sensitivity and specificity of flow cytometry (FC) compared to molecular analyses for MRD detection. A total of 462 CLL samples were evaluated by basic FC; in 143, ERIC consensus method was also performed and all three FC methodologies were applied in a subgroup of 10 cases. No discordance in defining MRD-positive/negative samples was observed between the FC methods; within positive samples, the ERIC consensus method and 8-colour analysis showed the most accurate results. MRD was analysed by FC and polymerase chain reaction (PCR) in 243 cases: concordant results were obtained in 199/243 samples (81·9%); 42/243 were FC-/PCR+. Overall, the sensitivity and specificity of FC compared to PCR was 96·5% and 77·2%, respectively. Both FC and PCR proved suitable for the detection of MRD and prediction of progression-free survival, which was significantly reduced in MRD-positive patients, regardless of the methodology. These results offer the rationale for a strategy to monitor MRD in CLL patients.
authors.affiliation: Haematology, Department of Cellular Biotechnologies and Haematology, Sapienza University, Rome, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Raponi
authors.forename: Irene
authors.initials: I
authors.lastname: Della Starza
authors.forename: Maria S
authors.initials: MS
authors.lastname: De Propris
authors.forename: Ilaria
authors.initials: I
authors.lastname: Del Giudice
authors.forename: Francesca R
authors.initials: FR
authors.lastname: Mauro
authors.forename: Marilisa
authors.initials: M
authors.lastname: Marinelli
authors.forename: Valeria
authors.initials: V
authors.lastname: Di Maio
authors.forename: Alfonso
authors.initials: A
authors.lastname: Piciocchi
authors.forename: Robin
authors.initials: R
authors.lastname: Foà
authors.forename: Anna
authors.initials: A
authors.lastname: Guarini
mesh_terms: D000483:Alleles; D005434:Flow Cytometry; D005500:Follow-Up Studies; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D016130:Immunophenotyping; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism / Q000401:mortality; D018365:Neoplasm, Residual / Q000175:diagnosis*; D011379:Prognosis; D060888:Real-Time Polymerase Chain Reaction; D012680:Sensitivity and Specificity
chemical_list: D007143:Immunoglobulin Heavy Chains
keywords: ASO IgH RQ-PCR; chronic lymphocytic leukaemia; flow cytometry; minimal residual disease