Reproducible diagnosis of chronic lymphocytic leukemia by flow cytometry: An European Research Initiative on CLL (ERIC) & European Society for Clinical Cell Analysis (ESCCA) Harmonisation project

Abstract

The diagnostic criteria for CLL rely on morphology and immunophenotype. Current approaches have limitations affecting reproducibility and there is no consensus on the role of new markers. The aim of this project was to identify reproducible criteria and consensus on markers recommended for the diagnosis of CLL. ERIC/ESCCA members classified 14 of 35 potential markers as “required” or “recommended” for CLL diagnosis, consensus being defined as >75% and >50% agreement, respectively. An approach to validate “required” markers using normal peripheral blood was developed. Responses were received from 150 participants with a diagnostic workload >20 CLL cases per week in 23/150 (15%), 5–20 in 82/150 (55%), and <5 cases per week in 45/150 (30%). The consensus for “required” diagnostic markers included: CD19, CD5, CD20, CD23, Kappa, and Lambda. “Recommended” markers potentially useful for differential diagnosis were: CD43, CD79b, CD81, CD200, CD10, and ROR1. Reproducible criteria for component reagents were assessed retrospectively in 14,643 cases from 13 different centers and showed >97% concordance with current approaches. A pilot study to validate staining quality was completed in 11 centers. Markers considered as “required” for the diagnosis of CLL by the participants in this study (CD19, CD5, CD20, CD23, Kappa, and Lambda) are consistent with current diagnostic criteria and practice. Importantly, a reproducible approach to validate and apply these markers in individual laboratories has been identified. Finally, a consensus “recommended” panel of markers to refine diagnosis in borderline cases (CD43, CD79b, CD81, CD200, CD10, and ROR1) has been defined and will be prospectively evaluated. © 2017 International Clinical Cytometry Society

CD200 is a useful marker in the diagnosis of chronic lymphocytic leukemia

“…In conclusion, CD200 is a valuable, albeit not specific, diagnostic marker for CLL that when incorporated to the MS increases its accuracy. In addition our study support the proposal formulated by the European Research Initiative on CLL (ERIC) and European Society for Clinical Cell Analysis (ESCCA) in which CD200 is considered as marker potentially useful in uncertain CLL cases particularly to distinguish them from MCL ; and indicate the need for prospective analysis and validation of the diagnostic importance of CD200 in B‐CLPD.…”

“…Flow cytometry immunophenotyping is an essential technique for the diagnosis of B lymphoproliferative disorders, including CLL . Developed more than 20 years ago, the so‐called MS, based on the expression of CD5, CD23, FMC7, SmIg, and CD22/CD79b by leukemic cells, continues being useful and is used by many laboratories .…”

“…It was shown subsequently that CD22 could be advantageously replaced by CD79b . The current criteria for CLL diagnosis have been updated by International Working Group on CLL (IWCLL), the World Health Organization (WHO), and the European Research Initiative on CLL (ERIC) . The MS, however, is still used in many centers .…”

Efficacy of venetoclax monotherapy in patients with relapsed chronic lymphocytic leukaemia in the post‐BCR inhibitor setting: a UK wide analysis

“…Patients were assessed by their treating clinician according to the iwCLL criteria (Hallek et al , ), although bone marrow biopsies and computed tomography imaging was not uniformly undertaken given the nature of this RWD collection. Data on MRD evaluation by flow cytometry of peripheral blood (as per the European Research Initiative on CLL consensus recommendations) (Rawstron et al , ) were collected where available.…”

From the Editor: Thank you! Remembrances and Issue Highlights

“…The initial contribution by Seegmiller, His and Craig [(3) & cover article] is a review of flow cytometry in the evaluation of mature B-cell neoplasms, a topic of regular interest to our readership as evidenced by these recent publications (3)(4)(5)(6)(7)(8). This is a joint effort of the ICCS and our Society's own Sa Wang and the Society of Hematopathology, represented by Magdalena Czader.…”