Chronic lymphocytic leukaemia Australasian consensus practice statement.

Chronic lymphocytic leukaemia (CLL) is the most common haematological malignancy in Australia and New Zealand (ANZ). Considerable changes to diagnostic and management algorithms have occurred within the last decade. The availability of next-generation sequencing and measurable residual disease assessment by flow cytometry allow for advanced prognostication and response assessments. Novel therapies, including inhibitors of Bruton's tyrosine kinase (BTKi) and B-cell lymphoma 2 (BCL2) inhibitors, have transformed the treatment landscape for both treatment-naïve and relapsed/refractory disease, particularly for patients with high-risk genetic aberrations. Recommendations regarding appropriate supportive management continue to evolve, and special considerations are required for patients with CLL with respect to the global SARS-CoV-2 pandemic. The unique funding and treatment environments in Australasia highlight the need for specific local guidance with respect to the investigation and management of CLL. This consensus practice statement was developed by a broadly representative group of ANZ experts in CLL with endorsement by peak haematology bodies, with a view to providing this standardised guidance.

Monoclonal B-cell Lymphocytosis - a review of diagnostic criteria, biology, natural history, and clinical management.

Since first described almost two decades ago, there has been significant evolution in our definition and understanding of the biology and implications of monoclonal B-cell lymphocytosis (MBL). This review provides an overview of the definition, classification, biology, and natural history of MBL, mainly focused on the dominant CLL-like phenotype form of MBL. The increasingly recognized implications of MBL with respect to immune dysfunction are discussed, particularly in view of the COVID-19 pandemic, along with management recommendations for MBL in the clinic.

COVID-19 vaccine failure in chronic lymphocytic leukaemia and monoclonal B-lymphocytosis; humoural and cellular immunity.

Chronic lymphocytic leukaemia (CLL) is associated with immunocompromise and high risk of severe COVID-19 disease and mortality. Monoclonal B-cell lymphocytosis (MBL) patients also have immune impairment. We evaluated humoural and cellular immune responses in 181 patients with CLL (160) and MBL (21) to correlate failed seroconversion [<50 AU/ml SARS-CoV-2 II IgG assay, antibody to spike protein; Abbott Diagnostics)] following each of two vaccine doses with clinical and laboratory parameters. Following first and second doses, 79.2% then 45% of CLL, and 50% then 9.5% of MBL patients respectively remained seronegative. There was significant association between post dose two antibody level with pre-vaccination reduced IgM (p < 0.0001), IgG2 (p < 0.035), and IgG3 (p < 0.046), and CLL therapy within 12 months (p < 0.001) in univariate analysis. By multivariate analysis, reduced IgM (p < 0.0002) and active therapy (p < 0.0002) retained significance. Anti-spike protein levels varied widely and were lower in CLL than MBL patients, and both lower than in normal donors. Neutralisation activity showed anti-spike levels <1000 AU/ml were usually negative for both an early viral clade and the contemporary Delta variant and 72.9% of CLL and 53.3% of MBL failed to reach levels ≥1000 AU/ml. In a representative sample, ~80% had normal T-cell responses. Failed seroconversion occurred in 36.6% of treatment-naïve patients, in 78.1% on therapy, and in 85.7% on ibrutinib.

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.

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.