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Amplicon-based next-generation sequencing (NGS) of immunoglobulin (IG) and T-cell receptor (TR) gene rearrangements for clonality assessment, marker identification and quantification of minimal residual disease (MRD) in lymphoid neoplasms has been the focus of intense research, development and application. However, standardization and validation in a scientifically controlled multicentre setting is still lacking. Therefore, IG/TR assay development and design, including bioinformatics, was performed within the EuroClonality-NGS working group and validated for MRD marker identification in acute lymphoblastic leukaemia (ALL). Five EuroMRD ALL reference laboratories performed IG/TR NGS in 50 diagnostic ALL samples, and compared results with those generated through routine IG/TR Sanger sequencing. A central polytarget quality control (cPT-QC) was used to monitor primer performance, and a central in-tube quality control (cIT-QC) was spiked into each sample as a library-specific quality control and calibrator. NGS identified 259 (average 5.2/sample, range 0-14) clonal sequences vs. Sanger-sequencing 248 (average 5.0/sample, range 0-14). NGS primers covered possible IG/TR rearrangement types more completely compared with local multiplex PCR sets and enabled sequencing of bi-allelic rearrangements and weak PCR products. The cPT-QC showed high reproducibility across all laboratories. These validated and reproducible quality-controlled EuroClonality-NGS assays can be used for standardized NGS-based identification of IG/TR markers in lymphoid malignancies.

Assessment of clonality, marker identification and measurement of minimal residual disease (MRD) of immunoglobulin (IG) and T cell receptor (TR) gene rearrangements in lymphoid neoplasms using next-generation sequencing (NGS) is currently under intensive development for use in clinical diagnostics. So far, however, there is a lack of suitable quality control (QC) options with regard to standardisation and quality metrics to ensure robust clinical application of such approaches. The EuroClonality-NGS Working Group has therefore established two types of QCs to accompany the NGS-based IG/TR assays. First, a central polytarget QC (cPT-QC) is used to monitor the primer performance of each of the EuroClonality multiplex NGS assays; second, a standardised human cell line-based DNA control is spiked into each patient DNA sample to work as a central in-tube QC and calibrator for MRD quantification (cIT-QC). Having integrated those two reference standards in the ARResT/Interrogate bioinformatic platform, EuroClonality-NGS provides a complete protocol for standardised IG/TR gene rearrangement analysis by NGS with high reproducibility, accuracy and precision for valid marker identification and quantification in diagnostics of lymphoid malignancies.

Discusses the clinical and biological features of B-prolymphocytic leukemia. Patient characteristics; Expression of immunoglobulin M and/or immunoglobulin D; Median overall survival time versus event-free survival; Mortality; Pattern of bone marrow infiltration.

According to the World Health Organization (WHO) classification, the nosology of B-cell neoplasms integrates clinical, morphological, phenotypic, and genetic data. In this retrospective analysis, we identified 18 patients with isolated neoplastic lymphocytosis that could not be accurately classified within the WHO classification. Most of them were asymptomatic at the time of diagnosis and the evolution was relatively indolent, as only five patients required treatment after a median follow-up of 48 months. The neoplastic B-cells expressed CD5 in most cases, but the Royal Marsden Hospital score was strictly below 3. Trisomy 12 was the most frequent cytogenetic abnormality. High-throughput sequencing highlighted mutations found in both chronic lymphocytic leukemia (CLL) and marginal zone lymphoma (MZL). Similarly, the immunoglobulin heavy chain variable region repertoire was distinct from those reported in CLL or MZL. However, as treatment choice is dependent on the correct classification of the lymphoproliferative disorder, a histological diagnosis should be performed in case patients need to be treated. [ABSTRACT FROM AUTHOR]

Highlights: [•] Heme induces polyreactivity of IgG cloned from splenic marginal zone B-cell lymphoma. [•] Heme-induced polyreactive antibody binds various autoantigens. [•] Induction of polyreactivity does not affect Fc-fragment dependant binding of IgG. [•] Heme-induced polyreactivity of BCR might have repercussions for the pathology. [ABSTRACT FROM AUTHOR]