Clonal Immunoglobulin Gene Rearrangements Research Articles

Cutaneous lymphoproliferative disorders: Back to the future.

In the 1980s, immunohistochemistry and clonality analyses became instrumental in the recognition and definition of new types of cutaneous T-cell lymphoma (CTCL) and cutaneous B-cell lymphoma (CBCL) and the development of new classifications. By accepting loss of pan-T-cell antigens and clonal T-cell receptor gene rearrangements as important criteria to differentiate between benign and malignant T-cell proliferations, and monotypic immunoglobulin light-chain expression and clonal immunoglobulin gene rearrangements as crucial criteria to distinguish between benign and malignant B-cell proliferations, many cases, until then diagnosed as cutaneous lymphoid hyperplasia or pseudolymphoma, were reclassified as primary cutaneous CD4+ small/medium T-cell lymphoma (PCSM-TCL) or primary cutaneous marginal zone lymphoma (PCMZL), respectively. However, in recent years there is growing awareness that neither these immunohistochemical criteria nor demonstration of T-cell or B-cell clonality is specific for malignant lymphomas. In addition, many studies have reported that these low-grade malignant CTCL and CBCL have an indolent clinical behavior and an excellent prognosis with disease-specific survival rates of or close to 100%. As a result, recent classifications have downgraded several low-grade malignant cutaneous lymphomas to lymphoproliferative disorder (LPD). Both the 5th edition of the WHO classification (2022) and the 2022 International Consensus Classification (ICC) of mature lymphoid neoplasms reclassified PCSM-TCL as primary cutaneous CD4+ small/medium T-cell LPD and primary cutaneous acral CD8+ T-cell lymphoma as primary cutaneous acral CD8+ T cell LPD. While the 2022 ICC introduced the term "primary cutaneous marginal zone LPD," in the 5th edition of the WHO classification PCMZL is maintained. In this review we describe the background and rationale of the continually changing terminology of these conditions and discuss the clinical consequences of downgrading malignant lymphomas to LPDs.

Molecular B-cell clonality assay in minor salivary glands as a useful tool for the lymphoma risk assessment in Sjögren's syndrome

ObjectivesNon-Hodgkin's lymphoma (NHL) risk assessment is crucial in Sjögren's syndrome (SS). We studied the prevalence of clonal immunoglobulin gene rearrangements in minor salivary glands (MSG) and their correlations with lymphoma occurrence and with previously established NHL predictors. MethodsMolecular B-cell expansion was studied in fresh-frozen MSG of 207 patients with either suspected SS or with suspected lymphoma during SS, using a standardised multiplex PCR assay combined with heteroduplex analysis by microcapillary electrophoresis. The assignation of clonal cases was based on EuroClonality consortium guidelines. ResultsAmong 207 studied patients, 31 (15%) had MSG monoclonal B-cell infiltration. Monoclonality was significantly more frequent in patients with SS (28/123, 22.8%) compared with patients without SS (3/84, 3.6%, P<0.001). Monoclonal B-cell infiltration in MSG of SS patients correlated significantly with ongoing salivary gland NHL, salivary gland swelling, CD4+ T-cell lymphopenia, rheumatoid factor (RF) activity, low complement levels and type 2 mixed cryoglobulinemia. The accumulation of biological risk factors was associated with a higher rate of MSG B-cell monoclonality given that patients with only positive RF had no probability of MSG B-cell monoclonality, RF-positive patients with 1 or 2 other risk factors had a 25.0% and 85.7% probability of MSG B-cell monoclonality, respectively. ConclusionThe detection of MSG monoclonal B-cell expansion by this easy-to-perform molecular assay is useful, both at the time of diagnosis and during the course of SS. Monoclonal B-cell expansion is associated with a subset of SS patients presenting either ongoing lymphoma or other established lymphoma predictive factors.

Angioimmunoblastic T-Cell Lymphoma Diagnosed From Serous Effusion by Integration of Cytologic Features and Ancillary Studies.

To explore the approach to the diagnosis of malignant serous effusion (SE) caused by angioimmunoblastic T-cell lymphoma (AITL). The clinical, cytomorphologic, immunophenotypic, and molecular features of 6 patients were summarized. Clinically, SE caused by AITL was predominant in middle-aged and older male patients with multiple SEs and lymphadenopathy. Cytomorphology showed small to medium-sized, irregular lymphocytes with clear cytoplasm and mixed with various inflammatory cells and apoptosis. Hodgkin/Reed-Sternberg-like cells were detected in 2 of 6 cases. Furthermore, 2 patterns of cytomorphology were described for the first time. Flow cytometry revealed abnormal T-cell populations with loss of surface CD3 (3/4 cases) and CD7 (3/4 cases). In addition, B-cell populations lacking surface immunoglobulin (Ig) were identified in 2 of 4 cases. Immunocytochemical staining revealed expression of at least 2 T follicular helper markers. Epstein-Barr virus-encoded RNA (EBER)-positive cells were demonstrated in 4 of 5 cases. Clonal T-cell receptor γ chain rearrangement was detected in 6 cases, and 3 of them had concomitant clonal immunoglobulin gene rearrangement. Moreover, 2 cases revealed discrepant findings regarding IgH/Igκ rearrangements in cytohistologic correlation. This study broadens the morphologic spectrum of malignant SE caused by AITL and provides diagnostic criteria in routine practice.

Clinicopathological analysis of primary thyroid non-Hodgkin lymphoma: a single-center study.

Primary thyroid lymphoma (PTL) is very rare. The aim of this study was to describe the clinical characteristics, pathological features, and survival outcomes of primary thyroid non-Hodgkin lymphoma, including the diagnostic value of clonal immunoglobulin (Ig) gene rearrangements in diagnosing mucosa-associated lymphoid tissue (MALT) lymphoma of the thyroid gland with co-existing Hashimoto thyroiditis (HT). Paraffin-embedded tissues of patients diagnosed in our institute with PTL between 2007 and 2021 were collected. Clinicopathological features and follow-up data were retrospectively analyzed. Analysis of clonal Ig gene rearrangements were performed in patients with suspected PTL. Of the 22 patients included in our study, 17 were female. The median age at diagnosis was 65.5 years (range, 44-80 years). We detected 11 cases of diffuse large B-cell lymphoma (DLBCL), 10 cases of MALT lymphoma, and 1 case of T-cell lymphoma. A total of 18 patients (81.8%) had early stage (I/II) disease. B-cell lymphoma showed diffuse positivity for CD20 but negative markers for thyroid-origin cells. Double-hit and triple-hit lymphomas were not found in the 8 DLBCL cases, and 2 cases of HT with lymphoid tissue dysplasia were diagnosed with MALT lymphoma with gene rearrangement testing. The median follow-up time was 47 months (range, 4-160 months), and the overall survival was 80% for MALT lymphoma (8 of 10), 72.7% for DLBCL lymphoma (8 of 11), and 100% for T-cell lymphoma (1 of 1). There was no significant difference between the groups. PTL mostly affects middle-aged and older adult females with HT, and its main histological type is non-Hodgkin B-cell lymphoma. For patients with HT along with a histologically benign lymphoepithelial lesion, the identification of clonal Ig gene rearrangements is important for differential diagnosis. The prognosis between DLBCL and MALT is not statistically significant.

A series of heterogeneous lymphoproliferative diseases with CD3 and MUM1 co-expressed in cats and dogs.

Lymphoma diagnosis in dogs and cats is continually evolving as new subtypes and human correlates are being recognized. In humans, T-cell lymphomas with MUM1 expressed and plasma cell neoplasia or B-cell lymphomas with CD3 expressed aberrantly are reported only rarely. We report here a case series of tumors in dogs and cats with CD3 and MUM1 co-expressed as determined by immunocytochemistry or immunohistochemistry. Lineage was assigned for these tumors by 3 board-certified pathologists and a veterinary immunologist based on review of clinical and cellular features and the results of ancillary testing including PCR for antigen receptor rearrangements, flow cytometry, and serum protein electrophoresis with immunofixation. In cats, 7 of 7 tumors, and in dogs, 3 of 6 tumors with CD3 and MUM1 co-expressed had clonal rearrangement of the immunoglobulin gene or serum monoclonal immunoglobulin, consistent with a diagnosis of a plasma cell neoplasia or myeloma-related disorder with CD3 expressed aberrantly. Disease was often disseminated; notably, 3 of 7 feline cases had cutaneous and/or subcutaneous involvement in the tarsal area. In dogs, 3 of 6 cases had a clonal T-cell receptor gamma result and no clonal immunoglobulin gene rearrangement and were diagnosed as a T-cell tumor with MUM1 expressed. The use of multiple testing modalities in our series of tumors with plasma-cell and T-cell antigens in dogs and cats aided in the comprehensive identification of the lymphoproliferative disease subtype.

Immunoglobulin High Throughput Sequencing (Ig-HTS) Minimal Residual Disease (MRD) Analysis Is an Effective Surveillance Tool in Patients with Mantle Cell Lymphoma

Introduction Mantle cell lymphoma (MCL) accounts for 4-6% of B-cell non-Hodgkin lymphoma (NHL), with historically poor outcomes. With the advent of targeted and cellular therapies, responses and durable remissions have improved although cure remains elusive. As patients experience longer remissions, this raises the question of the optimal surveillance modality. For NHL in general, surveillance imaging surveillance does not improve outcomes and is associated with increased radiation exposure, high costs, and anxiety to patients. Peripheral blood minimal residual disease (MRD) analysis offers a potential alternative to surveillance imaging that is more sensitive, less costly, and eliminates the risk of radiation exposure. The clonoSEQ® assay (Adaptive Biotechnologies) is an FDA-cleared Ig-HTS MRD assay which takes advantage of the fact that B-cell lymphomas nearly always have one or more unique clonal immunoglobulin (Ig) gene rearrangements which can serve as a tumor "marker". These sequences can be detected in the peripheral blood, as circulating tumor DNA (ctDNA), with a sensitivity as low as 1 cell in 1,000,000. Starting in 2015, our group has monitored many of our MCL patients using the clonoSEQ® MRD assay. This has been done in lieu of surveillance imaging, or to minimize its use. We performed a retrospective analysis to summarize our experience with this assay to demonstrate its utility as a surveillance tool for MCL patients. Methods We conducted retrospective data collection and analysis of outcomes in patients who underwent first-line treatment for MCL and were then monitored post-treatment using the clonoSEQ® assay. We captured baseline patient characteristics, as well as every time a surveillance imaging or ctDNA (clonoSEQ®) test was performed. We used swimmer plots to display timelines for individual patients, indicating all ctDNA tests (positive or negative), CT or PET scan results, as well as documented clinical relapse. We used Kaplan-Meier curves to show progression-free survival and overall survival of the entire cohort. We compared ctDNA to radiographic surveillance in terms of ability to detect relapse. Results A total of 31 patients were included. The median age of patients was 59, and the majority had low- or intermediate-risk disease by MIPI score, with 58% having a proliferation index above 30%. The majority (81%) underwent high-dose cytarabine-based induction, 77% underwent autologous transplant in first remission, and 42% received rituximab maintenance (see Table 1). With a median follow up of 5.8 years, overall outcomes with this cohort were excellent, with 69% and 60% progression-free at 5 and 10 years, respectively, and 96% and 92% alive at 5 and 10 years, respectively. Among the 12 patients who ultimately sustained a radiographic relapse, peripheral blood became MRD-positive in 11 patients (92%). The first positive MRD test came with a lead time of between 0-24 months (median 70 days) prior to radiographic relapse. Only one patient had a negative MRD result while being found to have progressive disease on imaging. That patient had a single site of disease at the base of tongue which caused symptoms early, despite a very low overall disease burden. Among the 19 patients who have been in continuous clinical remission, 17 have remained MRD-negative. The other 2 had "molecular relapse” (MRD positive without radiographic relapse), which allowed for pre-emptive rituximab treatment, which converted them back to an MRD-negative state. Several patients were able to enjoy 2-4 year intervals without any surveillance imaging, while still getting reassurance every few months from the negative ctDNA test (see Figure 1). Conclusions Our data suggests that the clonoSEQ® MRD assay is an effective surveillance tool for MCL patients following first-line therapy. In our experience, this MRD assay was predictive of relapse prior to imaging in all but one patient. In addition, the assay allowed for minimization of surveillance imaging, and early detection of MRD allowed for pre-emptive rituximab therapy in select patients. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Asymmetrical forward and reverse developmental trajectories determine molecular programs of B cell antigen receptor editing.

During B lymphopoiesis, B cell progenitors progress through alternating and mutually exclusive stages of clonal expansion and immunoglobulin (Ig) gene rearrangements. Great diversity is generated through the stochastic recombination of Ig gene segments encoding heavy and light chain variable domains. However, this commonly generates autoreactivity. Receptor editing is the predominant tolerance mechanism for self-reactive B cells in the bone marrow (BM). B cell receptor editing rescues autoreactive B cells from negative selection through renewed light chain recombination first at Igκ then Igλ loci. Receptor editing depends on BM microenvironment cues and key transcription factors such as NF-κB, FOXO, and E2A. The specific BM factor required for receptor editing is unknown. Furthermore, how transcription factors coordinate these developmental programs to promote usage of the λ chain remains poorly defined. Therefore, we used two mouse models that recapitulate pathways by which Igλ light chain-positive B cells develop. The first has deleted J kappa (Jκ) genes and hence models Igλ expression resulting from failed Igκ recombination (Igκdel). The second models autoreactivity by ubiquitous expression of a single-chain chimeric anti-Igκ antibody (κ-mac). Here, we demonstrated that autoreactive B cells transit asymmetric forward and reverse developmental trajectories. This imparted a unique epigenetic landscape on small pre-B cells, which opened chromatin to transcription factors essential for Igλ recombination. The consequences of this asymmetric developmental path were both amplified and complemented by CXCR4 signaling. These findings reveal how intrinsic molecular programs integrate with extrinsic signals to drive receptor editing.

Novel Approaches in Molecular Characterization of Classical Hodgkin Lymphoma.

Simple SummaryThe unique tumor composition of classical Hodgkin lymphoma (cHL), with only a small fraction of malignant Hodgkin and Reed–Sternberg cells within the tumor tissue, has created many challenges to characterize the genetic alterations that drive this lymphoid malignancy. Major advances in sequencing technologies and detailed analysis of circulating tumor DNA in blood samples of patients have provided important contributions to enhance our understanding of the pathogenesis of cHL. In this review, we provide an overview of the recent advances in genotyping the clonal and mutational landscape of cHL. In addition, we discuss different next-generation sequencing applications to characterize tumor tissue and cell-free DNA, which are now available to improve the diagnosis of cHL, and to monitor therapeutic response or disease progression during treatment and follow up of cHL patients.Classical Hodgkin lymphoma (cHL) represents a B-cell lymphoproliferative disease characterized by clonal immunoglobulin gene rearrangements and recurrent genomic aberrations in the Hodgkin Reed–Sternberg cells in a reactive inflammatory background. Several methods are available for the molecular analysis of cHL on both tissue and cell-free DNA isolated from blood, which can provide detailed information regarding the clonal composition and genetic alterations that drive lymphoma pathogenesis. Clonality testing involving the detection of immunoglobulin and T cell receptor gene rearrangements, together with mutation analysis, represent valuable tools for cHL diagnostics, especially for patients with an atypical histological or clinical presentation reminiscent of a reactive lesion or another lymphoma subtype. In addition, clonality assessment may establish the clonal relationship of composite or subsequent lymphoma presentations within one patient. During the last few decades, more insight has been obtained on the molecular mechanisms that drive cHL development, including recurrently affected signaling pathways (e.g., NF-κB and JAK/STAT) and immune evasion. We provide an overview of the different approaches to characterize the molecular composition of cHL, and the implementation of these next-generation sequencing-based techniques in research and diagnostic settings.

CfDNA-Based NGS IG Analysis in Lymphoma.

Liquid biopsy is a novel diagnostic approach at first developed to characterize the molecular profile of solid tumors by analyzing body fluids. For cancer patients, it represents a noninvasive way to monitor the status of the solid tumor with respect to representative biomarkers. There is growing interest in the utilization of circulating tumor DNA (ctDNA) analysis also in the diagnostic and prognostic fields of lymphomas. Clonal immunoglobulin (IG) gene rearrangements are fingerprints of the respective lymphoid malignancy and thus are highly suited as specific molecular targets for minimal residual disease (MRD) detection. Tracing of the clonal IG rearrangement patterns in ctDNA pool during treatment can be used for MRD assessment in B-cell lymphomas. Here, we describe a reproducible next-generation sequencing assay to identify and characterize clonal IG gene rearrangements for MRD detection in cell-free DNA.

Resistance of B-Cell Lymphomas to CAR T-Cell Therapy Is Associated With Genomic Tumor Changes Which Can Result in Transdifferentiation

Despite the impressive efficacy of chimeric antigen receptor (CAR) T-cell therapy (CART) in B-cell non-Hodgkin lymphomas, durable responses are uncommon. The histopathologic and molecular features associated with treatment failure are still largely unknown. Therefore, we have analyzed 19 sequential tumor samples from 9 patients, prior anti-CD19 CART (pre-CART) and at relapse (post-CART), using immunohistochemistry, fluorescence in situ hybridization, array comparative genomic hybridization, next-generation DNA and RNA sequencing, and genome-scale DNA methylation. The initial diagnosis was diffuse large B-cell lymphoma (n=6), double-hit high-grade B-cell lymphoma (n=1), and Burkitt lymphoma (n=2). Histopathologic features were mostly retained at relapse in 7/9 patients, except the frequent loss of 1 or several B-cell markers. The remaining 2 cases (1 diffuse large B-cell lymphoma and 1 Burkitt lymphoma) displayed a dramatic phenotypic shift in post-CART tumors, with the drastic downfall of B-cell markers and emergence of T-cell or histiocytic markers, despite the persistence of identical clonal immunoglobulin gene rearrangements. The post-CART tumor with aberrant T-cell phenotype showed reduced mRNA expression of most B-cell genes with increased methylation of their promoter. Fluorescence in situ hybridization and comparative genomic hybridization showed global stability of chromosomal alterations in all paired samples, including 17p/TP53 deletions. New pathogenic variants acquired in post-CART samples included mutations triggering the PI3K pathway (PIK3R1, PIK3R2, PIK3C2G) or associated with tumor aggressiveness (KRAS, INPP4B, SF3B1, SYNE1, TBL1XR1). These results indicate that CART-resistant B-cell non-Hodgkin lymphomas display genetic remodeling, which may result in profound dysregulation of B-cell differentiation. Acquired mutations in the PI3K and KRAS pathways suggest that some targeted therapies could be useful to overcome CART resistance.

NGS-Based MRD Quantitation: An Alternative to qPCR Validated on a Large Consecutive Cohort of Children with ALL

Together with multicolor flow cytometry, quantitation of clonal immunoglobulin (IG) and T-cell receptor (TR) gene rearrangements represents the current standard for the detection of minimal / measurable residual disease (MRD) in treatment protocols for pediatric acute lymphoblastic leukemia (ALL) patients. Despite the adoption of next generation sequencing (NGS) in the routine identification of clonal IG/TR gene rearrangements as markers for MRD detection, real-time quantitative (q)PCR is still the standard for MRD quantitation in follow-up samples. So far, no large-scale direct comparison of qPCR- and NGS-based MRD quantitation has been performed.We compared qPCR- and NGS-MRD evaluation in a cohort of children with B-cell precursor (BCP) ALL treated on the AIEOP-BFM ALL 2009 protocol and assessed the feasibility and relevance of this method for the stratification at day 33 (EOI).In total, 459 patients were diagnosed with BCP-ALL from 2010 to 2018, and 437 of them were included in our study based on the availability of residual DNA material isolated from day 33 bone marrow aspirates and having at least one IG/TR MRD marker detectable by standard qPCR with protocol-required sensitivity of 10 -4. Sequencing libraries were prepared according to the EuroClonality-NGS group SOP (Brüggemann et al, Leukemia 2019) with the total DNA input normalized to the equivalent of 150,000 nucleated cells to reach MRD sensitivity of 10 -5 and sequenced on Illumina NovaSeq and MiSeq instruments. In total of 780 IG/TR markers evaluated by both NGS and qPCR. Sequencing data were analyzed using the ARResT/Interrogate (Bystry et at, Bioinformatics 2017) pipeline and a custom bioinformatic analysis process and the NGS-MRD results were normalized to the EuroClonality-NGS central in-tube quality/quantification control (cIT-QC; Knecht et al, Leukemia 2019).From the total 780 IG/TR MRD markers evaluated by both methods, 629 (80.6%) were concordant with 242 markers being MRD positive and 387 negative. From 82 markers that were only positive by qPCR and not by NGS, 76 were positive below the quantitative range (positive non-quantifiable). Specificity analysis was performed for each marker by searching for the junction sequence across the dataset of all patients' NGS results. Based on these results, 22 out of 82 markers positive only by qPCR were classified as potentially unspecific (false positive) and similarly 32 unspecific markers were identified among the 69 positive only by NGS. This was also supported by unspecific amplification of the polyclonal control in 27 out of these 32 corresponding qPCR systems, in some cases leading to qPCR negative classification determined by the EuroMRD guidelines.Overall stratification of patients based only on day 33 MRD by qPCR or NGS was concordant in 76% of patients by both methods, while in 19% of patients, NGS-MRD quantitation led to the assignment to a lower-risk group, mainly due to the elimination of false-positive results. Furthermore, analysis of all positive markers across all patients' NGS libraries showed, that one out of 10 markers (mainly in the IGK, TRG and TRD loci) used for qPCR-MRD stratification did not provide satisfactory specificity, although they fully met EuroMRD criteria during the optimization of qPCR patient-specific assays.Our results show that NGS-MRD is highly concordant with traditional qPCR-based strategy and has comparable sensitivity and clinical value in the setting of a BFM-based clinical protocol, while being less laborious and providing significantly more specific results and additional information on the IG/TR repertoire (Kotrova et al, Blood 2016). Our study also emphasizes the importance of selecting MRD markers of adequate specificity at diagnosis. Currently, this selection can be assisted by these broad sequencing data on IG/TR repertoire of large number of patients. Based on these results, we propose that frontline NGS-MRD evaluation developed by the EuroClonality-NGS working group can be used as an alternative to traditional qPCR-based MRD quantitation in future MRD-based treatment protocols.Supported by grants NU20-03-00284 and NU20-07-00322 from the Czech Health Research Council and 534120 from Charles University. All methods were established through collaboration within the EuroClonality-NGS and EuroMRD groups. Disclosuresvan der Velden: Agilent: Research Funding; Navigate: Other: Service Level Agreement; Janssen: Other: Service Level Agreement; EuroFlow: Other: Service Level Agreement, Patents & Royalties: for network, not personally; BD Biosciences: Other: Service Level Agreement. Brüggemann: Incyte: Other: Advisory Board; Janssen: Speakers Bureau; Amgen: Other: Advisory Board, Travel support, Research Funding, Speakers Bureau. Langerak: Erasmus MS, University Medical Center: Current Employment; F. Hoffmann-La Roche Ltd/Genentech, Inc.: Research Funding; Gilead: Research Funding; Janssen: Speakers Bureau.

Comparison of Two Quantitative PCR–Based Assays for Detection of Minimal Residual Disease in B-Precursor Acute Lymphoblastic Leukemia Harboring Three Major Fusion Transcripts

Two quantitative PCR (qPCR)-based methods, for clonal immunoglobulin or T-cell receptor gene (Ig/TCR) rearrangements and for fusion transcripts, are widely used for the measurement of minimal residual disease (MRD) in patients with B-precursor acute lymphoblastic leukemia (ALL). MRD of bone marrow samples from 165 patients carrying the three major fusion transcripts, including 74 BCR-ABL1, 54 ETV6-RUNX1, and 37 TCF3-PBX1, was analyzed by using the two qPCR-based methods. The correlation coefficient of both methods was good for TCF3-PBX1 (R2=0.8088) and BCR-ABL1 (R2=0.8094) ALL and moderate for ETV6-RUNX1 (R2=0.5972). The concordance was perfect for TCF3-PBX1 ALL (97.2%), substantially concordant for ETV6-RUNX1 ALL (87.1%), and only moderate for BCR-ABL1 ALL (70.6%). The discordant MRD, positive for only one method with a difference greater than one log, was found in 4 of 93 samples (4.3%) with ETV6-RUNX1, 31 of 245 samples (12.7%) with BCR-ABL1, and none of TCF3-PBX1 ALL. None of the eight non-transplanted patients with BCR-ABL1-MRD (+)/Ig/TCR-MRD (-) with a median follow-up time of 73.5 months had hematologic relapses. Our study showed an excellent MRD concordance between the two qPCR-based methods in TCF3-PBX1 ALL, whereas qPCR for Ig/TCR is more reliable in BCR-ABL1 ALL.

Comparison of Genetic Profiling of Primary Central Nervous System (CNS) Lymphoma before and after Extra-CNS Relapse

IntroductionLymphomas of the central nervous system (CNS), including primary CNS lymphoma (PCNSL), have recently been focused on as promising targets for immune checkpoint blockade therapies. However, approximately one-third of patients with PCNSL are resistant to initial chemotherapies, and almost all patients will eventually develop recurrence or disease progression. During the clinical course, systemic extra-CNS lesions are observed in 3% of relapsed or refractory (r/r) PCNSL. To elucidate the mechanism of this uncommon recurrence suggestive of tumor oncogenic evolution and overcoming the immune privilege, we performed comprehensive genomic analysis comparing primary with systemic r/r PCNSL using next-generation sequencing approaches.MethodsPatients at our institute with an episode of both PCNSL and extra-CNS relapse or disease progression with a pathological diagnosis of diffuse large B-cell lymphoma were screened. Genomic DNA was extracted from primary, recurrent, or refractory tumors, and corresponding germline samples. The samples were either formalin-fixed, paraffin-embedded (FFPE) or fresh frozen tissue if available. Clonal immunoglobulin gene rearrangements were detected using the IdentiClone™ IGH Gene Clonality Assay (Invivoscribe Technologies). DNA sequencing was performed on the Ion Torrent Proton™ platform after targeted amplification with the customized panel designed using the Ion AmpliSeq Designer™ tool (Life Technologies). This panel consists of whole exons of 64 genes associated with lymphoid malignancies, including those involved with the NFκB pathway, B-cell differentiation, epigenetic regulation of transcription, immune surveillance, and tumor suppression. Single nucleotide variations (SNVs), short insertions and deletions (InDels), and copy number variations were called using the Biomedical Genomics Workbench (Qiagen) after filtering and annotation using public variant databases such as dbSNP, COSMIC, and GRCh37 hg19. From these SNVs and InDels, somatic mutations were defined as non-synonymous, with a minimal coverage of 100, and with a frequency of subtracting germline reads from tumor reads of 10% or more. To confirm targeted DNA sequencing findings, we performed Sanger sequencing. To determine the cell-of-origin (COO), immunohistochemistry (IHC) using the Hans algorithm was performed. The expression of HLA class I, HLA class II, PD-L1, and PD-L2 was also assessed with IHC.ResultsSix patients who were initially treated for PCNSL and who either relapsed (n = 5) or progressed (n = 1) were recruited. The relapse sites were the ileum (n = 2), testis with para-aortic lymph node (n = 1), intraabdominal lymph node (n = 1), and nasal sinuses (n = 1). The remaining refractory PCNSL was a patient who showed progression in multiple organs including the CNS with systemic lymph nodes. Only one relapsed patient was positive for HLA class I by IHC, with stronger staining seen at the relapsed site compared with the primary CNS site. Targeted DNA sequencing detected somatic PIM1 mutations in all primary and r/r tumors (Figure); nonsense mutations were detected in 50% of primary tumors and 67% of r/r ones. Compared to primary tumors, PIM1 was the most common gained mutation in r/r ones, and additionally gained somatic mutations such as CD79B, MLL2 and CD58 were observed. Partial loss of CIITA and the partial gain of NFκB pathway-related genes such as MALT1 and CARD11 were also detected. Somatic mutations were observed at a frequency of 1% in the germline sample of one patient (case 1 in Figure).ConclusionsOur study suggested that the evolution of mutations in PCNSL enabled systemic disease progression with a breakthrough of immune privilege. These findings were characterized not only by an immunological overpowering but also by the dysregulation of B-cell proliferation signaling, suggesting that loss of function of PIM1 had occurred. [Display omitted] DisclosuresToyoda:Chugai: Honoraria. Narita:Chugai, MSD, Eisai Co. Ltd., Nobelpharma Co.: Honoraria; Abbvie: Consultancy; Nihon Medi-Physics Co., Daiichi-Sankyo Co, Ono Pharmaceutical Co., AbbVie GK: Research Funding. Maruyama:Chugai, Kyowa Hakko Kirin, Ono, Celgene, Janssen, Eisai, Mundipharma, Takeda: Honoraria; Dai-ichi Sankyo, Chugai, Kyowa Hakko Kirin, Ono, Celgene, Janssen, GSK, Eisai, Mundipharma, Takeda, AbbVie, MSD, Sanofi, Pfizer, Otsuka, Novartis, Solasia, Zenyaku: Research Funding. Tobinai:Daiichi Sankyo Co., Ltd: Consultancy, Honoraria; Servier: Research Funding; Eisai: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Chugai: Honoraria, Research Funding; HUYA Bioscience: Honoraria; GlaxoSmithKline: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Kyowa Hakko Kirin: Honoraria, Research Funding; AbbVie: Research Funding; Takeda: Honoraria, Research Funding; Zenyaku Kogyo: Honoraria; Mundipharma: Honoraria, Research Funding; Ono Pharmaceutical: Honoraria, Research Funding. Kobayashi:Pfizer, Ohtsuka, Astellas, Ariad: Research Funding.

Lymphocyte predominant Hodgkin lymphoma, antigen-driven after all?

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) was suggested as an entity separate from other types of Hodgkin lymphoma 40 years ago and recognized in the WHO classification in 2001. Based on its relatively benign course with late distant relapses, relation with lymph node hyperplasia with progressively transformed germinal centers, presence of clonal immunoglobulin gene rearrangements with somatic hypermutations and ongoing mutations, and relation with a number of inherited defects affecting the immune system, it has been suspected that NLPHL might be antigen-driven. Recent evidence has shown that cases of IgD-positive NLPHL are associated with infection by Moraxella catarrhalis, a common bacterium in the upper respiratory tract and in lymph nodes. This review summarizes the evidence for NLPHL as a B-cell lymphoma involving follicular T-lymphocytes normally found in germinal centers, its molecular features and relation to inherited immune defects, and its relation and differential diagnosis from similar entities. Finally, it discusses the evidence that in many cases a watch and wait policy might be a viable initial management strategy. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Interim Results of a Multicenter, Single-Arm Study to Assess Blinatumomab in Adult Patients (pts) with Minimal Residual Disease (MRD) of B-Precursor (BCP) Acute Lymphoblastic Leukemia (GMALL-MOLACT1-BLINA)

Interim Results of a Multicenter, Single-Arm Study to Assess Blinatumomab in Adult Patients (pts) with Minimal Residual Disease (MRD) of B-Precursor (BCP) Acute Lymphoblastic Leukemia (GMALL-MOLACT1-BLINA)

Predictive Power of Early, Sequential MRD Monitoring in Peripheral Blood and Bone Marrow in Patients with Mantle Cell Lymphoma Following Autologous Stem Cell Transplantation with or without Rituximab Maintenance; Final Results from the LyMa-MRD Project, Conducted on Behalf of the Lysa Group

Predictive Power of Early, Sequential MRD Monitoring in Peripheral Blood and Bone Marrow in Patients with Mantle Cell Lymphoma Following Autologous Stem Cell Transplantation with or without Rituximab Maintenance; Final Results from the LyMa-MRD Project, Conducted on Behalf of the Lysa Group

Evaluation of Somatic Hypermutation Status in Chronic Lymphocytic Leukemia (CLL) in the Era of Next Generation Sequencing.

Somatic hypermutation (SHM) status provides an important prognostic indicator for chronic lymphocytic leukemia (CLL), a very common type of mature B-cell leukemia. Owing to the adverse prognosis associated with an unmutated immunoglobulin heavy chain variable (IGHV) status, SHM testing is performed as a standard of care in CLL. Conventionally, SHM testing has been performed using labor intensive and primarily analog Sanger sequencing method following PCR amplification of the clonal immunoglobulin heavy chain gene rearrangements in CLL cells. In comparison, recent availability of next generation sequencing (NGS) allows more versatile detection and direct identification of clonal immunoglobulin gene rearrangements in neoplastic B-cell populations. The ability to identify specific clonal IGHV signature(s) in both baseline (diagnostic) and post-treatment settings enables unique clinical applications of NGS such as determination of SHM status, minimal residual disease (MRD) monitoring, clonal heterogeneity and B cell receptor IG stereotypy. We provide a review of current practices and recommendations for SHM determination using NGS including examples of difficult cases.

MON-441 Primary Thyroid Maltoma: A Rare Non-hodgkin Malignancy

Introduction: Thyroid lymphoma is a rare malignancy; only 2% of extranodal lymphomas arise within the thyroid gland. Furthermore, lymphomas represent no more than 2% of all malignant thyroid tumors and almost always non-Hodgkin type. Case: A 58-year-old female with a medical history of rheumatoid arthritis treated with Golimumab for years. Exam revealed a right thyroid lobe enlargement with bilateral palpable nodules. Labs include TSH of 1.4 mU/L, Free T4 of 1.76 ng/dL, normal anti-thyroid peroxidase antibodies, but elevated anti-thyroglobulin. US of the thyroid showed right-sided, hyperechoic nodule measuring 1.3cm, and left-sided solid hypoechoic nodule measuring 2.2cm. US-guided FNA of the right nodule yielded atypical cells of undetermined significance (2017 Bethesda category III). FNA of the left nodule showed severe, chronic thyroiditis, with small clonal population of cells and suspicion for lymphoma. She underwent total thyroidectomy with left central lymph node dissection. Microscopic evaluation showed a predominant lymphocytic population with plasmacytoid/plasma cells. The histological finding was consistent with extranodal marginal zone lymphoma (EMZL) of mucosa-associated lymphoid tissue (MALT lymphoma or MALToma). However, thyroid tissues were negative for clonal immunoglobulin gene rearrangements (both immunoglobulin heavy and light chains). Immunohistochemistry demonstrated that the tumor cells were CD19, CD 20, CD 22, PAX5, CD78A positive, highlighting predominantly small to medium-sized B- cell lymphocytes, along with plasmacytoid/plasma cells (MUM1 and CD 75A positive). Furthermore, occasional reactive germinal centers (CD10, BCL6 positive, BCL2 negative) were noted. In conclusion, these features were consistent with a low grade, non-Hodgkin’s lymphoma of MALT type. Discussion: EMZL is a clinically indolent non-Hodgkin lymphoma, and growing evidence suggests that numerous cases originate in the background of chronic immune stimulation. MALToma is associated with Hashimoto’s thyroiditis or other immune diseases. Whereas half of EMZL can still arise without a Hashimoto thyroiditis background. Characteristics of the MALToma include reactive follicles, with the neoplastic cells invading the marginal zone (small lymphocytes, marginal zone B-cells, and plasma cells). The key findings are the presence of clonality (light chain restriction), and confirmation of B-cell origin (presence of B-cell markers). The immunophenotype is confirmed by immunohistochemistry and flow cytometry. Localized EMZL of the thyroid can be effectively treated with radiation alone. Surgery is usually used for diagnostic biopsy only. Chemotherapy is usually reserved for those with advanced stages

Detection of Immunoglobulin Heavy Chain Gene Clonality By High-Throughput Sequencing for Minimal Residual Disease Monitoring in Chronic Lymphocytic Leukaemia

Introduction: The negative minimal residual disease (MRD) after treatment has been recently accepted as endpoint for Chronic Lymphocytic Leukaemia (CLL) clinical trials. Conventionally, MRD can be detected by using multi-color Flow Cytometry (FC) with high sensitivity. Determination of the clonal immunoglobulin gene rearrangement can be a useful monitoring marker in a broad range of B-cell lymphoproliferative neoplasms. Moreover, the mutational status of immunoglobulin heavy chain variable (IgHV) rearrangement is considered one of the most important prognostic factors in CLL. Therefore, the identification of the IgHV rearrangement can be a useful marker both at diagnostic and as monitoring marker for MRD. Nowadays, high-throughput sequencing (HTS) technologies has enabled highly sensitive cancer genomic testing in clinical laboratories. There are same initiatives based on HTS to use IgHV rearrangement as marker for MRD monitoring in Acute lymphoblastic leukemia or multiple myeloma, but it remains unharmonized for application on CLL in the clinical laboratory. Objective: We evaluated the performance and clinical applicability of HTS assay for IgHV rearrangement in CLL MRD monitoring in 69 samples from 19 CLL patients treated. Methods: The libraries including IGH locus were performed using the Sequencing Multiplex Kit on IGH consensus primers. To simplify and make automatic the analysis of the data obtained, we developed a specific bioinformatic pipeline that covers from preprocessing to final data summarization and interpretation. The backbone of the analysis includes read preprocessing, mapping against IMGT reference sequences, consensus IgHV reads pairwise alignment to determine mutational status and read classification into rearrangements. Assessment of IgHV mutational status by Sseq, genomic DNA (gDNA; 50-100 ng), were used for IgHV analysis. gDNA was amplified using locus-specific primer sets for IgHV designed to allow for the amplification of all known alleles of the germline IgH sequence, as described previously. Inmunophenotypic studies were performed on erythrocyte-lysed whole PB samples according to Euroflow procedures. PB white blood cells (WBC) was systematically stained with the eight color combination panel recently proposed by the ERIC group for MRD detection (Rawstron AC et al. 2016). Data acquisition was performed on a FACSCanto II flow cytometer Becton-Dickinson Biociences using the FACSDiva software (V8.0; BD). For data analysis, the Infinicyt softwareTM (Cytognos SL, Salamanca, Spain) was used. The MRD levels were reported as fraction of CLL cells of all nucleated cells. MRD negativity was define as a fraction &lt;10 -4 However, for treatments that preferentially clear the blood (for example monoclonal antibodies) the MRD was confirm in the bone marrow as has been recommended. Results: Patient demographics and the results of IGH clonality tests are summarized in Table 1. Interpretable results were obtained with higher sensitivity compared with Sseq at diagnosis stage (19/19 samples), and we are able to determine the same clone at subsequent samples. Among 50 follow-up samples, 44 MRD were positive in both techniques (HTS and FC); 3 follow-up samples, were negative in both determinations (HTS and FC); in contrast, 3 follow-up samples, were negative by FC but positive by HTS (8.3, 17.2, 18.2 samples). This is the case of Patient 8, in which the last follow-up sample, the detection of the primary clone is positive by HTS, while by FC is undetected (Figure 1). In addition, it was possible to detect IgHV clone in all Patient 7 samples. It was under long-term monitoring by HTS and FC, and 17 months after initial diagnosis and first line of treatment (7.5 sample), it was detected a loss of response (Figure 2.). Conclusions: We evaluated an HTS IgHV assay using initial and follow-up samples of 19 CLL patients. Using our pre-designed primer set in library preparation, and developed our specific bioinformatic pipeline that covers from preprocessing to final data summarization and interpretation, we were able to demonstrate that our method was more sensitive than FC in detecting positive follow-up samples and could be able to propose it for MRD monitoring in CLL. However, the prognostic impact of these low-level MRD detected by HTS should be validated with further investigations. Samples were provided by the INCLIVA Biobank. Funded by Gilead Felowship 257/17 Disclosures Ortiz: GILEAD SCIENCES: Research Funding. Terol:Abbvie: Consultancy; Gilead: Research Funding; Janssen: Consultancy, Research Funding; Astra Zeneca: Consultancy; Roche: Consultancy.

Novel markers in pediatric-type follicular lymphoma

The aim of this study was to review the histopathological, phenotypic, and molecular characteristics of pediatric-type follicular lymphoma (PTFL) and to assess the diagnostic value of novel immunohistochemical markers in distinguishing PTFL from follicular hyperplasia (FH). A total of 13 nodal PTFLs were investigated using immunohistochemistry, fluorescence in situ hybridization (FISH), and PCR and were compared with a further 20 reactive lymph nodes showing FH. Morphologically, PTFL cases exhibited a follicular growth pattern with irregular lymphoid follicles in which the germinal centers were composed of numerous blastoid cells showing a starry-sky appearance. Immunohistochemistry highlighted preserved CD10 (13/13) and BCL6 (13/13) staining, CD20 (13/13) positivity, a K light chain predominance (7/13), and partial BCL2 expression in 6/13 cases (using antibodies 124, E17, and SP66). The germinal center (GC)–associated markers stathmin and LLT-1 were positive in most of the cases (12/13 and 12/13, respectively). Interestingly, FOXP-1 was uniformly positive in PTFL (12/13 cases) in contrast to reactive GCs in FH, where only a few isolated positive cells were observed. FISH revealed no evidence of BCL2, BCL6, or MYC rearrangements in the examined cases. By PCR, clonal immunoglobulin gene rearrangements were detected in 100% of the tested PTFL cases. Our study confirmed the unique morphological and immunophenotypic features of PTFL and suggests that FOXP-1 can represent a novel useful diagnostic marker in the differential diagnosis between PTFL and FH.