Nodular Lymphocyte Predominant Hodgkin Lymphoma Research Articles

P012: Nodular Lymphocyte-predominant Hodgkin Lymphoma a rare disease with good prognosis: a retrospective multicenter experience

P012: Nodular Lymphocyte-predominant Hodgkin Lymphoma a rare disease with good prognosis: a retrospective multicenter experience

P115: Distinct signaling pathways and checkpoint molecule expression across histological subtypes of nodular lymphocyte-predominant Hodgkin lymphoma

P115: Distinct signaling pathways and checkpoint molecule expression across histological subtypes of nodular lymphocyte-predominant Hodgkin lymphoma

Hodgkin lymphoma: 2023 update on diagnosis, risk-stratification, and management.

Hodgkin lymphoma (HL) is an uncommon B-cell lymphoid malignancy affecting 8540 new patients annually and representing approximately 10% of all lymphomas in the United States. HL is composed of two distinct disease entities: classical HL and nodular lymphocyte-predominant HL. Nodular sclerosis, mixed cellularity, lymphocyte depletion, and lymphocyte-rich HL are subgroups of classical HL. An accurate assessment of the stage of disease in patients with HL is critical for the selection of the appropriate therapy. Prognostic models that identify patients at low or high risk for recurrence, as well as the response to therapy as determined by positron emission tomography scan, are used to optimize therapy. Initial therapy for HL patients is based on the histology of the disease, the anatomical stage, and the presence of poor prognostic features. Patients with early-stage disease are typically treated with combined modality strategies utilizing abbreviated courses of combination chemotherapy followed by involved-field radiation therapy, while those with advanced-stage disease receive a longer course of chemotherapy, often without radiation therapy. However, newer agents, including brentuximab vedotin and anti-programmed death-1 (PD-1) antibodies, are now being incorporated into frontline therapy. High-dose chemotherapy (HDCT) followed by an autologous stem cell transplant (ASCT) is the standard of care for most patients who relapse following initial therapy. For patients who fail HDCT with ASCT, brentuximab vedotin, PD-1 blockade, non-myeloablative allogeneic transplant, or participation in a clinical trial should be considered.

Abstract A17: The immune checkpoints TIGIT and PD-1 are markedly upregulated in NLPHL compared to classical Hodgkin Lymphoma

Abstract Hodgkin lymphoma (HL) comprises two distinct disease entities based on clinical, morphologic and genotypic characteristics. Relative to classical Hodgkin Lymphoma (cHL), nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is rare, and its tumor microenvironment (TME) is very poorly characterized. With the exception of rituximab, there are no targeted treatments nor advances in the treatment of NLPHL for decades. Unlike cHL, the utility of immune-checkpoint blockade (ICB) has not been evaluated in NLPHL. Diagnostic samples were collected from 49 NLPHL patients from 4 Australian centres and compared with stage-matched cHL patients (and with normal lymph nodes). An integrative transcriptomic, proteomic, T-cell clonal and functional analysis was performed to enable a comparison of the composition of the TME and its contribution to immune-evasion in NLPHL with cHL. 730 cancer-immune related genes were digitally quantified. Relative to cHL, gene set enrichment analysis identified T-cell receptor (TCR) and immune-checkpoint signaling pathway dysregulation in NLPHL. Most striking was prominent differential expression of the immune-transcriptome, particularly enrichment for programmed cell death-1 (PD-1) and T-cell Ig and ITIM domain (TIGIT) in NLPHL versus cHL. These were also over expressed compared to normal lymph nodes. Consistent with this, there was also upregulation of numerous T-cell markers (CD247, CD3D, GZMK, CD28, EOMES) in NLPHL. In contrast, immunosuppressive macrophage (CD163, CD36, CD68, COLEC12, MARCO) and regulatory T-cell genes (FOXP3) were higher in cHL. Importantly, PD-L1 and CD155 (respective ligands for PD-1 and TIGIT) were expressed at the surface of NLPHL and cHL malignant B-cells. Multispectral immunofluorescent microscopy showed intratumoral TIGIT+CD4+ and PD-1+CD4+ T-cells were markedly increased in NLPHL versus cHL and localised within NLPHL follicles. Expanded populations of intratumoral CD4+ T-cell clones were predominantly PD-1+ and frequently also TIGIT+. Multi-parameter flow cytometry and dimensionality reduction was used to establish the distribution of immune checkpoints within circulating T-cell subsets. PD-1+TIGIT+CD4+ T-cells were raised in circulating Treg, TH1 and TH2 subsets in NLPHL versus cHL, and PD-1+TIGIT+ TH2 T-cells displayed raised levels of the exhaustion marker EOMES, collectively indicating systemic T-cell dysfunction. To functionally demonstrate the utility of ICB to stimulate T-cells, an assay using cHL and/or NLPHL cell-lines co-cultured with a genetically engineered effector T-cell-line was developed. This showed that TIGIT/PD-1 dual-blockade was more effective than mono-blockade in inducing NLPHL and cHL tumor-directed CD4+ T-cell activation. Overall, our results indicate that immune-evasion mechanisms in NLPHL are distinct to those operative in cHL, with markedly greater T-cell, PD-1 and TIGIT dysregulation. PD-1 and/or TIGIT blockade warrants evaluation in NLPHL. Citation Format: Jay Gunawardana, Soi C. Law, Muhammed B. Sabdia, Karolina Bednarska, Sandra Brosda, Andreea Zaharia, Hennes Tsang, Lilia M. de Long, Melinda Burgess, Dipti Talaulikar, Justina N. Lee, Emily Jude, Eliza A. Hawkes, Sanjiv Jain, Karthik Nath, Clare Gould, Fiona Swain, Joshua W. D. Tobin, Colm Keane, Simone Birch, Mohamed Shanavas, Cameron Snell, Maher K. Gandhi. The immune checkpoints TIGIT and PD-1 are markedly upregulated in NLPHL compared to classical Hodgkin Lymphoma [abstract]. In: Proceedings of the Third AACR International Meeting: Advances in Malignant Lymphoma: Maximizing the Basic-Translational Interface for Clinical Application; 2022 Jun 23-26; Boston, MA. Philadelphia (PA): AACR; Blood Cancer Discov 2022;3(5_Suppl):Abstract nr A17.

Proposal of 'reactive-lymphocyte/histiocyte rich large B-cell lymphoma' as an alternate term for 'nodular lymphocyte predominant Hodgkin lymphoma' that would also address its overlap with T-cell/histiocyte rich large B-cell lymphoma.

Proposal of 'reactive-lymphocyte/histiocyte rich large B-cell lymphoma' as an alternate term for 'nodular lymphocyte predominant Hodgkin lymphoma' that would also address its overlap with T-cell/histiocyte rich large B-cell lymphoma.

Nodular lymphocyte-predominant Hodgkin lymphoma and clinical impact of its variant histology: a clinicopathologic study from tertiary cancer centre in India

Nodular lymphocyte-predominant Hodgkin lymphoma and clinical impact of its variant histology: a clinicopathologic study from tertiary cancer centre in India

Characterizing the immune microenvironment for nodular lymphocyte-predominant Hodgkin lymphoma.

The microenvironment of nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) and its relationship to presentation and outcomes has not been widely investigated. In a large cohort of patients with NLPHL, Hartmann and colleagues showed an association between microenvironmental factors and clinical presentation serving to inform future studies evaluating the prognostic impact of the immunoarchitectural patterns and cell types present. Commentary on: Hartmann et al. Tumor cell characteristics and microenvironment composition correspond to clinical presentation in newly diagnosed nodular lymphocyte predominant Hodgkin lymphoma. Br J Haematol 2022;199:392-401.

Lymphome de Hodgkin nodulaire à prédominance lymphocytaire (paragranulome de Poppema) chez l’enfant : à propos d’un cas, revue de la littérature et traitement

We present the case of a 12year old child with a limp. The diagnostic work-up reveals splenomegaly, multifocal bone involvement and abdominal adenopathies. A biopsy of an intra-abdominal lesion shows a lymphoid mass with a nodular architecture composed of poorly defined nodules. We identify large cells with irregular, sometimes poly-lobulated nuclei with a particular immunohistochemical profile. Those "pop-corn" cells are positive for CD20, CD79a, pax-5and bcl-6and are negative for CD15, CD30, bcl-2, TdT, CD56and EMA. There is a diffuse follicular helper T cell population that is located in between the tumour cells. The overall picture is indicative of a nodular lymphocyte predominant Hodgkin lymphoma. Advanced stage of this disease is rare in children and there is currently little data to guide optimal treatment. Because of a stage IV disease, the patient is treated with chemotherapy after which complete metabolic remission is observed. 3.5years after the initial diagnosis, our patient relapses. He is treated with chemotherapy and an autologous peripheral blood stem cell transplantation. He remains in complete remission since then. This case illustrates the favorable prognosis of the disease even after relapse.

EBV-positive nodular lymphocyte predominant Hodgkin lymphoma: a single institution experience

The objective of this study is to characterize the clinicopathologic features of Epstein-Barr virus (EBV)-positive nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) at a single institution. A retrospective review of cases diagnosed with EBV-positive NLPHL was performed and the patients' demographic and pathologic features were collected by chart review. In this study, we identified 17 EBV-positive NLPHL patients whose clinicopathologic features are characterized. EBV was positive in lymphocyte predominant (LP) cells in 6 of 17 cases, whereas the remaining cases showed EBV positivity in background small cells. Immunohistochemical analysis showed that LP cells were positive for CD20 (94.1%) in most cases and positive for OCT2 (100%) in all cases with one case showing weak OCT2 expression, whereas PAX5 and CD79a were weak and/or variable in 9 of 12 and 3 of 7 cases, respectively. CD30 was positive in 7 of 17 cases with 5 cases showing only scattered positive cells. In addition, we report a patient who had a history of EBV-negative NLPHL and showed EBV-positive NLPHL at the time of recurrence. Molecular studies performed on the 2 biopsies in the patient indicated EBV infection involving the NF-kB pathway. Our study shows that EBV-positive NLPHL is rare and may be diagnostically challenging because of atypical immunophenotypic features, such as partial expression of CD30, and weak/variable PAX5 and/or CD79a expression. The overall retention of the B-cell phenotype with strong and diffuse expression of CD20 and OCT2 in LP cellssupports the diagnosis of EBV-positive NLPHL.

Tumour cell characteristics and microenvironment composition correspond to clinical presentation in newly diagnosed nodular lymphocyte-predominant Hodgkin lymphoma.

Different studies have characterized the microenvironment and its prognostic impact in classic Hodgkin lymphoma whereas such analyses are pending for nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). We thus investigated characteristics of tumour cells and microenvironment in NLPHL and evaluated possible correlations with the clinical presentation. Lymph node samples from 152 NLPHL patients who had first-line treatment within the randomized German Hodgkin Study Group HD16-HD18 trials were available and analysed with regard to IgD status and nuclear size of the tumour cells as well as presence of PD1-positive follicular T helper cells and CD163-positive macrophages in the microenvironment. While large tumour cell nuclei and high numbers of PD1-positive follicular T helper cells in the microenvironment were more common in patients presenting with early/intermediate stages than in patients with advanced-stage disease (p< 0.0001, unpaired t-test; p= 0.0022, Mann-Whitney test), no differences between risk groups were observed in terms of the IgD status of the tumour cells and the content of CD163-positive macrophages in the microenvironment. PD1-positive follicular T helper cells were present in both cases with typical and variant growth patterns and rosetting around the tumour cells was observed in 96% of patients, indicating an important role of PD1-positive follicular T helper cells in NLPHL.

Nodular Lymphocyte-Predominant Hodgkin Lymphoma in a Patient with Familial Mediterranean Fever.

Nodular Lymphocyte-Predominant Hodgkin Lymphoma in a Patient with Familial Mediterranean Fever.

KITE-363: A phase 1 study of an autologous anti-CD19/CD20 chimeric antigen receptor (CAR) T-cell therapy in patients with relapsed/refractory (R/R) B-cell lymphoma (BCL).

TPS7579 Background: One mechanism by which B-cell tumors can resist the effects of CD19-targeted CAR T-cell therapy is through CD19 antigen escape (Neelapu et al. ASH 2019). Recent analyses in large B-cell lymphoma (LBCL) demonstrated that approximately one-third to two-thirds of relapses after infusion of CAR T-cell therapy were CD19 negative (Plaks et al. Blood. 2021; Spiegel, Dahiya et al. Blood. 2021; Spiegel et al. Nat Med. 2021). KITE-363 is an autologous CAR T cell transduced with a bicistronic vector with resultant expression of a CD19 CAR with a CD28 costimulatory domain and a CD20 CAR with a 41BB costimulatory domain. In preclinical studies, KITE-363 recognized and eliminated tumor cells expressing CD19 and/or CD20. KITE-363 CAR T-cell therapy has the potential to rescue CD19-negative relapsing patients with BCL as well as prevent CD19 antigen escape by minimizing selective pressure through upfront therapeutic dual targeting. This Phase 1, first-in-human, open-label, multicenter study (NCT04989803) will evaluate the safety and preliminary efficacy of KITE-363 in patients with R/R BCL. Methods: The Phase 1 design includes a 3+3 dose-escalation portion (1A), with 5 planned CAR T-cell levels, and a dose expansion portion (1B). Patients may receive optional corticosteroid bridging therapy following leukapheresis. Patients will then receive conditioning chemotherapy (cyclophosphamide and fludarabine) on Day ‒5 to Day ‒3 followed by KITE-363 infusion on Day 0. The primary endpoint for Phase 1A is the incidence of adverse events defined as dose-limiting toxicities. The primary endpoint for Phase 1B is investigator-assessed objective response rate per Lugano criteria (Cheson et al. J Clin Oncol. 2014). Secondary endpoints include complete response rate, time to next treatment, duration of response, progression-free survival, overall survival, safety, and levels of CAR T cells in blood and cytokines in serum. Eligible adult patients have histologically confirmed BCL, including LBCL, indolent non-Hodgkin lymphoma, nodular lymphocyte-predominant Hodgkin lymphoma (HL), and BCL, unclassifiable (with features intermediate between diffuse LBCL and classical HL), that is R/R after ≥2 lines of therapy (patients with LBCL may have primary refractory disease). Other key inclusion criteria are adequate bone marrow and organ function and ECOG performance status 0‒1. Key exclusion criteria are central nervous system (CNS) involvement from lymphoma, active infection including hepatitis B and C, and clinically significant CNS disorder. This study is currently open and accruing patients. Clinical trial information: NCT04989803.

An Update on the Pathology and Molecular Features of Hodgkin Lymphoma.

Simple SummaryHodgkin lymphomas (HLs) include two main types, classic HL (CHL) and nodular lymphocyte predominant HL (NLPHL). Recent molecular findings in HLs have contributed to dramatic changes in the treatment and identification of tumor characteristics. For example, PD-1/PD-L1 blockade and brentuximab vedotin, an anti-CD30 antibody bearing a cytotoxic compound, are now widely used in patients with CHL. Biological continuity between NLPHL and T-cell/histiocyte-rich large B-cell lymphoma has been highlighted. An era of novel therapeutics for HL has begun. The aim of this paper is to review the morphologic, immunophenotypic, and molecular features of CHL and NLPHL, which must be understood for the development of novel therapeutics.Hodgkin lymphomas (HLs) are lymphoid neoplasms derived from B cells and consist histologically of large neoplastic cells known as Hodgkin and Reed–Sternberg cells and abundant reactive bystander cells. HLs include two main types, classic HL (CHL) and nodular lymphocyte predominant HL (NLPHL). Recent molecular analyses have revealed that an immune evasion mechanism, particularly the PD-1/PD-L1 pathway, plays a key role in the development of CHL. Other highlighted key pathways in CHL are NF-κB and JAK/STAT. These advances have dramatically changed the treatment for CHL, particularly relapsed/refractory CHL. For example, PD-1 inhibitors are now widely used in relapsed/refractory CHL. Compared with CHL, NLPHL is more characterized by preserved B cell features. Overlapping morphological and molecular features between NLPHL and T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) have been reported, and biological continuity between these two entities has been highlighted. Some THRLBCLs are considered to represent progression from NLPHLs. With considerable new understanding becoming available from molecular studies in HLs, therapies and classification of HLs are continually evolving. This paper offers a summary of and update on the pathological and molecular features of HLs for a better understanding of the diseases.

Nodular Lymphocyte-predominant Hodgkin Lymphoma With Nodular Sclerosis: An Underrecognized Feature Associated With Pattern D.

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) with unusual features, including some that can overlap morphologically with classic Hodgkin lymphoma (CHL), have been described. Herein, we describe 12 cases of NLPHL with fibrous bands and capsular fibrosis resembling, in part, nodular sclerosis (NS) CHL. Seven of 12 cases harbored Reed-Sternberg-like cells, further suggestive of CHL, but all cases lacked associated eosinophils and/or plasma cells in the background. In this cohort, all cases had areas of so-called pattern D (nodular T-cell rich) as a sole component in 7 (58%) cases or as a hybrid pattern along with pattern E (diffuse T-cell/histiocyte-rich) in 5 (42%) cases. The immunophenotype of the large neoplastic cells in these cases supported their being lymphocyte predominant cells of NLPHL, positive for CD20, CD79a, and OCT2, and negative for CD15 and CD30. However, PAX5 was weak in 9 of 11 cases similar to Hodgkin/Reed-Sternberg cells in CHL. We conclude that some cases of NLPHL are associated with fibrous bands and capsular fibrosis and resemble, in part, NS CHL. In our experience, NLPHL with NS-like features occurs in 10% to 15% of cases of NLPHL and is associated with a variant pattern (D and/or E). In addition, all patients in this cohort were not treated before biopsy, suggesting that the prominent sclerosis in these cases is inherent to disease biology. Recognition of NLPHL with NS-like features further expands the morphologic spectrum of NLPHL and helps avoid potential misdiagnosis as CHL.

Epstein-Barr virus infection patterns in nodular lymphocyte-predominant Hodgkin lymphoma.

To investigate Epstein-Barr virus (EBV) latency types in 19 cases of EBV-positive nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL), as such information is currently incomplete. Immunohistochemistry (IHC) for CD20, CD79a, PAX5, OCT2, CD30, CD15, CD3 and programmed cell death protein 1 was performed. For EBV detection, in-situ hybridisation (ISH) for EBV-encoded RNA (EBER) was employed combined with IHC for EBV-encoded latent membrane protein (LMP)-1, EBV-encoded nuclear antigen (EBNA)-2, and EBV-encoded BZLF1. In 95% of the cases, neoplastic cells with features of Hodgkin and Reed-Sternberg (HRS) cells were present, mostly showing expression of CD30. In all cases, the B-cell phenotype was largely intact, and delineation from classic Hodgkin lymphoma (CHL) was further supported by myocyte enhancer factor 2B (MEF2B) detection. All tumour cells were EBER-positive except in two cases. EBV latency type II was most frequent (89%) and type I was rare. Cases with latency type I were CD30-negative. Five cases contained some BZLF1-positive and/or EBNA-2-positive bystander lymphocytes. As HRS morphology of neoplastic cells and CD30 expression are frequent features of EBV-positive NLPHL, preservation of the B-cell transcription programme, MEF2B expression combined with NLPHL-typical architecture and background composition facilitate distinction from CHL. EBER ISH is the method of choice to identify these cases. The majority present with EBV latency type II, and only rare cases present with latency type I, which can be associated with missing CD30 expression. The presence of occasional bystander lymphocytes expressing BZLF1 and/or EBNA-2 and the partial EBV infection of neoplastic cells in some cases could indicate that EBV is either not primarily involved or is only a transient driver in the pathogenesis of EBV-positive NLPHL.

Nodular Lymphocytic Predominant Hodgkin Lymphoma (NLPHL); Treatment Outcome Study in a Tertiary Care Cancer Hospital in Pakistan

Objective: To determine the demographics, clinical characteristics and treatment outcomes of nodular lymphocytic predominant Hodgkin lymphoma (NLPHL) patients treated at our hospital.&#x0D; Study Design: Retrospective longitudinal study.&#x0D; Place and Duration of Study: Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan from 1996 to 2016.&#x0D; Methodology: We collected clinical data of all the cases of HL diagnosed over twenty years (between 1996 and 2016) from our electronic hospital information system (HIS). A total of 3426 HL patients were identified, out of whom the pathologically confirmed diagnosis of nodular lymphocytic predominant Hodgkin lymphoma (NLPHL) was identified.&#x0D; Results: In this study, eighty-four patients were studied. The majority of the patients were male (80%). B symptoms were present in 35%. There were 24% patients in stage-I (n=20/84), 33% in stage-II (n=28/84), 12% in stage III (n=10/84) and 31% in stage IV (n=26/84). Hence, early-stage was seen in 57% (n=48/84) and advanced stage was 43% (n=36/84) respectively. The Median follows up time was 30 months (range: 1-60 months). Patients were treated with chemotherapy in most cases (48%), radiotherapy alone in 14% cases, and combined modality (chemotherapy and radiotherapy) was used in 38% patients. The estimated 5–year disease-free survival was 73% and overall survival was 86%. Autologous stem cell transplant was done in only one patient whose disease had transformed from NLPHL to T-rich cell B cell lymphoma.&#x0D; Conclusion: This study confirmed the divergent features of NLPHL with a comparatively good long-term prognosis. Most patients achieved an excellent response to first-line therapy. There was...

Linfoma de Hodgkin (LH). Historia de un éxito a lo largo de 50 años

Hodgkin Lymphoma (HL) is a rare B-origin lymphoma that accounts for approximately 10% of all lymphomas. HL is made up of two different entities: on the one hand, the Classical Hodgkin Lymphoma (CHL), consisting of the histological forms of predominantly lymphocytic, nodular sclerosis, mixed cellularity and lymphocytic depletion and, on the other, the Nodular Lymphocyte-Predominant Hodgkin Lymphoma (NLPHL). During the last 50 years, we have seen a move from a monovalent therapy – with a 5-10% survival probability at 5 years – to a combination chemotherapy and a therapeutic approach aimed at reducing the treatment toxicity while maintaining a high probability of cure even in advanced cases. The curative role of radiotherapy in patients with localized Hodgkin’s lymphomas has been observed for about a century. New agents such as Brentuximab and PD-1 antibodies have recently proven to be efficient in recurrent cases and their incorporation to the first line is being studied. Likewise, the role of autologous haematopoietic stem cell transplantation after salvage chemotherapy in first relapse and the role of allogeneic transplantation and the use of anti-CD30 CAR T-cell therapy in relapsed or refractory Hodgkin’s lymphoma are discussed.

IRF8 as a Novel Marker to Differentiate Between CD30-Positive Large Cell Lymphomas.

Interferon regulatory factor 8 (IRF8) is a new biomarker shown to be positive in monocytic leukemias as well as in B cells. As a transcription factor, it plays a critical role in pre-B-cell differentiation and induction of tolerance pathways, among other functions. Given the frequent diagnostic dilemma in CD30-positive large cell lymphomas that could resemble both Hodgkin lymphoma and anaplastic large cell lymphoma (ALCL), we sought to determine whether IRF8 can be useful in distinguishing between these neoplasms that require different treatment strategies. In this retrospective study, 74 cases of classic Hodgkin lymphoma (CHL) and 7 cases of nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) on a tissue microarray (TMA), as well as 15 individual cases of ALK-negative ALCL and 4 cases of ALK-positive ALCL, were stained for IRF8. Paired box 5 (PAX5) immunostaining of the TMA was also performed and compared alongside since that marker is occasionally the only marker to help clinically differentiate between T- and B-cell lymphomas with anaplastic/Hodgkin-like cytology. None (0%) of the ALCLs were positive for IRF8 while all (100%) of the NLPHLs and 85% of the CHLs were positive for IRF8. Six (8%) cases of CHL were PAX5 negative but IRF8 positive. Conversely, seven (10%) cases of CHL were PAX5 positive but IRF8 negative. Four (6%) cases of CHL were negative for both PAX5 and IRF8. There is significant morphologic and immunophenotypic (CD30 positive and CD45 and CD20 negative) overlap between CHL and ALCL. Since many ALCLs show downregulation of lineage-specific T-cell markers or are "null cell" type, only PAX5 has been a reliable marker to differentiate between borderline cases. This is further confounded by positivity of PAX5 in some ALCLs due to amplification of PAX5. On the basis of recent discoveries of IRF8 function as well as performance as an immunostain, we tested this marker in human lymphoma samples and found that it aids in the discrimination between these tumors.

Aberrant expression of lymphoid enhancer–binding factor 1 in Hodgkin lymphoma

Lymphoid enhancer-binding factor 1 (LEF1) is a transcription factor involved in T-cell maturation and is usually absent in mature B cells. Previous studies have shown aberrant LEF1 expression as a sensitive and specific marker in chronic lymphocytic leukemia/small lymphocytic lymphoma. Our primary aims were i) to analyze LEF1 expression in classic Hodgkin lymphomas (CHLs), including de novo and Richter syndrome (RS), and to assess if LEF1 can be a surrogate marker to assess clonal relationship in RSand ii) to compare LEF1 expression in CHL and nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). We included 117 patients: 24 CHL-RS, 66 CHL-de novo, and 27 NLPHL. There was no significant difference in LEF1 expression between CHL-RS and CHL-de novo (79.2% vs 87.9%, P=0.299)or in type I and type II CHL-RS (75% vs 81.3%, P=1.000). However, CHL showed a significantly higher LEF1 expression than NLPHL (85.6% vs 44.4%, P<0.0001). As the Wnt/β-catenin pathway directly regulates LEF1 expression in a β-catenin-dependent way, β-catenin expression was assessed in 76 cases and all were negative. Additionally, no association between Epstein-Barr virus positivity and LEF1 expression was detected. Overall, our findings show high LEF1 expression in CHL, regardless of RS or de novo, indicating LEF1 cannot be utilized as a surrogate marker to suggest clonal relationship in RS. Compared with CHL, LEF1 expression is significantly less common in NLPHL, further attesting that they are biologically distinct entities. The absent β-catenin expression suggests LEF1 expression is independent of Wnt/β-catenin signaling pathway in Hodgkin lymphomas.

Late recurrence of lymphoid malignancies after initial treatment for Hodgkin lymphoma – A study from the Danish Lymphoma Registry

SummaryWe analysed a large cohort of Hodgkin lymphoma (HL) patients in order to characterize: (1) the pattern of late recurrence of lymphoid malignancies (LR) after initial treatment for HL over a 35‐year period; (2) the clinicopathological parameters influencing the risk of LR; and (3) the outcome of patients experiencing LR. We reviewed data of 3350 HL patients diagnosed in Denmark between 1982 and 2018 and registered in the Danish National Lymphoma Registry (LYFO). LR was defined as a recurrence of lymphoid malignancy at least five years after initial diagnosis. LR occurred in 58 patients, with a cumulative incidence at 10, 15 and 20 years of 2.7%, 4.0% and 5.4% respectively. LR was more frequently observed in patients with nodular lymphocyte‐predominant HL (NLPHL) [hazard ratio (HR) 4.5; 95% confidence interval (CI): 2.4–8.4, p < 0.001]. In classical HL (cHL) patients, older age and lymphocytopenia were risk factors for LR with HRs of 1.04 per additional year (95% CI: 1.02–1.06) and 5.6 (95% CI: 2.7–11.5) respectively. Mixed cellularity histological subtype was a risk factor for LR, but only in females, with a HR of 5.4 (95% CI: 1.4–20.4, p = 0.014). In contrast to what was observed in NLPHL, LR in cHL was associated with an almost threefold increased risk of death compared with patients in continuous complete remission. Approximately one fifth (22.4%) of patients with LR experienced a second relapse.