Malignant Lymphoproliferation Research Articles

Heterozygous SERPINA1 Defects and Their Impact on Clinical Manifestations of Patients with Predominantly Antibody Deficiencies.

Patients with predominantly antibody deficiencies (PADs) display hypogammaglobulinemia with a high prevalence of infections, along with autoimmune manifestations, benign and malignant lymphoproliferation and granulomatous disease. It is noteworthy that PAD patients, even those with defects in the same causative genes, display a variable clinical phenotype, suggesting that additional genetic polymorphisms, located in either immune-related or non-immune-related genes, may affect their clinical and laboratory phenotype. In this context, we analyzed 80 PAD patients, including 70 with common variable immunodeficiency (CVID) for SERPINA1 defects, in order to investigate the possible contribution to PAD clinical phenotype. Ten CVID patients carried heterozygous pathogenic SERPINA1 defects with normal alpha-1 antitrypsin levels. Interestingly, the presence of the Z allele (rs28929474), which was found in three patients, was significantly associated with liver disease; hepatic complications were also observed in patients carrying the p.Leu23Gln (rs1379209512) and the p.Phe76del (rs775982338) alleles. Conversely, no correlation of SERPINA1 defective variants with respiratory complications was observed, although patients with pathogenic variants exhibit a reduced probability of developing autoimmune diseases. Therefore, we recommend SERPINA1 genetic analysis in PAD in order to identify patients with a higher risk for liver disease.

Diagnostics différentiels de la maladie de Castleman

Clinicians are sometimes confronted with the diagnostic difficulties of the idiopathic form of Castleman's Disease (iMCD). As this review reports with demonstrative clinical cases, iMCD can mimic various serious systemic pathologies such as certain autoimmune diseases, Still's disease, POEMS syndrome, and malignant lymphoproliferations, sharing a very similar histology and identical symptoms. To make a diagnosis of iMCD, the clinician must eliminate all the pathologies mentioned above, but he must first think of it and evoke this diagnosis of rare disease before the first symptoms but also know how to evoke this diagnosis again even after several years of evolution of a disease like those mentioned above whose evolution is not favorable. © 2022 Published by Elsevier Masson SAS on behalf of Société nationale française de médecine interne (SNFMI).

Common variable immunodeficiency in two kindreds with heterogeneous phenotypes caused by novel heterozygous NFKB1 mutations.

NFKB1 haploinsufficiengcy was first described in 2015 in three families with common variable immunodeficiency (CVID), presenting heterogeneously with symptoms of increased infectious susceptibility, skin lesions, malignant lymphoproliferation and autoimmunity. The described mutations all led to a rapid degradation of the mutant protein, resulting in a p50 haploinsufficient state. Since then, more than 50 other mutations have been reported, located throughout different domains of NFKB1 with the majority situated in the N-terminal Rel homology domain (RHD). The clinical spectrum has also expanded with possible disease manifestations in almost any organ system. In silico prediction tools are often used to estimate the pathogenicity of NFKB1 variants but to prove causality between disease and genetic findings, further downstream functional validation is required. In this report, we studied 2 families with CVID and two novel variants in NFKB1 (c.1638-2A>G and c.787G>C). Both mutations affected mRNA and/or protein expression of NFKB1 and resulted in excessive NLRP3 inflammasome activation in patient macrophages and upregulated interferon stimulated gene expression. Protein-protein interaction analysis demonstrated a loss of interaction with NFKB1 interaction partners for the p.V263L mutation. In conclusion, we proved pathogenicity of two novel variants in NFKB1 in two families with CVID characterized by variable and incomplete penetrance.

Spatial Dispersal of Epstein-Barr Virus in South America Reveals an African American Variant in Brazilian Lymphomas.

Epstein–Barr virus (EBV) is a saliva-borne ɣ-herpesvirus associated with benign and malignant lymphoproliferation. EBV-mediated tumorigenic mechanisms are not fully understood and may be related to viral genetic variations. In this work, we characterize the genetic diversity of EBV from Brazil, assessing 82 samples derived from saliva from asymptomatic carriers (n = 45), biopsies of benign reactive hyperplasia (n = 4), and lymphomas (n = 33). Phylogenetic and phylogeographic analysis of the entire coding region of the LMP-1 was performed. Additionally, type 1/type 2 distinction by the EBNA3C gene and Zp variants were evaluated. Our results revealed a high diversity of EBV in Brazil, with the co-circulation of four main clades, described here as: Mediterranean (40.2%, n = 33), Raji/Argentine (39%, n = 32), B95-8 (6.1%, n = 5), and Asian II (1.2%, n = 1). The Raji/Argentine and Mediterranean clades were the most prevalent in South America (45% and 28%, respectively). The Raji/Argentine clade was associated with polymorphisms I124V/I152L, del30 bp, and ins15 bp (p < 0.0001, to all clades) and with a high haplotype diversity related to EBV type and Zp variants. We found that a Raji/Argentine subclade spread primarily from Brazil and later to other South American countries. Although no LMP1 variant has been directly associated with disease, the Raji/Argentine clade was predominantly clustered with lymphomas (61%) and the Mediterranean clade with non-malignant cases (59%) (p = 0.1). These data highlight the high genetic diversity of EBV circulating in Brazil, calling attention to a Raji-related variant with great recombination potential in Brazilian lymphomas.

Lymphoproliferation in Inborn Errors of Immunity: The Eye Does Not See What the Mind Does Not Know.

Inborn errors of immunity (IEIs) are a group of heterogeneous disorders characterized by a broad clinical spectrum of recurrent infections and immune dysregulation including autoimmunity and lymphoproliferation (LP). LP in the context of IEI may be the presenting feature of underlying immune disorder or may develop during the disease course. However, the correct diagnosis of LP in IEI as benign or malignant often poses a diagnostic dilemma due to the non-specific clinical features and overlapping morphological and immunophenotypic features which make it difficult to treat. There are morphological clues to LP associated with certain IEIs. A combination of ancillary techniques including EBV-associated markers, flow cytometry, and molecular assays may prove useful in establishing a correct diagnosis in an appropriate clinical setting. The present review attempts to provide comprehensive insight into benign and malignant LP, especially the pathogenesis, histological clues, diagnostic strategies, and treatment options in patients with IEIs.

The paradigm of hematological malignant versus non-malignant manifestations, driven by primary immunodeficiencies: a complex interplay.

Hematological malignancies (HM) developed on underlying primary immunodeficiencies (PID) are rare and of unusual features. Differentiating between malignant and non-malignant lymphoproliferation in cases of pediatric hematology and oncology and revealing their molecular predisposition demonstrate the complex interplay between PID and HM. We retrospectively studied a case series of seven pediatric patients, all with PID with manifestations raising suspicion for HM or hypereosinophilic syndrome (HES) or confirmed HM of lymphoid origin. Combined immunodeficiency (CID) without detection of a known mutated gene or with ataxia-telangiectasia (AT), STAT3 gain of function (GOF), DOCK8 deficiency, and CTLA4 deficiency were diagnosed in three, one, one, one, and one patient, respectively. Acute lymphoblastic leukemia and Hodgkin lymphoma followed by second primary Burkitt lymphoma were diagnosed in one patient with CID each, while lymphomatoid granulomatosis in one patient with AT. Lymphoproliferative disease occurred in STAT3 GOF, CTLA4 deficiency and CID, one patient each, and idiopathic HES in DOCK8 deficiency (median age at presentation of PID or any hematological manifestation: four years). Four patients underwent hematopoietic cell transplantation (HCT) for STAT3 GOF, DOCK8 deficiency and CID in one, one, and two cases, respectively (median age: 10years). At the last follow-up, all transplanted patients were alive. Reporting on patients' phenotype, genotype and course of disease shed light on the prevalence, characteristics, and pathophysiology of HM complicating PID. Discriminating the non-yet malignant lymphoproliferation from its malignant equivalent on the same pathophysiology background proved of additional value. Outcomes of PID after HCT, herein reported, are favorable.

Determination of the Expression of Latent Epstein Barr Virus in Omani Nasopharyngeal Carcinoma Patients

Background: Nasopharyngeal carcinoma(NPC) is a rare malignant carcinoma that develops in the epithelial lining of the nasopharyngeal mucosa It is the most common neoplasm of the Nasopharynxand it is associated with many risk factors; one of them is Epstein-Barr virus infection. An Epstein-Barr virus is a tumorigenic herpes virus that infects and persists in B-lymphocytes without causing disease. This virus is associated with significant pathological conditions, such as benign and malignant lymphoproliferation. Objectives: To determine Epstein -Barr encoded RNA 1&amp;2 (EBER1,2) and latent membrane protein (LMP) expressionin formalin-fixed paraffin-embedded tissue samples obtained from Omani patients diagnosed with nasopharyngeal carcinoma.Also, to identify the pattern and the type(s) of cells infected with EBV in nasopharyngeal carcinoma tissue samples obtained from Omani patients. Moreover, to compare the sensitivity of Immuno histochemistry and in-situ Hybridization for the detection of EBV in the nasopharyngeal carcinoma tissue sample. Materials and Method:Thirteen formalin-fixed paraffin-embedded nasopharyngeal carcinoma tissue samples archived from the period 2010 to 2017, were obtained from the Pathology Departments of Sultan Qaboos University Hospital and the Armed Force Hospital. These tissue samples were processed using two different methods Immunohistochemistry (IHC) and In situ hybridization (ISH). Results:Eleven out of thirteen NPC Omani patients were positive for EBV (84.61%) by either LMP-IHC or EBER-ISH. All cells stained positive for EBV in NPC tissue samples was of malignant type rather than normal cell type. EBV is mostly detected in patients in the age group of less than 50 years old. Also out of the 13 NPC patients, seven females (58.34%), and six males (46.15%) were positive for EBV. Conclusion:This study may provide evidence indicating an association between EBV and nasopharyngeal carcinoma. In addition, the detection of EBV in NPC obtained from Omani patients may encourage the physician to consider using anti-herpes virus drugs in the treatment of EBV positive NPC patients as an additional tool for the treatment of this kind of malignancy.

T-cell receptor antibodies expression in benign and malignant cutaneous lymphoid infiltrates in comparison with T-cell receptor gene rearrangement and its diagnostic utility in borderline cases

IntroductionCutaneous T-cell lymphoid infiltrate can represent reactive lesion or a malignant T-cell lymphoma. However, clinical and histopathological appearance can overlap in both groups with a risk of misdiagnosis. Aberrant expression of T-cell markers is not always applicable and T-cell receptor (TCR) gene rearrangement is not always accessible and diagnosis in borderline cases can be challenging. AimsSeveral types of TCR antibodies are currently available with limited knowledge of their expression in different cutaneous lymphoid infiltrates. Aim of the study is a comparison of expression of TCR antibodies in benign and malignant lymphoid infiltrates and their utility in borderline cases. MethodsRepresentative cases of reactive and malignant lymphoproliferations were collected. Separate group of lesions with borderline morphology was selected for comparison. Immunohistochemical expression of TCR-V-betaF1 (TCRBF1), TCR-C-beta1 (TCRJOVI.1), TCR gamma/delta (TCRGD) and TCR delta (TCRD) was performed in all cases. TCR gene rearrangement evaluation was performed in all cases using PCR BIOMED-2 assay. ResultsBenign lymphoid infiltrates were all negative in TCRD and TCRGD. Expression of TCRJOVI.1 was seen in 3/10 cases and TCRBF1 in one. T-cell lymphomas were positive for TCRBF1 and TCRGD in 60% and 30% of cases respectively. TCR gene rearrangement was confirmed in 90% of lymphoma cases. All benign lesions were polyclonal. Morphologically borderline lesions showed expression of TCRBF1 in 6/10 cases and TCR gene rearrangement in 4/10 cases. Re-evaluation of the cases and clinical correlation led to the change of the diagnosis and confirmation of T-cell lymphoma in 4/10 cases. ConclusionsExpression of TCRBF1 and TCR-gene rearrangement was significantly associated with malignant infiltrates. TCRBF1 positivity in borderline cutaneous lymphoproliferations can raise the suspicion of malignancy but confirmation by TCR gene rearrangement and careful clinical correlation is still advisable.

CAR-T Cells Targeting Epstein-Barr Virus gp350 Validated in a Humanized Mouse Model of EBV Infection and Lymphoproliferative Disease

Epstein-Barr virus (EBV) is a latent and oncogenic human herpesvirus. Lytic viral protein expression plays an important role in EBV-associated malignancies. The EBV envelope glycoprotein 350 (gp350) is expressed abundantly during EBV lytic reactivation and sporadically on the surface of latently infected cells. Here we tested T cells expressing gp350-specific chimeric antigen receptors (CARs) containing scFvs derived from two novel gp350-binding, highly neutralizing monoclonal antibodies. The scFvs were fused to CD28/CD3ζ signaling domains in a retroviral vector. The produced gp350CAR-T cells specifically recognized and killed gp350+ 293T cells in vitro. The best-performing 7A1-gp350CAR-T cells were cytotoxic against the EBV+ B95-8 cell line, showing selectivity against gp350+ cells. Fully humanized Nod.Rag.Gamma mice transplanted with cord blood CD34+ cells and infected with the EBV/M81/fLuc lytic strain were monitored dynamically for viral spread. Infected mice recapitulated EBV-induced lymphoproliferation, tumor development, and systemic inflammation. We tested adoptive transfer of autologous CD8+gp350CAR-T cells administered protectively or therapeutically. After gp350CAR-T cell therapy, 75% of mice controlled or reduced EBV spread and showed lower frequencies of EBER+ B cell malignant lymphoproliferation, lack of tumor development, and reduced inflammation. In summary, CD8+gp350CAR-T cells showed proof-of-concept preclinical efficacy against impending EBV+ lymphoproliferation and lymphomagenesis.

Exhausted phenotype of follicular CD8 T cells in CVID

Exhausted phenotype of follicular CD8 T cells in CVID

Role of Vav1 Genomic Alterations in T-Cell Differentiation and Transformation in Peripheral T-Cell Lymphoma

Peripheral T-cell lymphomas (PTCL) are highly aggressive, malignant hematologic tumors that arise from clonal proliferation of mature post-thymic T-cells. Among these, angioimmunoblastic T-cell lymphoma (AITL), and peripheral T-cell lymphomas not otherwise specified (PTCL, NOS) account for &amp;gt;45% diagnoses, show limited response to intensified chemotherapy treatment with dismal overall survival rate. Our genomic studies have uncovered recurrent mutations and novel cancer-associated gene fusions involving the guanine nucleotide exchange factor VAV1 in AITL and PTCL, NOS, supporting a role for the VAV1 oncogene in the pathogenesis of PTCL. Genetic alterations in VAV1 found in PTCL included recurrent deletions resulting in the in-frame deletion of 9 codons (DV778_T786) in the linker region connecting the C-terminal SH2 domain to the downstream SH3 domain on VAV1 as well as recurrent different gene-fusion transcripts encoding proteins in which the C-terminal SH3 domain of VAV1 is replaced by different domains of the fusion partner. Consistent with the auto-inhibitory role of the C-SH3 domain, the PTCL-associated VAV1 alterations resulted in increased VAV1 activity and strong activation of the mitogen-activated protein kinase (ERK1/2), c-Jun N-terminal kinase (JNK) and nuclear factor of activated T-cells (NFAT) pathways. Interestingly, mutation co-occurrence analysis shows significant mutual exclusivity of the highly prevalent AITL RHOA G17V mutation and VAV1 genomic alterations (p-value 0.0142) in AITL and PTCL, NOS. This observation supports that VAV1 genetic alterations and RHOA G17V could share a common mechanism of action. To study the role and mechanisms of VAV1 alterations in PTCL in vivo we have engineered a C57/BL6 mouse lines with conditional expression of the recurrent Vav1-Myo1f fusion. By crossing Vav1-myo1f conditional knockin with CD4-CreERT2 mouse deletor line, we have generated animals with CD4+ T cell-specific and tamoxifen-inducible expression of Vav1-myo1f. Preliminary studies indicate that expression of Vav1-myo1f in CD4+ cells induces expansion of TFH cells. This phenotype partially resembles that of animals with CD4 specific expression of Rhoa G17V, indicating a potential convergent effect and mechanisms for VAV1 alterations and RHOA G17V in T-cell development and transformation. However, and more interestingly, Vav1-myo1f expressing cells specifically present a memory cell-associated immunophenotype (CD44+ CD62L-) and characteristic Th2-like features that had not been observed in the Rhoa G17V model. Analysis of signaling pathways activated in control and Vav1-myo1f expressing CD4+ cells showed increased phosphorylation of Vav1 and increased activation of the MAPK pathway upon expression of Vav1-myo1f, supporting the role of Vav1 alterations as regulators of T-cell activation. Notably, single cell transcriptome analysis of bulk splenic cells isolated from CD4-CreERT2 control and CD4-CreERT2Vav1co-Vav1-myo1f/WT mice indicate that expression of Vav1-myo1f in CD4+ cells leads to a significant expansion of monocytes and TFH cells and a decrease in B-cell, both naïve and memory. These results support that expression of Vav1-myo1f in CD4+ cells can deeply modify the lymphoid microenvironment. Finally, preliminary analysis of a limited number of mice with targeted expression of the Vav1-Myo1f fusion in CD4+ cells (CD4-Cre Vav1co-Vav1-Myo1f /WT) showed development of a fatal CD4+ malignant lymphoproliferation with a latency of 6-14 months. Histological examination showed disrupted splenic architecture accompanied with clonal expansion of CD4+ cells indicative of T-cell lymphoma with PTCL, NOS characteristics and verified expression of both wild type Vav1 and Vav1-myo1f alleles. Interestingly, Vav1-myo1f lymphoma cells showed Th2 associated features including expression of Gata3, c-Maf and IL4 and Il10. These results support an important role for VAV1 alterations in T-cell differentiation, remodeling of the tumor microenvironment and T-cell lymphoma development and highlight the importance of our model as a new experimental system to study the evolution of PTCL and develop novel targeted therapies for this disease. Disclosures Palomero: Kura Oncology: Research Funding.

Cytokine Networks Dysregulation during HTLV-1 Infection and Associated Diseases.

Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of a neural chronic inflammation, called HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and of a malignant lymphoproliferation, called the adult T-cell leukemia/lymphoma (ATLL). The mechanisms through which the HTLV-1 induces these diseases are still unclear, but they might rely on immune alterations. HAM/TSP is associated with an impaired production of pro-inflammatory cytokines and chemokines, such as IFN-γ, TNF-α, CXCL9, or CXCL10. ATLL is associated with high levels of IL-10 and TGF-β. These immunosuppressive cytokines could promote a protumoral micro-environment. Moreover, HTLV-1 infection impairs the IFN-I production and signaling, and favors the IL-2, IL-4, and IL-6 expression. This contributes both to immune escape and to infected cells proliferation. Here, we review the landscape of cytokine dysregulations induced by HTLV-1 infection and the role of these cytokines in the HTLV-1-associated diseases progression.

The Pathological Spectrum of Systemic Anaplastic Large Cell Lymphoma (ALCL).

Anaplastic large cell lymphoma (ALCL) represents a group of malignant T-cell lymphoproliferations that share morphological and immunophenotypical features, namely strong CD30 expression and variable loss of T-cell markers, but differ in clinical presentation and prognosis. The recognition of anaplastic lymphoma kinase (ALK) fusion proteins as a result of chromosomal translocations or inversions was the starting point for the distinction of different subgroups of ALCL. According to their distinct clinical settings and molecular findings, the 2016 revised World Health Organization (WHO) classification recognizes four different entities: systemic ALK-positive ALCL (ALK+ ALCL), systemic ALK-negative ALCL (ALK− ALCL), primary cutaneous ALCL (pC-ALCL), and breast implant-associated ALCL (BI-ALCL), the latter included as a provisional entity. ALK is rearranged in approximately 80% of systemic ALCL cases with one of its partner genes, most commonly NPM1, and is associated with favorable prognosis, whereas systemic ALK− ALCL shows heterogeneous clinical, phenotypical, and genetic features, underlining the different oncogenesis between these two entities. Recognition of the pathological spectrum of ALCL is crucial to understand its pathogenesis and its boundaries with other entities. In this review, we will focus on the morphological, immunophenotypical, and molecular features of systemic ALK+ and ALK− ALCL. In addition, BI-ALCL will be discussed.

Cutaneous lymphomas with a panniculitic presentation.

Subcutaneous panniculitis-like T-cell lymphoma and primary cutaneous gamma/delta T-cell lymphoma are the two most common types of cutaneous T-cell lymphoma presenting with panniculitis-like lesions. In this article the characteristic clinical, histological and immunophenotypical features of these conditions are reviewed and criteria to differentiate these tumors from other benign and malignant lymphoproliferations presenting with panniculitis-like lesions are discussed.

Chronic and recurrent benign lymphadenopathy without constitutional symptoms associated with human herpesvirus-6B reactivation.

Chronic/recurrent behaviour may be encountered in some distinct atypical or malignant lymphoproliferations, while recurrences are not generally observed in reactive/benign lymphadenopathies. We retrospectively analysed a consecutive series of 486 human immunodeficiency virus-negative adults, who underwent lymphadenectomy. Neoplastic and benign/reactive histopathological pictures were documented in 299 (61·5%) and 187 (38·5%) cases, respectively. Of note, seven of the 111 (6·3%) patients with benign lymphadenopathy without well-defined aetiology, showed chronic/recurrent behaviour, without constitutional symptoms. Enlarged lymph nodes were round in shape and hypoechoic, mimicking lymphoma. Reactive follicular hyperplasia and paracortical expansion were observed. Human herpesvirus (HHV)-6B positive staining in follicular dendritic cells (FDCs) was documented in all seven patients. Serological, molecular and immunological examinations suggested HHV-6B reactivation. Among the remaining 104 cases with reactive lymphoid hyperplasia in the absence of well-known aetiology and without recurrences, positivity for HHV-6B on FDCs was found in three cases, whereas in seven further patients, a scanty positivity was documented in rare, scattered cells in inter-follicular regions. Immunohistochemistry for HHV-6A and HHV-6B was invariably negative on 134 lymph nodes, with either benign pictures with known aetiology or malignant lymphoproliferative disorders, tested as further controls. Future studies are warranted to investigate a potential association between HHV-6B reactivation and chronic/recurrent benign lymphadenopathy.

Treatment of an aggressive STLV-1 associated lymphoma in a naturally infected baboon

Human T Lymphotropic Virus type 1 infection is associated with a malignant lymphoproliferation named Adult T cell Leukemia/Lymphoma (ATLL). STLV-1, the simian counterpart of HTLV-1 also causes an ATLL-like disease. During the surveillance of our STLV-1 naturally infected Papio anubis cohort (n=45), we identified a 9 years-old female baboon exhibiting dyspnea, marked emaciation, and a lymphocyte count over 1010/L, pulmonary metastases and skin lesions similar to that observed in human ATLL patients. These symptoms suggested a hematologic malignancy induced by STLV1. This diagnosis was confirmed by the evidence of massive lymphoproliferation in an inguinal lymph node biopsy and the presence of lymphocytes with characteristic abnormal nuclei (i.e. flower cells) in blood smears. As is the case for humans, the animal received a combination of AZT (Combivir) and alpha interferon (viraferon, 50 μg/week) for 4 months. During this period, blood proviral load (PVL) was measured every week. Due to the absence of health improvement and only a slight decrease in the PVL, the animal was euthanased. Histological analysis of the secondary lymphoid organs was performed, and PVL was measured in 25 different organs. All lymphoid organs contained CD3+, CD25+ lymphocytic infiltrates. Furthermore, lymphoma cells were found in lungs and liver. Tax-positive cells were detected by immunohistochemistry in spleen, lung, mesenteric, axillary, inguinal, tracheo-bronchial, lymph nodes. While all organs were PCR positive, the highest PVL was found in lymph nodes, spleen and lungs. Finally, the oligoclonality and the clonal diversity was analyzed in PBMCs throughout the treatment but also in the different organs. In conclusion, non-human primates naturally infected with STLV-1 represent a useful model to study viral pathogenesis and to evaluate new treatments.

Inhibition of UDP-glucosylceramide synthase in mice prevents Gaucher disease-associated B-cell malignancy.

Clonal B-cell proliferation is a frequent manifestation of Gaucher disease - a sphingolipidosis associated with a high risk of multiple myeloma and non-Hodgkin lymphoma. Gaucher disease is caused by genetic deficiency of acid β-glucosidase, the natural substrates of which (β-d-glucosylceramide and β-d-glucosylsphingosine) accumulate, principally in macrophages. Mice with inducible deficiency of β-glucosidase [Gba(tm1Karl/tm1Karl)Tg(MX1-cre)1Cgn/0] serve as an authentic model of human Gaucher disease; we have recently reported clonal B-cell proliferation accompanied by monoclonal serum paraproteins and cognate tumours in these animals. To explore the relationship between B-cell malignancy and the biochemical defect, we treated Gaucher mice with eliglustat tartrate (GENZ 112638), a potent and selective inhibitor of the first committed step in glycosphingolipid biosynthesis. Twenty-two Gaucher mice received 300 mg/kg of GENZ 112638 daily for 3-10 months from 6 weeks of age. Plasma concentrations of β-d-glucosylceramide and the unacylated glycosphingolipid, β-d-glucosylsphingosine, declined. After administration of GENZ 112638 to Gaucher mice for 3-10 months, serum paraproteins were not detected and there was a striking reduction in the malignant lymphoproliferation: neither lymphomas nor plasmacytomas were found in animals that had received the investigational agent. In contrast, 14 out of 60 Gaucher mice without GENZ 112638 treatment developed these tumours; monoclonal paraproteins were detected in plasma from 18 of the 44 age-matched mice with Gaucher disease that had not received GENZ 112638. Long-term inhibition of glycosphingolipid biosynthesis suppresses the development of spontaneous B-cell lymphoma and myeloma in Gaucher mice.

EBV Microrna Mir-BHRF1-2 Targets PRDM1/Blimp1: Potential Role in EBV Lymphomagenesis

PRDM1/Blimp1, a master regulator of B-cell terminal differentiation, has been identified as a tumor suppressor gene in the pathogenesis of diffuse large B-cell lymphoma (DLBCL). In DLBCL, PRDM1 is inactivated by mutations and deletions; however, there is also evidence that PRDM1 is down-regulated by microRNAs (miRNAs) in DLBCL and Hodgkin/Reed-Sternberg cells of classical Hodgkin lymphoma (cHL). A decrease in PRDM1 activity contributes to the pathogenesis of DLBCL and cHL by inhibiting plasma cell differentiation triggered by signal transduction pathways such as the NF-kB pathway. Since malignant EBV-positive B-cell lymphoproliferations are often associated with increased NF-kB activity, it is conceivable that abnormal PRDM1 down-regulation may play a role in their pathogenesis.EBV-positive B-cell lymphomas are postulated to originate from EBV-infected B-cells with latency III growth program of EBV gene expression. Thus, EBV-immmortalized lymphoblastoid cell lines (LCLs), which are of latency III type, serve as a good model to study EBV lymphomagenesis. We observed discordance in PRDM1 mRNA and protein levels in LCLs. By quantitative real-time reverse transcriptase PCR, PRDM1 mRNA levels in LCLs varied from 14.6% to 1259.7% relative to the multiple myeloma cell line U266, which expresses high levels of PRDM1. However, PRDM1 protein was discordantly low in LCLs compared to U266 based on immunohistochemistry and Western blotting assays, consistent with post-transcriptional regulation. EBV encodes 25 viral miRNAs, and we postulate that one of more of them may function to dampen PRDM1 expression. Indeed, a miRNA binding site containing seed match to bases 2-7 of EBV miR-BHRF1-2 was identified in positions 1565 to 1589 of PRDM1 3’ untranslated region. MiR-BHRF1-2 functionally targeted this specific binding site and repressed luciferase reporter activity. Mutation in the seed region of this site relieved the repression in comparison to the wild type control.MiR-BHRF1-2 was highly expressed in LCLs, while it was barely detectable in the EBV-positive Burkitt lymphoma cell line MUTU I, which has latency type I. Importantly, immunoblotting assay demonstrated an up-regulation of PRDM1 protein level in CCL156 and CCL159 LCL cells transfected with miR-BHRF1-2 inhibitor relative to those transfected with miRNA Inhibitor negative control, supporting a role of miR-BHRF1-2 in PRDM1 down-regulation in vivo. To examine the biological consequences of increased PRDM1 expression in LCL cells, PRDM1 was over-expressed in JY25 and CCL159 LCL cell lines. Enforced expression of PRDM1 induced apoptosis in both cell lines. Furthermore, bromodeoxyuridine (Brdu) incorporation study demonstrated that overexpression of PRDM1 reduced the percentage of S phase from 43.4% to 27.6% in CCL159 cells, and 39.5% to 27.9% in JY25 cells, respectively. Whole transcriptome sequencing (RNA-seq) identified a set of potential PRDM1 direct target genes whose expressions decreased in both LCL cell lines upon PRDM1 over-expression. These genes have broad functions including cell proliferation and survival, transcription and translation, mitochondrial functions, and cytoskeleton. Although no significant changes in cell cycle and apoptosis were observed upon transfection of miR-BHRF1-2 inhibitor, RNA-seq analysis of CLL159 cells transfected with miR-BHRF1-2 inhibitor revealed a small subset of repressed genes which overlapped with those identified by PRDM1 over-expression. This finding suggests that the increase in PRDM1 expression upon miR-BHRF1-2 inhibition, albeit small, is capable of repressing a subset of PRDM1 target genes with potential biological effects.In summary, our findings demonstrate that PRDM1 is a target of EBV miR-BHRF1-2. MiR-BHRF1-2 mediated PRDM1 down-regulation may contribute to the pathogenesis of EBV-associated B-cell lymphomas by inhibiting the transcription repression program of PRDM1 and limiting PRDM1-mediated cellular changes detrimental to tumor growth, including cell cycle arrest and apoptosis. Further characterization of the target genes whose expression is up-regulated by miR-BHRF1-2-mediated PRDM1 down-regulation may provide important clues to the pathogenetic function of miR-BHRF1-2 and EBV oncogenesis in general. DisclosuresNo relevant conflicts of interest to declare.

The analysis of clonal diversity and therapy responses using STAT3 mutations as a molecular marker in large granular lymphocytic leukemia.

T-cell large granular lymphocytic leukemia and chronic lymphoproliferative disorder of natural killer cells are intriguing entities between benign and malignant lymphoproliferation. The molecular pathogenesis has partly been uncovered by the recent discovery of somatic activating STAT3 and STAT5b mutations. Here we show that 43% (75/174) of patients with T-cell large granular lymphocytic leukemia and 18% (7/39) with chronic lymphoproliferative disorder of natural killer cells harbor STAT3 mutations when analyzed by quantitative deep amplicon sequencing. Surprisingly, 17% of the STAT3-mutated patients carried multiple STAT3 mutations, which were located in different lymphocyte clones. The size of the mutated clone correlated well with the degree of clonal expansion of the T-cell repertoire analyzed by T-cell receptor beta chain deep sequencing. The analysis of sequential samples suggested that current immunosuppressive therapy is not able to reduce the level of the mutated clone in most cases, thus warranting the search for novel targeted therapies. Our findings imply that the clonal landscape of large granular lymphocytic leukemia is more complex than considered before, and a substantial number of patients have multiple lymphocyte subclones harboring different STAT3 mutations, thus mimicking the situation in acute leukemia.

Anakinra treatment in Schnitzler syndrome - results of the first retrospective multicenter study in six patients from the Czech Republic

Schnitzler syndrome is a very rare, acquired, autoinflammatory disease of mostly adult onset with characteristic combination of chronic recurrent urticaria and monoclonal immunoglobulin M or G gammopathy predisposing the patients to malignant lymphoproliferation. In this work, we analyzed the results of bio-logical therapy with anakinra on a national level aiming to supply data for effective pharmaco-economic estimates, lay the grounds of nationwide patient registry, raise awareness among professional public and optimize provided health care. The retrospective study (10/ 2006- 9/ 2013) included six males with definite Schnitzler syndrome verified by the new Strasbourg criteria. All patients were pretreated with antihistamines, nonsteroidal antiinflammatory drugs and glucocorticoids. Four patients underwent two or more treatment lines including intravenous bisphosphonates, 2- chlorodeoxyadenosine (cladribine), interferonα, PUVA photochemotherapy, cyclosporine A, thalidomide, bortezomib, chlorambucil, cyclophosphamide, colchicine and methotrexate. Anakinra monotherapy was initiated in standard dosing (100 mg subcutaneously daily). Complete and partial remissions were achieved in five (83%) and one patients (17%), respectively. Complete remission was characterized by urticaria and pain regression (within hours), normalization of inflammatory markers (with--in days) and bone metabolism improvement assessed by the markers of osteoblastic osteoformation and osteoclastic osteoresorption in one case (within weeks). With normalized inflammatory markers (including interleukin6 and interleukin18), arthralgia and sporadic exacerbations of urticaria and fevers persist in the patient in partial remission with proven Q703K polymorphism in NLRP3 gene. The median treatment followup was 30.5 months (37.2 ± 31.2 (n = 6)). The dosing interval was prolonged in one case of complete remission to 48 hours. No serious adverse reactions occurred during anakinra application. In Schnitzler syndrome, anakinra represents an effective, verified and safe medication with potentionally longterm administration not compromising its original efficacy and subjective tolerance. Anakinra, blocking autonomous inflammatory reaction of the organism via interleukin1 pathway, is a generally accepted first line treatment that should be made available in standard dosing for all Schnitzler patients.