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N-linked glycans play an important role in immunity. Although the role of N-linked glycans in the Fragment crystallizable (Fc) region of immunoglobulins has been thoroughly described, the function of N-linked glycans present in Ig-variable domains is only just being appreciated. Most of the N-linked glycans harbored by immunoglobulin variable domain are of the complex biantennary type and are found as a result of the presence of N-linked glycosylation that most often have been introduced by somatic hypermutation. Furthermore, these glycans are ubiquitously present on autoantibodies observed in some autoimmune diseases as well as certain B-cell lymphomas. For example, variable domain glycans are abundantly found by anti-citrullinated protein antibodies (ACPA) in rheumatoid arthritis (RA) as well as by the B-cell receptors of follicular lymphoma (FL). In FL, variable domain glycans are postulated to convey a selective advantage through interaction with lectins and/or microbiota, whereas the contribution of variable domain glycans on autoantibodies is not known. To aid the understanding how these seemingly comparable phenomena contribute to a variety of deranged B-responses in such different diseases this study summarizes the characteristics of ACPA and other auto-antibodies with FL and healthy donor immunoglobulins, to identify the commonalities and differences between variable domain glycans in autoimmune and malignant settings. Our finding indicate intriguing differences in variable domain glycan distribution, frequency and glycan composition in different conditions. These findings underline that variable domain glycosylation is a heterogeneous process that may lead to a number of pathogenic outcomes. Based on the current body of knowledge, we postulate three disease groups with distinct variable domain glycosylation patterns, which might correspond with distinct underlying pathogenic processes. [ABSTRACT FROM AUTHOR]

The article focuses on immunoglobulin class switch recombination (CSR) of B-cell receptors (BCR) in follicular lymphoma (FL), particularly on the impact of class switching on a more aggressive FL. Topics discussed include procedure observed in BCR selection, prognostic significance of N-glycosylation sites found in most FL, and BCR as a stable immunobiological feature of FL.

Extra-nodal NK/T lymphoma (ENKTL) is rare and more frequently encountered in East Asia. The role of high-dose therapy and autologous stem cell transplantation (HDT-ASCT) for ENKTL is unclear. Twenty-eight evaluable patients who had undergone HDT-ASCT in Europe from 2000–2009 were studied. The median age was 47 years and patients had received a median of two lines of prior therapy. Some 57% of patients were not in complete remission or beyond first complete remission at HDT-ASCT. The 1-year non-relapse mortality (NRM) was 11%; 2-year progression-free survival (PFS) and overall survival (OS) rates were 41% and 52%, respectively. Notably, the 2-year PFS and OS for those with stage III/IV disease were 33% and 40%, respectively, with no relapses beyond 1-year post-HDT-ASCT. This is the largest analysis of HDT-ASCT for patients with ENKTL reported from the Western hemisphere. Survival is comparable to East Asian cohorts and outcomes are encouraging for patients with advanced disease. [ABSTRACT FROM AUTHOR]

Studies on pharmacokinetics and pharmacodynamics of high-dose methotrexate chemotherapy (HD-MTX) in elderly primary central nervous system lymphoma (PCNSL) patients are rare. MTX exposure time has recently been proposed as an outcome determining factor in PCNSL. We investigated 49 immunocompetent PCNSL patients (female N = 30, male N = 19, median age 73 years) who were treated according to HD-MTX-based protocols. A two-compartment pharmacokinetic model was used to describe the MTX clearance. Response to treatment was assessed by MRI. We used multivariable models to investigate the association between MTX exposure and tumor response as well as survival. Dose normalized MTX peak serum levels [ C, μmol/L g] and dose normalized area under the curve [AUC, μmol h/L g] were higher in females than in males, respectively [59.4 (f) vs. 48.1 (m), P < 0.001; 373.2 (f) vs. 271.9 (m), P = 0.008]. Increasing AUC was inversely correlated with tumor response. AUC values above 2,126 h μmol/L were independently associated with shorter overall and progression-free survival [hazard ratio (HR), 4.56, 95 % CI 1.74-11.94; HR 2.87, 95 % CI 1.18-7.00]. Exceedingly high MTX AUC levels can have a negative impact on progression-free and overall survivals in elderly PCNSL patients. [ABSTRACT FROM AUTHOR]

Activation-induced deaminase (AID) is required for somatic hypermutation in immunoglobulin genes, but also induces off-target mutations. Follicular lymphoma (FL) and chronic lymphocytic leukemia (CLL), the most frequent types of indolent B-cell tumors, are exposed to AID activity during lymphomagenesis. We designed a workflow integrating de novo mutational signatures extraction and fitting of COSMIC (Catalogue Of Somatic Mutations In Cancer) signatures, with tridimensional chromatin conformation data (Hi-C). We applied the workflow to exome sequencing data from lymphoma samples. In 33 FL and 30 CLL samples, 42% and 34% of the contextual mutations could be traced to a known AID motif. We demonstrate that both CLL and FL share mutational processes dominated by spontaneous deamination, failures in DNA repair, and AID activity. The processes had equiproportional distribution across active and nonactive chromatin compartments in CLL. In contrast, canonical AID activity and failures in DNA repair pathways in FL were significantly higher within the active chromatin compartment. Analysis of DNA repair genes revealed a higher prevalence of base excision repair gene mutations (p = 0.02) in FL than CLL. These data indicate that AID activity drives the genetic landscapes of FL and CLL. However, the final result of AID-induced mutagenesis differs between these lymphomas depending on chromatin compartmentalization and mutations in DNA repair pathways. [ABSTRACT FROM AUTHOR]

Interaction of cancer cells with their microenvironment generated by stromal cells is essential for tumor cell survival and influences the localization of tumor growth. Here we demonstrate that hedgehog ligands secreted by bone-marrow, nodal and splenic stromal cells function as survival factors for malignant lymphoma and plasmacytoma cells derived from transgenic Eμ-Myc mice or isolated from humans with these malignancies. Hedgehog pathway inhibition in lymphomas induced apoptosis through downregulation of Bcl2, but was independent of p53 or Bmi1 expression. Blockage of hedgehog signaling in vivo inhibited expansion of mouse lymphoma cells in a syngeneic mouse model and reduced tumor mass in mice with fully developed disease. Our data indicate that stromally induced hedgehog signaling may provide an important survival signal for B- and plasma-cell malignancies in vitro and in vivo. Disruption of this interaction by hedgehog pathway inhibition could provide a new strategy in lymphoma and multiple myeloma therapy. [ABSTRACT FROM AUTHOR]

Objectives: Extranodal marginal B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) accounts for about 7% to 8% of all B-cell lymphomas and 50% of all gastric lymphomas. Long-term localized growth is typical of MALT lymphoma. Multifocal manifestations are possible in advanced stages. MALT lymphoma of the larynx is a very rare disease; only 15 cases have been reported in the literature. Methods: We report a case of multifocal MALT lymphoma affecting the larynx associated with extraesophageal reflux, chronic laryngitis, and gastric Helicobacter pylori infection. The staging revealed a recurrent tumor of MALT lymphoma in the stomach and an involvement of the right conjunctiva. Results: Following recent reports on successful treatment of MALT lymphoma with antibiotics, initial empirical therapy with doxycycline calcium led to a subjective clinical symptom improvement but no objective response as assessed by laryngoscopy, magnetic resonance imaging of the larynx, and esophagogastroduodenal endoscopy. Because of the advanced stage and multiple extranodal manifestations of the MALT lymphoma, the patient received 3 cycles of chemoimmunotherapy according to the FCR protocol (fludarabine phosphate-cyclophosphamide-rituximab). No evidence of disease was observed after a 6-month follow-up. Conclusions: In the rare diagnosis of MALT lymphoma of the larynx, comprehensive staging is indispensable to exclude multifocal involvement. In contrast to the treatment of primarily localized MALT lymphoma, multifocal disease warrants systemic therapy. [ABSTRACT FROM AUTHOR]

Objectives: Individual immunoglobulins expressed by B-cell lymphomas represent tumor-specific antigens (‘idiotypes’). Immunization with idiotype in follicular lymphoma patients may induce specific immune responses, sustained progression-free survival, and disappearance of minimal residual disease. Manufacturing of idiotype vaccines has mostly relied on heterohybridomas established from viable lymphoma cells. This paper describes the feasibility of production of GMP-grade idiotype vaccines as recombinant Fab fragments in Escherichia coli. Methods: IgH and IgL transcripts were analyzed by anchored PCR from 106 lymphoma and nine control biopsies. Lymphoma-derived V segments were inserted into prokaryotic expression plasmids. Recombinant idiotype Fab fragments were expressed in E. coli in a fermentation system. Results: Idiotype IgH and IgL transcripts were identified in 95% of 106 lymphoma biopsies according to stringent clonality criteria. Large-scale idiotype expression was successful in 69 of 78 cases (89%) and yielded a median of 17 mg (range: 1.2–250 mg) recombinant Fab protein. After affinity chromatography, median vaccine purity was 99% heterodimeric Fab protein (range: 72–100%). Bacterial protein contamination was detectable in one vaccine only. Fab proteins with IgL lambda chains had a tendency for inferior yield and lesser purity than κ-type Fabs. Among other structural idiotype features (isotype, V family usage, somatic hypermutation pattern, novel glycosylation sites, CDR III net charge), no consistent influences on Fab yield or purity were detected. Conclusions: Anchored PCR cloning and subsequent protein expression in E. coli provides a reliable technological basis for clinical idiotype vaccination trials. [ABSTRACT FROM AUTHOR]

The antigen receptors expressed by follicular lymphomas represent tumor-specific antigens (“idiotypes”). In murine models, vaccination with tumor-derived idiotype in a variety of formulations can induce protective lymphoma-specific immunity. Phase II clinical trials in follicular lymphoma have also demonstrated idiotype-specific immune responses. Clinical data from these trials indicate sustained progression-free survival, disappearance of minimal residual disease, and even frank lymphoma regression in some cases. Phase III trials to prove the beneficial effects of active immunotherapy are currently being conducted. Additional research efforts focus on the most efficacious vaccination route and on the development of convenient methods to manufacture individual idiotype vaccines. [Copyright &y& Elsevier]

Malignant lymphomas are clonal neoplasms of lymphoid origin. By definition, all cells of the malignant clone have undergone the same rearrangement of antigen receptor genes and express identical antigen receptor molecules (immunoglobulin for B cell lymphomas, T cell receptor for T cell lymphomas). The hypervariable stretches within the variable regions of these receptors are considered true tumor-specific antigens (‘idiotypes’). In several animal models, protective humoral or cellular immunity can be induced against the malignant lymphoma by vaccination with the tumor-derived idiotype. Successful experimental immunization strategies in animals include idiotype protein vaccines combined with various adjuvants, genetically or immunologically modified lymphoma cells, idiotype-presenting dendritic cells, idiotype-encoding viral vectors, and DNA immunization. Firm evidence for the induction of lymphoma-specific immunity has also been obtained from human idiotype vaccination trials. Furthermore, some trials have provided strong but hitherto formally unproven evidence for clinical benefit of idiotype-vaccinated patients. Alternative vaccination approaches are based on immunologically modified tumor cells. Current research efforts concentrate on the identification of the most efficacious vaccination route, on definitive proof of clinical efficacy, and on the development of convenient methods to manufacture individual idiotype vaccines.Copyright © 2002 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Biopsies of various tissues from eight patients with confirmed cutaneous T-cell lymphoma were analyzed for lymphomatous involvement using V-J junctional sequences in rearranged T-cell receptor-γ genes as specific molecular markers for the malignant clone, The patients included one stage IA, one stage IB, and six stage IVA. Twenty-five specimens were analyzed including 14 skin, five lymph node, four blood, and two bone-marrow samples. Ten skin samples and four lymph node samples were histologically positive for lymphoma. The other specimens were morphologically uninvolved. An assay involving polymerase chain reaction (PCR) amplification of T-cell receptor-γ gene rearrangements and denaturing gradient gel electrophoresis was used to identify the tissue specimen containing the greatest tumor clone density in each case. This specimen was then used to generate a tumor-specific RNA probe that was used to molecularly stage each patient by means of an assay involving PCR gene amplification and RNase protection analysis (PCR/RPA). This assay detected malignant cells in all available biopsies, including morphologically uninvolved extracutaneous tissue samples (two blood, one lymph node, and one bone marrow) obtained from the two patients in pathologic stage I. Microscopic examination and the less sensitive PCR/denaturing gradient gel electrophoresis technique failed to detect lymphomatous involvement in 11 (44%) and eight (32%) of these 25 specimens, respectively. We conclude that molecular biologic staging using PCR/RPA is able to demonstrate morphologically occult dissemination of cutaneous T-cell lymphona in early disease. In addition, PCR/RPA may be able to monitor tumor response to therapy and detect early recurrence of malignant lymphomas during clinical remission. [ABSTRACT FROM AUTHOR]

The article discusses research which was conducted to investigate whether template-switching anchored polymerase chain reaction (PCR) reliably amplifies functional lambda light chain transcripts of malignant lymphoma. Researchers used an alternative approach to current strategies for analysis of immunoglobulin transcripts that did not rely on the use of multiplex PCR to amplify the rearranged variable regions of antigen receptor loci. They found that their strategy was able to amplify the light chain transcripts of malignant lymphoma.