Critical role of γ4 chain in the expression of functional Vγ4Vδ1 T cell receptor of gastric tumour-infiltrating γδT lymphocytes

Vγ4Vδ1 T cell receptor (TCRγ4δ1)-expressing γδT cells were the most dominant subset in gastric tumour-infiltrating γδT cells (γδTIL) we recently analyzed. To study the essential roles of γ and δ chains in assembly and function of TCRγ4δ1, we sequenced and constructed them into lentiviral vectors for the reconstitution of TCRγ4δ1 using different modalities of transduction. We were able to efficiently reconstitute TCRγ4δ1 with functional activities when both γ4 and δ1 chains are coexpressed in TCR-negative J.RT3-T3.5 cells. However, the expression of δ1 chain is greatly diminished when γ4 expression is absent, suggesting that the coexpressing γ4 is critical in maintaining the folding and stability of δ1 product. To functionally study the reconstituted TCRγ4δ1, we examined the cytolytic activity of TCRγ4δ1-reconstituted J.RT3-T3.5 cells and cytokine secretion and found the receptors are fully functional, but their functionality also requires the presence of γ4. Our results demonstrated that γ4 is critical for the stability of δ1 and the function of TCRγ4δ1.     

V gene replacement in T and B lymphocytes: illicit or regimented rearrangement?

Lymphocytes can undergo novel types of secondary genetic rearrangements that alter the specificity of a pre-existing B cell receptor (BCR) or T cell receptor (TCR). V gene replacement is one of them and it replaces an already rearranged V gene segment with an upstream germline V gene segment. This review focuses on the molecular aspect of rearrangement. The role of this mechanism in the immune system is debated.     

Cytolytic mechanisms and T-cell receptor Vβ usage by ex vivo generated Epstein–Barr virus-specific cytotoxic T lymphocytes

Ex-vivo-generated Epstein–Barr virus (EBV)-specific cytotoxic T lymphocytes (CTL) have been used for cellular adoptive immunotherapy of EBV-associated lymphomas. Here we investigated the phenotypes, cytolytic mechanisms, polyfunctionality and T-cell receptor (TCR) usage in growing and established CTL, generated by weekly stimulation with an EBV-transformed autologous lymphoblastoid cell line (LCL). Our results showed that phenotypically mature CTL developed within the first 4 weeks of culture, with an increase in CD45RO and CD69, and a decrease in CD45RA, CD62L, CD27 and CD28 expression. Spectratyping analysis of the variable β-chain of the TCR revealed that TCR repertoire remained diverse during the course of culture. Cytotoxicity of CTL was significantly inhibited by concanamycin A (P < 0·0001) and ethylene glycol-bis tetraacetic acid (P < 0·0001), indicating that a calcium and perforin-mediated exocytosis pathway with the release of granzyme B was the principal cytotoxic mechanism. The CTL mainly produced interferon-γ (IFN-γ) or tumour necrosis factor-α (TNF-α) upon restimulation with autologous LCL, although there were some polyfunctional cells producing IFN-γ and TNF-α. Granzyme B, perforin and Fas ligand were detected in CD8⁺ and CD4⁺ cells in all CTL; however, a greater proportion of CD8⁺ than CD4⁺ T cells expressed granzyme B (P < 0·0001) and more granzyme B was detected in CD8⁺ T cells than in CD4⁺ T cells (P = 0·001). This difference was not observed with Fas ligand or perforin expression. Our results provide insight into the basic characteristics of ex-vivo-generated CTL.     

Coexistence of Epstein–Barr virus-associated gastric carcinoma with malignant lymphoma: report of two cases

Epstein–Barr virus (EBV)-associated gastric carcinoma (EBV-GC) is not rare, accounting for 5 to 18% of all gastric carcinomas. Recently, we encountered two cases of EBV-GC of ordinary histopathological type coexistent with malignant lymphoma. One patient was a 71-year-old Japanese man who had two lesions, one in the cardia and the other in the antrum of the stomach. The former was EBV-GC without lymphoma, and antral one was EBV-GC with diffuse large B-cell lymphoma (DLBCL). The other patient was a 49-year-old Japanese man who had received chemotherapy for pelvic DLBCL 3 years earlier. He had EBV-GC with follicular lymphoma in the fundus of the stomach. In both cases, gastric carcinomas were positive for EBV-encoded small RNA by in situ hybridization, whereas the lymphoma cells, infiltrating nonneoplastic lymphocytes, and nonneoplastic epithelial cells were negative. The present cases suggest that focal immunosuppression by adjacent gastric lymphomas might be related to the alteration of the microenvironment and development of EBV-GC.     

Restricted V gene usage and VH/VL pairing of mouse humoral response against the N-terminal immunodominant epitope of the amyloid β peptide

Over the last decade, the potential of antibodies as therapeutic strategies to treat Alzheimer's disease (AD) has been growing, based on successful experimental and clinical trials in transgenic mice. Despite, undesirable side effects in humans using an active immunization approach, immunotherapy still remains one of the most promising treatments for AD. In this study, we analyzed the V genes of twelve independently isolated monoclonal antibodies raised against the N-terminal immunodominant epitope of the amyloid β peptide (Aβ or A beta). Surprisingly, we found a high and unusual level of restriction in the VH/VL pairing of these antibodies. Moreover, these antibodies mostly differ in their heavy chain complementary determining region 3 (HCDR3) and the residues in the antibodies which contact Aβ are already present in the germline V-genes. Based on these observations and or co-crystal structures of antibodies with Aβ, the aim of the current study was to better understand the role of antibody V-domains, HCDR3 regions, key contact residue (H58) and germline encoded residues in Aβ recognition. For that purpose, we designed and produced a range of recombinant Fab constructs. All the Fabs were tested and compared by surface plasmon resonance on Aβ(1-16), Aβ(1-42) high molecular weight and Aβ(1-42) low molecular weight soluble oligomers. Although all the Fabs recognized the Aβ(1-16) peptide and the Aβ(1-42) high molecular weight soluble oligomers, they did not bind the Aβ(1-42) low molecular weight soluble oligomers. Furthermore, we demonstrated that: (1) an aromatic residue at position H58 in the antibody is essential in the recognition of Aβ and (2) Fabs based on germline V-genes bind to Aβ monomers with a low affinity. These findings may have important implications in designing more effective therapeutic antibodies against Aβ.     

Time-to-treatment of diffuse large B-cell lymphoma in São Paulo

OBJECTIVE:

Diffuse large B-cell lymphoma is the most common type of non-Hodgkin lymphoma, accounting for nearly 50% of the cases in the Hematology Department of the Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo and Instituto do Câncer do Estado de São Paulo. The treatment outcome is influenced by age, abnormal lactate dehydrogenase levels, extranodal infiltration, the disease stage and the patient''s performance status. In this study, we sought to report the time-to-treatment of diffuse large B-cell lymphoma in São Paulo''s public health system network and its impact on patient outcomes.

METHODS:

We prospectively followed a cohort of 42 consecutive patients with de novo diffuse large B-cell lymphoma between 2008 and 2012.

RESULTS:

Our patients had more advanced disease than that reported in the literature (61.9% vs. 46%). In São Paulo''s public health system network, it took an average of 7.4 months for a diagnosis to be made and an additional 1.4 months to obtain an appointment with a specialist. Once at our Hematology Department, it took less than 20 days for staging, confirmation of the diagnosis and treatment initiation. An interval from signs or symptoms to treatment of more than 6 months was associated with inferior progression-free survival in 3 years (p = 0.049).

CONCLUSION:

A delay in the diagnosis of diffuse large B-cell lymphoma is a public health problem and may be associated with worse progression-free survival.     

Nuclear factor-κB activation in primary lymphoma of bone

Primary lymphoma of bone is a rare type of extranodal diffuse large B-cell lymphoma with a relatively favourable outcome. Recent scientific interest has focused on elucidating the role of nuclear factor-κB pathway in lymphomagenesis and its potential significance as a therapeutic target. In nodal B-cell non-Hodgkin lymphomas, constitutive activation of nuclear factor-κB appears to be involved in tumour cell survival, notably in the non-germinal centre type of diffuse large B-cell lymphoma. We investigated nuclear factor-κB activation via the classical and alternative pathway in primary lymphoma of bone, through immunohistochemical staining for nuclear factor-κB family members on tumour tissues of 50 patients. Nine cases (18 %) showed nuclear staining for p50, and one case showed nuclear co-expression of p52. None of the cases showed nuclear staining for c-Rel. The nuclear staining of p50 suggests that in a minority of primary lymphomas of bone nuclear factor-κB is constitutively activated via the classical pathway. In contrast to other extranodal types of diffuse large B-cell lymphoma, there was a lack of nuclear co-expression of p65, which might suggest activation of a different pathway. Activation of nuclear factor-κB through the alternative pathway does not appear to be significantly involved, as only one case showed significant nuclear expression for p52. Finally, nuclear expression of p50 was neither preferentially detected in non-germinal centre type or germinal centre type primary lymphoma of bone, nor related to poor prognosis. Therefore, in contrast to nodal diffuse large B-cell lymphoma, the nuclear factor-κB pathway does not appear to be an attractive therapeutic target in primary lymphoma of bone.     

High content of Langerhans cells in malignant lymphoma—incidence and significance

We describe 25 patients, 14 with classical Hodgkin lymphoma and 11 with non-Hodgkin lymphoma, in all of whom an excess of Langerhans cells was evident. Except for the first three cases, in which the excess of Langerhans cells was identified on routine slides, the remaining cases were disclosed by actively investigating lymphomas with excess of CD68+ histiocytes and performing CD1a and S-100 protein immunostains. Although no clonality study was performed on the Langerhans cells, we endorse the view which states that in the above association, the Langerhans cells are polyclonal. Fourteen cases of Hodgkin lymphoma with a large number of Langerhans cells were identified in a cohort of 231 classical Hodgkin lymphomas. We compared the features of classical Hodgkin lymphoma with abundant Langerhans cells with those without Langerhans cells. Our analysis reveals that Hodgkin lymphoma with Langerhans cell excess shows greater LMP1/EBV expression (P = .007) and lower p53 expression (P = .042) in the Hodgkin–Reed–Sternberg cells but is not associated with a poorer outcome.     

Early activation of γδ T lymphocytes in the elderly

T cell function is altered in vivo and in vitro in elderly compared with young subjects, and this alteration is believed to contribute to morbidity and mortality in man due to the greater incidence of infection, as well as autoimmunity and cancer in elderly. The majority of T cells express TCRαβ whereas TCRγδ is expressed on a minority of T cells. Moreover, it is known that γδ T lymphocytes display major histocompatibility complex (MHC)- unrestricted cytotoxicity that is reminiscent of natural killer (NK) activity. In view of earlier findings on both T cells and NK cells in the elderly, we hypothesised a different behaviour of γδ T lymphocytes from old subjects when compared with γδ T lymphocytes obtained from young people. Therefore, to gain further insight into mechanisms of immunosenescence in this little-studied population, we studied immunofluorescence analysis γδ T cells from the elderly. Our preliminary results show that the percentage of blood γδ T cells in lymphocytes from old subjects is decreased when compared with the young. Interestingly, these cells are more activated in the elderly than in young subjects; expression of CD69, an early activation marker, is increased in γδ T lymphocytes from old subjects after three hours of in vitro culture both with and without lipopolysaccharide stimulation. Thus, our findings, which need confirmation, strongly suggest that, in humans, γδ T cells are early responders when compared with αβ T cells. They may act as ‘first aid’ cells to replace the described deficit of the specific and aspecific immunity in elderly. In this view, the proinflammatory status, observable in the elderly, renders them ready to be stimulated by exogenous agents.     

Diffuse large B-cell lymphoma occurring in patients with lymphoplasmacytic lymphoma/Waldenström macroglobulinemia. Clinicopathologic features of 12 cases

Of 92 patients with lymphoplasmacytic lymphoma/Waldenstr?m macroglobulinemia (LPL/WM) treated at our institution, diffuse large B-cell lymphoma (DLBCL) also developed in 12 (13%). In 10 patients, DLBCL developed 12 to 128 months (median, 44 months) after the diagnosis of LPL/WM. Two patients had LPL/WM and DLBCL simultaneously. Clinicopathologic features at diagnosis of LPL/WM did not predict the risk of DLBCL. Onset of DLBCL was characterized by worsening constitutional symptoms, profound cytopenias, extramedullary disease, and organomegaly. Immunoglobulin light chain expression was identical in both LPL/WM and DLBCL. In situ hybridization for Epstein-Barr virus (EBV) in 8 cases of DLBCL was negative. Of 11 patients with clinical follow-up information available, 8 (73%) died within 10 months of diagnosis of DLBCL. DLBCL, most likely as a result of histologic transformation, occurs in a subset of patients with LPL/WM and is associated with aggressive clinical course and poor outcome. EBV is unlikely to be involved in transformation.     

Fine-needle aspiration cytopathology in diagnosis and classification of malignant lymphoma: accurate and reliable?

Diagnosis of malignant lymphoma by fine-needle aspiration biopsy (FNAB) remains a topic of skepticism and controversy. Because of the limitations of pure morphology, subclassfication of non-Hodgkin malignant lymphoma (NHML) by FNAB often requires ancillary studies which impose a challenge not typically required of other FNAB diagnoses. Despite the dubiousness expressed by many, the evidence shows that a large percentage of NHML cases can be recognized and correctly classified using FNAB. Diagnostic accuracy is dependent on several factors including the type of NHML. The emergent WHO classification of lymphomas is one that appears to more readily accommodate the cytologic methods for NHML diagnosis.     

HER2 testing in malignant effusions of metastatic gastric carcinoma: Is it feasible?

HER2 testing on effusions of metastatic gastric carcinoma may provide a valuable alternative to testing on primary biopsies. This study assessed the feasibility of this method by immunohistochemistry (IHC) and silver in situ hybridization (SISH). Cell blocks from 46 effusions from metastatic gastric carcinoma were examined. IHC was scored using the modified criteria of Hofmann et al. An average of ≥6 signals per nucleus was considered amplification on SISH. Results were compared with histological specimens to assess HER2 status concordance. Cell blocks showed a poorly cohesive pattern in 30 (65%), aggregates in 7 (15%), and mixed pattern in 9 (20%). Seven (15%) showed an IHC 2+/3+ reaction with a membranous pattern, appearing more granular than in histology. Three (7%) showed HER2 amplification on SISH. In 18 cases (39%), HER2 status was compared with histological specimens, showing 100% concordance. Difficulties were encountered in distinguishing malignant cells from reactive mesothelial cells in 12 (26%). This study supports the feasibility of HER2 assessment on effusions. The incidence of HER2 positivity (7% with SISH+ and IHC 2+/3+) was lower than reported in histological samples. Further refinement and validation will enhance the use of this method in clinical practice and overcome difficulties encountered. Diagn. Cytopathol. 2015;43:80–85. © 2014 Wiley Periodicals, Inc.     

Effect of ER-β gene disruption on estrogenic regulation of anxiety in female mice

It has been shown that long-term estrogen treatment in gonadectomized female mice increases anxiety levels. On the other hand, a recent study has reported that estrogen may down-regulate the levels of anxiety by acting through estrogen receptor (ER) β. In the present study, we investigated the role of ER-β in the regulation of anxiety levels in female mice after long-term estrogen treatment. Gonadectomized ER-β knockout (βERKO) female mice and their wild type (βWT) littermates were implanted several different doses (experiment 1: 2.0 μg/day, experiment 2: 1.0, 0.4, 0.2 or 0.1 μg/day) of an estradiol benzoate (EB) or placebo pellet. Ten days after pellet implant, behavioral tests commenced to measure the anxiety levels (experiment 1: light-dark transition test (LDT), experiment 2: LDT, elevated plus maze test (EPM) and social investigation test (SIT)). We found that, at higher-doses, long-term treatment of EB had anxiogenic effects in both βWT and βERKO mice as indicated by a decrease of the time spent in the light side and the number of transitions between two sides during LDT. In contrast, several behavioral measurements indicated that the lower-doses treatment of EB might reduce the anxiety levels possibly through ER-β. Particularly, the anxiolytic effects of EB in the SIT were more pronounced in βWT mice than βERKO mice. Together, the findings in the present study suggest that estrogen may have both anxiolytic and anxiogenic effects in female mice, and that ER-β gene disruption did not affect anxiogenic regulation by estrogen in female mice, but partially affected anxiolytic regulation.     

Increase of bone marrow lymphocytes in systemic mastocytosis: reactive lymphocytosis or malignant lymphoma? Immunohistochemical and molecular findings on routinely processed bone marrow biopsy specimens

AIMS: To clarify the nature (reactive or neoplastic) of lesional, perifocally aggregated lymphocytes in bone marrow infiltrates of systemic mastocytosis (SM), the histopathology of which can resemble malignant lymphoma with focal bone marrow involvement, particularly low grade malignant B cell lymphoma of lymphoplasmacytic immunocytoma subtype, which frequently exhibits increased mast cell (MC) numbers. METHODS: Thirteen cases of SM and three of lymphoplasmacytic immunocytoma with predominant focal bone marrow infiltration were investigated. Immunostaining of formalin fixed, paraffin wax embedded bone marrow specimens was performed using antibodies against CD2, CD5, CD20, CD23, and CD25; kappa and lambda immunoglobulin light chains; and MC markers chymase, tryptase, and CD117 (KIT). Monoclonal rearrangements of IgH and TCRgamma were studied using seminested polymerase chain reaction (PCR). c-kit point mutation Asp816-Val was detected by PNA mediated PCR clamping and hybridisation probes. RESULTS: The lymphocytic clusters in SM contained nearly equal numbers of mature T and B cells, the latter with no coexpression of aberrant antigens, such as CD5 or CD23. Most MCs in SM cases constantly coexpressed tryptase, CD25, and CD117. No monoclonal rearrangements were seen for IgH or TCRgamma. In contrast, B cells from immunocytomas showed light chain restriction and monoclonal rearrangement for IgH, confirming their neoplastic nature. c-kit point mutation Asp816-Val was found in ten of 13 SM cases, but in none of the three immunocytomas. CONCLUSIONS: Focal accumulations of lymphocytes in the bone marrow of SM are reactive in nature and could be termed lymphocytosis. A diagnosis of SM-AHNMD/immunocytoma should not be made.     

High-throughput sequencing reveals restricted TCR Vβ usage and public TCRβ clonotypes among pancreatic lymph node memory CD4+ T cells and their involvement in autoimmune diabetes

Islet-reactive memory CD4⁺ T cells are an essential feature of type 1 diabetes (T1D) as they are involved in both spontaneous disease and in its recurrence after islet transplantation. Expansion and enrichment of memory T cells have also been shown in the peripheral blood of diabetic patients. Here, using high-throughput sequencing, we investigated the clonal diversity of the TCRβ repertoire of memory CD4⁺ T cells in the pancreatic lymph nodes (PaLN) of non-obese diabetic (NOD) mice and examined their clonal overlap with islet-infiltrating memory CD4 T cells. Both prediabetic and diabetic NOD mice exhibited a restricted TCRβ repertoire dominated by clones expressing TRBV13-2, TRBV13-1 or TRBV5 gene segments. There is a limited degree of TCRβ overlap between the memory CD4 repertoire of PaLN and pancreas as well as between the prediabetic and diabetic group. However, public TCRβ clonotypes were identified across several individual animals, some of them with sequences similar to the TCRs from the islet-reactive T cells suggesting their antigen-driven expansion. Moreover, the majority of the public clonotypes expressed TRBV13-2 (Vβ8.2) gene segment. Nasal vaccination with an immunodominat peptide derived from the TCR Vβ8.2 chain led to protection from diabetes, suggesting a critical role for Vβ8.2⁺ CD4⁺ memory T cells in T1D. These results suggest that memory CD4⁺ T cells bearing limited dominant TRBV genes contribute to the autoimmune diabetes and can be potentially targeted for intervention in diabetes. Furthermore, our results have important implications for the identification of public T cell clonotypes as potential novel targets for immune manipulation in human T1D.     

Is a duplication of 14q32 a new recurrent chromosomal alteration in B-cell non-Hodgkin lymphoma?

Identification of clonal chromosomal abnormalities involving 14q32 and its association with specific histological subtypes of non-Hodgkin lymphoma (NHL) has provided substantial insight to the genetic events leading to the disease. However, in some cases with inferior morphology of tumor cell chromosomes, the additional segment on chromosome 14 remains unidentified by cytogenetic banding techniques alone. To elucidate the origin of the additional chromosomal segment and to correlate the newly determined alterations with histology, metaphases from 15 NHL patients with add(14)(q32) were examined using fluorescence in situ hybridization (FISH) techniques after cytogenetic analysis had been performed. We found the duplication of 14q involving the q32 region in 6 cases with a dup(14) (q32) in 4 cases and a dup(14)(q24q32) in 2 cases. In 8 cases, FISH unveiled known NHL associated translocations; a t(14;18)(q32;q21) in 4 cases, a t(11;14)(q13;q32) in 2 cases, a t(8;14)(q24;q32) and a t(9;14)(p13;q32) in 1 case each. We also noted a t(14;17)(q32;q21) in 1 case. The use of FISH was a valuable asset in determining the origin of the additional material on chromosome 14q32, and helped resolve a group of B-cell NHLs with involvement of a duplicated 14q32 region.     

T regulatory cells in B-cell malignancy – tumour support or kiss of death?

It is well established that T regulatory (Treg) cells counteract tumour immunity. However, conflicting results describing the role of Treg cells in haematological tumours warrant further investigations to clarify the interactions between Treg cells and the tumour. B-cell malignancy derives from different stages of B-cell development and differentiation in which T cells play a profound role. The transformed B cell may still be in need of T-cell help to thrive but simultaneously they may be recognized and destroyed by cytotoxic lymphocytes. Recent reports demonstrate that Treg cells can suppress and even kill B cells as part of their normal function to rescue the body from autoimmunity. An emerging body of evidence points out that Treg cells not only inhibit tumour-specific T cells but may also have a role in suppressing the progression of the B-cell tumour. In this review, we discuss the origin and function of Treg cells and their role in patients with B-cell tumours.