Study of Regulatory T-Cells in Patients with Gastric Malt Lymphoma: Influence on Treatment Response and Outcome

Purpose

FOXP3+ regulatory T cells (Treg) play an essential role in modulating host responses to tumors and infections. The role of these cells in the pathogenesis of MALT lymphomas remains unknown. The aims of the study were to quantify the number of infiltrating FOXP3+ and CD3+ cells in patients with gastric MALT lymphoma at diagnosis and to study kinetics of these cells and CD20+ tumor cells after treatment and during long-term follow-up.

Methods

FOXP3+, CD3+ and CD20+ cells were analyzed by immunohistochemistry and the number of cells was quantified using a micrometric ocular. Samples of 35 patients with gastric MALT lymphoma at diagnosis and after treatment were included. Diagnostic samples were compared to 19 cases of chronic gastritis and diffuse large B-cell lymphoma (DLBCL) of the stomach.

Results

The median number of FOXP3+ infiltrating cells was higher (27 cells/cm²) in gastric MALT patients than in DLBCL (10 cells; p = 0.162) but similar to chronic gastritis (20 cells; p = 0.605). No characteristic or specific distribution pattern of infiltrating FOXP3+ cells was found. Gastric MALT lymphoma patients responding to bacterial eradication therapy had higher number of FOXP3+ cells at study entry. Kinetics of both infiltrating FOXP3+ cells and tumor CD20+ cells were strongly dependent on the treatment administered.

Discussion

Gastric MALT lymphomas have a number of Treg cells more similar to chronic gastritis than to DLBCL. Patients with higher number of tumor infiltrating FOXP3+ cells at study entry seem to have better response to antibiotics. Kinetics of Treg and tumor cells are influenced by type of treatment.     

PD-1+ immune cell infiltration inversely correlates with survival of operable breast cancer patients

The programmed death-1 (PD-1) molecule is mainly expressed on functionally “exhausted” CD8⁺ T cells, dampening the host antitumor immune response. We evaluated the ratio between effective and regulatory T cells (Tregs) and PD-1 expression as a prognostic factor for operable breast cancer patients. A series of 218 newly diagnosed invasive breast cancer patients who had undergone primary surgery at Ruijin Hospital were identified. The influence of CD8⁺ cytotoxic T lymphocytes, FOXP3⁺ (Treg cell marker), and PD-1⁺ immune cell counts on prognosis was analyzed utilizing immunohistochemistry. Both PD-1⁺ immune cells and FOXP3⁺ Tregs counts were significantly associated with unfavorable prognostic factors. In bivariate, but not multivariate analysis, high tumor infiltrating PD-1⁺ cell counts correlated with significantly shorter patient survival. Our results suggest a prognostic value of the PD-1⁺ immune cell population in such breast cancer patients. Targeting the PD-1 pathway may be a feasible approach to treating patients with breast cancer.     

CTLA-4在弥漫大B细胞淋巴瘤患者外泌体的表达及初步机制研究

摘要 目的：探讨细胞毒性T淋巴细胞相关抗原4（CTLA-4）在弥漫大B细胞淋巴瘤（DLBCL）患者外泌体的表达及初步机制。方法：2019年6月至2020年11月就诊于本院的DLBCL患者纳入本项研究,分为缓解组和复发组;选取来医院体检的健康志愿者做为对照组;采用试剂盒分离外泌体,CD63抗体包被磁珠结合后,流式细胞术检测CTLA-4+外泌体的比例;流式细胞术检测CD4⁺T细胞、CD8⁺T细胞和调节性T细胞（Treg细胞）的比例。结果：相对于对照组,缓解组DLBCL患者CTLA-4+外泌体的比例升高了37.42%;复发组DLBCL患者CTLA-4+外泌体的比例为6.04%,相对于缓解组,差异具有显著的统计学意义;复发组DLBCL患者CD4/CD8⁺T细胞比值和Treg细胞比例分别为0.85和0.44%,相对于缓解组,差异均具有显著的统计学意义;相关性分析结果显示CTLA-4+外泌体比例与CD4/CD8⁺T细胞比值呈负相关,而与Treg细胞比例呈正相关。结论：CTLA-4+外泌体比例在DLBCL患者显著升高,且与淋巴瘤的治疗效果和抗肿瘤免疫反应均具有紧密的相关性。     

PD-1 Blockade Can Restore Functions of T-Cells in Epstein-Barr Virus-Positive Diffuse Large B-Cell Lymphoma In Vitro

Epstein–Barr virus-positive diffuse large B-cell lymphoma (EBV+DLBCL) is an aggressive malignancy that is largely resistant to current therapeutic regimens, and is an attractive target for immune-based therapies. Anti-programmed death-1 (PD-1) antibodies showed encouraging anti-tumor effects in both preclinical models and advanced solid and hematological malignancies, but its efficacy against EBV+DLBCL is unknown. Herein, we performed experiments using co-culture system with T cells and lymphoma cell lines including EBV+DLBCL and EBV-DLBCL [including germinal center B-cell like (GCB)-DLBCL and non-GCB-DLBCL] in vitro. We show that lymphoma cells augmented the expression of PD-1 on T cells, decreased the proliferation of T cells, and altered the secretion of multiple cytokines. However, through PD-1 blockade, these functions could be largely restored. Notbaly, the effect of PD-1 blockade on antitumor immunity was more effective in EBV+DLBCL than that in EBV-DLBCL in vitro. These results suggest that T-cell exhaustion and immune escape in microenvironment is one of the mechanisms underlying DLBCL; and PD-1 blockade could present as a efficacious immunotherapeutic treatment for EBV+DLBCL.     

The presence of LC3B puncta and HMGB1 expression in malignant cells correlate with the immune infiltrate in breast cancer

Several cell-intrinsic alterations have poor prognostic features in human breast cancer, as exemplified by the absence of MAP1LC3B/LC3B (microtubule-associated protein 1 light chain 3 β)-positive puncta in the cytoplasm (which indicates reduced autophagic flux) or the loss of nuclear HMGB1 expression by malignant cells. It is well established that breast cancer is under strong immunosurveillance, as reflected by the fact that scarce infiltration of the malignant lesion by CD8⁺ cytotoxic T lymphocytes or comparatively dense infiltration by immunosuppressive cell types (such as FOXP3⁺ regulatory T cells or CD68⁺ tumor-associated macrophages), resulting in low CD8⁺:FOXP3⁺ or CD8⁺:CD68⁺ ratios, has a negative prognostic impact. Here, we reveal the surprising finding that cell-intrinsic features may influence the composition of the immune infiltrate in human breast cancer. Thus, the absence of LC3B puncta is correlated with intratumoral (but not peritumoral) infiltration by fewer CD8⁺ cells and more FOXP3⁺ or CD68⁺ cells, resulting in a major drop in the CD8⁺:FOXP3⁺ or CD8⁺:CD68⁺ ratios. Moreover, absence of HMGB1 expression in nuclei correlated with a general drop in all immune effectors, in particular FOXP3⁺ and CD68⁺ cells, both within the tumor and close to it. Combined analysis of LC3B puncta and HMGB1 expression allowed for improved stratification of patients with respect to the characteristics of their immune infiltrate as well as overall and metastasis-free survival. It can be speculated that blocked autophagy in, or HMGB1 loss from, cancer cells may favor tumor progression due to their negative impact on anticancer immunosurveillance.     

Altered frequency of CD8+CD11c+ T cells and expression of immunosuppressive molecules in lymphoid organs of mouse model of colorectal cancer

CD11c is a member of the β2-integrin family typically used to define myeloid dendritic cells (DCs). Recent reports identify CD11c-expressing CD8⁺ T cells as a new subset of CD8⁺ regulatory T cells (Treg). Evidence exists that CD11c⁺CD8⁺ T cells may exert their effector or regulatory functions under different conditions. To date, no studies have addressed the frequency of CD11c⁺ T cells in cancer. Limited evidence exists in terms of expression of immune-checkpoint receptors, programmed cell death protein 1 (PD-1) and T-lymphocyte-associated antigen 4 (CTLA-4), as well as forkhead box P3 (Foxp3) in mouse lymphoid organs. Here, we have assessed CD11c⁺CD8⁺ and CD11c⁺CD4⁺ T cells, Foxp3, PD-1, and CTLA-4 expressing CD4⁺ T cells and CD8⁺ T cells in different tissues from three groups of male BALB/c mice—young, mature, and those with colorectal cancer (CRC). Analysis of CD3⁺CD11c⁺ T cells in the bone marrow (BM), spleen, and lymph nodes (LN) in each group showed a higher percentage of CD3⁺CD11c⁺ T cells in the BM from all groups and in the lymphoid organs of the cancer group compared with the young and mature groups. CD4^low and CD4^high cell fractions in mice BM have different expression patterns for Foxp3 and CTLA-4. We have observed a higher frequency of CD8⁺PD-1⁺ T cells in the BM, spleen, and LN of CRC mice compared with normal mice. T-cell exhaustion is associated with inhibitory receptor PD-1. According to the regulatory roles of CD11c expression in CD8⁺ T cells, we have proposed that the elevated percentage of CD11c, Foxp3, CTLA-4, and PD-1 expressing T cells were associated with immune response dysregulation in CRC.     

Graves病患者外周血中CD4+CD25+Treg细胞上的PD-1/PD-L1的表达及意义

目的:探究Graves病患者外周血中CD4+CD25+Treg细胞上的PD-1/P-L1的表达及意义。方法:收集2017年6月至2017年12月就诊于西南医科大学附属医院内分泌科的Graves病、Graves眼病及体检中心的健康者的外周血进行流式检测。结果:与正常对照组相比,Graves病及Graves眼病组CD4+CD25+Treg细胞比例明显降低(P0.05);PD-1+Treg、PD-L1+Treg、PD-1+/PD-L1+Treg细胞比例均较正常组明显降低(P0.05);此外,Graves眼病组的结果较Graves病组更低(P0.05)。结论:CD4+CD25+Treg的降低会导致Graves病和Graves眼病患者的免疫状态活化,甲状腺自身抗体的增加和活化,促进疾病的发生。此外于PD-1和PD-L1阳性细胞比例的减少对于其对免疫的负向调节有所减弱,从而导致患者体内免疫耐受的降低和免疫稳态的打破,可能导致机体对甲状腺抗原的耐受消失,导致GD及眼病的发生发展。     

The expression of FOXP3 in lesions of several forms of leprosy in patients co-infected with HIV

BackgroundBrazil remains endemic for infection by the human immunodeficiency virus (HIV) and leprosy, having a major impact on public health and the life quality of affected patients. Although the relevance of this co-infection is recognized, several aspects, such as the immune response, are not yet fully understood. The objective of this study was to investigate the expression of FOXP3⁺ Treg cells in leprosy skin lesions and to correlate their clinical forms, laboratory characteristics (CD4, CD8, and CV), and the immune reconstitution syndrome in HIV-leprosy co-infection.Methodology/Principal findingsAn observational, cross-sectional, and analytical study was carried out comparing four groups of patients: those with concomitant diagnosis of leprosy and HIV infection without a leprosy reaction, those with leprosy and HIV co-infection patients with a reverse reaction (RR), those with leprosy without HIV and without reaction, and those with leprosywithout HIV and with RR. The patients were diagnosed at a dermatology outpatient clinic located in Belém, Pará, Brazil, from 2003 to 2017. In the sample studied, there was a positive correlation between FOXP3⁺ cell density and viral load, negative correlation with blood CD4⁺ (not statistically significant), significant positive correlation in CD8 count in patients with leprosy reaction, and positive relationship in patients with IRIS. The density of cells expressing FOXP3 was higher in the BL/LL forms in patients without HIV, although the difference was not statistically significant. However, the cell mean was higher in the TT/BT forms in patients co-infected with leprosy and HIV, showing contradictory results.Conclusions/SignificanceThese findings support that higher activity of the HIV may stimulate or result in a higher expression of FOXP3-Tregs and that they may be involved in active immunosuppression observed at the infection site at the tissue level. This supports the need to expand studies on FOXP3⁺ Treg cells in co-infected patients.     

The Ratios of CD8+ T Cells to CD4+CD25+ FOXP3+ and FOXP3- T Cells Correlate with Poor Clinical Outcome in Human Serous Ovarian Cancer

Ovarian cancer is an immune reactive malignancy with a complex immune suppressive network that blunts successful immune eradication. This suppressive microenvironment may be mediated by recruitment or induction of CD4⁺ regulatory T cells (Tregs). Our study sought to investigate the association of tumor-infiltrating CD4⁺CD25⁺FOXP3⁺ Tregs, and other immune factors, with clinical outcome in serous ovarian cancer patients. We performed immunofluorescence and quantification of intraepithelial tumor-infiltrating triple positive Tregs (CD4⁺CD25⁺FOXP3⁺), as well as CD4⁺CD25⁺FOXP3^-, CD3⁺ and CD8⁺ T cells in tumor specimens from 52 patients with high stage serous ovarian carcinoma. Thirty-one of the patients had good survival (i.e. > 60 months) and 21 had poor survival of < 18 months. Total cell counts as well as cell ratios were compared among these two outcome groups. The total numbers of CD4⁺CD25⁺FOXP3⁺ Tregs, CD4⁺CD25⁺FOXP3^-, CD3⁺ and CD8⁺ cells were not significantly different between the groups. However, higher ratios of CD8⁺/CD4⁺CD25⁺FOXP3⁺ Treg, CD8⁺/CD4⁺ and CD8/CD4⁺CD25⁺FOXP3^- cells were seen in the good outcome group when compared to the patients with poor outcome. These data show for the first time that the ratios of CD8⁺ to both CD4⁺CD25⁺FOXP3⁺ Tregs and CD4⁺CD25⁺FOXP3^- T cells are associated with disease outcome in ovarian cancer. The association being apparent in ratios rather than absolute count of T cells suggests that the effector/suppressor ratio may be a more important indicator of outcome than individual cell count. Thus, immunotherapy strategies that modify the ratio of CD4⁺CD25⁺FOXP3⁺ Tregs or CD4⁺CD25⁺FOXP3^- T cells to CD8⁺ effector cells may be useful in improving outcomes in ovarian cancer.     

Human Blood and Mucosal Regulatory T Cells Express Activation Markers and Inhibitory Receptors in Inflammatory Bowel Disease

Background

FOXP3⁺ regulatory T cells (Tregs) are critical for preventing intestinal inflammation. However, FOXP3⁺ T cells are paradoxically increased in the intestines of patients with the inflammatory bowel disease (IBD) ulcerative colitis (UC) or Crohn’s disease (CD). We determined whether these FOXP3⁺ cells in IBD patients share or lack the phenotype of such cells from patients without IBD.

Methods

We quantified and characterized FOXP3⁺ Treg populations, as well as FOXP3^- CD4⁺ T cells, in the lamina propria lymphocytes (LPL) of intestine surgically resected from patients with and without IBD, and in the blood of controls or Crohn’s patients with or without disease activity.

Results

In all samples, a similar fraction of FOXP3⁺ cells expressed the “natural” Treg (nTreg) marker Helios, suggesting that, in IBD, these cells are not entirely “induced” Tregs (iTregs) derived from activated effector T cells. Helios⁺ and Helios^- FOXP3⁺ T cells demonstrated similar expression of maturation markers, activation markers, and inhibitory molecules between IBD patients and controls, while FOXP3^- cells paradoxically expressed more of the inhibitory receptors CD39, CTLA4, and PD-1 in inflamed mucosa. Greater expression of activation markers was also seen in both Helios⁺ and Helios^- Tregs, relative to FOXP3^- cells, in both IBD patients and controls, indicating that Tregs are effectively activated by antigen in IBD.

Conclusions

Extensive immunophenotyping revealed that Helios⁺ and Helios^- mucosal Tregs exist at a similar frequency, and have a similar expression of inhibitory molecules and activation markers in patients with IBD as in healthy controls.     

Tumour-draining lymph nodes in head and neck cancer are characterized by accumulation of CTLA-4 and PD-1 expressing Treg cells

IntroductionHigh Tregs infiltration within the tumour microenvironment (TME) of various cancers shows a positive correlation with poor prognosis. Despite the fact that tumour draining lymph nodes (TDLNs) are recognized as key organs playing a crucial role in response to immunotherapy and modulating anti-cancer immunity, the distribution of Tregs and their role in TDLNs remain uncertain thus far. The purpose of this project is to investigate the density of Tregs in TDLNs and non-TDLNs and their expression of immune checkpoint molecules – PD-1 and CTLA-4.MethodsSamples including TDLNs, non-TDLNs and metastatic lymph nodes (LNs) from 23 patients with oral squamous cell carcinoma (OSCC) were analyzed by multicolour flow cytometry with a focus on Tregs population and expression of CTLA-4 and PD-1.ResultsTDLNs and metastatic LNs were characterized by a significantly higher infiltration of Tregs defined as CD4+FoxP3+CD25^highCD127^low cells and significantly higher expression of CTLA-4 and PD-1 on Tregs compared with non-TDLNs. Tregs in TDLNs and metastatic LNs co-expressed CTLA-4 and PD-1 abundantly. High expression of these immune check-point molecules correlated with positive N-stage but not with T-stage.ConclusionTDLNs and metastatic LNs are characterized by a high accumulation of Tregs expressing high levels of CTLA-4 and PD-1. High infiltration of Tregs can be a potential driver of an immunosuppressive milieu in TDLNs that can, in turn, favour cancer progression. High accumulation of Tregs expressing CTLA-4 and PD-1 in TDLNs is associated with lymph node involvement, but not with the size of the primary tumour.     

Tumor microenvironment disparity in multiple primary lung cancers: Impact of non-intrinsic factors,histological subtypes,and genetic aberrations

IntroductionMultiple primary lung cancers (MPLCs) occur in common carcinogenetic risks such as lifestyle, biological aging, immune responses, hormones, and metabolism. Although MPLCs harbor various genetic profiles within the same individuals, differences in the tumor microenvironment (TME) are unclear. We investigated the impact of genetic aberrations, non-intrinsic factors, and pathological subtypes on tumor immunity.Materials and MethodsIn total, 73 surgically resected specimens from 32 patients with MPLC were analyzed. PD-L1 expression in tumor cells (TCs) and immune cells (ICs), CD3-positive tumor-infiltrating lymphocytes (TILs), CD8/CD3 ratios, and FOXP3-positive TILs that compose TMEs were evaluated by immunohistochemistry and classified on a score of 0–2. 38 tumors were sequenced for somatic mutations in 409 cancer-associated genes.ResultsFemales and never or light smokers had a higher incidence of PD-L1-negative tumors and a higher concordance rate. PD-L1 positivity in TCs and ICs was significantly less frequent in EGFR-mutated than in wild-type tumors. Differences in the score of TMEs were observed between the KRAS-mutated-only tumor and the KRAS and TP53-co-mutated tumors, and between the KRAS-mutated-only tumor and the KRAS and STK11-co-mutated tumors. Significantly more FOXP3-high TILs were observed in invasive pathological subtypes than in non-invasive ones.ConclusionComparing TMEs among MPLCs revealed that non-smokers or light smokers and females were unlikely to express PD-L1 regardless of tumor site and confirmed that the EGFR mutations and co-occurring KRAS and STK11 or TP53 mutations were associated with TME. Pathological subtypes may impact the efficacy of immune therapy due to their potential correlations with regulatory T cells.     

Characterization of PD-1/PD-L1 immune checkpoint expression in soft tissue sarcomas

Inhibitors of the programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) immune checkpoint system are used for treating various malignancies. However, evidence on their use in soft tissue sarcomas (STS) is limited. This study aimed to retrospectively investigate the relationship between the expression of PD-1/PD-L1 and related antigens in STS, and their association with clinical characteristics. Immunostaining for CD4, CD8, PD-1, PD-L1, IL-2, and IFN-γ was performed using pathological specimens harvested at the time of biopsy from 10 patients with undifferentiated pleomorphic sarcoma (UPS), nine with myxofibrosarcoma (MFS), and three with malignant peripheral nerve sheath tumor (MPNST) who were treated at our hospital. Subsequently, the positive immunostaining cell rates were calculated. We also examined the correlation between each immune positive cell rate and age, tissue grade, size, and maximum standardized uptake (SUV-max) values. The 3-year event-free survival (EFS) and overall survival (OS) rates were compared between the positive and negative groups (positive rate >10%; negative <10%) for various immune stains. The positive rates were also compared between the presence and absence of events groups. There was positive staining for the immune checkpoint molecules in every STS type except for PD-1 in MPNST. CD4, CD8, and PD-1 stained lymphocytes in close proximity to the tumor in adjacent tissue sections. A positive correlation was observed between the positive cell rates of each immune component including inflammatory cytokines such as IL-2 and IFN-γ. Additionally, the clinical features positively correlated with the positive PD-1/PD-L1 expression rates. No significant differences in the 3-EFS and OS rates were observed between the PD-1/PD-L1 positive and negative groups. Our results suggest that an inducible immune checkpoint mechanism may be involved in UPS, MFS, and MPNST.Key words: Immune checkpoint inhibitors, PD-1/PD-L1, soft tissue sarcoma, programmed death-1, programmed death-ligand 1     

The PD-1/B7-H1 Pathway Modulates the Natural Killer Cells versus Mouse Glioma Stem Cells

Purpose

Glioblastoma multiforme (GBM) is the most malignant primary type of brain tumor in adults. There has been increased focus on the immunotherapies to treat GBM patients, the therapeutic value of natural killer (NK) cells is still unknown. Programmed death-1 (PD-1) is a major immunological checkpoint that can negatively regulate the T-cell-mediated immune response. We tested the combination of the inhibiting the PD-1/B7H1 pathway with a NK-cell mediated immune response in an orthotopic mouse model of GBM.

Methods and Materials

Mouse glioma stem cells (GL261GSCs) and mouse NK cells were isolated and identified. A lactate dehydrogenase (LDH) assay was perfomed to detect the cytotoxicity of NK cells against GL261GSCs. GL261GSCs were intracranially implanted into mice, and the mice were stratified into 3 treatment groups: 1) control, 2) NK cells treatment, and 3) PD-1 inhibited NK cells treatment group. Overall survival was quantified, and animal magnetic resonance imaging (MRI) was performed to determine tumor growth. The brains were harvested after the mice were euthanized, and immunohistochemistry against CD45 and PCNA was performed.

Results

The mouse NK cells were identified as 90% CD3^- NK1.1⁺CD335⁺ by flow cytometric analysis. In the LDH assay, the ratios of the damaged GL261GSCs, with the E:T ratios of 2.5:1, 5:1, and 10:1, were as follows: 1) non-inhibited group: 7.42%, 11.31%, and 15.1%, 2) B7H1 inhibited group: 14.75%, 18.25% and 29.1%, 3) PD-1 inhibited group: 15.53%, 19.21% and 29.93%, 4) double inhibited group: 33.24%, 42.86% and 54.91%. In the in vivo experiments, the mice in the PD-1 inhibited NK cells treatment group and IL-2-stimulated-NK cells treatment group displayed a slowest tumor growth (F = 308.5, P<0.01) and a slower tumor growth compared with control group (F = 118.9, P<0.01), respectively. The median survival of the mice in the three groups were as follows: 1) conrol group: 29 days, 2) NK cells treatment group: 35 days (P = 0.0012), 3) PD-1 inhibited NK cells treatment group: 44 days (P = 0.0024). Immunologic data of PCNA-positive cell ratios and CD45-positive cell ratios of the tumor specimens in the three groups were as follows: 1) control group: 65.72% (PCNA) and 0.92% (CD45), 2) NK treatment group: 27.66% (PCNA) and 13.46% (CD45), and 3) PD-1 inhibited NK cells treatment group: 13.66% (PCNA) and 23.66% (CD45) (P<0.001).

Conclusion

The results demonstrated that blockade of PD-1/B7H1 pathway could promote mouse NK cells to kill the GL261GSCs, and the PD-1-inhibited NK cells could be a feasible immune therapeutic approach against GBM.     

CD3+/CD16+CD56+ cell numbers in peripheral blood are correlated with higher tumor burden in patients with diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma is the commonest histological type of malignant lymphoma, and remains incurable in many cases. Developing more efficient immunotherapy strategies will require better understanding of the disorders of immune responses in cancer patients. NKT (natural killer-like T) cells were originally described as a unique population of T cells with the co-expression of NK cell markers. Apart from their role in protecting against microbial pathogens and controlling autoimmune diseases, NKT cells have been recently revealed as one of the key players in the immune responses against tumors. The objective of this study was to evaluate the frequency of CD3(+)/CD16(+)CD56(+) cells in the peripheral blood of 28 diffuse large B-cell lymphoma (DLBCL) patients in correlation with clinical and laboratory parameters. Median percentages of CD3(+)/CD16(+)CD56(+) were significantly lower in patients with DLBCL compared to healthy donors (7.37% vs. 9.01%, p = 0.01; 4.60% vs. 5.81%, p = 0.03), although there were no differences in absolute counts. The frequency and the absolute numbers of CD3(+)/CD16(+)CD56(+) cells were lower in advanced clinical stages than in earlier ones. The median percentage of CD3(+)/CD16(+)CD56(+) cells in patients in Ann Arbor stages 1-2 was 5.55% vs. 3.15% in stages 3-4 (p = 0.02), with median absolute counts respectively 0.26 G/L vs. 0.41 G/L (p = = 0.02). The percentage and absolute numbers of CD3(+)/CD16(+)CD56(+) cells were significantly higher in DL -BCL patients without B-symptoms compared to the patients with B-symptoms, (5.51% vs. 2.46%, p = 0.04; 0.21 G/L vs. 0.44 G/L, p = 0.04). The percentage of CD3(+)/CD16(+)CD56(+) cells correlated adversely with serum lactate dehydrogenase (R= -445; p 〈 0.05) which might influence NKT count. These figures suggest a relationship between higher tumor burden and more aggressive disease and decreased NKT numbers. But it remains to be explained whether low NKT cell counts in the peripheral blood of patients with DLBCL are the result of their suppression by the tumor cells, or their migration to affected lymph nodes or organs.     

Commentary on the WHO classification of tumors of lymphoid tissues (2008): ��Gray zone�� lymphomas overlapping with Burkitt lymphoma or classical Hodgkin lymphoma

The 2008 WHO Classification of Tumors of Haematopoietic and Lymphoid Tissues has introduced two new categories of high-grade B-cell lymphomas: entities in which features of diffuse large B-cell lymphoma (DLBCL) overlap with Burkitt lymphoma (DLBCL/BL) or classical Hodgkin lymphoma (DLBCL/HL). The DLBCL/BL category encompasses cases that resemble Burkitt lymphoma morphologically, but have one or more immunophenotypic or molecular genetic deviations that would exclude it from the BL category; conversely, some cases have immunophenotypic and/or genetic features of BL, but display cytologic variability unacceptable for BL. Many of the cases in the DLBCL/BL category contain a translocation of MYC as well as either BCL2 or BCL6 (so-called double-hit lymphomas) and have a very aggressive clinical behavior. The DLBCL/HL category encompasses lymphomas that exhibit the morphology of classical Hodgkin lymphoma but the immunophenotype of DLBCL, or vice versa. Most DLBCL/HL cases described present as mediastinal masses, but this category is not limited to mediastinal lymphomas. These new categories acknowledge the increasing recognition of cases that display mixed features of two well-established diseases. Whether the existence of such cases reflects shortcomings of our current diagnostic armamentarium or a true disease continuum in which such hybrid or intermediate neoplasms actually exist remains to be determined.     

Spatial differences in the presence of FOXP3+ and GranzymeB+ T cells between the intra- and extravascular compartments in renal allograft vasculopathy

Background

Allograft vasculopathy (AV) and native atherosclerosis (NA) share the presence of a T-cell mediated inflammatory response, but differ in overall plaque morphology and growth rate. We studied the distribution and frequency of regulatory- and cytotoxic T cells in the arterial intima lesions in both conditions.

Methodology/Principal Findings

The study is based on vessels of 15 explanted human renal allografts with AV and 10 carotid artery plaques obtained at surgery. Distribution and frequency of cytotoxic- and regulatory T cells, as identified by the expression of Granzyme B (GrB) and FOXP3 was established in NA and AV. Furthermore, we compared the distribution of these cells in AV with the perivascular, interstitial renal tissue using immunohistochemistry. The total number of T cells was much higher in AV than in NA lesions (711±135 and 37±8 CD3/mm² respectively, p<0.005, mean, ± SEM). Total numbers of FOXP3⁺ regulatory cells were also significantly increased in AV (36±10 and 0.9±0.3 FOXP3⁺/mm² p<0.05), but relative numbers, expressed as a percentage of the total number of CD3⁺ T cells ((FOXP3⁺/CD3⁺) ×100), were not significantly different (4.6%±0.9 and 2.7%±0.6). GrB⁺ cells were rare in NA, but significantly increased numbers of GrB⁺ cells were found in AV lesions (85±24 and 0.2±0.1 GrB⁺/mm², p<0.05). Perivascular tissues in the allografts showed a higher relative frequency of FOXP3⁺ cells than adjacent intimal lesions (14.0%±2.7 and 4.6%±0.9, respectively, p<0.05), but a lower frequency of GrB⁺ cytotoxic T cells (16.1%±2.7 and 22.6%±3.6, p<0.05).

Conclusions

Similar to NA, AV is characterized by a low frequency of intimal FOXP3⁺ regulatory T cells. Moreover, significant spatial differences exist in the distribution of functional T cell subsets between the intra- and extravascular micro-environments of the graft.     

Diverse Hematological Malignancies Including Hodgkin-Like Lymphomas Develop in Chimeric MHC Class II Transgenic Mice

A chimeric HLA-DR4-H2-E (DR4) homozygous transgenic mouse line spontaneously develops diverse hematological malignancies with high frequency (70%). The majority of malignancies were distributed equally between T and B cell neoplasms and included lymphoblastic T cell lymphoma (LTCL), lymphoblastic B cell lymphoma (LBCL), diffuse large B cell lymphoma (DLBCL), the histiocyte/T cell rich variant of DLBCL (DLBCL-HA/T cell rich DLBCL), splenic marginal zone lymphoma (SMZL), follicular B cell lymphoma (FBL) and plasmacytoma (PCT). Most of these neoplasms were highly similar to human diseases. Also, some non-lymphoid malignancies such as acute myeloid leukemia (AML) and histiocytic sarcoma were found. Interestingly, composite lymphomas, including Hodgkin-like lymphomas, were also detected that had CD30⁺ Hodgkin/Reed-Sternberg (H/RS)-like cells, representing a tumor type not previously described in mice. Analysis of microdissected H/RS-like cells revealed their origin as germinal center B cells bearing somatic hypermutations and, in some instances, crippled mutations, as described for human Hodgkin lymphoma (HL). Transgene integration in an oncogene was excluded as an exclusive driving force of tumorigenesis and age-related lymphoma development suggests a multi-step process. Thus, this DR4 line is a useful model to investigate common molecular mechanisms that may contribute to important neoplastic diseases in man.     

A Decreased Frequency of Regulatory T Cells in Patients with Common Variable Immunodeficiency

Introduction

Common variable immunodeficiency disorder (CVID) is a heterogeneous syndrome, characterized by deficient antibody production and recurrent bacterial infections in addition abnormalities in T cells. CD4⁺CD25^high regulatory T cells (Treg) are essential modulators of immune responses, including down-modulation of immune response to pathogens, allergens, cancer cells and self-antigens.

Objective

In this study we set out to investigate the frequency of Treg cells in CVID patients and correlate with their immune activation status.

Materials and Methods

Sixteen patients (6 males and 10 females) with CVID who had been treated with regular intravenous immunoglobulin and 14 controls were enrolled. Quantitative analyses of peripheral blood mononuclear cells (PBMC) were performed by multiparametric flow cytometry using the following cell markers: CD38, HLA-DR, CCR5 (immune activation); CD4, CD25, FOXP3, CD127, and OX40 (Treg cells); Ki-67 and IFN-γ (intracellular cytokine).

Results

A significantly lower proportion of CD4⁺CD25^highFOXP3 T cells was observed in CVID patients compared with healthy controls (P<0.05). In addition to a higher proportion of CD8⁺ T cells from CVID patients expressing the activation markers, CD38⁺ and HLA-DR⁺ (P<0.05), we observed no significant correlation between Tregs and immune activation.

Conclusion

Our results demonstrate that a reduction in Treg cells could have impaired immune function in CVID patients.     

Experimental Persistent Infection of BALB/c Mice with Small-Colony Variants of Burkholderia pseudomallei Leads to Concurrent Upregulation of PD-1 on T Cells and Skewed Th1 and Th17 Responses

BackgroundBurkholderia pseudomallei (B. pseudomallei), the causative agent of melioidosis, is a deadly pathogen endemic across parts of tropical South East Asia and Northern Australia. B. pseudomallei can remain latent within the intracellular compartment of the host cell over prolonged periods of time, and cause persistent disease leading to treatment difficulties. Understanding the immunological mechanisms behind persistent infection can result in improved treatment strategies in clinical melioidosis.MethodsTen-day LD₅₀ was determined for the small-colony variant (SCV) and its parental wild-type (WT) via intranasal route in experimental BALB/c mice. Persistent B. pseudomallei infection was generated by administrating sub-lethal dose of the two strains based on previously determined LD₅₀. After two months, peripheral blood mononuclear cells (PBMCs) and plasma were obtained to investigate host immune responses against persistent B. pseudomallei infection. Lungs, livers, and spleens were harvested and bacterial loads in these organs were determined.ResultsBased on the ten-day LD₅₀, the SCV was ~20-fold less virulent than the WT. The SCV caused higher bacterial loads in spleens compared to its WT counterparts with persistent B. pseudomallei infection. We found that the CD4+ T-cell frequencies were decreased, and the expressions of PD-1, but not CTLA-4 were significantly increased on the CD4+ and CD8+ T cells of these mice. Notably, persistent infection with the SCV led to significantly higher levels of PD-1 than the WT B. pseudomallei. Plasma IFN-γ, IL-6, and IL-17A levels were elevated only in SCV-infected mice. In addition, skewed plasma Th1 and Th17 responses were observed in SCV-infected mice relative to WT-infected and uninfected mice.ConclusionB. pseudomallei appears to upregulate the expression of PD-1 on T cells to evade host immune responses, which likely facilitates bacterial persistence in the host. SCVs cause distinct pathology and immune responses in the host as compared to WT B. pseudomallei.