Search

It was assessed the immunohistochemical profile of CD25+ cells in cases of chronic gingivitis (CG) and chronic periodontitis (CP). Immunohistochemistry was carried out using streptoavidin-biotin complex and anti-CD25 antibody in 17 cases of CG and 25 cases of CP. Sixteen cases (94.1%) of CG were immunopositive. CD25 was focally expressed in 50% of the sample and diffusely expressed in 25%. The stained cells were localized not only beneath the epithelium, but also far from it. In relation to the cellular density quantification of CD25+ cells, score ++ was the most common. Concerning CP, all cases were immunopositive. CD25+ cells were expressed in focal or diffuse pattern either close or far from the epithelium. Diffuse distribution of positive cells throughout the connective tissue was seen in 60% of the cases and 32% showed focal or diffuse cellular pattern. Sixteen cases (64%) received score +++. It was identified that CD25+ cells are present in either a focal or a diffuse pattern in connective tissue. Significant differences in the density of cellular immunostaining between CG and CP were found. The greatest density was observed in CP cases, which suggests that the infiltrate of lymphocytes show a higher degree of cellular activation in periodontitis compared with gingivitis.

Thymic CD4(+)CD25(+) cells have regulatory-T-cell-like properties in chickens. This study examined the ontogeny of CD4(+)CD25(+) cells in the thymus and in peripheral compartments in chickens. CD4(+)CD25(+) cells started to appear in the thymus at day 15 of incubation (E15), although at low percentages. Expressed as a percentage of CD4(+) cells, CD4(+)CD25(+) cells increased (P<0.01) from 1.7% at E20 to 7.3% at 0 d post-hatch (D0). CD4(+)CD25(+) cells did not appear in the spleen or cecal tonsils of embryos. Expressed as a percentage of CD4(+) cells, CD4(+)CD25(+) cells increased (P<0.01) from 0% at D0 to 27% at D1 in cecal tonsils and from 0% at D0 to 11% at D1 in the spleen. Expressed as a percentage of all mononuclear cells, cecal tonsils at D1 had approximately 3.5-fold higher percentage of CD4(+)CD25(+) cells than the spleen at D1. CD4(+)CD25(+) cells from cecal tonsils of chicks at D1 were suppressive. CD4(+)CD25(+) cells from D0 thymus, when injected back into MHC-compatible chicks, migrated to cecal tonsils and lungs and were detected until 10 d post-injection. CD4(+)CD25(+) cells from cecal tonsils had a higher (P = 0.01) relative amount of CCR9 mRNA than CD4(+)CD25(+) cells from the thymus. It could be concluded that in chickens CD4(+)CD25(+) cells migrate from the thymus immediately post-hatch and preferentially colonize the gut associated lymphoid tissues. CD4(+)CD25(+) cells' preferential migration to cecal tonsils is likely directed through the CCR9 pathway in chickens.

Extrapulmonary tuberculosis may be due to underlying immune compromise. Immunosuppressive regulatory T cells (Treg cells), and CD4(+) T lymphocytes in general, are important in the host immune response to Mycobacterium tuberculosis. We evaluated T lymphocytes from patients after recovery from extrapulmonary tuberculosis, which may reflect conditions before M. tuberculosis infection. A case-control study was conducted among HIV-uninfected adults with previously treated extrapulmonary tuberculosis and 3 sets of controls: (i) subjects with previously treated pulmonary tuberculosis, (ii) close tuberculosis contacts with M. tuberculosis infection, and (iii) close tuberculosis contacts with no infection. Monocyte-depleted peripheral blood mononuclear cells (PBMC-M) were stained for CD4(+) CD25(hi) CD127(low) FoxP3(+) cell (Treg cell) and T lymphocyte activation. Both characteristics were compared as continuous variables between groups with the Kruskal-Wallis test. There were 7 extrapulmonary tuberculosis cases, 18 pulmonary tuberculosis controls, 17 controls with M. tuberculosis infection, and 18 controls without M. tuberculosis infection. The median Treg cell proportion was highest among persons with previous extrapulmonary tuberculosis (1.23%) compared to subjects with pulmonary tuberculosis (0.56%), latent M. tuberculosis infection (0.14%), or no M. tuberculosis infection (0.20%) (P = 0.001). The median proportion of CD4(+) T lymphocytes that expressed the activation markers HLA-DR and CD38 was highest for CD4(+) T lymphocytes from persons with previous extrapulmonary tuberculosis (0.79%) compared to subjects with pulmonary tuberculosis (0.44%), latent M. tuberculosis infection (0.14%), or no M. tuberculosis infection (0.32%) (P = 0.005). Compared with controls, persons with previously treated extrapulmonary tuberculosis had the highest Treg cell frequency, but also the highest levels of CD4(+) T lymphocyte activation. Immune dysregulation may be a feature of individuals at risk for extrapulmonary tuberculosis.

Background: Autologous haematopoietic stem cells transplantation (HSCT) has been shown to be effective in refractory Crohn's disease., Aim: We analysed the effects of HSCT on the immune response of patients treated for moderate-severe Crohn's disease, refractory or intolerant to multiple drugs., Methods: Unselected peripheral blood stem cells were collected after mobilisation with cyclophosphamide (CTX) and G-CSF. The conditioning regimen included CTX and rabbit antithymocyte globulin. Blood samples for immunological analyses were collected at baseline, after mobilisation, and 3, 6 and 12 months after transplantation. Immunological analyses evaluated: (1) CD4(+)/CD25(high+)/FoxP3(+) regulatory T cells (T-regs); (2) Toll-like receptor 2-(TLR2) and TRL4-expressing monocytes (CD14(+) cells); (3) IL-12, IL-10, TNF-alpha-production by mitogen-stimulated CD14(+) cells and IFN-gamma production by CD4(+) T cells. Immunological results were compared with healthy donors and associated with clinical and endoscopic response during 12 months of follow-up., Results: Overall, T-regs increased, whilst TLR4-expressing cells, as well as TNF-alpha and IL-10, all higher than healthy donors at baseline, significantly decreased after transplantation. Full responders at T(3) had higher T-regs and lower IFN-gamma and IL12. T-regs decreased and IL12 and TLR2 increased in the only relapsed patient., Conclusions: HSCT can induce and maintain clinical and endoscopic remission in refractory Crohn's disease, which is associated with immunomodulation., (Copyright © 2011. Published by Elsevier Ltd.)

Purpose: Immunotherapy could be a useful adjunct to standard cytotoxic therapies such as radiation in patients with micrometastatic disease, although successful integration of immunotherapy into treatment protocols will require further understanding of how standard therapies affect the generation of antitumor immune responses. This study was undertaken to evaluate the impact of radiation therapy (RT) on immunosuppressive T regulatory (Treg) cells., Methods and Materials: Treg cells were identified as a CD4(+)CD25(hi)Foxp3(+) lymphocyte subset, and their fate was followed in a murine TRAMP C1 model of prostate cancer in mice with and without RT., Results: CD4(+)CD25(hi)Foxp3(+) Treg cells increased in immune organs after local leg or whole-body radiation. A large part, but not all, of this increase after leg-only irradiation could be ascribed to radiation scatter and Treg cells being intrinsically more radiation resistant than other lymphocyte subpopulations, resulting in their selection. Their functional activity on a per-cell basis was not affected by radiation exposure. Similar findings were made with mice receiving local RT to murine prostate tumors growing in the leg. The importance of the Treg cell population in the response to RT was shown by systemic elimination of Treg cells, which greatly enhanced radiation-induced tumor regression., Conclusions: We conclude that Treg cells are more resistant to radiation than other lymphocytes, resulting in their preferential increase. Treg cells may form an important homeostatic mechanism for tissues injured by radiation, and in a tumor context, they may assist in immune evasion during therapy. Targeting this population may allow enhancement of radiotherapeutic benefit through immune modulation., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background: According to the World Health Organization (WHO) classification the diagnosis of systemic mastocytosis (SM) relies on bone marrow (BM) examination and is based on one major and four minor criteria. Herein, we used WHO criteria to compare flow cytometry (FC) with other available techniques in the diagnosis of SM after BM examination., Methods: We analyzed a cohort of 95 patients with suspect SM. All patients underwent comprehensive BM examination by using cytology, immunohistochemistry, FC and molecular study for mutation of c-Kit and serum tryptase dosage. FC evaluation was based on a combination of monoclonal antibodies, specifically CD25/CD2/CD45/CD34/CD117., Results: Seventy-four out of ninety-five patients were diagnosed with indolent SM (n = 59) or monoclonal mast cell activation syndrome (n = 15) because satisfying less than 3 minor criteria. Thirty-nine out of these seventy-four patients fulfilled the major histological criterion, whereas the presence of a minor criterion was assessed by FC, molecular study, cytology, and tryptase level in 70/74, 52/67, 56/74, and 42/74 patients, respectively. FC showed higher sensitivity than IHC in detection of CD25+ mast cells (MC) (92.9% vs. 73.8%; P = 0.019), especially in the absence of the major histological criterion (90.5% vs. 47.6%; P = 0.003). Moreover, CD2 expression was documented by FC and IHC in 97.1% and 35.3% of cases, respectively (P < 0.001)., Conclusions: FC showed the best sensitivity for identifying abnormal MC compared to other techniques, especially in cases with low MC burden. Therefore, we hope for a major role of FC in the diagnostic work-up of clonal MC disorders., (2011 International Clinical Cytometry Society.)

Helicobacter pylori blocks the proliferation of human CD4(+) T cells, facilitated by vacuolating exotoxin (VacA) and γ-glutamyl transpeptidase (GGT). H. pylori-triggered T-cell reactions in mice correlate with bacterial cholesterol and cholesterol α-glucoside content but their role in human cells is unclear. We characterized the effect of VacA, GGT, and cholesterol on T-helper 1, T-helper 2, T-regulatory and T-helper 17 associated cytokines and T-cell proliferation. VacA, GGT, and bacterial cholesterol content exhibited differential and synergistic inhibitory effects on the expression of activation markers CD25 and CD69 and on interleukin 2, interleukin 4, interleukin 10, and interferon γ production. These factors did not affect the H. pylori-mediated abrogation of transforming growth factor β secretion or increased interleukin 6 production. Cholesterol α-glucosyltransferase-deficient bacteria exerted strongly reduced antiproliferative effects on primary human CD4(+) T cells. In conclusion, H. pylori shapes rather than suppresses human CD4(+) T-cell responses, and glucosylated cholesterol is a relevant bacterial component involved in this modulation.

FOXP3 is critical for the development and function of CD4(+)CD25(bright) natural regulatory T cells (nTreg). Individuals harboring mutations in FOXP3 develop immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome (IPEX). We describe a child diagnosed with IPEX who underwent a reduced intensity, T and B cell depleted, matched unrelated donor bone marrow transplant followed by clinical resolution. Using lineage-specific donor chimerism studies, we demonstrate that non-myeloablative HSCT resolves disease in the context of low level donor hematopoietic stem cell (HSC) engraftment. Despite low-levels of donor HSC, thymically-derived nTreg and to a lesser extent CD4(+) and CD8(+) T cells, exhibit a selective in vivo growth advantage for populations containing a functional FOXP3 gene. Moreover, nTreg from this patient show regulatory function directly ex vivo. These results have implications for improving clinical therapy for patients with IPEX and provide mechanistic insight into the in vivo development of human nTreg and unexpectedly, non-regulatory T cells., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Hookworm infection is considered one of the most important poverty-promoting neglected tropical diseases, infecting 576 to 740 million people worldwide, especially in the tropics and subtropics. These blood-feeding nematodes have a remarkable ability to downmodulate the host immune response, protecting themselves from elimination and minimizing severe host pathology. While several mechanisms may be involved in the immunomodulation by parasitic infection, experimental evidences have pointed toward the possible involvement of regulatory T cells (Tregs) in downregulating effector T-cell responses upon chronic infection. However, the role of Tregs cells in human hookworm infection is still poorly understood and has not been addressed yet. In the current study we observed an augmentation of circulating CD4(+)CD25(+)FOXP3(+) regulatory T cells in hookworm-infected individuals compared with healthy non-infected donors. We have also demonstrated that infected individuals present higher levels of circulating Treg cells expressing CTLA-4, GITR, IL-10, TGF-β and IL-17. Moreover, we showed that hookworm crude antigen stimulation reduces the number of CD4(+)CD25(+)FOXP3(+) T regulatory cells co-expressing IL-17 in infected individuals. Finally, PBMCs from infected individuals pulsed with excreted/secreted products or hookworm crude antigens presented an impaired cellular proliferation, which was partially augmented by the depletion of Treg cells. Our results suggest that Treg cells may play an important role in hookworm-induced immunosuppression, contributing to the longevity of hookworm survival in infected people.

Objective: Anti-TNF-α antibodies has been suggested to modulate regulatory T cell (Treg) percentages in rheumatoid arthritis, but results from studies of Crohn's disease (CD) are conflicting. We investigated dynamic changes of circulating Tregs in CD during treatment with the anti-TNF-α-antibody adalimumab (Humira®, Abbott Laboratories A/S, Emdrupvej 28C, DK-2100 Copenhagen)., Material and Methods: Blood samples from 26 CD patients were analysed using flow cytometry before and 1 and 26 weeks after initiation of adalimumab treatment to determine the percentage of Tregs among CD4+ T cells., Results: In spite of a significant decline in disease activity scores and biochemical markers of inflammation, during the first week of treatment, we did not observe early modulating effects of adalimumab on Treg percentages. However, we found a long-term increase in Treg percentages in responders who had low Treg percentages (<5%) at baseline (p = 0.04). Treg percentage was inversely associated with disease activity (CD activity index or CDAI) (Spearman's rank correlation, ρ = -0.47, p = 0.02). High Treg percentages among CD4+ T cells at baseline predicted clinical response to adalimumab., Conclusions: Adalimumab treatment did not induce early modulatory effects on Treg percentage, even in responders. This finding suggests that adalimumab does not have a direct or selective effect on Tregs. However, Treg percentage was associated with disease activity and high Treg percentage predicted response to adalimumab.

Our and others' previous studies have shown that Schistosoma japonicum (SJ) infection can inhibit allergic reactions. Moreover, we found that adoptive transfer of dendritic cells (DCs) from inhibited mice showed a similar inhibitory effect on allergy, suggesting a critical role of DCs in SJ-infected mediated inhibition of allergy. In this study, we further examined the mechanism by which DCs contribute to inhibition of allergy. Our results showed that DCs from SJ-infected mice (SJDCs) produced significantly higher levels of IL-10 compared to those from naive control mice (NDCs). Adoptive transfer of SJDCs, unlike NDCs, significantly increased CD4+CD25+Foxp3+ T cells and CD4+CD25+IL-10+ T cells regulatory T-cell responses in vivo. This was correlated with significantly reduced production of IL-4 and IL-5 by CD4+ T cells, eotaxin in lung tissues and reduced airway allergic inflammation in the SJDC recipients following allergen sensitization and challenge. These data suggest that helminth infection may induce tolerogenic DCs that can inhibit the development of airway allergic inflammation through enhancing T regulatory cell responses., (© 2011 Blackwell Publishing Ltd.)

Objective: Natural CD4+CD25+FoxP3+ Treg cells play a crucial role in maintaining immune homeostasis and controlling autoimmunity. In patients with juvenile idiopathic arthritis (JIA), inflammation occurs despite the increased total numbers of Treg cells in the synovial fluid (SF) compared to the peripheral blood (PB). This study was undertaken to investigate the phenotype of CD4+ T cells in PB and SF from JIA patients, the function of synovial Treg cells, and the sensitivity of PB and SF CD4+CD25- effector T cells to the immunoregulatory properties of Treg cells, and to study the suppression of cytokine secretion from SF effector T cells by Treg cells., Methods: The phenotypes of effector T cells and Treg cells of PB and SF from JIA patients and healthy donors were determined by flow cytometry. The functionality of isolated Treg cells and effector T cells was quantified in (3) H-thymidine proliferation assays. Cytokine levels were analyzed using Bio-Plex Pro assay., Results: Compared to PB, SF showed significantly elevated numbers of activated and differentiated CD4+CD45RO+ T cells. Sensitivity of SF effector T cells to the suppressive effects of Treg cells from both PB and SF was impaired, correlating inversely with the expression of CD69 and HLA-DR. However, SF effector T cell cytokine secretion was partly suppressed by SF Treg cells., Conclusion: Our findings indicate that regulation is impaired in the SF of patients with JIA, as shown by the resistance of effector T cells to immunoregulation by functional Treg cells. This resistance of the SF effector T cells might be due to their activated phenotype., (Copyright © 2011 by the American College of Rheumatology.)

Background and Aim: A new subset of Treg cells, CD4(+) CD69(+) CD25(-) T cells, has been identified in mice. Herein, we aimed to identify this subset of T cells and to evaluate its function in patients with hepatocellular carcinoma (HCC)., Methods: We detected CD4(+) CD69(+) CD25(-) T cells and its expression of CCR6 and transforming growth factor-β1 (TGF-β1) in peripheral blood of 91 HCC patients, 38 chronic hepatitis patients and 34 healthy donors by flow cytometry. CD4(+) CD69(+) CD25(-) T cells in HCC tissues were also analyzed., Results: CD4(+) CD69(+) CD25(-) T cells were significantly increased in peripheral blood of HCC patients compared with healthy persons and chronic hepatitis patients (8.74% ± 0.42% vs 4.55% ± 0.33% and 5.15% ± 0.36%, P < 0.0001). The percentage of peripheral CD4(+) CD69(+) CD25(-) T cells was significantly higher in HCC patients with Tumor Node Metastasis (TNM) stage III plus IV (P < 0.05). Patients with large tumor size and tumor vascular invasion were inclined to obtain high percentage of CD4(+) CD69(+) CD25(-) T cells (P < 0.05). The frequency of membrane-bound TGF-β1 positive cells in CD4(+) CD69(+) CD25(-) T cells from HCC patients was higher than that from the other two groups (P < 0.0001). A considerable proportion of CD4(+) CD69(+) CD25(-) T cells were present in HCC tissues, which has significant correlation with tumor size and TNM stage. Few CD4(+) CD69(+) CD25(-) T cells express CCR6 both in peripheral blood and tumor tissues from HCC patients., Conclusions: Increased CD4(+) CD69(+) CD25(-) T cells in HCC patients are significantly correlated with tumor size, vascular invasion and TNM stage. Thus, increased CD4(+) CD69(+) CD25(-) T cells exert a critical role in HCC progression and might be a clinically aggressive phenotype of HCC., (© 2011 Journal of Gastroenterology and Hepatology Foundation and Blackwell Publishing Asia Pty Ltd.)

Eggs of the helminth Schistosoma mansoni accumulate in the colon following infection and generate Th2-biassed inflammatory granulomas which become down- modulated in size as the infection proceeds to chronicity. However, although CD4+CD25+FoxP3+ regulatory T cells (T(regs)) are known to suppress Th1-mediated colitis, it is not clear whether they control Th2-associated pathologies of the large intestine which characterise several helminth infections. Here we used a novel 3D-multiphoton confocal microscopy approach to visualise and quantify changes in the size and composition of colonic granulomas at the acute and chronic phases of S. mansoni infection. We observed decreased granuloma size, as well as reductions in the abundance of DsRed+ T cells and collagen deposition at 14 weeks (chronic) compared to 8 weeks (acute) post-infection. Th2 cytokine production (i.e. IL-4, IL-5) in the colonic tissue and draining mesenteric lymph node (mLN) decreased during the chronic phase of infection, whilst levels of TGF-β1 increased, co-incident with reduced mLN proliferative responses, granuloma size and fibrosis. The proportion of CD4+CD25+FoxP3+T(regs): CD4+ cells in the mLN increased during chronic disease, while within colonic granulomas there was an approximate 4-fold increase. The proportion of CD4+CD25+FoxP3+T(regs) in the mLN that were CD103+ and CCR5+ also increased indicating an enhanced potential to home to intestinal sites. CD4+CD25+ cells suppressed antigen-specific Th2 mLN cell proliferation in vitro, while their removal during chronic disease resulted in significantly larger granulomas, partial reversal of Th2 hypo-responsiveness and an increase in the number of eosinophils in colonic granulomas. Finally, transfer of schistosome infection-expanded CD4+CD25+T(regs) down-modulated the development of colonic granulomas, including collagen deposition. Therefore, CD4+CD25+FoxP3+T(regs) appear to control Th2 colonic granulomas during chronic infection, and are likely to play a role in containing pathology during intestinal schistosomiasis.

A patient with well-defined acute HIV infection who developed concomitant pulmonary tuberculosis during the retroviral acute syndrome is reported here. In this patient high levels of T-regulatory cells (Tregs) and a low proliferation response to M. tuberculosis were initially detected, which normalized throughout follow-up. This case calls for the consideration of tuberculosis in patients in the early stages of HIV, and emphasizes the need for further study of the potential causal relationship between Treg cells and the risk of TB reactivation in HIV patients.

Regulatory T cells (T(regs) ) play a key role in the prevention of acute graft-versus-host disease (aGVHD). To investigate the association between T(reg) subsets and aGVHD, we prospectively analysed T cell subsets in the allografts of 35 patients undergoing myeloablative unmanipulated haematopoietic stem cell transplantation. Multivariate analysis found that patients infused with less than 0·29 × 10(6) /kg of CD4(+) CD25(high) CD45RA(+) CD62L(+) T cells during transplantation exhibited an increased incidence of II-IV aGVHD [hazard ratio (HR) = 0·000, 95% CI = 0·000-0·106, P = 0·013]. Next, we compared the reconstitution characteristics of T cell subsets between haploidentical haematopoietic stem cell transplantation (HSCT) and sibling HSCT by collecting peripheral blood samples at regular intervals (days 30, 60 and 90) after transplantation. No significant differences were observed in the reconstitution of conventional T cells between haploidentical HSCT and sibling identical HSCT. However, total counts of recovered naiveT(regs) and CD62L(+) naive T(regs) from haploidentical HSCT were significantly lower compared to sibling identical HSCT; P-values were 0·045 and 0·021, respectively. Although total counts of conventional T cells in aGVHD patients reached similar levels compared to non-aGVHD patients before day 60 post-HSCT, total counts of naive T(regs) and CD62L(+) naive T(regs) in aGVHD patients did not reach similar levels to non-aGVHD patients until 90 days post-HSCT. Taken together, our findings demonstrate that a large population of CD62L(+) naive T(regs) in allografts reduces the incidence of aGVHD. Further, development of aGVHD is related closely to the delayed reconstitution of the naive T(reg) population., (© 2011 The Authors. Clinical and Experimental Immunology © 2011 British Society for Immunology.)

Both T-helper 17 cells (Th-17) and CD4(+)CD25(+) regulatory T cells (Tregs) play important roles in the pathogenesis of hepatitis B virus (HBV) infection. Recent studies have suggested that Th-17 and Treg cells are increased in patients with chronic hepatitis B (CHB). This study further characterizes Th-17 and Treg cells in the blood of HBV-associated acute-on-chronic liver failure (ACLF) patients, and aids our understanding of how the two subsets of CD4(+) T cells affect each other and contribute to survival. Blood samples were obtained from 30 patients with HBV-associated ACLF, 30 patients with CHB, and 30 normal controls (NC). The frequencies of Th-17 and Treg cells were determined by intracellular cytokine staining analysis. To observe the suppressive function of Tregs, purified CD4(+)CD25(+) Tregs from peripheral blood mononuclear cells (PBMCs) were co-cultured with CD4(+)CD25(-) T cells for 48 h, and then IFN-γ and IL-17A from the supernatants were measured by ELISA. We found that both Th-17 and FoxP3(+) Treg cells were increased in ACLF patients. IL-17A secretion by CD4(+) T cells was not regulated by Treg cells, even though Tregs exhibited significant inhibition of IFN-γ production. Most importantly, the ratio of Th-17 to Treg cells was associated inversely with the survival of ACLF patients. These findings provide new information regarding the pathogenesis of HBV-associated ACLF, and the ratio of Th-17 to Tregs may represent a potential prognostic marker for the disease.

Background: Antigenic variation is an effective way by which viruses evade host immune defense leading to viral persistence. Little is known about the inhibitory mechanisms of viral variants on CD4 T cell functions., Results: Using sythetic peptides of a HLA-DRB1*15-restricted CD4 epitope derived from the non-structural (NS) 3 protein of hepatitis C virus (HCV) and its antigenic variants and the peripheral blood mononuclear cells (PBMC) from six HLA-DRB1*15-positive patients chronically infected with HCV and 3 healthy subjects, the in vitro immune responses and the phenotypes of CD4+CD25+ cells of chronic HCV infection were investigated. The variants resulting from single or double amino acid substitutions at the center of the core region of the Th1 peptide not only induce failed T cell activation but also simultaneously up-regulate inhibitory IL-10, CD25-TGF-β+ Th3 and CD4+IL-10+ Tr1 cells. In contrast, other variants promote differentiation of CD25+TGF-β+ Th3 suppressors that attenuate T cell proliferation., Conclusions: Naturally occuring HCV antigenic mutants of a CD4 epitope can shift a protective peripheral Th1 immune response into an inhibitory Th3 and/or Tr1 response. The modulation of antigenic variants on CD4 response is efficient and extensive, and is likely critical in viral persistence in HCV infection.

We compared the effects of yeast-treated human dendritic cells (DCs) with CD40L-matured human DCs for the induction of effector cells and the number and functionality of CD4(+)CD25(+)CD127(-)FoxP3(+) regulatory T cells (Tregs). DCs were treated with yeast or CD40L and cocultured with isolated autologous CD4(+) T cells. CD4(+)CD25(+)CD127(-) T cells isolated from the coculture of CD4(+) T cells plus yeast-treated DCs (yeast coculture) had a lower expression of FoxP3 and decreased suppressive function compared to CD4(+)CD25(+)CD127(-) T cells isolated from the coculture of CD4(+) T cells plus CD40L-treated DCs (CD40L coculture). Also, compared to the CD40L coculture, the yeast coculture showed increases in the ratio of CD4(+)CD25(+) activated T cells to Tregs and in the production of Th1-related cytokines (IL-2, TNF-α, IFN-γ) and IL-6. In addition, yeast-treated DCs used as antigen-presenting cells (APCs) incubated with the tumor antigen CEA enhanced the proliferation of CEA-specific CD4(+) T cells compared to the use of CD40L-matured DCs used as APCs. This is the first study to report on the role of yeast-treated/matured human DCs in reducing Treg frequency and functionality and in enhancing effector to Treg ratios. These results provide an additional rationale for the use of yeast as a vector in cancer vaccines., (Published by Elsevier Ltd.)

Background: Hepatocellular carcinoma (HCC) is notorious for poor prognosis with limited therapeutic options. A better understanding of the role of regulatory T-cells (Tregs) in HCC is important for design of immunotherapy based clinical protocol. The objective of the present study was to evaluate the presence of Tregs in tumor microenvironment in patients with HCC compared to chronic hepatitis (CH)., Materials and Methods: The frequency of CD4 + CD25 + Treg cells was evaluated from peripheral blood (PB) of 28 patients of HCC and 30 controls including CH cases and healthy donors using flowcytometry. Intratumoral Treg were also analyzed in tissue samples from 17 HCC cases and 15 CH cases. In addition the expression of FOXP3 and CTLA-4 was also studied by RT-PCR., Results: Frequency of CD4 + CD25 + cells in the PBMCs of HCC cases was significantly higher than in HC (10.8 ± 7.64 vs 3.05 ± 1.30, P < 0.005) and CH patients (2.88 ± 1.92, P < 0.005). Also Treg population was significantly higher in HCC tumor microenvironment compared to CH biopsies (15.8 ± 5.32 vs 5.51 ± 3.40, P < 0.05). Expression of FOXP3 and CTLA-4 was also significantly higher in HCC patients ( P < 0.05) compared to CH group., Conclusions: We provide evidence of an increased population of Treg not only in the PB but also in tumor microenvironment of HCC patients, suggesting association of enhanced Treg activity with poor immune responses to tumor antigens. These findings may in future play a significant role in designing immunotherapeutic approaches in HCC.

In areas where Plasmodium falciparum is endemic, pregnancy is associated with accumulation of infected red blood cells (RBCs) in the placenta, a condition referred to as placental malaria (PM). Infants born to PM-positive mothers are at an increased risk of malaria, which is putatively related to the transplacental passage of parasite-derived antigens, with consequent tolerization of the fetal immune system. Here we addressed the impact of PM on the regulation of neonatal T cell responses. We found that the frequency of regulatory CD25(+) CD127(-/low) Foxp3(+) CD4(+) T cells was significantly decreased in neonates born to mothers with high levels of P. falciparum-induced placental inflammation, consisting mainly of primigravid mothers. However, at the individual level, the ratio between regulatory and effector (CD25(+) CD127(+) Foxp3(-)) CD4(+) T cells was unaffected by PM. In addition, parasite-induced CD4(+) T cell activation and production of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and IL-10 were strongly reduced in neonates born to PM-positive mothers. Thus, our results show that active PM at delivery is associated with a marked suppression of P. falciparum-specific cellular neonatal immune responses, affecting secretion of both pro- and anti-inflammatory cytokines. Additionally, our results suggest that, as in adults, effector and regulatory CD4(+) T cell populations are tightly coregulated in all neonates, irrespective of the maternal infection status.

Treatment with anti-CD3 mAb modulates immune responses that cause type 1 diabetes and other diseases. CD8+ Tregs can be induced in vitro and in vivo by mAb. However, 1/3 of patients do not respond to drug therapy and in an equal proportion, anti-CD3 mAb does not induce Tregs in vitro. The acquisition of CD8+ Treg activity is a function of the CD8+ cells and not the targets in the assay. To identify markers to differentiate responses of CD8+ Tregs, we analyzed genes differentially expressed in CD8+ T cells of non-responders compared with responders, and found that an inhibitory receptor NKG2A (CD159a) was highly expressed in cells from all non-responders tested. Application of a mAb agonistic to NKG2A during in vitro CD8+ Treg induction by anti-CD3 prevented induction of CD8+ Tregs. CD8+ T cells that are TNFR2+ but NKG2A- are the most potently induced Tregs. The level of NKG2A expression on resting CD8+ T cells inversely correlated with acquisition of regulatory function when activated. We suggest that the induction of human CD8+ Tregs by anti-CD3 mAb is controlled by a negative signaling through NKG2A, and that NKG2A may serve as a negative marker of human CD8+ Tregs., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The biological behavior of immune cells is determined by their intrinsic properties and interactions with other cell populations within their microenvironment. Several studies have confirmed the existence of tight spatial interactions between mast cells (MCs) and Tregs in different settings. For instance, we have recently identified the functional cross-talk between MCs and Tregs, through the OX40L-OX40 axis, as a new mechanism of reciprocal influence. However, there is scant information regarding the single-cell dynamics of this process. In this study, time-lapse video microscopy revealed direct interactions between Tregs and MCs in both murine and human cell co-cultures, resulting in the inhibition of the MC degranulation response. MCs incubated with WT, but not OX40-deficient, Tregs mediated numerous and long-lasting interactions and displayed different morphological features lacking the classical signs of exocytosis. MC degranulation and Ca2+ mobilization upon activation were inhibited by Tregs on a single-cell basis, without affecting overall cytokine secretion. Transmission electron microscopy showed ultrastructural evidence of vesicle-mediated secretion reconcilable with the morphological pattern of piecemeal degranulation. Our results suggest that MC morphological and functional changes following MC-Treg interactions can be ascribed to cell-cell contact and represent a transversal, non-species-specific mechanism of immune response regulation. Further research, looking at the molecular composition of this interaction will broaden our understanding of its contribution to immunity., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We observed by flow cytometry that the frequency of both gastric infiltrating Tregs and PD-1-positive CD4 T cells is correlated with the density of Helicobacter pylori, suggesting that cellular immunity against this pathogen is inhibited.

The aim of the present work was to decipher the cellular basis of the immunoregulatory role of peroxisome proliferator-activated receptor (PPAR)-α in cutaneous hypersensitivity reactions. After challenge with a contact allergen, we observed augmented hypersensitivity reactions with increased numbers of activated T lymphocytes in the skin of PPAR-α-/- mice. Furthermore, following antigen challenge, the percentages of Tregs in the blood, draining lymph nodes and skin were decreased in these mice. PPAR-α deficiency impaired the production of IL-2 in lymph nodes, whereas TGF-β levels remained unchanged. Injection of IL-2 into PPAR-α-/- mice restored the Treg population in the skin-draining lymph nodes of allergen-challenged mice. In vivo induction of Tregs from WT CD4+ CD25- T cells was impaired when adoptively transferred into PPAR-α-/- mice as compared with transfer into WT mice, and reversed by injection of IL-2 into PPAR-α-/- mice. Furthermore, the suppressive capacity of PPAR-α-/- Tregs was impaired when compared to WT Tregs in vitro and in co-adoptive transfer experiments. Finally, injection of IL-2 to PPAR-α-/- mice decreased skin inflammation to a level similar to WT mice. In conclusion, the pro-inflammatory skin phenotype of PPAR-α-/- mice is due to lack of IL-2-mediated Treg induction in these mice., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Anaplastic large cell lymphoma (ALCL) is a distinct type of CD30+ T/null-cell non-Hodgkin's lymphoma that frequently involves nodal and extranodal sites. The presence of leukemic phase in ALCL is extremely rare and occurs exclusively with ALK1-positive ALCL. We describe two patients with ALK1-positive ALCL who developed a leukemic phase with rapid progression of the disease. Immunophenotypic pattern assessed on peripheral blood by flow cytometry revealed CD45, CD30, and CD25 positivity in both cases but NPM-ALK1 was expressed in only one case. Both patients developed leukemic phase as a terminal event of the disease and we share the immunophenotypic features of both cases.

Background: Regulatory T cells have been implicated in the pathogenesis of COPD by the increased expression of CD25 on helper T cells along with enhanced intracellular expression of FoxP3 and low/absent CD127 expression on the cell surface., Method: Regulatory T cells were investigated in BALF from nine COPD subjects and compared to fourteen smokers with normal lung function and nine never-smokers., Results: In smokers with normal lung function, the expression of CD25+CD4+ was increased, whereas the proportions of FoxP3+ and CD127+ were unchanged compared to never-smokers. Among CD4+ cells expressing high levels of CD25, the proportion of FoxP3+ cells was decreased and the percentage of CD127+ was increased in smokers with normal lung function. CD4+CD25+ cells with low/absent CD127 expression were increased in smokers with normal lung function, but not in COPD, when compared to never smokers., Conclusion: The reduction of FoxP3 expression in BALF from smokers with normal lung function indicates that the increase in CD25 expression is not associated with the expansion of regulatory T cells. Instead, the high CD127 and low FoxP3 expressions implicate a predominantly non-regulatory CD25+ helper T-cell population in smokers and stable COPD. Therefore, we suggest a smoking-induced expansion of predominantly activated airway helper T cells that seem to persist after COPD development.

Background: Both regulatory T cells (Tregs) and PD-1/PD-L1 pathway were critically involved in HCV viral persistence. However, the association between them was not well investigated. Herein, we aimed to investigate the distributional profiles of Tregs subsets and association between PD-1 expression on these subsets and development of HCV long-term persistence., Methods: CD45RA and CD27 were employed to separate peripheral Tregs as naïve/central memory/effector memory/effector subsets. The phenotypic characteristics and PD-1 expression of Tregs were studied by flow cytometry., Results: In the present study, the majority of Tregs was identified as central memory phenotype in chronic hepatitis C patients compared with nearly equal contribution of naïve and central memory subsets in healthy individuals. PD-1 expression was elevated in all CD4+ T cell subset in chronic HCV infected patients, including Tregs. Of note, higher level of PD-1 expression was found on TEM- and effector-Treg than naïve- and TCM-Tregs subsets. The ratio of TEM-Tregs/naive-Tregs and TEM-Tregs/TCM-Tregs regarding to PD-1 MFI were significantly lower in CHC patients compared to controls., Conclusions: Our study indicated that distinctive characteristics of PD-1 expression on Tregs in HCV infection suggests associated with impaired adaptive immunity as well as viral long-term persistence. The cross talk between Treg cells and PD-1 induced inhibition in chronic HCV infection deserved further exploration for HCV infection associated immune pathogenesis.

Aquaporin-4 (AQP4) is highly expressed in mammalian brains and is involved in the pathophysiology of cerebral disorders, including stroke, tumors, infections, hydrocephalus, epilepsy, and traumatic brain injury. We found that AQP4-deficient mice were hypersensitive to stimulations such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or lipopolysaccharide compared to wild-type (WT) littermates. In a mouse model of MPTP-induced Parkinson's disease (PD), AQP4-deficient animals show more robust microglial inflammatory responses and more severe loss of dopaminergic neurons (DNs) compared with WT mice. However, a few studies have investigated the association of abnormal AQP4 levels with immune dysfunction. Here, for the first time, we report AQP4 expression in mouse thymus, spleen, and lymph nodes. Furthermore, the significantly lower numbers of CD4(+) CD25(+) regulatory T cells in AQP4-deficient mice compared to WT mice, perhaps resulting from impaired thymic generation, may be responsible for the uncontrolled microglial inflammatory responses and subsequent severe loss of DNs in the substantia nigra pars compacta in the MPTP-induced PD model. These novel findings suggest that AQP4 deficiency may disrupt immunosuppressive regulators, resulting in hyperactive immune responses and potentially contributing to the increased severity of PD or other immune-associated diseases., (© 2011 The Authors. Aging Cell © 2011 Blackwell Publishing Ltd/Anatomical Society of Great Britain and Ireland.)

According to the etiology of acute pancreatitis, the authors identified the most common phenotypes of superficial antigens of peritoneal macrophages: CD14(+) CD25(-)CD64(-)HLA-DR(-) in acute biliary pancreatitis, CD14(+) CD25(+)CD64(+)HLA-DR(+) in nonbiliary pancreatitis; moreover, all the patients were found to have increased expression of early (CD25+) and late (HLA-DR+) markers of cell activation. A comparative study was conducted and the most informative tools to evaluate the adhesive, cytokine-producing, phagocytic, and oxygen-dependent activities of peritoneal macrophages were recognized.

Following infection with the hepatitis C virus (HCV), in most cases immunity fails to eradicate the virus, resulting in slowly progressing immunopathology in the HCV-infected liver. We are the first to examine intrahepatic T cells and CD4(+) CD25(+) FoxP3(+) regulatory T cells (Treg) in patients chronically infected with HCV (chronic HCV patients) during and after antiviral therapy by collecting multiple aspiration biopsy samples from the liver at different time points. We found that intrahepatic Treg frequencies were increased upon alpha interferon and ribavirin administration in about 50% of chronic HCV patients, suggesting stronger regulation of intrahepatic immunity by Treg during antiviral therapy. After cessation of antiviral therapy, the frequency of intrahepatic Treg remained above baseline in the large majority of livers of individuals who successfully cleared the virus. The phenotype of those Treg that were retained in the liver months after therapy-induced clearance of HCV RNA indicated a reduced contribution of effector memory cells. Our findings, gathered by multiple samplings of the liver, indicate that successful antiviral therapy of chronic HCV patients does not lead to normalization of the local immune response to a resting state comparable to that for healthy livers. The continuous presence of high numbers of Treg, with a phenotype reflecting a relatively weak suppressive activity, suggests ongoing residual regulation of immunopathology. These findings provide important insight into the dynamics of the immune response to HCV, as well as the effect of therapy on intrahepatic immunity.

Background: Chandipura virus produces acute infection in mice. During infection drastic reduction of CD4+, CD8+ and CD19 + cell was noticed. Depletion of lymphocytes also noticed in spleen. The reduction may be due to the regulatory mechanism of immune system to prevent the bystander host tissue injury. There are several mechanisms like generation of regulatory cells, activation induced cell death (ACID) etc were indicated to control the activation and maintain cellular homeostasis. Role of regulatory cells in homeostasis has been described in several viral diseases. This study was undertaken to characterize CD4+T regulatory cells from the infected mice., Method: In this study we purified the CD4+ T cells from Chandipura virus infected susceptible Balb/c mice. CD4+ T regulatory cells were identified by expression of cell surface markers CD25, CD127 and CTLA-4 and intracellular markers Foxp3, IL-10 and TGF-beta. Antigen specificity and ability to suppress the proliferation of other lymphocytes were studied in vitro by purified CD4+CD25+T regulatory cells from infected mice. The proliferation was calculated by proliferation module of Flow Jo software. Expression of death receptors on regulatory cells were studied by flowcytometer., Results: The CD4+ T cells isolated from infected mice expressed characteristic markers of regulatory phenotype at all post infective hours tested. The CD4+ T regulatory cells were proliferated when stimulated with Chandipura virus antigen. The regulatory cells did not suppress the proliferation of splenocytes stimulated with anti CD3 antibody when co cultured with them. Interesting observation was, while purification of CD4+ T cells by negative selection, the population of cells negative for CD4 also co purified along with CD4+ T cell. Flow cytometry analysis and light microscopy revealed that CD4 negative cells were of different size and shape (atypical) compared to the normal lymphocytes. Greater percentage of these atypical lymphocytes expressed Fas Ligand and Programmed Death1 (PD-1) receptor., Conclusion: From these results we concluded that virus specific CD4+T regulatory cells are generated during Chandipura virus infection in mice and these cells might control the activated lymphocytes during infection by different mechanism.

According to the hygiene hypothesis, the increased incidence of allergic and autoimmune diseases in developed countries is mainly explained by the decreased contact between the human population and certain environmental agents as lactobacillus, mycobacteria and helminths. In this study, we evaluated the effect of multiple infections with Strongyloides venezuelensis on the development of experimental autoimmune encephalomyelitis (EAE) in Lewis rats. Multiple infections before EAE induction were not able to change the evolution of the disease. No alterations were observed in weight loss, clinical score and inflammation intensity at the central nervous system. The presence of significant levels of parasite-specific IgG1 but not IgG2b suggested a Th2 polarization. However, the percentage and absolute number of CD4+CD25+Foxp3+ T cells were not changed, being their levels in the spleen and lymph nodes of infected rats comparable to the ones found in normal animals. These results suggest that a Th2-polarized response without concomitant expansion of Foxp3+ regulatory T cells was not able to modify EAE progression. Even though these results do not threaten the hygiene hypothesis, they suggest that this paradigm might be an oversimplification. They also emphasize the need of a study to compare the immunoregulatory ability associated with different helminth spp.

Dendritic cells (DCs) are specialized antigen-presenting cells (APCs) required for T-cell activation and are classified into several subtypes by phenotypic and functional characteristics. However, it remains unclear if distinct transcription factors control the development of each DC subpopulation. In this report, we demonstrate that Notch signaling controls the development of a novel DC subtype that expresses Thy1 (Thy1(+) DCs). Overstimulation of bone marrow cells with the Notch ligand Delta-like 1 promoted the development of Thy1(+) DCs. Thy1(+) DCs are characterized as CD11c(+) MHC class II(+) NK1.1(-) B220(-) CD8α(+) , and are present in the thymus but not in the spleen and lymph nodes. Thymic Thy1(+) DCs are able to capture exogenous proteins and delete CD4(+) CD8(+) T cells. Transplantation experiments demonstrated that CD44(+) CD25(-) and CD44(+) CD25(+) thymocytes can differentiate into Thy1(+) DCs. Recombination signal binding protein for immunoglobulin kappa J region (RBP-J) deficiency in lineage-negative bone marrow cells, but not CD11c(+) cells, disrupted Thy1(+) DC development in the thymus. Our data indicate that Notch signaling controls the development of a novel type of Thy1-expressing DC in the thymus that possibly controls negative selection, and indicates that there may be highly regulated, differential transcriptional control of DC development. Furthermore, our findings suggest that Notch signaling regulates T-cell development not only by intrinsically inducing T-cell lineage-specific gene programs, but also by regulating negative selection through Thy1(+) DCs., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Tolerance to self-antigens expressed in peripheral organs is maintained by CD4(+) CD25(+) Foxp3(+) Treg cells, which are generated as a result of thymic selection or peripheral induction. Here, we demonstrate that steady-state migratory DCs from the skin mediated Treg conversion in draining lymph nodes of mice. These DCs displayed a partially mature MHC II(int) CD86(int) CD40(hi) CCR7(+) phenotype, used endogenous TGF-β for conversion and showed nuclear RelB translocation. Deficiency of the alternative NF-κB signaling pathway (RelB/p52) reduced steady-state migration of DCs. These DCs transported and directly presented soluble OVA provided by s.c. implanted osmotic minipumps, as well as cell-associated epidermal OVA in transgenic K5-mOVA mice to CD4(+) OVA-specific TCR-transgenic OT-II T cells. The langerin(+) dermal DC subset, but not epidermal Langerhans cells, mediated conversion of naive OT-II×RAG-1(-/-) T cells into proliferating CD4(+) CD25(+) Foxp3(+) Tregs. Thus, our data suggest that steady-state migratory RelB(+) TGF-β(+) langerin(+) dermal DCs mediate peripheral Treg conversion in response to epidermal antigen in skin-draining lymph nodes., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Increasing evidence suggests that B lymphocytes play a central role in inhibiting the immune response against certain tumors, but the underlying mechanisms by which B cells facilitate tumor growth are still poorly understood. In this study, we investigated how the presence or absence of B cells affects expansion and function of T-regulatory cells ('T-regs') in a murine breast tumor model (EMT-6). We compared tumor growth, and the number and function of T-reg cells in wild-type immune-competent mice (ICM) and B-cell-deficient mice (BCDM). Mice were either tumor-naive or implanted with EMT-6 mammary adenocarcinoma cells. Tumor growth was markedly inhibited in BCDM, compared to wild-type mice (ICM). Increased T-reg expansion as defined by CD4+/CD25+/FOXP3+ cells was evident following EMT-6 inoculation in ICM in comparison with non-tumor-bearing mice or compared to BCDM in which tumor had been implanted. The percentage and absolute number of T-regs in the spleen, tumor draining lymph nodes, and tumor bed were significantly reduced in BCDM compared to ICM. T-reg function, measured by suppression and proliferation assays, was also reduced in tumor inoculated BCDM compared to ICM. Our studies indicate that absence of B cells may play a role in augmenting the T-cell anti-tumor response, in part due to effects on T-regulatory cell expansion and function.

Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is a key negative regulator of T cell activation and proliferation. Ipilimumab is a human monoclonal antibody that specifically blocks the binding of CTLA-4 to its ligand. To test the hypothesis that blockade of CTLA-4 by ipilimumab could augment graft-versus-malignancy (GVM) effects without a significant impact on graft-versus-host disease (GVHD), we conducted a phase I clinical trial of ipilimumab infusion in patients with relapsed malignancy following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Here, we report the analysis of peripheral blood T lymphocyte reconstitution, T regulatory cell (Treg) expression, and T cell activation markers after a single dose of ipilimumab in 29 patients. Peripheral blood samples were collected from all patients before and after ipilimumab infusion. Lymphocyte immunophenotyes, including levels of CD4(+)CD25(high) cells and T cell activation markers, were analyzed in all cases. Levels of CD4(+)CD25(high)Foxp3(+) cells and intracellular CTLA-4 in CD4(+) T cells also were evaluated in the last 11 cases. We found lower baseline levels of CD4(+) and CD45RO(+) T cells in patients compared with normal controls. More than 50% of the patients had abnormally low lymphocyte counts (CD4 or/and CD8 T cells), and some had no circulating B lymphocytes. The percentages of both CD4(+)CD25(high) and CD4(+)CD25(high)Foxp3(+) T cells were significantly higher in patients before ipilimumab infusion than in healthy donors. Twenty of 29 patients exhibited an elevated level of CD4(+)CD25(low) activated T cells at baseline, compared with only 3 of 26 healthy donors. Both CD4(+) and CD8(+) T lymphocyte counts were significantly increased after ipilimumab infusion. There was no consistent change in absolute lymphocyte count or in the number of T cells expressing the activation marker CD69. However, increases in CD4(+)CD25(low) T cells were seen in 20 of 29 patients and increases in CD4(+)HLA-DR(+) T cells were seen in the last 10 patients in the first 60 days after ipilimumab infusion. Although the percentages of both CD4(+)CD25(high) and CD4(+)CD25(high)Foxp3(+) T cells decreased significantly during the observation period, the absolute cell counts did not change. Intracellular CTLA-4 expression in CD4(+)CD25(lo/-) T cells increased significantly after ipilimumab infusion. We conclude that CTLA-4 blockade by a single infusion of ipilimumab increased CD4(+) and CD4(+)HLA-DR(+) T lymphocyte counts and intracellular CTLA-4 expression at the highest dose level. There was no significant change in Treg cell numbers after ipilimumab infusion. These data demonstrate that significant changes in T cell populations occur on exposure to a single dose of ipilimumab. Further studies with multiple doses are needed to explore this phenomenon further and to correlate changes in lymphocyte subpopulations with clinical events., (Copyright © 2011 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Background and Objective: Heat shock protein 60 (HSP60) of Porphyromonas gingivalis, a major periodontal pathogen, might be a trigger molecule linking infectious periodontitis and autoimmune atherosclerosis. The aim of this study was to identify the peptide specificity of anti-P. gingivalis HSP60 monoclonal antibodies and their cross-reactivity with bacterial and human HSPs. Their specific immunoreactivity to periodontal or atherosclerotic lesions was also investigated., Methods: Twenty patients with chronic periodontitis and 20 atherosclerosis patients who had undergone surgical intervention for atheromatous plaques with evidence of ongoing periodontal disease, were selected. Synthetic peptide 19 ((TLVVNRLRGSLKICAVKAPG)-specific T-cell lines were established from inflamed gingiva and atheromatous plaque and the phenotypes and cytokine profiles were characterized., Results: Thirty per cent of periodontitis patients and 100% of atherosclerosis patients reacted positively to cross-reactive peptide 19 from both P. gingivalis and human HSP60. The peptide 19-specific T-cell lines demonstrated the phenotype characteristic of helper T cells (CD4(+)) but did not express CD25 or FOXP3. The interleukin-10 levels were elevated significantly in the peptide 19 T-cell line., Conclusion: Synthetic peptide 19 of P. gingivalis HSP60 is an immunoreactive epitope in the periodontitis-atherosclerosis axis., (© 2011 John Wiley & Sons A/S.)

Objective: To study the levels of CD4+CD25+CD127- and CD3+CD4-CD8- regulatory T (Treg) cells in peripheral blood of children with idiopathic thrombocytopenic purpura (ITP)., Methods: The flow cytometry was used to detect the expression of CD4+CD25+CD127- and CD3+CD4-CD8- Treg cells in peripheral blood of 33 children with ITP and 21 healthy children., Results: The expression levels of CD4+CD25+CD127-［(2.7±1.7)% vs (4.8±1.6)%; P<0.01］and CD3+CD4-CD8-［(5.2±3.1)% vs (8.1±3.5)%; P<0.01］Treg cells in children with ITP were significantly lower than in the controls., Conclusions: The expression levels of CD4+CD25+CD127- and CD3+CD4-CD8- Treg cells decrease in children with ITP, suggesting that CD4+CD25+CD127- and CD3+CD4-CD8- Treg cells might play a role in the pathogenesis of ITP.

Hepatitis C virus (HCV) has a propensity to establish chronic infection that is characterized by attenuated virus-specific T-cell responses. Mechanisms leading to T-cell attenuation are poorly understood and likely involve dysfunctional interactions between antigen-presenting cells (APC) and effector/regulatory T-cells. Reports on dendritic cells (DC) have described only minor dysfunction during HCV infection. However, there is a paucity of reports regarding B-cell function, despite clear associations with B-cell-related secondary sequelae. In this study we evaluated the state of B-cells during chronic HCV infection, and observed a diminished ability to respond to mitogenic stimuli, correlating with increased apoptosis. This was in contrast to their ex vivo phenotype, which indicated ongoing chronic activation in vivo. There was a high association of HCV-positive strand RNA with B-cells in a subset of HCV patients. Interestingly, ex-vivo-derived HCV RNA-positive B-cells induced significantly greater proliferation in allogeneic T-cells than in HCV-negative B-cells, correlating with an increased generation of CD4(+)CD25(+)FOXP3(+) regulatory T-cells (Tregs). In-vitro exposure of healthy peripheral blood mononuclear cells (PBMC) to HCV resulted in robust activation of resting B-cells. These HCV-exposed B-cells also showed an enhanced ability to generate Tregs. Our results provide strong evidence for a novel and paradoxical link between HCV-induced enhanced APC function and the generation of Tregs.

CD4+CD25+ regulatory T cells (Tregs) are known to inhibit immune responses to antigens. Since, the process of antigen uptake by dendritic cells (DC) is central to induction of immune responses, we analyzed the effect of Tregs on the expression of endocytic receptors on DC and its repercussion on antigen uptake. Our results demonstrate that Tregs down-regulate the expression and uptake of antigens via C-type lectin-like receptors CD206 and DC-SIGN, restrain the pinocytosis process of DC and augment the expression of FcγRIIB, an inhibitory Fcγ receptor the engagement of which by IgG-bound antigens leads to inhibition of DC activation. Our results thus provide an additional insight on the pertinence of strategies aimed at blocking Treg functions towards improved vaccination protocols., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background and Aims: To observe safety and influence on viral load and peripheral T lymphocyte subsets of combination therapy with percutaneous microwave ablation (PMWA) and adoptive immunotherapy in hepatocellular carcinoma (HCC) with hepatitis B., Results: No adverse effects of grade Ⅲ/Ⅳ were observed. Viral load was decreased in 57.14% (four of seven) of patients and was undetectable in two (28.6%) patients without antiviral therapy. The percentage of CD4(+)CD25(high) regulatory T lymphocytes decreased significantly, and the percentage of CD8(+)CD28(-) effector cells increased significantly 1 month after therapy. However, 6 months after therapy, there was no significant difference., Methods: Ten HCC (D≤5 cm, fewer than 3 tumors) patients were treated with radical PMWA and three courses of immunotherapy, which were started with PMWA, 2 weeks post-PMWA, and 3 months after PMWA. Peripheral blood mononuclear cells were differentiated into phenotypically confirmed DCs and effector cells. Immature DCs, cytokine-induced killer cells (CIK) and cytotoxic T lymphocytes (CTL) were injected into the marginal area of ablated tumors under contrast-enhanced sonographic guidance. Under sonographic guidance, tumor lysate-pulsed DC was injected into groin lymph nodes, while DC-CIK and CTL were injected into the abdominal cavity. CIK was infused intravenously., Conclusion: Adoptive immunotherapy prescribed soon after PMWA for HCC patients was safe and ameliorated the percentage of peripheral lymphocytes.

Heligmosomoides bakeri infection in mice is associated with a dominant CD4(+) T-cell response and with the activity of natural Treg cells with CD4(+) CD25(+) phenotype. The polarization of Th2 T-cell phenotype and the increase in the CD4(+) CD25(+) T cell population are regulated by glucocorticoids that induce apoptosis in CD4(+) CD25(-) T cells and inhibit apoptosis in CD4(+) CD25(+) T cells. However, exposure of mice to H. bakeri antigen induces a high glucocorticoid concentration in serum and a reduction in the number of CD4-positive; CD4(+) CD25(-) and CD4(+) CD25(+) apoptotic T cells in mesenteric lymph node cells. In this study to evaluate the in vitro effect of the anti-apoptotic property of H. bakeri antigen on T cells, apoptosis of these cells was induced by glucocorticoids-dexamethasone (Dex). Excretory-secretory (ES) antigen of the nematode prevented Dex-induced apoptosis in CD4-positive T cells with CD4(+) CD25(-) and CD4(+) CD25(High) phenotype by Bcl-2 protein expression. Contrary to the effect on CD4-positive T cells, survival of CD8(+) T cells was not connected with expression of Bcl-2 protein. This suggest that H. bakeri antigen modulates CD4-positive T cell sensitivity to glucocorticoid-induced apoptosis by induction of Bcl-2 protein., (© 2011 Blackwell Publishing Ltd.)

Regulatory T cells (Tregs) blunt uncontrolled immune responses. In advanced human immunodeficiency virus (HIV) infection, the total number of Tregs is decreased, but the proportion of T cells with a regulatory phenotype is highly variable. We studied CD4(+)CD25(+)FoxP3(+) T cells from patients successfully treated with combination antiretroviral therapy (ART). The proportion of CD4(+)CD25(+)FoxP3(+) cells transiently increased and then decreased from a median of 13% at baseline to 5.1% at 48 weeks, similar to values in normal subjects. These data suggest that with effective therapy, the regulatory cell numbers normalize, and that the inflammatory signals driving their production may also abate.

Regulatory T cells (Tregs) are a subset of T cells that play an important role in the regulation of T-cell function. In a previous study, CD25 was used as a marker of Tregs; however, FoxP3 was recently discovered to be a valuable phenotype of Tregs. In this study, we compared the frequency of Tregs in HIV-1-infected long-term nonprogressors (LTNP), AIDS patients (AP), HIV-exposed seronegative (ES) persons, and healthy controls (HC), by using CD4+CD25+FoxP3+ as a marker of Tregs. The results showed that the frequency of Tregs in AP was significantly higher than in the LTNP, ES, and HC, which suggests that Tregs may play a role in disease progression. Another unique finding in this study is that we found a decrease of Tregs in ES.

Rheumatoid arthritis (RA) is a chronic inflammatory disease, with a clinical manifestation both systemic and in joints. It has been suggested that age at disease onset and/or patients' age have influence on disease activity and clinical outcome. The reasons for the different course of RA in older people are not known; however, the activation status of peripheral blood lymphocytes could be responsible. Our aim was to relate expression of activation markers in peripheral blood CD4(+) T cells of RA patients with patients' age and/or onset age and disease activity measured by DAS28. Seventy RA patients were included into the immunological study. Two separation criteria were performed: based on age of RA onset and on the biological age of patients. We examined different activation markers, CD69, CD25, CD95 and human leucocyte antigen D-related (HLA-DR), on the CD4(+) T cell surface. Division of RA patients in 10-year intervals at 40, 50 and 60 years revealed that RA patients with later disease onset were characterized by higher DAS28. This phenomenon was not limited to the division at 60 years of age but, surprisingly, the major differences were found for the 40-year onset division. Analysis of all four components of DAS28 revealed that disease activity in older disease onset was dependent on all components. Older-onset RA patients had a higher percentage of CD4(+) CD25(+) and CD4(+) CD95(+) T cells. Summarizing the major differences in DAS28 and activation status of CD4(+) T cells observed for onset of disease at 40 years seems to be the most informative about the immunological status of RA patients., (© 2010 The Authors. Clinical and Experimental Immunology © 2010 British Society for Immunology.)

Immunomodulatory function of bone marrow derived mesenchymal stem cells in cancer has recently been investigated. But the resident mesenchymal stem cells as whole in cancer and in the breast cancer tissue have not been studied well. In the present work we isolated adipose derived stem cells (ASCs) from breast cancer and normal breast tissues to investigate the expressions of IL-4, IL-10 and transforming growth factor (TGF)-β1 in ASCs and to see if ASCs isolated from patients can modulate the regulatory molecules on peripheral blood lymphocytes. Our results showed that IL-10 and TGF-β1 have significantly higher mRNA expressions in ASCs isolated from breast cancer patients than those from normal individuals (P value <0.05). The culture supernatant of ASCs isolated from breast cancer patients with pathological stage III induced upregulation of the mRNA expression levels of IL-4, TGF-β1, IL-10, CCR4 and CD25 in PBLs. In addition, the percentage of CD4+CD25(high)Foxp3(+) T regulatory cells was increased in vitro. When the same culture supernatant was added to ASCs isolated from normal subjects augmentation of the mRNA expressions of IL-4, IL-10, IL-8, MMP2, VEGF and SDF-1 in normal ASCs was also observed. These data collectively conclude that resident ASCs in breast cancer tissue may have crucial roles in breast tumor growth and progression by inducing regulatory molecules and promoting anti-inflammatory reaction within the tumor microenvironment. Further investigation is required to see if the immune suppression induced by ASCs is an independent property from tumor cells or ASCs gain their immunosuppressive potential from malignant cells., (Copyright © 2010 Elsevier Inc. All rights reserved.)