Circulating CD4(+) CD25(high) FoxP3(+) T-regulatory cells in patients with atopic dermatitis after narrowband-ultraviolet B phototherapy.

BACKGROUND: Previous studies showed controversial results regarding CD4(+) CD25(high) FoxP3(+) T-regulatory cells (Tregs) in atopic dermatitis (AD) and effect of therapy. METHODS: Circulating CD4(+) CD25(high) FoxP3(+) Tregs were assessed by flow cytometry in 20 controls and 20 patients with AD at baseline and after narrowband ultraviolet B with assessment of disease severity. RESULTS: Patients showed higher pretreatment T-effector cells (Teffs) (%) and lower pretreatment Tregs FoxP3 expression% than controls (P = 0.003 and 0.01, respectively). Mild AD showed a lower Tregs/Teffs ratio compared to controls (P = 0.013), while moderate group showed higher Teffs%, and lower Tregs FoxP3 expression% and Tregs/Teffs compared to controls (P = 0.016, 0.007, and 0.009 respectively). The severe group had higher Tregs% and Teffs%, yet with a lower Tregs FoxP3 expression% compared to controls (P < 0.001, P = 0.043, P = 0.044, respectively). There was significant reduction of severity after narrowband ultraviolet B (P = 0.007), with overall significant elevation of Tregs FoxP3 expression% in patients (P = 0.004). All patients' post-treatment laboratory findings were statistically matched to each other and to controls whatever their previous severity or therapeutic response. The improvement of severity score correlated with the change in both Tregs% and Tregs/Teffs. CONCLUSIONS: Significant reduction in AD disease severity is correlated with the change in Tregs% and Tregs/Teffs.

Systemic immune tuning in renal cell carcinoma: favorable prognostic impact of TGF-ß1 mRNA expression in peripheral blood mononuclear cells.

Renal cell carcinoma (RCC) can inhibit protective immunity by induction of immunosuppressive cells that produce inhibitory cytokines such as interleukin (IL)-10 and transforming growth factor (TGF)-ß. If this immunosuppression influences response to kinase inhibitors such as sorafenib is not known. Therefore, we asked for the prognostic influence of cells with immunosuppressive properties in peripheral blood (pB) in a cohort of metastatic clear cell renal cell carcinoma (mRCC) patients uniformly receiving sorafenib treatment. IL-10 and TGF-ß mRNA levels, regulatory T-cell (Treg) counts, and frequencies of IL-10/TGF-ß producing mononuclear cell subsets were determined in pB from 46 patients with mRCC before receiving sorafenib treatment. Relationship between established clinical and laboratory prognostic factors and outcome were examined by univariate and multivariate Cox regression analysis. IL-10 and TGF-ß1 mRNA levels, and frequencies of CD4(+)CD25high/CD3(+) and CD4(+)CD25highFoxP3(+)/CD3(+)Treg cells were significantly higher in mRCC patients compared with healthy individuals. Monocytes were suggested as main producers of IL-10 and TGF-ß. In a multivariate analysis low ECOG score and-surprisingly-high TGF-ß1 mRNA levels were independently associated with favorable progression-free survival (P=0.005 and P=0.003, respectively) and overall survival (P=0.001 and P=0.039, respectively). In conclusion, mRCC is associated with an immunosuppressive phenotype in peripheral blood. The positive prognostic influence of high TGF-ß1 mRNA expression levels may reflect immune promoting functions of TGF-ß in combined activity with inflammatory cytokines.

Astragalus membranaceus injection delayed allograft survival related with CD4+ CD25+ regulatory T cells.

INTRODUCTION: Recently it has been reported that Astragalus membranaceus injection (AMI) inhibits immune responses, but whether it affects alloimmunity is not clear. It has been shown that the CD4(+) CD25(+) regulatory T cells (Treg) down-regulate immune responses. The aim of our study was to investigate the effects of AMI on allograft survival and its relation to Treg. MATERIALS AND METHODS: Allografted mice were administered AMI for 14 consecutive days with observations of graft survival. The specific recall response, the ratio of Treg, the expression of Foxp3 mRNA, and interleukin (IL)-10 secretion were measured by mixed lymphocyte reactions (MLR), FCM, reverse transcriptase-polymerase chain reaction, and radioimmunoassay, respectively. RESULTS: AMI significantly prolonged allograft survival by up-regulating the Treg ratio and promoting Foxp3 expression (P < .05). The ratio of Tregs, the expression of Foxp3 mRNA, and the IL-10 level in the AMI administration group increased from day 7, to reach a maximum at day 14, recovering to the initial level on day 21. No obvious difference was detected between the AMI and a cyclosporine group. CONCLUSION: AMI administered in vivo prolonged allograft survival associated with promotion of Treg activities.

Vitamin D supplementation and regulatory T cells in apparently healthy subjects: vitamin D treatment for autoimmune diseases?

BACKGROUND: Epidemiological data show significant associations of vitamin D deficiency and autoimmune diseases. Vitamin D may prevent autoimmunity by stimulating naturally occurring regulatory T cells. OBJECTIVES: To elucidate whether vitamin D supplementation increases Tregs frequency (%Tregs) within circulating CD4+ T cells. METHODS: We performed an uncontrolled vitamin D supplementation trial among 50 apparently healthy subjects including supplementation of 140,000 IU at baseline and after 4 weeks (visit 1). The final follow-up visit was performed 8 weeks after the baseline examination (visit 2). Blood was drawn at each study visit to determine 25-hydroxyvitamin D levels and %Tregs. Tregs were characterized as CD4+CD25++ T cells with expression of the transcription factor forkhead box P3 and low or absent expression of CD127. RESULTS: Forty-six study participants (65% females, mean age +/- SD 31 +/- 8 years) completed the trial. 25(OH)D levels increased from 23.9 +/- 12.9 ng/ml at baseline to 45.9 +/- 14.0 ng/ml at visit 1 and 58.0 +/- 15.1 ng/ml at visit 2. %Tregs at baseline were 4.8 +/- 1.4. Compared to baseline levels we noticed a significant increase of %Tregs at study visit 1 (5.9 +/- 1.7, P < 0.001) and 2 (5.6 +/- 1.6, P < 0.001). CONCLUSIONS: Vitamin D supplementation was associated with significantly increased %Tregs in apparently healthy individuals. This immunomodulatory effect of vitamin D might underlie the associations of vitamin D deficiency and autoimmune diseases. Hence, our finding provides a rationale for further studies to investigate vitamin D effects on autoimmunological processes.

Interactions between ω3 polyunsaturated fatty acids and arginine on nutritional and immunological aspects in severe inflammation.

BACKGROUND & AIMS: Immune-enhancing diets (IEDs) contain a mixture of nutrients claimed to have immunological properties. Therefore, it seemed relevant to determine the effect of each of their components. The aim of this study was to examine the role of arginine (Arg) and ω3 polyunsaturated fatty acids (ω3 PUFAs) in the effect of an IED (Crucial(®)) in a validated rat model of inflammation induced by turpentine (TI). METHODS: Forty-two rats were randomized into five groups: AL (ad libitum), TI-EN (TI+standard enteral nutrition (EN): Sondalis(®)HP), TI-EN-Arg (TI+standard EN+Arg in equimolar concentration to Arg in the IED), TI-M-IED (TI+modified IED containing the same ω6/ω3 ratio as in standard EN) and TI-IED (TI+Crucial(®)). Blood was sampled to determine CD25 receptor density on lymphocytes. TNF-α, IL-6 and NO (production and expression) were evaluated on isolated macrophages. Mesenteric lymph nodes, spleen and liver were cultured for analysis of enterobacterial translocation and dissemination. RESULTS: CD25 density was decreased after TI and was corrected in the TI-EN-Arg, TI-M-IED and TI-IED groups (p<0.05). TI induced an alteration of macrophage mRNA expression of IL-6, TNF-α and iNOS, corrected in the TI-EN-Arg and TI-M-IED groups (p<0.05), but not by the IED. Enterobacterial translocation was observed in all treated groups, nevertheless the amount tended (p=0.054) to be lower in the TI-EN-Arg group. CONCLUSIONS: Arg and ω3 PUFAs make a major contribution to IED effects, but our study shows interaction between them on macrophage reactivity. This indicates that the individual properties of each pharmaconutrient are not additive in IEDs.

Activation of T lymphocytes by polysaccharide-protein complex from Lycium barbarum L.

T lymphocytes play central roles in adaptive immunity. Lycium barbarum L. (L. barbarum), also known as wolfberry, is a Chinese herbal medicine with various biological activities, such as enhancing immunity, protecting liver damage, and reducing the side effects of chemotherapy and radiotherapy. Here, we report that polysaccharide-protein complex from L. barbarum (LBP) is able to activate T cells. LBP was isolated from L. barbarum and separated to five homogenous fractions, designated LBPF1, LBPF2, LBPF3, LBPF4, and LBPF5. We found that LBP, LBPF4, and LBPF5 significantly stimulated mouse splenocyte proliferation. The proliferation proved to be of T cells, but not B cells. Cell cycle profile analysis indicated that LBP, LBPF4, and LBPF5 markedly reduced sub-G1 cells. LBP, LBPF4, and LBPF5 could activate transcription factors NFAT and AP-1, prompt CD25 expression, and induce IL-2 and IFN-gamma gene transcription and protein secretion. LBP (i.p. or p.o.) significantly induced T cell proliferation. Our results suggest that activation of T lymphocytes by LBP may contribute to one of its immuno-enhancement functions.

Depletion of CD4+CD25+CD127lo regulatory T cells does not increase allergen-driven T cell activation.

BACKGROUND: It has been suggested that allergic diseases are caused by defective suppression of allergen-specific Th2 cells by CD4(+)CD25(+) regulatory T cells. However, such studies have been hampered by the difficulty in distinguishing regulatory T cells from CD25-expressing activated T cells. Recently, it was shown that conventional T cells expressed high levels of CD127, whereas regulatory T cells were CD127(lo), allowing discrimination between these distinct T cell subpopulations. OBJECTIVE: The aim of this study was to study whether the putative regulatory subset defined as CD4(+)CD25(+)CD127(lo) was involved in grass pollen-reactive T cell responses. METHODS: Peripheral blood mononuclear cells (PBMCs) were obtained from allergic donors and non-atopic controls out of season. Grass pollen-induced cytokine production and proliferation were compared in cultures of undepleted cells and cells depleted of CD4(+)CD25(+), CD4(+)CD25(+)CD127(hi) or CD4(+)CD25(+)CD127(lo) T cells. RESULTS: Undepleted cell cultures from allergic patients showed significantly increased proliferation and Th2 cytokine production compared with non-atopic controls. Depletion of all CD25(+) T cells did not increase cytokine production or proliferation, and more importantly, no increase in Th2 cytokine production or proliferation was observed in cell cultures depleted of CD4(+)CD25(+)CD127(lo) cells (putative regulatory T cells) compared with undepleted PBMCs in both the allergic and the non-atopic group. CONCLUSION: Our study showed that T cells from grass pollen-allergic patients and non-atopic controls responded very differently to grass pollen extract, but this difference could not be explained by differences in regulatory T cell function. Further studies are needed to understand the importance of regulatory T cells in allergy.

Pollen grains induce a rapid and biphasic eczematous immune response in atopic eczema patients.

INTRODUCTION: Eczematous reactions to type I allergy-inducing antigens are documented in a subgroup of patients with atopic eczema. Yet, the underlying immunological mechanisms are not well understood. MATERIAL AND METHODS: To delineate the effect of native pollen grains on human skin of healthy and atopic individuals we performed patch tests (atopy patch test with native pollen grains, PPT). Nickel patch tests (NPT) served as an established model of contact dermatitis. Skin site biopsies were taken 6-96 h after allergen application and investigated immunohistochemically. RESULTS: Histology of positive patch tests showed an influx of mononuclear cells (predominantly CD4+, CD25+, CD45RO+). This influx was detected earlier in the PPT reaction than in the immune response to nickel. A biphasic cytokine response could be detected in the PPT: IL-5 dominated in the early, IFN-gamma in the late phase. The NPT was continuously dominated by IFN-gamma. Dendritic cell subpopulations imitated the earlier kinetics of the mononuclear infiltrate. DISCUSSION: Thus, pollen grains induce eczematous reactions in susceptible individuals. This reaction appears clinically and immunohistochemically similar to the contact hypersensitivity reaction to nickel but follows a faster kinetic and a biphasic course: Th2 and IgE in the early (24 h) and Th1 predominance in the late (96 h) phase.

Natural killer cell activation and modulation of chemokine receptor profile in vitro by an extract from the cyanophyta Aphanizomenon flos-aquae.

The present research was designed to study the effects of an extract from the edible cyanophyta Aphanizomenon flos-aquae on human natural killer (NK) cells. We have previously shown, using a double-blind randomized placebo-controlled crossover design, that ingestion of 1.5 g of dried whole A. flos-aquae resulted in a transient reduction in peripheral blood NK cells in 21 healthy human volunteers, suggesting increased NK cell homing into tissue. We have now identified an extract from A. flos-aquae (AFAe) that directly activates NK cells in vitro and modulates the chemokine receptor profile. NK cell activation was evaluated by expression of CD25 and CD69 on CD3-CD56+ cells after 18 hours. Changes in CXCR3 and CXCR4 chemokine receptor expression after 5-60 minutes were evaluated by immunostaining and flow cytometry. AFAe induced the expression of CD69 on CD3-CD56+ NK cells, induced CD25 expression on 25% of these cells, and acted in synergy with interleukin 2. NK cells enriched by RosetteSep (StemCell Technologies Inc., Vancouver, BC, Canada) were not activated by AFAe, indicating that the NK activation was dependent on other cells such as monocytes. The low-molecular-weight fraction <5,000 of AFAe was responsible for the most robust NK cell activation, suggesting novel compounds different from previously reported macrophage-activating large polysaccharides.

A role for dietary selenium and selenoproteins in allergic airway inflammation.

Asthma is driven by allergic airway inflammation and involves increased levels of oxidative stress. This has led to speculation that antioxidants like selenium (Se) may play important roles in preventing or treating asthma. We fed diets containing low (0.08 parts per million), medium (0.25 parts per million), or high (2.7 parts per million) Se to female C57BL/6 mice and used an established OVA challenge protocol to determine the relationship between Se intake and the development of allergic airway inflammation. Results demonstrated that mice fed medium levels of Se had robust responses to OVA challenge in the lung as measured by lung cytokine levels, airway cellular infiltrate, eosinophilia, serum anti-OVA IgE, airway hyperreactivity, goblet cell hyperplasia, and phosphorylated STAT-6 levels in the lung. In contrast, responses to OVA challenge were less robust in mice fed low or high levels of Se. In particular, mice fed low Se chow showed significantly lower responses compared with mice fed medium Se chow for nearly all readouts. We also found that within the medium Se group the expression of lung glutathione peroxidase-1 and liver selenoprotein P were increased in OVA-challenged mice compared with PBS controls. These data suggest that Se intake and allergic airway inflammation are not related in a simple dose-response manner, which may explain the inconsistent results obtained from previous descriptive studies in humans. Also, our results suggest that certain selenoproteins may be induced in response to Ag challenges within the lung.

IL-7-mediated protection against minor-antigen-mismatched allograft rejection is associated with enhanced recovery of regulatory T cells.

BACKGROUND AND OBJECTIVES: Interleukin-7 (IL-7) has been studied for its possible immunorestorative capacities following stem cell transplantation and has been shown to enhance post-transplant immune recovery predominantly by peripheral T-cell expansion. A major concern of IL-7 is its possible aggravating effect on graft-versus-host and host-versus-graft reactivity. DESIGN AND METHODS: To study the effect of IL-7 on host-versus-graft reactivity, we applied IL-7 in an experimental transplantation model using RAG-1-/- mice supplied with B6 CD45.1 congenic T cells as recipients of T-cell depleted allogeneic bone marrow grafts. RESULTS: Rejection of minor antigen-mismatched bone marrow was significantly reduced in IL-7 treated recipients compared with PBS treated control mice. Rejection was observed in 2 out of 18 IL-7 treated mice compared with 9 out of 17 PBS treated mice (11% vs. 53%; p=0.012). IL-7 administration resulted in enhanced recovery of peripheral blood CD4+CD25+ regulatory T cells (Treg) with a concomitant increase in peripheral blood Foxp3 mRNA expression. IL-7Ra (CD127) was expressed by the vast majority of CD4+Foxp3+ T cells. The incidence of graft rejection following fully MHC mismatched bone marrow transplantation was not reduced nor enhanced by IL-7 administration. INTERPRETATION AND CONCLUSIONS: Post-transplant IL-7 administration protects against minor antigen-mismatched bone marrow rejection, which may be due to enhanced Treg recovery.

CD4+CD25+ T cells regulate the intensity of hypersensitivity responses to peanut, but are not decisive in the induction of oral sensitization.

BACKGROUND: Naturally occurring CD4+CD25+ regulatory T cells (Tregs) play a critical role in the maintenance of self-tolerance and it has been suggested that these Tregs may also be involved in preventing allergic disease. OBJECTIVE: The precise role of CD4+CD25+ T cells in the regulation of allergic responses to mucosal antigens remains to be elucidated. In the present study, it was investigated whether CD4+CD25+ T cells are involved in the induction of oral tolerance and whether they play a role in controlling hypersensitivity responses to food proteins. METHODS: CD4+CD25+ T cells were depleted with PC61 mAb before the induction of low dose oral tolerance to peanut extract (PE). In addition, CD4+CD25+ T cell depletion was performed during sensitization or before oral challenge, using a C3H/HeOuJ mouse model of allergic sensitization to peanut. RESULTS: Oral tolerance to PE could not be induced in CD4+CD25+ T cell-depleted mice. However, CD4+CD25+ T cell depletion during long-term exposure to PE alone did not result in allergic sensitization. In sensitized mice, anti-CD25 treatment during oral exposure resulted in higher levels of PE-specific IgE and increased mast cell degranulation upon an oral challenge. In contrast, anti-CD25 treatment of PE-sensitized mice before oral challenges did not affect the level of mast cell degranulation. CONCLUSION: These results indicate that CD4+CD25+ Tregs are involved in maintaining tolerance to oral antigens and regulate the intensity of an IgE-mediated food hypersensitivity response, but are not crucial in preventing sensitization. Accordingly, CD4+CD25+ Tregs may represent a potential tool for the treatment of food allergic disorders.

The immunosuppressive drug FK778 induces regulatory activity in stimulated human CD4+ CD25- T cells.

The induction of transplantation tolerance involves a T-cell-mediated process of immune regulation. In clinical transplantation, the use of immunosuppressive drugs that promote or facilitate this process would be highly desirable. Here, we investigated the tolerance-promoting potential of the immunosuppressive drug FK778, currently under development for clinical therapy. Using a human allogeneic in vitro model we showed that, upon T-cell receptor (TCR) triggering, FK778 induced a regulatory phenotype in CD4+ CD25- T cells. Purified CD4+ CD25- T cells primed in the presence of FK778 showed hyporesponsiveness upon restimulation with alloantigen in the absence of the drug. This anergic state was reversible by exogenous interleukin-2 (IL-2) and was induced independent of naturally occurring CD4+ CD25+ regulatory T cells. Pyrimidine restriction was a crucial requirement for the de novo induction of regulatory activity by FK778. The FK778-induced anergic cells showed suppressor activity in a cell-cell contact-dependent manner; were CD25(high), CD45RO+, CD27-, and CD62L-; and expressed cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4), glucocorticoid-induced tumor necrosis factor receptor (GITR), and FoxP3. The cells revealed delayed p27(kip1) degradation and enhanced phosphorylation of STAT3. In conclusion, the new drug FK778 shows tolerizing potential through the induction of a regulatory T-cell subset in CD4+ CD25- T cells.

Effect of improved zinc status on T helper cell activation and TH1/TH2 ratio in healthy elderly individuals.

Mild zinc deficiency is a common condition in healthy elderly individuals leading to impaired cell-mediated immune response. Here we report the effect of improved zinc status on TH1/TH2 balance and on the activation status of T helper cells in 19 healthy elderly subjects aged 69.8 +/- 5.1 years. Our investigations revealed a mild zinc deficiency which was adjusted by oral zinc supplementation for seven weeks. Improved serum zinc levels significantly reduced levels of activated T helper cells whereas changes in TH1/TH2 ratio (determined by CCR4 and CCR5 expression) were not observed. These findings suggest that elderly individuals may benefit from moderate zinc supplementation due to improved immune response leading to reduced incidences of autoimmune diseases and infections.