B7-H1 and B7-H4 expression in colorectal carcinoma: Correlation with tumor FOXP3 regulatory T-cell infiltration

B7-H1 and B7-H4 are newly discovered members of the B7-CD28 family. They can inhibit T cell activation and proliferation and regulate T cell immune response negatively. Both B7-H1 and B7-H4 are expressed in many tumors and are classified as co-inhibitors of cell-mediated immunity. FOXP3⁺ regulatory T cells (Tregs) play an important role in the maintenance of tumor immunity tolerance. However, the implication of B7-H1 and B7-H4 expression and their interaction with Tregs infiltration in colorectal cancer are unknown. The present study aimed to determine the expression of B7-H1 and B7-H4 as well as Tregs infiltration in colorectal cancer and to explore the clinical and pathological implication of suppressor immune cells and molecules. Frozen sections and immunohistochemical assay were undertaken to assess B7-H1, B7-H4 expression and Tregs infiltration in fresh specimens collected from 56 patients with colorectal carcinoma. The results showed that expression of B7-H1 and B7-H4 in colorectal carcinoma tissues was significantly higher than in adjacent normal mucosa (P < 0.001). B7-H1 expression was positively correlated to the infiltration depth, lymph node metastasis and advanced Duke's stage (P < 0.05, P < 0.05 and P < 0.05, respectively), whereas B7-H4 expression was positively related to the infiltration depth and lymph node metastasis (P < 0.01 and P < 0.05, respectively). Furthermore, Tregs infiltration was more frequent in tumor tissue than in adjacent normal mucosa and was associated with poor differentiation and positive lymph node metastasis (P < 0.01, and P < 0.01, respectively). The statistical analysis indicated a significant correlation between Tregs infiltration and B7-H1 or B7-H4 expression respectively. These results suggest that over-expression of B7-H1 and B7-H4 has stronger prognostic significance and promote tumor tolerance, and they might contribute to Tregs development in the colorectal carcinoma tolerogenic milieu.     

Deacetylase inhibition increases regulatory T cell function and decreases incidence and severity of collagen-induced arthritis

Collagen-induced arthritis (CIA) is an established mouse model of disease with hallmarks of clinical rheumatoid arthritis. Histone/protein deacetylase inhibitors (HDACi) are known to inhibit the pathogenesis of CIA and other models of autoimmune disease, although the mechanisms responsible are unclear. Regulatory T cell (Treg) function is defective in rheumatoid arthritis. FOXP3 proteins in Tregs are present in a dynamic protein complex containing histone acetyltransferase and HDAC enzymes, and FOXP3 itself is acetylated on lysine residues. We therefore investigated the effects of HDACi therapy on regulatory T cell function in the CIA model. Administration of an HDACi, valproic acid (VPA), significantly decreased disease incidence (p < 0.005) and severity (p < 0.03) in CIA. In addition, VPA treatment increased both the suppressive function of CD4⁺CD25⁺ Tregs (p < 0.04) and the numbers of CD25⁺FOXP3⁺ Tregs in vivo. Hence, clinically approved HDACi such as VPA may limit autoimmune disease in vivo through effects on the production and function of FOXP3⁺ Treg cells.     

High intratumoral FOXP3+ T regulatory cell (Tregs) density is an independent good prognosticator in nodal negative colorectal cancer

Immunologic profiling of colorectal cancer (CRC) may help to predict the tumors metastatic potential and patients with an aggressive tumor, although not yet metastasized at time of surgery might benefit from adjuvant therapy. In this study we evaluated the prognostic significance of FOXP3⁺ T regulatory cells (Tregs), CD3⁺ and CD8⁺ lymphocyte densities and conventional histopathologic features in nodal negative (n = 820, UICC stage II) CRC. Immunohistochemical studies showed that high expression of FOXP3⁺ Tregs is significantly linked to a better clinical outcome (P = 0.0001). In multivariate analysis including tumor stage, tumor grade, type of tumor invasion margin (pushing vs. infiltrating type), lymphovascular invasion (absent vs. present), CD3⁺, CD8⁺ and FOXP3⁺ Tregs expression, only low tumor stage, absence of lymphovascular invasion and high Foxp3 Tregs density showed prognostic significance (P = 0.0132, P = 0.0022 AND P = 0.0234, respectively). Our findings argue towards a clinical utility of FOXP3⁺ Tregs immunostaining as an independent good prognostic biomarker in stage II colorectal cancers. FOXP3⁺ Tregs immunoscoring, assessment of tumor stage and lymphovascular invasion may help to define stage II cancers with a potentially aggressive behavior and CRC patients who might benefit from adjuvant therapy. A two-scale immunosore related to the median count of FOXP3⁺ Tregs proved to be easy and quick to perform.     

Tumor-Associated Macrophages and Regulatory T Cells Infiltration and the Clinical Outcome in Colorectal Cancer

The aim of the study is the assessment of the intensity of the infiltration of tumor-associated macrophages (TAMs) CD68⁺/iNOS⁻ and Tregs CD8⁺/FoxP3⁺ in colorectal cancer (CRC) patients as prognostic factors with respect to disease-free survival (DFS) and overall survival (OS). In this retrospective study, tissue samples were obtained from 89 patients undergoing resection for CRC (stage IIA, pT3N0M0 and stages IIIB and IIIC, pT3N1-2M0). Recurrence was observed in 45 patients at the time of the follow-up (10 local recurrences, 35 distant metastases). In patients with recurrence the following were present: a tendency to an older average age at the time of diagnosis (p = 0.07), higher nodal involvement (p = 0.002) and more advanced clinical disease (p = 0.01). The analysis of the clinical data and immunohistochemical studies were performed with the methodology of identification of TAM and Treg subsets in histological sections, with the aim to use it in routine clinical management. Both DSF and OS were the clinical parameters assessed in the study. The presence of intense infiltration of TAMs in the tumor stroma was related to shorter DFS (p = 0.005) and OS (p = 0.006). The opposite tendency was observed in the tumor front (p = 0.061). The relative risks of recurrence and cancer-related death were more than twice higher in the group of patients with intense infiltration of TAMs in the tumor stroma (RR 2.05, 95% CI 1.33–3.14; p = 0.001 and RR 2.08, 95% CI 1.28–3.39; p = 0.003, respectively). Intense infiltration of Tregs in the tumor stroma was related to shorter DFS and OS (p < 0.0001). The relative risks of recurrence and death in a group of patients with intense infiltration of Tregs in the tumor stroma were more than 12 times higher than in patients with less intense infiltration (RR 12.3, 95% CI 5.44–27.9; p < 0.0001 and RR 12.5, 95% CI 4.9–32.4; p < 0.0001, respectively). Infiltration of TAMs CD68⁺/iNOS⁻ and Tregs CD8⁺/FoxP3⁺ in the tumor stroma are negative prognostic factors with a positive correlation between them. Tregs may constitute an independent prognostic factor in patients with CRC.

     

Correlation between infiltration of FOXP3 regulatory T cells and expression of B7-H1 in the tumor tissues of gastric cancer

Background

Substantial evidence suggests that the expansion of regulatory T cells (T_regs) plays a pivotal role in immunological evasion of tumors. Recent studies have demonstrated that a majority of tumor cells overexpress B7-H1, and this overexpression is associated with poor disease prognosis. Although an increase of T_regs and B7-H1 has been revealed in several malignancies, their correlation in gastric cancer has not been studied.

Methods

Tumor sections from 111 gastric cancer patients were stained for FOXP3 and B7-H1 by immunohistochemistry. The expression levels of these two molecules were statistically associated with various factors involved in disease progression and prognosis. The correlation between their expression levels was analyzed.

Results

The infiltration of FOXP3⁺ Tregs and expression of B7-H1 were observed in gastric cancer tissues, and there was a highly significant correlation between these two molecules (P < 0.01). The expression of FOXP3⁺ Tregs and B7-H1 was associated with lymph node metastasis and the clinicopathological stage and prognosis of gastric cancer patients. The expression levels of these two determinants in patients with lymph node metastasis and an advanced clinicopathological stage were distinctly higher (P < 0.05). The patients with enhanced expression of FOXP3⁺ Tregs and B7-H1 exhibited a lower overall survival rate and a worse prognosis (P < 0.05).

Conclusions

Increased expression of FOXP3⁺ Tregs and B7-H1 was observed in gastric cancer tissues; the two molecules were closely correlated with each other, suggesting that they might be used as new biomarkers to predict the disease progression and prognosis. Combinatorial immunotherapeutic approaches based on depleting the T_regs and blocking B7-H1 might improve therapeutic efficacy in gastric cancer.     

B7-H4 overexpression impairs the immune response of T cells in human cervical carcinomas

Objective

To investigate B7-H4 expression and its correlation with the number of infiltrating T lymphocytes and cytokine production by those lymphocytes in human cervical cancer and to determine the effect of recombinant B7-H4 on the active peripheral blood T cells of the patients in vitro.

Methods

B7-H4 expression was detected in 67 cases of cervical cancer using immunohistochemical staining. Tumor-infiltrating CD8⁺T, CD4⁺T, and FOXP3⁺ (Forkhead Box P3) T lymphocytes and their levels of IFN-γ and TGF-β₁ production were determined by immunofluorescent double-staining. After the peripheral blood T lymphocytes of patients were co-cultured with B7-H4, proliferation, apoptosis, and cell subtypes were analyzed using flow cytometry. Cytokines in the supernatant were detected by ELISA.

Results

B7-H4 was expressed in 46% (31/67) of the cases of cervical cancer. The number of infiltrating CD8⁺T lymphocytes and their IFN-γ production in positive B7-H4 expression cervical cancers was significantly lower than in negative B7-H4 cases (P < 0.01, P < 0.05), but there was no significant difference between cases positive and negative for B7-H4 with respect to infiltrating FOXP3⁺T and CD4⁺T cells or TGF-β1 production. After co-culture with B7-H4 for 48 h, the patients’ activated T lymphocytes were arrested at G1/G2 phase. The Ki67 positive rates of CD4⁺T and CD8⁺T cells were 2.13 ± 0.13% and 1.03 ± 1.33%, and they were lower than in the blank group. The proportion of CD4⁺T and CD8⁺T cells decreased, but CD4⁺T/CD8⁺T and the proportion of CD4⁺CD25⁺Foxp3⁺T cells increased. In addition, concentrations of IL-10 and TGF-β1 in the supernatant of co-cultured T cells increased significantly (P < 0.05, P < 0.05), but that of IFN-γ decreased. B7-H4 had no significant effect on apoptosis of the T cells.

Conclusion

B7-H4 is overexpressed in human cervical cancers, and it is associated with lower numbers of tumor-infiltrating CD8⁺T lymphocytes and therefore less IFN-γ production. In vitro, B7-H4 inhibits the proliferation of CD4⁺T and CD8⁺T but promotes the proliferation of Tregs and the secretion of IL-10 and TGF-β1. B7-H4 plays an important role in depressing the anti-tumor immunity of CD8⁺T cell in microenvironments of cervical cancer.     

IDO expressing fibroblasts promote the expansion of antigen specific regulatory T cells

Regulatory CD4⁺CD25⁺Foxp3⁺ T cells (Tregs) can be induced and expanded by dendritic cells (DCs) in the presence of the enzyme indoleamine 2,3-dioxygenase (IDO). Here we report that a possible alternative to DCs are IDO expressing dermal fibroblasts (DFs), which are easier to isolate and sustain in culture compared to DCs. When mouse splenocytes were co-cultured with IDO expressing DFs, a significant increase in frequency and the number of Tregs was found compared to those of control group (13.16% ± 1.8 vs. 5.53% ± 1.2, p < 0.05). Despite observing a higher total number of dead CD4⁺ cells in the IDO group, there was a more abundant live CD4⁺CD25⁺ subpopulation in this group. Further analysis reveales that these CD4⁺ CD25⁺ cells have the capacity to expand in the presence of IDO expressing DFs. Greater number of CTLA-4⁺ cells and high expression of TGF-β and IL-10 were found in CD4⁺ cells of the IDO group compared to those of the controls. This finding confirmed a suppressive functionality of the expanded Tregs. Furthermore, CD4⁺ CD25⁺ cells isolated from the IDO group showed an alloantigen specific suppressive effect in a mixed lymphocyte reaction assay. These results confirm that IDO expressing dermal fibroblasts can expand a population of suppressive antigen specific Tregs. In conclusion, IDO expressing dermal fibroblasts have the capacity to stimulate the expansion of a subset of Tregs which can be used to generate antigen-specific immune tolerance.     

Increased frequency and FOXP3 expression of human CD8+CD25High+ T lymphocytes and its relation to CD4 regulatory T cells in patients with hepatocellular carcinoma

The mechanism of action of CD8⁺CD25^High+FOXP3⁺ T cells in hepatocellular carcinoma (HCC) has not been fully understood. Herein, the role of CD8⁺CD25^High+FOXP3⁺ T cells in HCC was compared with that of CD4⁺CD25^High+FOXP3⁺ regulatory T cells (conventional Tregs). Thirty-five patients with HCC and twenty age and sex-matched healthy adults (controls) were enrolled. The percentage of CD8⁺CD25^High+FOXP3⁺ T cells and conventional Tregs in peripheral blood was measured by flow cytometry. Our results revealed that the percentage of peripheral CD8⁺CD25^High+FOXP3⁺ T cells in HCC patients was significantly higher than controls (P = 0.005). The conventional Tregs showed the same trend with a higher level in HCC than controls (P < 0.0001). FOXP3 expression of CD8⁺CD25^High+ T cells is higher than that of CD8⁺CD25^low+ and CD8⁺CD25^Negative T cells. The percentage of CD8⁺CD25^High+FOXP3⁺ T cells positively correlated with that of conventional Tregs in HCC patients but not in controls. The higher alpha-fetoprotein positively correlated with the higher CD8⁺CD25^High+FOXP3⁺ T cells and conventional Tregs (R2 = 0.481, P < 0.0001 and R2 = 0.249, P = 0.001, respectively). The frequency of both CD8⁺CD25^High+FOXP3⁺ T cells and conventional Tregs was significantly increased in HCC with multiple lesions compared with those with one or two lesions. In conclusion: CD8⁺CD25^High+FOXP3⁺ T cells similar to conventional Tregs might be used as biomarkers of HCC progression. Therapy targeting the peripherally expanded CD8⁺CD25^High+FOXP3⁺ T cells may provide a novel perspective for HCC treatment.     

Clinicopathologic correlation of cancer stem cell markers CD44, CD24, VEGF and HIF-1α in ductal carcinoma in situ and invasive ductal carcinoma of breast: an immunohistochemistry-based pilot study

CD24^−/lowCD44⁺ cells have been identified as putative cancer stem cells (CSCs) in breast cancer. However, the expression of these markers, as well as their association with clinical parameters or tumor microenvironment of breast cancer, remains largely unknown. In the present study, we examined the expression of CD44, CD24, VEGF, and HIF-1α in human breast tumor tissues and assessed their clinicopathological correlations. We investigated tissue samples, including 117 cases of invasive ductal carcinoma (IDCa), 14 cases of ductal carcinoma in situ (DCIS), and 15 cases of intraductal hyperplasia (IDH) from breast tissues. The expression of CD44, CD24, HIF-1α, and VEGF was evaluated using immunohistochemical staining. CD24, CD44, HIF-1α, and VEGF were expressed in 49 (41.9%), 51 (43.6%), 32 (27.4%), and 97 cases (82.9%), respectively, in IDCa. CD24^−/lowCD44⁺ cells were noted in 48 (41.3%) cases. The levels of CD24 and VEGF expression correlated positively with tumor malignancy (P < 0.05). Meanwhile, the expression of CD24, CD44, and VEGF correlated significantly positively with increasing tumor grade (P < 0.05). In addition, associations between CD44 and VEGF, CD24 and VEGF, HIF-1α and VEGF, CD24^−/lowCD44⁺ and VEGF, CD24^−/lowCD44⁺ and HIF-1α were also observed (P < 0.05). The HIF-1α expression level was relatively higher in early stage breast cancer patients with CD24^−/lowCD44⁺ cells. Taken together, our results suggest that CD24 and VEGF may play important roles in breast tumorigenesis and progression, while HIF-1α may play a role in the early stage of breast carcinogenesis.     

Effects of in vivo injection of anti-chicken CD25 monoclonal antibody on regulatory T cell depletion and CD4+CD25- T cell properties in chickens

Regulatory T cells (Tregs) are defined as CD4⁺CD25⁺ cells in chickens. This study examined the effects of an anti-chicken CD25 monoclonal antibody injection (0.5 mg/bird) on in vivo depletion of Tregs and the properties of CD4⁺CD25⁻ cells in Treg-depleted birds. The CD4⁺CD25⁺ cell percentage in the blood was lower at 8 d post injection than at 0 d. Anti-CD25-mediated CD4⁺CD25⁺ cell depletion in blood was maximum at 12 d post injection. The anti-CD25 antibody injection depleted CD4⁺CD25⁺ cells in the spleen and cecal tonsils, but not in the thymus, at 12 d post antibody injection. CD4⁺CD25⁻ cells from the spleen and cecal tonsils of birds injected with the anti-chicken CD25 antibody had higher proliferation and higher IL-2 and IFNγ mRNA amounts than the controls at 12 d post injection. At 20 d post injection, CD4⁺CD25⁺ cell percentages in the blood, spleen and thymus were comparable to that of the 0 d post injection. It could be concluded that anti-chicken CD25 injection temporarily depleted Treg population and increased and IL-2 and IFNγ mRNA amounts in CD4⁺CD25⁻ cells at 12 d post injection.     

Isolation and expansion of thymus-derived regulatory T cells for use in pediatric heart transplant patients

Regulatory T-cells (Tregs) are a subset of T cells generated in the thymus with intrinsic immunosuppressive properties. Phase I clinical trials have shown safety and feasibility of Treg infusion to promote immune tolerance and new studies are ongoing to evaluate their efficacy. During heart transplantation, thymic tissue is routinely discarded providing an attractive source of Tregs. In this study, we developed a GMP-compatible protocol for expanding sorted thymus-derived CD3⁺CD4⁺CD25⁺CD127^– (Tregs) as well as CD3⁺CD4⁺CD25⁺CD127^–CD45RA⁺ (RA⁺Tregs) cells. We aimed to understand whether thymic RA⁺Tregs can be isolated and expanded offering an advantage in terms of stability as it has been previously shown for circulating adult CD45RA⁺ Tregs. We show that both Tregs and RA⁺Tregs could be expanded in large numbers and the presence of rapamycin is essential to inhibit the growth of IFN-γ producing cells. High levels of FOXP3, CTLA4, and CD25 expression, demethylation of the FOXP3 promoter, and high suppressive ability were found with no differences between Tregs and RA⁺Tregs. After freezing and thawing, all Treg preparations maintained their suppressive ability, stability, as well as CD25 and FOXP3 expression. The number of thymic Tregs that could be isolated with our protocol, their fold expansion, and functional characteristics allow the clinical application of this cell population to promote tolerance in pediatric heart transplant patients.     

Silencing of tumoral carbohydrate sulfotransferase 15 reactivates lymph node pancreatic cancer T cells in mice

Limited intratumoral T-cell infiltration in pancreatic ductal adenocarcinoma (PDAC) is an obstacle to immunotherapy, yet the efficient approach to enhance tumor-infiltrating T cells is not fully established. Here, we show that tumor-specific knockdown of carbohydrate sulfotransferase 15 (CHST15), a tumor stromal proteoglycan-synthetic enzyme, suppresses tumor growth in a T-cell-dependent manner in a murine model of PDAC. Silencing of tumoral CHST15 unexpectedly expanded CD4⁺ and CD8⁺ T cells in tumor draining LN (TDLN), leading to accelerated accumulation of EdU⁺ proliferating CD4⁺ and CD8⁺ T cells and granzyme B⁺ CD8⁺ T cells in the tumor. RNA expression analysis indicated that tumoral CHST15 knockdown (KD) downregulated matrix remodeling-related genes, while upregulated anti-tumor T-cell activity-related genes in both tumor and TDLN. CHST15 KD significantly diminished intratumoral and TDLN Ly6C/G⁺ myeloid-derived suppressor cells prior to TDLN T-cell expansion, suggesting that tumoral CHST15 remotely regulated myeloid-derived suppressor cell mediated T-cell suppression in the TDLN. Our findings illustrate a novel immunotherapeutic potential of tumoral CHST15 blockage by reactivating T cells in immune suppressive TDLN of PDAC.     

Targeting the tumor-draining lymph node with adjuvanted nanoparticles reshapes the anti-tumor immune response

Accumulating evidence implicates the tumor-draining lymph node (TDLN) in tumor-induced immune escape, as it drains regulatory molecules and leukocytes from the tumor microenvironment. We asked whether targeted delivery of adjuvant to the TDLN, presumably already bathed in tumor antigens, could promote anti-tumor immunity and hinder tumor growth. To this end, we used 30 nm polymeric nanoparticles (NPs) that effectively target dendritic cells (DCs, CD11c⁺) within the lymph node (LN) after intradermal administration. These NPs accumulated within the TDLN when administered in the limb ipsilateral (i.l.) to the tumor or in the non-TDLN when administered in the contralateral (c.l.) limb. Incorporating the adjuvants CpG or paclitaxel into the NPs (CpG-NP and PXL-NP) induced DC maturation in vitro. When administered daily i.l. and thus targeting the TDLN of a B16–F10 melanoma, adjuvanted NPs induced DC maturation within the TDLN and reshaped the CD4⁺ T cell distribution within the tumor towards a Th1 (CXCR3⁺) phenotype. Importantly, this also led to an increase in the frequency of antigen-specific CD8⁺ T cells within the tumor. This correlated with slowed tumor growth, in contrast to unhindered tumor growth after c.l. delivery of adjuvanted NPs (targeting a non-TDLN) or i.l. delivery of free adjuvant. CpG-NP treatment in the i.l. limb also was associated with an increase in CD8⁺/CD4⁺ T cell ratios and frequencies of activated (CD25⁺) CD8⁺ T cells within the TDLN whereas PXL-NP treatment reduced the frequency of regulatory T (FoxP3⁺ CD4⁺) cells in the TDLN. Together, these data implicate the TDLN as a delivery target for adjuvant therapy of solid tumors.     

Frequency and Expression of Inhibitory Markers of CD4+CD25+FOXP3+ Regulatory T Cells in Patients with Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is the most symptomatic primary antibody deficiency associated with recurrent infections and chronic inflammatory diseases as well as autoimmunity. CD4⁺CD25⁺FOXP3⁺ regulatory T cells (Tregs) are critical T cell subsets for maintaining self‐tolerance and regulation of immune response to antigens thus play a pivotal role in preventing autoimmunity. Thirty‐seven CVID patients and 18 age‐/sex‐matched controls were enrolled. Peripheral blood mononuclear cells (PBMCs) were obtained from both groups, and the percentage of Tregs was calculated using flow cytometry method. The mRNA expression of Tregs' surface markers cytotoxic T lymphocyte–associated antigen‐4 (CTLA‐4) and glucocorticoid‐induced tumour necrosis factor receptor (GITR), which are associated with Tregs' inhibitory function, was compared between patients and controls by quantitative real‐time PCR TaqMan method. The results revealed that the frequency of Tregs was significantly lower in CVID patients than normal individuals (P < 0.001). In addition, CVID patients with autoimmunity were found to have markedly reduced proportion of Tregs compared to those cases without autoimmune diseases (P = 0.023). A significant difference was seen in factor forkhead box P3 (FOXP3) expression between CVID patients and controls (P < 0.001). The mRNAs of CTLA‐4 and GITR genes were expressed at lower levels in CVID patients compared to control group (P = 0.005 and <0.001, respectively). Our findings showed reduced proportion of Tregs in CVID patients together with downregulation of FOXP3 protein and diminished expression of inhibitory Tregs' markers. It could be concluded that all of these changes may be responsible for cellular immune dysregulation observed in these patients especially those with autoimmune manifestation.     

PDCD5 negatively regulates autoimmunity by upregulating FOXP3+ regulatory T cells and suppressing Th17 and Th1 responses

Maintenance of FOXP3 protein expression is crucial for differentiation and maturation of regulatory T (Treg) cells, which play important roles in immune homeostasis and immune tolerance. We demonstrate here that PDCD5 interacts with FOXP3, increases acetylation of FOXP3 in synergy with Tip60 and enhances the repressive function of FOXP3. In PDCD5 transgenic (PDCD5tg) mice, overexpression of PDCD5 enhanced the level of FOXP3 protein and percentage of CD4⁺CD25⁺FOXP3⁺ cells. Naïve CD4⁺ T cells from PDCD5tg mice were more sensitive to TGF-β-induced Treg polarization and expansion. These induced Tregs retained normal suppressive function in vitro. Severity of experimentally-induced autoimmune encephalomyelitis (EAE) in PDCD5tg mice was significantly reduced relative to that of wild-type mice. The beneficial effect of PDCD5 likely resulted from increases of Treg cell frequency, accompanied by a reduction of the predominant pathogenic Th17/Th1 response. Activation-induced cell death enhanced by PDCD5 was also linked to this process. This is the first report revealing that PDCD5 activity in T cells suppresses autoimmunity by modulating Tregs. This study suggests that PDCD5 serves as a guardian of immunological functions and that the PDCD5-FOXP3-Treg axis may be a therapeutic target for autoimmunity.     

T regulatory cells lacking CD25 are increased in MS during relapse

Dysregulation of inflammatory responses is considered to be a key element in autoreactive immune responses. T regulatory cells (Tregs) are important to maintain self-tolerance and the role of CD4⁺CD25⁺FoxP3⁺ Tregs in autoimmunity has been extensively investigated. Recently, it was shown that Tregs in systemic lupus erythematosus lacked CD25 but were biologically functional. These data warrants for further investigation of CD25^? Tregs in human autoimmunity. We analyzed relapsing–remitting multiple sclerosis (MS) patients by multicolor flow cytometry for the expression of CD3, CD4, IL2R (CD25), FoxP3, and the IL7R (CD127). Further, the level of Tregs was compared in remitting and relapsing patients and correlated with disease duration. Patients in relapse exhibited higher levels of FoxP3-positive Tregs lacking CD25 compared to healthy controls (p < 0.05), indicating that Tregs attempt to restrain immune activity during relapse. The proportion of Tregs tended to be decreased with disease duration, while CD25⁺CD4⁺ and CD25⁺CD8⁺ effector T-cell proportions were elevated and positively correlated with overall disease duration (p < 0.05). In conclusion, while MS patients in remission have normal levels of Tregs of different phenotype, relapsing patients show an increased proportion of systemic CD25^? FoxP3⁺ Tregs. With time, the proportion of Tregs decrease while effector T cells expand.     

Peripherally Circulating CD4(+) FOXP3(+) CXCR3(+) T Regulatory Cells Correlate with Renal Allograft Function

Peripheral immunoregulation depends on T regulatory cell trafficking into the allograft to modulate the local alloresponse. Little is known about the relevance of trafficking receptors for Tregs after solid organ transplantation in humans. In this study, expression of the peripheral chemokine receptors CXCR3 and CCR5 on CD4⁺ FOXP3⁺ Treg cells was analysed and correlated with allograft function in renal transplant recipients. Flow cytometry analysis of peripheral blood mononuclear cells of 54 renal transplant recipients receiving a calcineurin inhibitor‐based immunosuppression was performed for CD4, CD25, FOXP3, CXCR3 and CCR5 within the first 18 months post‐transplantation. Correlation analysis of chemokine receptor expression and glomerular filtration rate as calculated by MDRD (eGFR) was performed. Expression of the peripheral homing receptors CXCR3 (r = 0.44, P < 0.05) and CCR5 (r = 0.45, P < 0.05) on FOXP3⁺ Tregs correlated with renal allograft function (eGFR) in patients receiving tacrolimus (n = 28), but not cyclosporine A (CsA) (n = 26). CsA but not tacrolimus reduced surface expression of CXCR3 on FOXP3⁺ Tregs in renal transplant recipients as correlated to trough levels (r = ?0.42, P < 0.05). In contrast to CD4⁺ CXCR3⁺ CD25^lo T cells, flow‐sorted CD4⁺ CXCR3⁺ CD25^hi Tregs isolated from healthy individuals did not produce IFNγ or IL‐17 ex vivo and expressed high levels of GARP mRNA both at baseline as well as after TCR activation indicating functional regulatory activity. Expression of the peripheral trafficking receptors CXCR3 and CCR5 on FOXP3⁺ Tregs is associated with renal allograft function. These results suggest that Treg trafficking may also depend on the interaction of CXCR3 or CCR5 and their respective ligands.