Treg Frequency In Blood Research Articles

Type 1 diabetes linked PTPN22 gene polymorphism is associated with the frequency of circulating regulatory T cells.

Dysfunction of FOXP3-positive regulatory Tcells (Tregs) likely plays a major role in the pathogenesis of multiple autoimmune diseases including type 1 diabetes (T1D). Whether genetic polymorphisms associated with the risk of autoimmune diseases affect Treg frequency or function is currently unclear. Here, we analysed the effect of T1D-associated major HLA class II haplotypes and seven single nucleotide polymorphisms in six non-HLA genes [INS (rs689), PTPN22 (rs2476601), IL2RA (rs12722495 and rs2104286), PTPN2 (rs45450798), CTLA4 (rs3087243), and ERBB3 (rs2292239)] on peripheral blood Treg frequencies. These were determined by flow cytometry in 65 subjects who had progressed to T1D, 86 islet autoantibody-positive at-risk subjects, and 215 islet autoantibody-negative healthy controls. The PTPN22 rs2476601 risk allele A was associated with an increase in total (p = 6 × 10-6 ) and naïve (p = 4 × 10-5 ) CD4+CD25+CD127lowFOXP3+ Treg frequencies. These findings were validated in a separate cohort comprising ten trios of healthy islet autoantibody-negative children carrying each of the three PTPN22 rs2476601 genotypes AA, AG, and GG (p = 0.005 for total and p = 0.03 for naïve Tregs, respectively). In conclusion, our analysis implicates the autoimmune PTPN22 rs2476601 risk allele A in controlling the frequency of Tregs in human peripheral blood.

Correlation of interleukin 6 and transforming growth factor β1 with peripheral blood regulatory T cells in rheumatoid arthritis patients: a potential biomarker.

IntroductionProinflammatory cytokines and regulatory T cells (Tregs) are considered as important factors involved in autoimmunity development especially in rheumatoid arthritis (RA).Aim of the studyTo investigate the frequency of peripheral blood Tregs and related cytokines in RA patients and to determine the possible correlation between Treg percentage and interleukin 6 (IL-6) and transforming growth factor β1 (TGF-β1) as indicators in assessment of Treg function and mechanisms preceding autoimmunity in RA.Material and methodsThirty-seven Iranian RA patients with a moderate (3.2-5.1) disease activity score (DAS) and the same number of healthy age- and sex-matched individuals were enrolled. Frequency of peripheral blood Tregs (CD4+FoxP3+CD25high) was determined by flow cytometry. Serum levels of IL-6 and TGF-β1 and their expression levels in peripheral blood mononuclear cells (PBMCs) were evaluated by ELISA and Q-PCR, respectively.ResultsRheumatoid arthritis patients showed significantly lower peripheral blood Treg frequencies compared to healthy individuals. Additionally, Treg (%) showed a significant inverse correlation between serum concentrations of IL-6 and mRNA expression of PBMCs, whereas there was no significant correlation between Treg (%) and TGF-β1 levels.ConclusionsThe current study revealed that Treg numbers were reduced in peripheral blood of RA patients. This reduction inversely correlated with IL-6 levels, which may lead to persistent autoimmune and inflammatory conditions in RA patients.

Low Molecular Weight Heparin Modulates Maternal Immune Response in Pregnant Women and Mice with Thrombophilia

Thrombophilia is associated with pregnancy complications. Treatment with low molecular weight heparin (LMWH) improves pregnancy outcome, but the underlying mechanisms are not clear. We analyzed Treg frequency in blood from thrombophilic pregnancies treated with LMWH (n = 32) or untreated (n = 33) and from healthy pregnancies (n = 39) at all trimesters. Additionally, we treated pregnant wild-type, heterozygous and homozygous factor-V-Leiden (FVL) mice with LMWH or PBS and determined Treg frequency, pro-/anti-inflammatory cytokine levels and Caspase-3-activity in placenta and decidua. Treg frequencies were increased in second and third trimester in LMWH-treated thrombophilic pregnancies compared to controls. Treg levels were comparable to those of normal pregnancies. Homozygous FVL mice had decreased decidual Tregs compared to wild-type mice. LMWH treatment normalized Tregs and was associated with increased decidual IL-10 mRNA. LMWH diminished Caspase-3-activity in mice of all genotypes. We demonstrated anti-apoptotic and anti-inflammatory effects of LMWH in pregnant FVL mice. LMWH increased Treg levels in mice and humans, which suggests benefits of LMWH treatment for thrombophilic women during pregnancy.

Assessment of peripheral blood T regulatory cells (Tregs) in PNET/Ewing sarcoma: A prospective study.

9580 Background: Tregs in bone marrow have been previously evaluated in PNET patients; however, data on peripheral blood ccirculating Tregs is lacking. The objective of our study was to determine baseline Treg frequency in PNET patients and correlate the same with patient characteristics and outcome. Methods: Samples of 5ml venous blood were obtained from 38 newly diagnosed PNET patients at diagnosis along with six healthy controls. Flow cytometric analysis was done for detecting Treg cells [CD4+CD25+FoxP3+]. Results: Thirty-eight patients with median age 17 years; male/female ratio of 5.5:1 had significantly higher baseline Tregs than healthy controls [9.17%±.3.08 vs 3.16±1.49%; p=<0.0001]. Eight patients (21.1%) had fever at baseline presentation. The disease was extra-skeletal in one and metastatic at baseline in 11 (28.9%) patients. Ten patients relapsed on standard protocol of therapy and seven died. The median Treg frequency was 8.84% (Range: 2.49-16.31). When the Tregs were categorized as high and low based on the median value, patients with fever had a significantly higher Tregs than those without fever [11.3%±.3.5% vs 8.6% ±. 2.7%; p=0.02]. No significant association of peripheral blood Treg cells frequency was noted with other factors like age, sex, metastatic disease, relapse or death. The EFS was 55% and OS 70% of the entire cohort at a median follow up of 14 months. There was no significant difference in the EFS or OS between the high and low Treg cell groups [EFS- 52% vs 64%; p=0.99 and OS-75% vs 70%; p=0.26]. Conclusions: This is the first study on circulating Tregs in PNET, and it shows that the peripheral blood Treg frequencies are higher in these patients as compared to healthy controls. Further, PNET patients with fever had significantly higher Treg frequency. However, Tregs did not differ with respect to metastatic disease at presentation, EFS or OS.

Mesenchymal stem cells are conditionally therapeutic in preclinical models of rheumatoid arthritis

ObjectiveThe role of mesenchymal stem cells (MSC) in experimental arthritis is undoubtedly conflicting. This study explored the effect of bone marrow-derived MSC in previously untested and pathogenetically different models of...

Murine Melanoma-Infiltrating Dendritic Cells Are Defective in Antigen Presenting Function Regardless of the Presence of CD4+CD25+ Regulatory T Cells

Tumor-infiltrating dendritic cells are often ineffective at presenting tumor-derived antigen in vivo, a defect usually ascribed to the suppressive tumor environment. We investigated the effects of depleting CD4+CD25+ “natural” regulatory T cells (Treg) on the frequency, phenotype and function of total dendritic cell populations in B16.OVA tumors and in tumor-draining lymph nodes. Intraperitoneal injection of the anti-CD25 monoclonal antibody PC61 reduced Treg frequency in blood and tumors, but did not affect the frequency of tumor-infiltrating dendritic cells, or their expression of CD40, CD86 and MHCII. Tumor-infiltrating dendritic cells from PC61-treated or untreated mice induced the proliferation of allogeneic T cells in vitro, but could not induce proliferation of OVA-specific OTI and OTII T cells unless specific peptide antigen was added in culture. Some proliferation of naïve, OVA-specific OTI T cells, but not OTII T cells, was observed in the tumor-draining LN of mice carrying B16.OVA tumors, however, this was not improved by PC61 treatment. Experiments using RAG1−/− hosts adoptively transferred with OTI and CD25-depleted OTII cells also failed to show improved OTI and OTII T cell proliferation in vivo compared to C57BL/6 hosts. We conclude that the defective presentation of B16.OVA tumor antigen by tumor-infiltrating dendritic cells and in the tumor-draining lymph node is not due to the presence of “natural” CD4+CD25+ Treg.

Frequency of Circulating Tregs with Demethylated FOXP3 Intron 1 in Melanoma Patients Receiving Tumor Vaccines and Potentially Treg-Depleting Agents

Regulatory T cells (Tregs) are thought to inhibit antitumor immune responses, and their depletion could therefore have a synergistic effect with therapeutic cancer vaccines. We investigated the impact of three medications on blood Treg frequency in vaccinated cancer patients. To date, the most specific marker for human Tregs is demethylation in the DNA that encodes the transcription factor FOXP3. Thus, we used a FOXP3 methylation-specific quantitative PCR assay (MS-qPCR) to measure Treg frequencies in the peripheral blood mononuclear cells (PBMCs) of melanoma patients. The patients participated in three clinical trials that combined tumor vaccines with potential Treg-depleting agents: low-dose cyclophosphamide, anti-CD25 monoclonal antibody daclizumab, and the IL-2/diphtheria toxin fusion protein denileukin diftitox. In the nine control patients, blood Treg frequencies varied over time; there was a 46% reduction in one patient. In treated patients, a more than 2-fold decrease in Tregs was observed in one out of 11 patients receiving cyclophosphamide and in four out of 13 receiving daclizumab, but there was no such Treg decrease in any of the six patients who received denileukin diftitox. As a positive control, a more than 2-fold increase in blood Tregs was detected in four out of nine patients who were treated with interleukin-2. We used a MS-qPCR method that detects Tregs but not other activated T lymphocytes; however, none of the Treg-depleting strategies that we tested led, in the majority of patients, to a conservative 50% reduction in blood Tregs.