A study on FoxP3 and Tregs in paired samples of peripheral blood and synovium in rheumatoid arthritis

T-regulatory cells from patients with rheumatoid arthritis retain suppressor functions in vitro

Rheumatoid arthritis (RA) is a chronic disease of connective tissue caused by intolerance to self-antigens. Regulatory T cells (Tregs) are key players in maintaining autotolerance through a variety of suppressor mechanisms. RA is generally believed to develop due to disorders in Tregs; however, there is no consensus on this issue. Thus, the present study focused on phenotypical analysis of Treg cells and their ability to suppress CD4⁺ and CD8⁺ cell proliferation. The present study used peripheral blood samples from 21 patients with RA and 22 healthy donors. The CD25⁺FoxP3⁺ subpopulation of Tregs was analyzed using flow cytometry to evaluate the expression of CTLA-4, PD-L1, HLA-DR, CCR4, CD86 and RORyt. Tregs suppressor activity was calculated in terms of suppression of the proliferation of CD4⁺ and CD8⁺ lymphocytes in vitro. Suppressor activity of the total Treg population did not differ between patients with RA and healthy donors. However, the patients had elevated CD25^loFoxP3⁺ levels and lower CD25^hiFoxP3⁺ levels; in addition, they had more activated Tregs expressing PD-L1, HLA-DR, CCR4 and CD86. The surface expression of CTLA-4 was below the reference level. The patients also had transitional FoxP3⁺RORyt⁺ cells and elevated CD4⁺RORyt⁺ levels, which were highly correlated with disease activity. These results show that in RA, Treg cells are activated and have an immunosuppressive activity. However, it is the transitional FoxP3⁺RORyt⁺ cells and increased CD4⁺RORyt⁺ percentages in peripheral blood that appear to be associated with the pathological conversion of some Treg cells into Th-17. This process appears to be key in RA pathogenesis.

Regulatory T Cell Plasticity and Stability and Autoimmune Diseases

CD4⁺CD25⁺ regulatory T cells (Tregs) are a class of CD4⁺ T cells with immunosuppressive functions that play a critical role in maintaining immune homeostasis. However, in certain disease settings, Tregs demonstrate plastic differentiation, and the stability of these Tregs, which is characterized by the stable expression or protective epigenetic modifications of the transcription factor Foxp3, becomes abnormal. Plastic Tregs have some features of helper T (Th) cells, such as the secretion of Th-related cytokines and the expression of specific transcription factors in Th cells, but also still retain the expression of Foxp3, a feature of Tregs. Although such Th-like Tregs can secrete pro-inflammatory cytokines, they still possess a strong ability to inhibit specific Th cell responses. Therefore, the plastic differentiation of Tregs not only increases the complexity of the immune circumstances under pathological conditions, especially autoimmune diseases, but also shows an association with changes in the stability of Tregs. The plastic differentiation and stability change of Tregs play vital roles in the progression of diseases. This review focuses on the phenotypic characteristics, functions, and formation conditions of several plastic Tregs and also summarizes the changes of Treg stability and their effects on inhibitory function. Additionally, the effects of Treg plasticity and stability on disease prognosis for several autoimmune diseases were also investigated in order to better understand the relationship between Tregs and autoimmune diseases.

Fas, FasL and Foxp3 gene expression in post-liver transplant autoimmune hepatitis patients with and without acute rejection

Aim of the study

In this study we investigated Fas, FasL and Foxp3 expression in relation to liver graft rejection and its severity in autoimmune hepatitis (AIH) patients.

Material and methods

Twenty-three AIH patients including five post-transplant patients with acute rejection (AR) and 18 patients without AR (non-AR) were studied for Fas, FasL and Foxp3 gene expression in peripheral blood mononuclear cells on days 1, 3 and 7 after transplantation by real-time PCR. The relationships between gene expression and clinical features were determined.

Results

Real-time PCR showed various Fas gene expression levels with no significant difference between the days in AR patients (p = 0.52). In non-AR patients, Fas level increased from 0.98 ±0.24 fold on the first day to 1.89 ±0.42 fold on day 3 after transplantation (p < 0.01). In this group of patients, we also found a significant increase in FasL expression on day 7 (29.91 ±6.89 fold) compared to day 1 (13.50 ±7.44 fold, p < 0.05). Foxp3 gene expression in both groups showed decreased levels during the first week after transplantation. The decreased Foxp3 expression in AR patients was correlated with rejection activity index (r = 0.86, p < 0.0001).

Conclusions

Increased Fas and FasL gene expression levels in non-AR patients and decreased Foxp3 gene expression in both groups suggested the important role of these molecules in the alloreactive response after liver transplantation in AIH patients. Foxp3 expression might be useful for monitoring rejection severity.

Lectin, galactoside-binding, soluble, 3 rs4652 A/C gene variation and the risk for rheumatoid arthritis

Rheumatoid arthritis (RA) is a complex genetic disease. The lectin, galactoside-binding, soluble, 3 (LGALS3) gene, encodes a member of the galectin family of carbohydrate binding proteins, and is one of the best examples of a non-human leukocyte antigen gene associated with a risk for RA in various populations. In the current study, the association between LGALS3 rs4652 gene polymorphism and RA was examined. This case-control study was performed on the 120 patients with RA and 120 healthy subjects. Genomic DNA was extracted from whole blood, and gene polymorphism was tested using a tetra-primer amplification refractory mutation system-polymerase chain reaction. The results demonstrated that LGALS3 rs4652 AC genotype increased the risk of RA (OR=11.622, 95% CI=4.473-28.656; P=0.001) when compared with the AA genotype. However, the CC genotype and the C allele were not associated with RA. These findings indicated an association between LGALS3 rs4652 variation and the risk of RA in a sample of Iranian individuals. Further studies with larger sample sizes and populations of different ethnicities are required to validate our findings.