Increased levels of mitochondrial DNA copy number in patients with vitiligo

BACKGROUND

Oxidative stress is known to be involved in the pathogenesis of autoimmune diseases such as vitiligo. Evidence suggests that the human mitochondrial DNA copy number (mtDNAcn) is vulnerable to damage mediated by oxidative stress. The purpose of this study was to examine and compare peripheral blood mtDNAcn and oxidative DNA damage byproducts (8-hydroxy-2-deoxyguanosine; 8-OHdG) in patients with vitiligo and healthy controls (HCs).

METHODS

The relative mtDNAcn and the oxidative damage (formation of 8-OHdG in mtDNA) of each sample were determined by real-time quantitative PCR. Blood samples were obtained from 56 patients with vitiligo and 46 HCs.

RESULTS

The mean mtDNAcn and the degree of mtDNA damage were higher in patients with vitiligo than in HCs.

CONCLUSION

These data suggest that increase in mtDNAcn and oxidative DNA damage may be involved in the pathogenesis of vitiligo.

Differential expression of mRNA for T-bet and GATA-3 transcription factors in peripheral blood mononuclear cells of patients with vitiligo

BACKGROUND

There is accumulating evidence that aberrant T helper (Th)1 and Th2 cell responses play critical roles in the pathogenesis of autoimmune diseases. However, their importance in the pathobiology of vitiligo have yet to be elucidated.

AIM

To evaluate the expression profile of two transcription factors, namely, T-bet, a Th1-specific T box transcription factor and GATA binding protein 3 (GATA-3), a Th2-specific transcription factor, and to measure expression levels of interferon (IFN)-γ and interleukin (IL)-4 mRNAs as the signature cytokines of Th1 and Th2 cells, respectively.

METHODS

Gene expression analysis of peripheral blood mononuclear cells (PBMCs) was performed using real-time reverse transcriptase PCR.

RESULTS

In patients with vitiligo compared with controls, mRNA expression was significantly higher for T-bet and IFN-γ, and significantly lower for GATA-3 and IL-4 mRNAs (P ≤ 0.05).

CONCLUSION

These data suggest additional implications for the role of Th1/Th2 balance in the immunopathogenesis of vitiligo.

T cell immune responses in psoriasis

A central role for T cells and their cytokines in the pathogenesis of psoriasis has been proposed; however, there are controversies over the details of this issue. The goal of this study is to summarise currently available data on the importance of T cells in psoriasis pathogenesis. A systematic review of the English medical literature was conducted by searching PubMed, Embase, ISI Web of Knowledge, and Iranian databases including Iranmedex, and SID for studies on associations between the involvement of T cell subsets and psoriasis. The results of the present study indicate that alterations in the number and function of different subsets of T-cells are associated with psoriasis. It appears that studies on T cell subsets contributed to understanding the immunopathogenesis of psoriasis. In addition, it may have provided novel therapeutic opportunities in ameliorating immunopathologies.

Th1/Th2 cytokines in patients with Graves' disease with or without ophthalmopathy

About 25-50% of Graves' disease (GD) patients develop thyroid eye diseases, which is associated with inflammatory process and abnormalities in the levels of several cytokines in orbital tissues in GD. The aim of this study was to determine the Th1 and Th2 serum cytokines in patients with GD with or without ophthalmopathy. Serum levels of cytokines and autoantibodies including Interferon-gamma (IFN-γ), Interleukin-2 (IL-2), Interleukin-4 (IL-4), Interleukin-10 (IL-10), TSH receptor autoantibody (TRAb), thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody(TgAb) were measured by enzyme linked immunosorbent assay(ELISA) in 34 patients with GD and in 33 normal controls. Patients were also divided in two subgroups: 18 cases with ophthalmopathy and 16 cases without ophthalmopathy. Cytokine and antibody responses were analyzed in both groups. Compared with control subjects, patients with GD showed elevated levels of IL-2 and IL-10. IFN-γ levels were lower in patients in comparison to the controls. No significant differences were found between patients and controls regarding the IL-4. There was no statistically significant difference in cytokine levels between those with or without ophthalmopathy. Quantitative-cytokine analysis demonstrated that a combination of Th1 and Th2 cytokines may contribute to the pathogenesis of GD. These results also indicate that IL-10, but not IL-4, is related to the moderate and severe forms of thyroid associated ophthalmophathy.

Interaction of CpG-oligodeoxynucleotides with Toll like receptor 9 induces apoptosis and modulates metaloproteinase-2 activity in human intestinal epithelium

Recent reports have indicated different effects of immunostimulatory sequences containing CpG-Oligodeoxynucleotides (ODN) on various immune cells. However, the exact role of CpG-ODN in the human gut is unclear. In the present study, we assessed potential effects of CpG-ODN on non lymphoid cell (intestinal epithelial cell line HT-29) on a dose-response and time-course basis. Intestinal epithelial cell line HT-29 was treated with CpG-ODN (CpG 2006) and lipopolysaccharide (LPS) at 5, 10, 25, 50 microg/ ml and 1, 5, 10 microg/ ml concentrations, respectively. Following treatments, dose- response and time-course cytotoxicity using a colorimetric method, Metaloproteinase-2 (MMP-2) activity (using gelatin zymography) and apoptosis (using annexin-v flowcytometry method) assays were performed. Chloroquine treatment was also used for its inhibitory effect on endosomal acidification process to verify specific CpG-ODN and Toll Like Receptor 9 (TLR9) interactions. Cytotoxicity analysis of CpG-ODN showed that CpG-ODN increased significantly the proliferation of CpG-ODN treated cells, as compared to untreated cells, at concentrations of 10-25 microg/ml (p < 0.05). Overall MMP-2 activity analysis showed significant differences between treated and untreated cells. However, minimal changes were observed when MMP-2 activity was assessed per cell. Moreover, CpG-ODN treated cells demonstrated an increasing apoptosis rate of 0.8 %, 6.46 % and 14.21% at concentrations of 5, 10, 25 microg/ml, respectively. Collectively, our data indicated that intestinal epithelial cell line HT-29 is highly responsive to CpG effect in vitro and exhibits modified activities. The direct CpG-ODN and TLR-9 interactions in HT-29 cells could provide new approaches in malignant tumor therapeutic strategies.

Identification of peptides specific for antibodies in vitiligo using a phage library

Patients with vitiligo produce specific autoantibodies that can be detected in their sera. These antibodies are believed to play a role in the pathogenesis of this disease. A random peptide library displayed on phage is a technique that can be used to identify the epitopes that react with monoclonal and polyclonal antibodies. We used this technique to identify the epitopes that react specifically with the vitiligo autoantibodies. By screening the random peptide phage library and using ELISA, two clones that showed a higher frequency of reactivity with the antibodies in the sera of patients with vitiligo were identified. The peptides do not show any similarity with the autoantigens so far implicated in vitiligo, indicating that these epitopes may mimic conformational epitopes in proteins.