Background: Rheumatoid arthritis (RA) is defines as a Th1 dominant disease. Tregs cell are a rather new group of T cells that regulates other immune cells including Th1 and Th2. Foxp3 is a lineagedetermining factor for Treg cells. Several subsets of Foxp3+regulatory T cells are ever identified. In this study we investigated the frequency of CD4+Foxp3+Treg and CD8+Foxp3+Treg cells in patients with rheumatoid arthritis.Methods: Peripheral blood samples were obtained from 31 patients with rheumatoid arthritis and 21 healthy controls. Monoclonal antibodies including anti-CD4 and anti-CD8 and anti-Foxp3 were used and the staining process was performed. Flow cytometry were applied to evaluate the markers.Findings: The percentage of CD4+Foxp3+Treg cells was 1.03% ± 0.28 % in rheumatoid arthritis and 1.25% ± 0.3% in control group (P=0.010). The percentage of CD8+Foxp3+Treg cells was 0.79 ± 0.18, and 0.63 ± 0.16 in rheumatoid arthritis and control groups respectively (P=0.002). The WBC and Lymphocytes population in rheumatoid arthritis group were higher than control group (P=0.001).Conclusion: These data demonstrate that frequency of Treg cells might be involved in the pathogenesis of rheumatoid arthritis. This may be a contributory factor in the susceptibility to rheumatoid arthritis (Th1 dominant), or it may achieved during the progression of the disease.

Background & aim: CD4+CD25+FOXP3+ regulatory T cells (CD4+CD25+FOXP3+ Tregs) are a group of T lymphocytes that play an important role in regulating immune system responses by suppressing the activity of other T cells and establishing homeostasis in the immune system. be. Th1 and Th2 cells are another group of CD4+ cells that play an important role in the formation of inflammatory responses. Considering the important role of Treg, Th1 and Th2 cells in immune responses in patients with lymphoma, the present study investigated the frequency of Treg/Th1 and Treg/Th2 lymphocytes in Hodgkin's lymphoma patients who were in different phases of the disease (new patients, patients in recovery phase and patients in the relapse phase) and their relationship with disease prognosis. Methods: In the present cross-sectional descriptive study, 47 Hodgkin's lymphoma patients including 10 new cases, 24 remission cases and 13 relapsed cases were included in the study. Due to the limited number of patients with Hodgkin's lymphoma, all eligible patients who referred to the hematology and oncology department of Shahid Motahari Clinic and Amir Hospital between 2019 and 2017 were included in the study. The frequency of Treg, Th1 and Th2 lymphocytes in peripheral blood was measured with the help of flow cytometry method and then the ratio of Treg/Th1 and Treg/Th2 populations was determined. Collected data were analyzed using MannWhitney and Croxall-Wallis tests. P value less than 0. 05 was considered significant. Results: The results indicated that the ratio of Treg/Th1 lymphocytes in recovered cases (0. 025%) and relapsed cases (0. 007%) compared to new cases (0. 16%) (respectively with p<0. 001* and p<0. 001*) and relapsed cases were significantly reduced compared to recovered cases (p*=0. 023). Regarding the ratio of Treg/Th2 lymphocytes, their significant decrease was observed in recovered cases (0. 43%) and relapsed (0. 34%) compared to new cases (4. 27%) (p<0. 001, respectively). * and p<0. 001*). Also, taking into account the International Prognostic Index (IPI) score parameter, the ratio of Treg/Th1 cells in lymphoma patients in the low-moderate risk group was higher than the high-risk group (median). 0. 031% versus 0. 013%, p=0. 007*). In addition, the ratio of Treg/Th1 and Treg/Th2 cells in Hodgkin's lymphoma patients was higher in the group with performance status (PS) less than 2 (PS<2) than in the group with performance status equal to or greater than 2 (PS≥, 2). The median of 0. 036% versus 0. 013%, p=0. 001 and 0. 78% versus 0. 37%, p=0. 013) respectively. Conclusion: The results of the present study indicated that an increase in the ratio of Treg/Th1 and Treg/Th2 lymphocytes is related to better response to treatment and better prognosis in Hodgkin's lymphoma patients.