Systemic Sclerosis Th17 Cells In Peripheral Blood Of Patients, CD4 + CD25 + Treg Cells And B Cells

BackgroundSystemic sclerosis (SSc) is a chronic autoimmune disease of unknown origin. It is characterized by progressive fibrosis of the skin and visceral organs, microvascular alterations and a variety of cellular or humoral immune abnormalities. These changes finally lead to atrophy of the tissues and the organs, so SSc has a poor prognosis. T cells and B cells play important roles in the pathogenesis of this disease. T cells promote inflammations and fibrosis by secreting the cytokines or contact with the fibroblasts. B cells generate a series of autoantibodies to induce the alterations. T-helper17(Th17) cells and CD4+CD25+regulatory T cells (Treg) are two kinds of special T lymphocytes. They respectively enhance and control inflammatory responses. CD27molecules and CD38molecules were respectively expressed on the surface of memory B cells and plasma cells. CD268molecules are the dominant receptors of B cell activating factor (BAFF). The effects of Th17, Treg, CD27, CD38and CD268in autoimmune diseases are becoming the foci of the researchers. But there are few reports in SSc. EULAR Scleroderma Trial and Research group (EUSTAR) is a global research organization on scleroderma. Peking Union Medical College Hospital is one of its members. In our study, objects are chosen from EUSTAR patients.ObjectiveTo measure the ratios of Th17, CD4+CD25+Treg cells and cells expressing CD27, CD38or CD268molecules in the peripheral blood mononuclear cells (PBMC) of the SSc patients. To analyze the relativities of the cell ratios and the clinical data of the patients.MethodsTh17cells (CD4+IL-17+), Treg cells (CD4+CD25+Foxp3+), CD27+, CD38+or CD268+B cells in the PBMC of SSc patients and healthy controls were counted by flow cytometry. The different results of the patients and the healthy controls and the relativities of the cell counts and the clinical data in the patients were analyzed.Results1. The ratio of Th17cells in SSc patients is significantly higher than the ratio in healthy controls. The level of Th17cells correlates with the duration of the disease.2. The ratio of CD4+CD25+Treg cells in SSc patients is significantly higher than the ratio in healthy controls.3. The ratio of CD27+B cells in SSc patients is significantly lower than the ratio in healthy controls. The level of CD27+B cells negatively correlates with the anti-U1RNP antibody.4. The ratio of BAFF-R+cells in SSc patients did not show significant difference with the ratio in healthy controls.5. The ratio of CD38+cells in SSc patients did not show significant difference with the ratio in healthy controls.ConclusionsThere are remarkable T cell and B cell abnormalities in systemic sclerosis.1. Proliferation of Th17cells in the periphery:Th17cells participate in inflammatory and fibrotic processes by secreting IL-172. Proliferation of CD4+CD25+Treg cells in the periphery:Treg cells participate in fibrotic process3. Proliferation of naive B cells; Reduction of memory B cells4. Activation of BAFF--BAFF-R system does not rely on the proliferation of BAFF-R positive B cells.