Abstract:

Objective To investigate changes of helper T lymphocytes in peripheral blood and parameters of oxidative stress of patients with end-stage renal disease (ESRD) and to explore correlation between immune function and oxidative stress. Methods Forty ESRD patients were divided into hemodialysis group (HD group, n=20) and nonhemodialysis group （NHD group, n=20) based on receiving or not receiving hemodialysis. Twenty healthy volunteers over the same period served as normal control group (NC group). Vein blood samples of all patients and subjects were collected. T lymphocytes were counted and cell subsets were selected by using flow cytometry. Percentages of T lymphocyte (CD3+ T cell) and helper T lymphocyte (CD4+ T cell) in peripheral blood and ratio of CD4+ T to another T cell subset (CD8+ T cell) (CD4+/CD8+) were calculated. Rates of proliferation and apoptosis of CD4+ T cell were measured. ELISA was used to detect contents of cytokines, interferon gamma (IFN-γ) and interleukin-4 (IL-4), in cell culture medium. Parameters of oxidative stress, superoside dismutase (SOD) and malondialdehyde (MDA), were determined by xanthinoxidase method and thiobarbituric acid spectrophotometric method,respectively. The correlations between indexes were analyzed. Results Compared with NC group, percentages of CD3+ T cell and CD4+ T cell in peripheral blood and ratio of CD4+/CD8+ in HD and NHD groups decreased significantly, accompanying increased apoptosis and decreased proliferation of CD4+T cell, increased level of IL-4, decreased level of IFN-γ, decreased level of SOD, and increased level of MDA (P＜0.05 or P＜0.01). Percentages of CD3+ and CD4+ T cells, apoptosis rate of CD4+ T cell, contents of IL-4 and IFN-γ had significant differences between HD and NHD groups (P＜0.05). The percentage of CD4+ T cell in ESRD patients was negatively correlated with the apoptosis (r=-0.87，P＜0.01), and positively correlated with the proliferation (r=0.73，P＜0.01). The rate of apoptosis of CD4+ T cell was positively correlated with the level of MDA (r=0.58, P＜0.01), and negatively correlated with SOD (r=-0.51，P＜0.01). The level of IL-4 was positively correlated with the level of MDA (r=0.47，P＜0.01). Conclusion The ESRD patients, especially those not receiving hemodialysis, had reduction in helper T lymphocytes in peripheral blood and abnormal secretion of relative cytokines. The excessive apoptosis of CD4+T cell and Th1/Th2 cytokine imbalance may be induced by oxidative stress, which aggravates immune functional defect.

Key words: end-stage renal disease, helper T lymphocyte, cytokines, oxidative stress