Objective: To study the effect and mechanism of the dysfunction of CD4+ T cells in the disease process of chronic cardiac failure (CHF).Methods:According to different group technologies, 100 CHF patients were divided into the following groups: ischemia group and non-ischemia group, heart function Ⅰ-Ⅱ group and heart function Ⅲ-Ⅳ group, event group and non-event group, and 50 healthy volunteers were included in the control group. Realtime PCR was used to detect transcription factors T-bet and GATA-3 of Th1 and Th2; flow cytometry was applied to determine the ratio of Th17 and Treg cells; ELISA was employed to test cytokines IFN-γ, IL-4, IL-17 and IL-10 of peripheral blood Th1, Th2, Th17 and Treg cells, respectively; ultrasonic cardiogram was used to exploit to LVEF and LVEDd; and electrochemilu minescene immunoassay was used to examine plasma BNP. The differences of all indexes of all groups were analyzed and the correlation between CD4 T cells and clinical indexes was analyzed by Pearson correlation analysis. Results: As compared to the control group, the transcription factors T-bet and GATA-3 of Th1 and Th2, the ratio of cytokines Th17 and IFN-γ, cytokines IL-17, T-bet/GATA-3, IFN-γ/IL-4, Th17 cells/Treg cells, IL-17/IL-10 of the ischemia group and non-ischemia group, heart functionⅠ-Ⅱgroup and heart function Ⅲ-Ⅳ group, event group and non-event group were all increased significantly, while their transcription factor GATA-3 of Th2, cytokines IL4, Treg cells ratio, cytokines IL10 were decreased obviously. The differences showed statistical significance (P < 0.05). The increase or decrease of the partial CD4+ T cells of the ischemia group, heart function Ⅲ-Ⅳ group and event group was more distinctly. The results of Pearson correlation analysis showed that IFN-γ and IL-17 were significantly positively correlated with LVEDd and BNP, IL-4 and IL-10 were also significantly positively correlated with LVEF, but correlated negatively with BNP, and IL-17 was negatively correlative with LVEF. Conclusions: There was a correlation between CHF and the dysfunction of CD4+ T cells showing immune activation phenomenons of deviations from the Th1/Th2 balance towards Th1 and from the Th17/Treg balance towards Th17, which was also related to the types, severity and prognosis of the disease. Objective: To study the effect and mechanism of the dysfunction of CD4 + T cells in the disease process of chronic cardiac failure (CHF). Methods: According to different group technologies, 100 CHF patients were divided into the following groups: ischemia group and non- ischemia group, heart function Ⅰ-Ⅱ group and heart function Ⅲ-Ⅳ group, event group and non-event group, and 50 healthy volunteers were included in the control group. Realtime PCR was used to detect transcription factors T-bet and GATA- 3 of Th1 and Th2; flow cytometry was applied to determine the ratio of Th17 and Treg cells; ELISA was employed to test cytokines IFN-γ, IL-4, IL-17 and IL-10 of peripheral blood Th1, Th2, Th17 and Treg cells, respectively; ultrasonic cardiogram was used to exploit to LVEF and LVEDd; and electrochemilu minescene immunoassay was used to examine plasma BNP. The differences of all indexes of all groups were analyzed and the correlation between CD4 T cells and clinical indexes was analyze d by Pearson correlation analysis. Results: As compared to the control group, the transcription factors T-bet and GATA-3 of Th1 and Th2, the ratio of cytokines Th17 and IFN- γ, cytokines IL- 17, T-bet / GATA -3, IFN-γ / IL-4, Th17 cells / Treg cells, IL-17 / IL-10 of the ischemia group and non-ischemia group, heart function Ⅰ-Ⅱgroup and heart function Ⅲ-Ⅳ group, event group and non The increase or decrease of the partial CD4 (superscript +) T-cell subsets was significantly increased (P <0.05) The results of Pearson correlation analysis showed that IFN-γ and IL-17 were significantly positively correlated with LVEDd and BNP, IL-4 and IL- 10 were also significantly positively associated with LVEF, but correlated negatively with BNP, and I. L-17 was negatively correlative with LVEF. Conclusions: There was a correlation between CHF and the dysfunction of CD4 + T cells showing immune activation phenomenons of deviations from the Th1 / Th2 balance towards Th1 and from the Th17 / Treg balance towards Th17, which was also related to the types severity and prognosis of the disease.