Abstract: AIM:To investigate the effects of pentoxifylline (PTX) on the immune modulatory mechanism of CD4+Th and soluble Fas in patients with chronic heart failure (CHF). METHODS: Cytokine-producing Th lymphocytes were quantified by 3-color flow cytometry in 40 CHF patients. Concentrations of TNF-α, IL-10 and Fas/Apo-1 were examined by ELISA, and the ejection fraction was measured by ultrasound echocardiography. RESULTS: The frequencies of IFN-γ-producing Th1 cells were significantly lower and the frequency of IL-10-producing Th2 cells was higher (P<0.01). Levels of TNF-α and Fas/Apo-1 were lower (P<0.05, P<0.01) and the ejection fraction was higher in PTX group than those in routine group after 1-month therapy. CONCLUSION: The improvement of ejection fraction resulting from conventional treatment plus pentoxifylline may be related with the effects of pentoxifylline on the immune modulation on Th1/Th2 functional imbalance in CHF patients and on the activation and secretion of inflammatory cytokines and Fas/Apo-1 through immune modulatory mechanisms.