['The T-helper (Th)1/Th2 imbalance has been demonstrated to be involved in chronic heart failure (CHF). We sought to determine whether atorvastatin exhibited any effect on CHF through modulating the Th1/Th2 response.', 'We measured serum concentrations of interleukin (IL)-12, -18, interferon (IFN)-gamma, IL-4, and IL-10 from 20 controls and 72 patients with nonischemic CHF by enzyme-linked immunosorbent assay. To investigate the effect of atorvastatin in vivo, CHF patients were either classified into a usual therapy group (n = 35) or usual therapy plus atorvastatin (10 mg/day) group (n = 37). Patient serum levels of IFN-gamma and IL-4 were measured at time of admission and 2 weeks after treatment. Peripheral blood mononuclear cells from patients of CHF group were cultured in the presence or absence of atorvastatin (0, 0.4, 1, and 4 micromol/L) in vitro, and IFN-gamma and IL-4 levels were detected. Serum levels of IL-12, IL-18, and IFN-gamma were significantly higher in the CHF group than in the control group. The levels of IFN-gamma and the ratios of IFN-gamma:IL-4 were significantly decreased with atorvastatin treatment both in vivo and in vitro, whereas levels of IL-4 did not differ significantly.'] Does atorvastatin modulate Th1/Th2 response in patients with chronic heart failure?