Changes in the frequency of circulating type 1 helper T (Th1) cells and type 17 helper T (Th17) cells. Changes in the frequency of circulating Th1 and Th17 cells were not significantly different in the two groups (P = 0.126 and P = 0.740, respectively). Data are expressed as mean values with error bars of 95% CI. Post 1h = at 1 h postoperatively; Post 24h = at 24 h postoperatively; Preop = immediately before anesthesia induction.