Toll-like receptor (TLR)4 expression on alveolar macrophages (AMs). The TLR4 expression did not differ before or after surgery in group 1 (n = 29) (P = 0.15). In group 2 (n = 3), TLR4 expression tended to be reduced (P not applicable (n/a)). Comparing the groups the baseline of TLR4 did not differ (P = 0.45). However, after surgery the TLR4 expression was significantly diminished in group 2 (P = 0.041). Box plots represent median and IQR; blue, values before surgery; green, values after surgery. The Wilcoxon test was used for dependent groups and the Mann–Whitney U-test for independent groups; *P <0.05.