Human leukocyte antigen-DR (HLA-DR) expression on alveolar macrophages (AMs). HLA-DR expression on AM in group 1 (n = 28) showed a significant reduction after surgery (P = 0.002). In group 2 (n = 3), HLA-DR expression was highly diminished after surgery not possible to calculate P value with only 3 patients. Comparing both groups the baseline had a tendency to be lower (P = 0.20) and the postoperative HLA-DR expression was significantly reduced in group 2 (P = 0.024). 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.