Objective: To assess changes of interleukin 6 (IL-6) and interleukin 1 receptor antagonist (IL-1ra) in serum, sputum, and drained pleural fluid of patients operated on due to lung cancer.
Methods: Twenty-seven patients treated with lobectomy or pneumonectomy, including 14 with complications and 13 without complications, were analyzed. Serum IL-6 and IL-1ra concentration was measured before, at the end of surgery, and on postoperative day 1, 3, and 7, by ELISA test. Additionally, concentration of IL-6 and IL-1ra was measured in sputum at the end of surgery and in pleural fluid on postoperative day 1.
Results: In the entire group serum concentrations of IL-6 and IL-1ra were significantly elevated after surgery, in comparison with preoperative values. Serum IL-6 concentration was higher in patients with complications only on day 7 (median 59.0 (range: 41.25-76.65) pg/ml vs 21.5 (9.87-35.0) pg/ml; p=0.012). Patients with complications had higher concentration of IL-6 in pleural fluid (91312 (51812-94872) pg/ml vs 2006 (1926-2108) pg/ml; p=0.00008). Serum IL-1ra concentration was higher in patients with complications on day 1 (1832.4 (1144.7-2362.2) pg/ml vs 1088.4 (817.5-1312.5) pg/ml; p=0.01). Concentration of IL-1ra in drained fluid was higher in patients with complications (68128.8 (48104-108564) pg/ml vs 16470 (15930-16875) pg/ml; p=0.0003). On day 1 after surgery a significant correlation between serum and pleural fluid concentration for IL-6 as well as for IL-1ra were observed (Spearman test for IL-6: r=0.47; p=0.02; for IL-1ra: r=0.48; p=0.02).
Conclusions: Elevated concentrations of IL-6 and IL-1ra in pleural fluid on postoperative day 1 are promising early markers of postoperative complications. Elevated concentrations of IL-6 and IL-1ra in serum are good early markers of severity of surgical injury and may reflect development of postoperative complications.