Evaluation of interleukin-6 in bronchoalveolar lavage fluid and serum of patients with lung cancer

Increased levels of serum interleukin 6 (IL-6) are found in patients with l ung cancer, and it has been shown that this is part of a systemic inflammat ory response syndrome. This study was designed to measure IL-6 levels in br onchoalveolar lavage (BAL) fluid of patients with lung cancer and to descri be the relationship of BAL fluid IL-6 to the known systemic increase in IL- 6. Increased levels of BAL fluid IL-6 can be found in patients with lung ca ncer as compared with patients with chronic obstructive pulmonary disease w ho have acute infection (P =.007), In patients with cancer, no correlation between BAL fluid IL-6 and serum IL-6 was found (P =.8), BAL fluid IL-6 did not correlate with the number of lymphocytes or macrophages found in this fluid. BAL fluid IL-6 does not correlate with tumor size, Although serum IL -6 was higher in patients with extensive stage small cell lung cancer as co mpared with levels in patients with limited stage disease (P =.06), their c orresponding BAL fluid levels were not different (P =.9). Serum IL-6 correl ated with other acute phase reactants, This study thus demonstrates the fea sibility of utilizing BAL fluid analysis for local cytokine/tumor marker pr oduction in lung carcinoma. It also shows that a local increase in IL-6 in the BAL fluid is independent of the systemic inflammatory response syndrome , whereas the serum increase in IL-6 is part of this syndrome.