 Th1 cytokines play a central role in inflammation and activation of macrophages, NK cells and neutrophils. Th2 cytokines inhibit Th1 immune response. This causes a systemic systemic inflammatory response syndrome. Also, toll-like receptors-2 TLR2 and -4 TLR4 play a crucial role in chronic obstructive pulmonary disease COPD. Their activation by LPS of Gram - and Gram bacteria leads to activation of neutrophils, NK cells, T-, B- cells and inflammatory cytokines. In chronic disease, dysregulated inflammation maintains these systems in a state of constant activation, potentially resulting in tissue damage and progressive disease. Understanding the TLR system should offer invaluable opportunity for manipulating host immune responses. 