Chronic obstructive pulmonary disease and emphysema are common destructive inflammatory diseases that are leading causes of death worldwide. Here we show that emphysema is an autoimmune disease characterized by the presence of antielastin antibody and T-helper type 1 (T(H)1) responses, which correlate with emphysema severity. These findings link emphysema to adaptive immunity against a specific lung antigen and suggest the potential for autoimmune pathology of other elastin-rich tissues such as the arteries and skin of smokers.

BackgroundChronic obstructive pulmonary disease and emphysema are a frequent result of long-term smoking, but the exact mechanisms, specifically which types of cells are associated with the lung destruction, are unclear.Methods and FindingsWe studied different subsets of lymphocytes taken from portions of human lungs removed surgically to find out which lymphocytes were the most frequent, which cell-surface markers these lymphocytes expressed, and whether the lymphocytes secreted any specific factors that could be associated with disease. We found that loss of lung function in patients with chronic obstructive pulmonary disease and emphysema was associated with a high percentage of CD4+ and CD8+ T lymphocytes that expressed chemokine receptors CCR5 and CXCR3 (both markers of T helper 1 cells), but not CCR3 or CCR4 (markers of T helper 2 cells). Lung lymphocytes in patients with chronic obstructive pulmonary disease and emphysema secrete more interferon gamma—often associated with T helper 1 cells—and interferon-inducible protein 10 and monokine induced by interferon, both of which bind to CXCR3 and are involved in attracting T helper 1 cells. In response to interferon-inducible protein 10 and monokine induced by interferon, but not interferon gamma, lung macrophages secreted macrophage metalloelastase (matrix metalloproteinase-12), a potent elastin-degrading enzyme that causes tissue destruction and which has been linked to emphysema.ConclusionsThese data suggest that Th1 lymphoctytes in the lungs of people with smoking-related damage drive progression of emphysema through CXCR3 ligands, interferon-inducible protein 10, and monokine induced by interferon.

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