COPD as a Disease of Immunosenescence.

Although chronic obstructive pulmonary disease (COPD) is regarded as a chronic inflammatory lung disease, the disease mechanism is still not known. Intriguingly, aging lungs are quite similar to COPD-affected lungs in many ways, and COPD has been viewed as a disease of accelerated premature aging of the lungs. In this paper, based on a literature review, we would like to propose immunosenescence, age-associated decline in immunity, as a critical mechanism for the development of COPD. Immunosenescence can cause a low-grade, systemic inflammation described as inflammaging. This inflammaging may be directly involved in the COPD pathogenesis. The potential contributors to the development of inflammaging in the lungs possibly leading to COPD are discussed in the review paper. A notable fact about COPD is that only 15% to 20% of smokers develop clinically significant COPD. Given that there is a substantial inter-individual variation in inflammaging susceptibility, which is genetically determined and significantly affected by the history of the individual's exposure to pathogens, immunosenescence and inflammaging may also provide the answer for this unexpectedly low susceptibility of smokers to clinically significant COPD.