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Immune dysregulation in the aging human lung
K C Meyer1, W Ershler, N S Rosenthal
1Department of Medicine, University of Wisconsin Medical School, Madison 53792-3240, USA.
Summary
Aging lungs show signs of immune changes and inflammation even in healthy individuals. This study found increased immune cells and inflammatory markers in older adults, suggesting age-related respiratory tract alterations.
Area of Science:
- Immunology
- Pulmonology
- Gerontology
Background:
- Aging is linked to reduced lung function and higher infection risk.
- Immune dysregulation and inflammation may occur in the aging lung.
- The respiratory tract's immune status in healthy aging individuals requires further investigation.
Purpose of the Study:
- To investigate age-related changes in immune and inflammatory markers in the lower respiratory tract.
- To compare these markers across different adult age groups in clinically normal volunteers.
Main Methods:
- Bronchoalveolar lavage (BAL) was performed on three age groups: 20-36, 45-55, and 65-78 years old.
- BAL fluid was analyzed for immunoglobulin (IgG, IgA, IgM), albumin, and interleukin-6 (IL-6).
- Cellular profiles, cell surface antigen expression, superoxide anion production, and lymphocyte subsets (CD4+/CD8+) were measured.
Main Results:
- The oldest group showed increased total cells, neutrophils, and immunoglobulin levels in BAL fluid.
- Lymphocyte subset ratios (CD4+/CD8+) were higher in both blood and BAL fluid in older adults.
- BAL cells from older individuals exhibited increased superoxide anion production, and IL-6 levels were elevated.
Conclusions:
- Asymptomatic, clinically normal older adults exhibit altered inflammatory cell profiles in their lower respiratory tracts.
- Evidence suggests the presence of low-grade inflammation in the aging lung.
- These findings indicate age-associated immune changes in the respiratory system of healthy individuals.