Among healthy adults, shorter T-cell telomere length is associated with an increased risk of developing an upper respiratory infection after exposure to rhinovirus, according to results from a study published in the February 20 issue of JAMA.
The study, led by Sheldon Cohen, PhD, from Carnegie Mellon University, Pittsburgh, Pennsylvania, evaluated peripheral blood mononuclear cells and T-cell subsets in 152 healthy individuals aged 18 to 55 years between 2008 and 2011. Patients were exposed to a rhinovirus (RV39) via nasal drops and monitored for 5 days for development of upper respiratory infection (documented by virus shedding or 4-fold increase in virus-specific antibody titer) and/or signs of clinical illness.
Overall 105 (69%) participants developed an infection. The researchers saw an association between tertile of telomere length and infection rate in several cell populations, including peripheral blood mononuclear cells (odds ratio [OR] per 1-SD decrease in telomere length, 1.71; 95% confidence interval (CI), 1.08-2.72), CD4+ T cells (OR, 1.76; 95% CI, 1.15-2.70), CD8CD28+ T cells (OR, 1.93; 95% CI, 1.21 - 3.09), and CD8CD28 − T cells (OR, 2.02; 95% CI, 1.29 - 3.16).
Tertile of telomere length was also associated with greater risk for clinical illness in CD8CD28− cells (OR, 1.69; 95% CI, 1.01 - 2.84) but not in the other cell types. The overall rate of clinical illness was 22% (n = 33).
All logistic regression models were adjusted for prechallenge viral-specific antibody titer, age, body mass index, race, sex/contraceptive use (men, women taking contraceptives, women not taking contraceptives), season of exposure, and days between blood draw for telomere assay and viral challenge.
"We found that shorter telomere lengths in all 4 cell types were associated with greater odds of infection following experimental exposure to RV39. However, CD8CD28− telomere length had the largest association with infection," the authors write. "Further, only CD8CD28− telomere length was associated with clinical illness."
Researchers also found that older age was correlated to shorter CD8CD28− telomere length and increased risk for infection.
The authors acknowledge that there is a lack of data comparing CD8CD28+ and CD8CD28− cell function in light of rhinovirus infection, so these study findings are speculative. They note, however, that shorter telomeres indicate these cells are at or near their replicative sencence and have reduced proliferation in response to antigens.
"There has been the general observation that immune function is less robust, especially with advanced age," said Paul Auwaerter, MD, from the Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland, in an email interview with Medscape Medical News. "This is one of the first studies to examine responses to a pedestrian and self-limiting infection, especially in a younger population, as opposed to one of a more chronic nature such as [cytomegalovirus] or [human immunodeficiency virus]."
Other questions, however, such as "the significance of the shortening, and whether there are compensatory mechanisms carried out by other components of the immune system," remain to be answered, notes Dr. Auwaerter.
Funding for this study was provided by the National Center for Complementary and Alternative Medicine, the National Institute of Allergy and Infectious Diseases, the John D. and Catherine T. MacArthur Foundation's Research Network on Social Economic Status and Health, the Eberly Foundation, the Hamburg Fellowship, and National Institutes of Health funding to the University of Pittsburgh Clinical and Translational Science Institute. One author served as a consultant for and received grants/has grants pending from Janssen Research and Development. One author is a cofounder of and holds stock in Telomere Health Inc. The independent commentator and other authors report no relevant financial relationships.
JAMA. 2013;309:699-705. Abstract
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Cite this: Telomere Length Linked to Common Cold Risk - Medscape - Feb 19, 2013.
