Increased Circulating Anti-inflammatory Cells in Marathon-trained Runners

Area of Science:

• Immunology
• Exercise Physiology
• Endurance Sports Medicine

Background:

• Exercise training significantly impacts immune function.
• Marathon training is linked to increased infectious and inflammatory disease risk, but mechanisms remain unclear.

Purpose of the Study:

• To compare circulating CD4+ T cell subsets in marathon runners versus non-marathon controls.
• Investigate potential immune mechanisms underlying altered disease susceptibility in endurance athletes.

Main Methods:

• Flow cytometry was used to measure CD4+ T cell subpopulations in 19 marathoners and 19 controls.
• Key subsets analyzed included T helper 1, T helper 2, regulatory T cells, CD4+ IL10+, and CD4+ TGFβ+.

Main Results:

• Marathon runners exhibited significantly lower T helper 1 and regulatory T cells compared to controls.
• Marathon runners showed significantly higher T helper 2, CD4+ IL10+, and TGFβ+ cells.
• A significantly lower T helper 1/T helper 2 ratio was observed in marathon-trained runners.

Conclusions:

• Endurance training, like marathon running, increases anti-inflammatory immune cells.
• This shift in immune cell populations may underlie the increased incidence of infectious and inflammatory diseases in endurance athletes.