Natural killer (NK) cell activity and concentration of CD16+ cells (NK cells) and
CD20+ cells (monocytes) in peripheral blood were measured in highly trained racing
cyclists and in age- and sex-matched untrained controls. Median NK cell activity was
38.1% (range 20.0%-57.1%) in trained vs 30.3% (range 19.7%-43.1%) in untrained (P = 0.008). Median%CD16+ cells was 17% (range 7%-33%) in trained vs 11% (3%-29%) in
untrained (P = 0.007). Indometacin in vitro enhanced the NK cell activity in both groups. There
was, however, no significant difference between the NK cell activity in trained and
untrained after exposure to indomethacin in vitro. In-domethacin-enhanced NK cell
activity was 45.9% (range 24.4%-67.5%) in trained and 40.0% (range 23.9%-68.5%) in
untrained (P = 0.138). Mean%CD14+ cells was 8.3% (range 2%-15%) in trained vs 3.8% (2%-8%) in
untrained (P < 0.0001). The increased NK cell function thus demonstrated in highly trained persons
might result in better resistance against infectious disease.
Bicycle exercise - training - natural killer cells - immune system - lymphocytes -
monocytes
