title: Endurance exercise diverts the balance between Th17 cells and regulatory T cells.
abstract: Endurance, marathon-type exertion is known to induce adverse changes in the immune system. Increased airway hyper-responsiveness and airway inflammation are well documented in endurance athletes and endurance exercise is considered a major risk factor for asthma in elite athletes. Yet, the mechanisms underlying this phenomenon are still to be deduced. We studied the effect of strenuous endurance exercise (marathon and half-ironman triathlon) on CD4+ lymphocyte sub-populations and on the balance between effector and regulatory CD4+ lymphocytes in the peripheral blood of trained athletes, Endurance exercise induced a significant increase in Th17 cells and a sustained decrease in peripheral blood regulatory T cells (Tregs). While interleukin (IL)-2 levels remained undetectable, post-race serum IL-6 and transforming growth factor (TGF) β levels were significantly elevated. Treg levels in sedentary controls' decreased in vitro after incubation with athletes' post-exercise serum, an effect that was attenuated by supplements of IL-2 or anti IL-6 neutralizing antibodies. Our data suggest that exercise-induced changes in serum cytokine levels promote alterations in Tregs and Th17 cell populations, which may divert the subtle balance in the immune system towards inflammation. This may explain allergic and autoimmune phenomena previously reported in endurance athletes and contribute to our understanding of exercise-related asthma.
authors.affiliation: Department of Hematology and Bone Marrow Transplantation, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
authors.forename: Chava
authors.initials: C
authors.lastname: Perry
authors.forename: Marjorie
authors.initials: M
authors.lastname: Pick
authors.forename: Nir
authors.initials: N
authors.lastname: Bdolach
authors.forename: Inbal
authors.initials: I
authors.lastname: Hazan-Halevi
authors.forename: Sigi
authors.initials: S
authors.lastname: Kay
authors.forename: Idit
authors.initials: I
authors.lastname: Berr
authors.forename: Adi
authors.initials: A
authors.lastname: Reches
authors.forename: Yair
authors.initials: Y
authors.lastname: Harishanu
authors.forename: Dan
authors.initials: D
authors.lastname: Grisaru
mesh_terms: D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D016207:Cytokines / Q000097:blood; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D058504:Th17 Cells / Q000276:immunology*
chemical_list: D016207:Cytokines; D007376:Interleukin-2; D015850:Interleukin-6