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Indexed/Abstracted in: Chemical Abstracts, CINAHL, Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 1,111
Online ISSN 1827-1928
Rebelo A. N. 1, Candeias J. R. 2, Fraga M. M. 2, Duarte J. A. R. 1, Soares J. M. C. 1, Magalhaes C. 2, Torrinha J. A. 2
1 Faculty of Sport Sciences, University of Porto, Portugal;
2 Immunology Department, S. João Hospital, Porto, Portugal
Objective. The aim of this study was to evaluate whether the level of some immune markers changed in soccer players during pre-season and during playing-season.
Design. An observational study for one soccer season (one year).
Setting. Professional soccer players.
Participants. Thirteen professional soccer players (age: 26.3±3.7 years).
Measures. The effect of 11 months of soccer training sessions and matches on circulating leukocyte and lymphocyte subpopulations was investigated. Blood samples were taken before the season and also 6 weeks, 6 months and 11 months later. All samples were taken at 08:00h.
Results. Total lymphocyte counts did not change in all samples. During the pre-season, however, the concentrations of some inflammatory lymphocyte subpopulations were changed: CD4CD45RA+ was elevated and CD57 and CD8CD57 showed a significant decrease (p<0.05), At the end of the competitive period, CD4 and CD8 were increased. At the end of the season there were significant changes in some immune cells: total leukocyte and neutrophil number and CD8+ cell concentration was increased compared to pre-season values and the CD4/CD8 ratio was decreased.
Conclusions. The results suggest that athletes exposed to a long-term training periods can exhibit variations in some immune cells. The clinical significance of these variations requires more detailed investigation.