Immunological patterns during regular intensive training in athletes: quantification and evaluation of a preventive pharmacological approach.

The effects of regular intensive exercise training on immune system homeostasis and the potential value of treatment with an immunostimulating agent were assessed in this randomized, double-blind, placebo-controlled, parallel-group study. A total of 60 athletes were studied over a 3-month period of regular intensive physical activity. After 1 and 3 months there were significant decreases in the immunoglobulin levels in the whole athlete population compared with baseline values. Specifically there were significant decreases in immunoglobulin M and immunoglobulin G (G1 and G2 subclasses). There was also a significant decrease in natural killer cells and a slight but significant increase in B and T lymphocytes. In the thymomodulin-treated group, unlike the placebo group, there was no significant decrease in the immunoglobulin G2 subclass and there was a significant increase in the T-helper cell subpopulation. The clinical relevance of these immunological findings should be evaluated in larger clinical and epidemiological studies.