Leucocytes, lymphocytes, activation parameters and cell adhesion molecules in middle-distance runners under different training conditions.

20 young male track and field runners (400 m-3000 m) with a 4 mmol/l lactic acid threshold of x = 4.97 +/- 0.35 m/s were tested after three different training periods: 1. at the end of a two month endurance training, practised nearly every day; 2. after a period of speed and strength training, which was specific with respect to their discipline, with anaerobic lactic energy production up to 15 mmol/l lactic acid; 3. during the competition period. The blood samples were taken at rest (4 p.m.) and 22 hrs after the last exercise. On the cell surface the antigens CD3+, CD20+CD23+, CD4+HLADR, CD4+CD25+, CD8+CD28+, CD4+CD45RO+, CD16+CD56+, CD54+ and in the blood serum the concentrations of s-IL-2-R, s-ICAM-1 were analysed. 13 students of physical education served as a control group. The main results were: Only at the end of the endurance training period (1) an increase of s-ICAM-1 was found, which may be interpreted as a protective mechanism against infections. Compared with the control group CD20+CD23+ antigen was constantly elevated and during the transition from the training to the competition period the CD4+CD45RO+ subset increased. These results may provide evidence for a connection to a susceptibility to allergic disease and to overtraining. Furthermore, an activation of the specific immune system was indicated by an elevation of the s-IL-2-R and an activation of the monocytic-phagocytic system was shown by increased levels of ICAM-1. The importance of these results for the training process and with regard to susceptibility to infections is discussed.