IMMUNE-SYSTEM OF COLD-EXPOSED AND COLD-ADAPTED HUMANS

The aim of this study was to investigate whether or not the human immu ne system can be activated by a noninfectious stimulus, thereby improv ing the physiological status of the individual. The effect of a single cold water immersion (14 degrees C for 1 h) on the immune system of a thletic young men, monitored immediately after immersion, was minimal. With the continuation of the cold water immersions (three times a wee k for a duration of 6 weeks) a small, but significant, increase in the proportions of monocytes, lymphocytes with expressed IL2 receptors (C D25) and in plasma tumour necrosis factor alpha content was induced. A n increase in the plasma concentrations of some acute phase proteins, such as haptoglobin and haemopexin, was also observed. After 6 weeks o f repeated immersions a trend towards an increase in the plasma concen trations of IL6 and the amount of total T lymphocytes (CD3), T helper cells (CD4), T suppressor cells (CD8), activated T and B lymphocytes ( HLA-DR)and a decrease in the plasma concentration of alpha(1)-antitryp sin was observed. Concentrations of IL1 beta, neopterin, C-reactive pr otein, orosomucoid, ceruloplasmin, macroglobulin, immunoglobulins (IgG , IgM, IgA) and C3, C4 components of the complement, as well as the to tal number of erythrocytes, leucocytes, granulocytes and neutrophils s howed no significant changes after the repeated cold water immersions. It was concluded that the stress-inducing noninfectious stimuli, such as repeated cold water immersions, which increased metabolic rate due to shivering the elevated blood concentrations of catecholamines, act ivated the immune system to a slight extent. The biological significan ce of the changes observed remains to be elucidated.