Acute experimental stress and white blood cells count in capillary blood

Recent studies in psychoneuroimmunology have shown alterations in the immune response of human subjects under acute experimental stressors. Activation of the sympathetic nervous system and the consequent release of catecholamines could be responsible for these changes, since catecholamines lead to transient changes in immune cells migration. The effects of acute psychological stress induced by two cognitive tasks (Stroop’s test and mental arithmetic) on white blood cells count in samples of capillary blood obtained by digital punctures were studied in 31 healthy young subjects. After the tasks, significant changes in self-reported emotional state and heart rate were observed. Nevertheless, there were not significant changes in differential leukocyte count. These results suggest that the percentage of leukocyte subpopulations in capillary blood may not be appropiate to measure the effects of an acute psychological stress.