Immunoregulation by neuroendocrine factors.

The influence of the pituitary gland and of steroid hormones on the lymphoid system was demonstrated experimentally over half a century ago. Observations indicating the possibility of behavioural modification of immunity were also made at about the same time. Although these initial observations were followed by numerous investigations, the lack of sufficient basic knowledge of the endocrine and immune systems and serious methodological difficulties led to contradictions from which no definite conclusions could be drawn. Thus, the idea of neurohormonal-immune interaction fell gradually into disrepute. The remarkable effect of corticosteroids and their analogues on the immune system was regarded as a pharmacological phenomenon, rather than a physiological mechanism. During the past decade, this area gradually again became one of the forefronts of biomedical investigation and recently a number of volumes have been published on the subject of neurohormonal-immune interactions. Because of space limitations, only a brief overview of the subject can be given below and the reader is referred to the cited literature for detailed information.