Biology Reference
In-Depth Information
5
Role of the Sympathetic Nervous
System in Immunity
Jaclyn W. McAlees‚ Virginia M. Sanders
Department of Molecular Virology, Immunology and Medical Genetics,
The Ohio State University Columbus, OH
5.1 Early Evidence for Nervous System-Immune System
Communication
Early in the history of medicine, it was noted that disease development and/or pro-
gression was associated with a change in an individual's behavior, which was often
induced by life circumstances and/or environment. Because behavior was associated
with the nervous system and certain diseases were associated with the immune sys-
tem, clinicians believed that one system could influence the other. However, finding
definitive proof for such an association took almost a century of research. One of the
earliest studies to suggest that a relationship might exist between the immune status
of an individual and his or her behavioral state was a 1919 study, which reported that
one's mental state was associated with the incidence of tuberculosis infections
[1]
.
In 1925, another study reported that inducing a state of fatigue in rabbits increased
disease susceptibility to, and mortality from,
Streptococcus pneumoniae
[2]
. In 1936,
Selye
[3,4]
described a myriad of structural changes that occurred in various organ
tissues during the biological response to stress, including the appearance of lymphoid
organ atrophy. By 1960, studies were specifically designed to show the existence of
an association between the psychological and immunological profiles of individuals
afflicted with rheumatoid arthritis, which is an immune-mediated disease
[5,6]
. The
scientific basis for a possible association between behavior and immunity remained
unknown until more data accumulated to show that the behavior associated with
disease states, as referred to in the earlier studies, could affect, and be changed by,
the activity of cells within the immune system. Therefore, these early studies pro-
vided a basis for the suggestion that changes in behavior might influence the level of
immunity, which subsequently would affect the development and/or progression of
disease. If true, then some mechanism had to exist by which the center for coordinat-
ing behavior, that is, the brain, influenced the center for coordinating health, that is,
the immune system. It then took almost 15 years for a series of experiments to be
designed to prove that such a connection truly exists.
