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Immune System and DHEA
DHEA
has been shown to enhance the immune response against a wide range of viral,
bacterial and parasitic pathogens.
Clinical studies have reported
that DHEA helps regulate the immune system and may play a role in the
prevention and treatment
of certain auto-immune diseases.
It is suggested by some
textbooks and review articles that DHEA can stimulate the immune system.
It is in the field of
immunology that DHEA has perhaps shown its most broad-spectrum positive
action.
Clinical Studies
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In one animal study, DHEA supplementation
showed a significant reduction in the level of internal parasites
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A recent study found a strong inverse
correlation between human serum DHEA-S levels and interleukin 6 (IL-6)
levels.
IL-6 is one of many cytokines, or immune cell "quasi-hormones,"
which collectively regulate immune activity. High interleukin levels are
implicated as a causal factor in many diseases, such as rheumatoid
arthritis, osteoporosis, B-cell cancers, atherosclerosis and Parkinson's
disease. Interleukin 6 levels tend to dramatically increase with aging,
just as DHEA-S levels decrease with aging. After studying 120 healthy
human subjects, 15-75 years of age, R.H. Straub and colleagues concluded:
"decreased DHEA serum concentrations during aging or inflammatory diseases
will be paralleled
by a significant increase in interleukin production.
Thus, we conclude that the decrease in DHEA levels is a deleterious
process, in particular during chronic inflammatory diseases."
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O.Khorram, L.Vu and S.S.C. Yen, long-time DHEA
researchers, published an important DHEA study in 1997.
Nine healthy
"age-advanced men" (mean age: 63) were given 50 mg DHEA daily for 20 weeks
after 2 weeks' placebo treatment. They noted that the study demonstrates
the stimulatory effects of DHEA on the immune function of age-advanced
men. DHEA rejuvenated the immune system by increasing the secretion of
IL-2, a potent T-cell growth factor, increasing the number of cells
expressing the IL-2 receptor, and enhancing T cell responsiveness to
mitogen stimulation.
All of which decline during physiologic aging. The
significant increase in NK [natural killer] cell cytotoxicity in DHEA
treated subjects was potentially related to the increased number of NK
cells, both events being mediated by DHEA-induced IL-2 stimulation. There
were no adverse effects noted with DHEA administration.
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In a recent study with eleven postmenopausal
women, P.R. Casson and co-workers administered 50 mg DHEA daily in a
double-blind crossover study. They reported that "The major finding in
this study was the dramatic enhancement in natural killer cell activity.
This natural killer cell enhancement was seen in each of the 11 subjects.
In this study DHEA appeared to suppress the unexplained increase in
stimulated interleukin production seen in the placebo group" Natural
killer cells are a key part of the immune stystem. They are (ideally) in
constant surveillance mode, looking especially for viruses and cancer
cells to destroy.
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Various abnormalities of immune system function
have been described in the elderly. Among them, increased concentrations
of neopterin have been reported, which is produced by human
monocytes/macrophages upon stimulation by interferon-gamma. In order to
examine the relation of serum DHEA to serum neopterin, we studied 281
otherwise healthy outpatients, who visited the physician's office for a
medical health check-up. 10% presented with increased neopterin
concentrations, 0.4% had increased DHEA sulfate (DHEAs) concentrations.
DHEAs concentrations were significantly higher in patients with lower
neopterin concentrations (Mann-Whitney test: U=4793, P<0.0001). There
existed a rather strong inverse correlation between DHEAs concentrations
and serum neopterin concentrations (Spearman's rank correlation:
r(s)=-0.221, P<0.0001). The data support the concept that the decrease of
DHEA with increasing age is related to immune system activation.
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