NEW YORK (Reuters Health) - Chickenpox may seem only a scourge of
childhood, but new research suggests that infection with the chickenpox virus
somehow protects against the development of brain tumors later in life.
A few years ago, researchers came across an unexpected finding in a study
of patients with brain tumors called gliomas: patients were less likely than
healthy people to report having ever had chickenpox or shingles, another
condition caused by the chickenpox virus, varicella-zoster.
Now, in a new study delving deeper into the link, the investigators have
found that glioma patients are also less likely than people without the
cancer to have antibodies to varicella-zoster circulating in their blood.
Once a person has had chickenpox, varicella-zoster remains in the central
nervous system and years later can be reactivated to cause shingles, a
painful condition that affects the nerves and skin.
The 134 glioma patients in this study were 60% less likely than similarly
aged, healthy participants to have antibodies to varicella-zoster virus--an
indicator of past infection. By comparison, their rates of antibodies to
three other viruses in the same family as varicella-zoster (herpesviruses)
were similar to those among healthy participants, according to the report in
the July 15th issue of the American Journal of Epidemiology.
``We really don't know what it means,'' the study's lead author, Dr.
Margaret Wrensch of the University of California, San Francisco, told Reuters
Health.
In the original study, she explained, ``we just kind of stumbled on the
association'' between chickenpox history and glioma risk.
Now that this study gives more weight to the relationship, Wrensch noted,
more research will be needed to figure out why chickenpox infection--or lack
thereof--might play a role in glioma formation.
She speculated that varicella-zoster cells and developing glioma cells may
have some of the same antigens on their surfaces. Antigens are substances on
cell surfaces that draw an immune system attack. So a person who has had
chickenpox may have an immune system that is primed to fight gliomas ``before
they become dangerous,'' Wrensch suggested.
Other immune system factors may be at play as well. Wrensch noted that because
varicella-zoster is ``so ubiquitous''--most adults today have had
chickenpox--it is very unlikely that different exposures to the virus explain
the different rates of infection between glioma patients and people without
the brain tumors.
Gliomas are the most common of the tumors that can arise in the brain.
Although occupational exposure to certain industrial chemicals has been tied
to an increased brain cancer risk, little else is known about why brain
tumors develop.
Wrensch said there is growing interest in the role various viruses might
play.
SOURCE: American Journal of Epidemiology 2001;154:161-165.
ALL
INFORMATION, DATA, AND MATERIAL CONTAINED, PRESENTED, OR PROVIDED HERE IS FOR
GENERAL INFORMATION PURPOSES ONLY AND IS NOT TO BE CONSTRUED AS REFLECTING THE
KNOWLEDGE OR OPINIONS OF THE PUBLISHER, AND IS NOT TO BE CONSTRUED OR INTENDED
AS PROVIDING MEDICAL OR LEGAL ADVICE. THE DECISION WHETHER OR NOT TO
VACCINATE IS AN IMPORTANT AND COMPLEX ISSUE AND SHOULD BE MADE BY YOU, AND YOU
ALONE, IN CONSULTATION WITH YOUR HEALTH CARE PROVIDER.
"A foolish faith in authority is the worst enemy of truth."
-- Albert Einstein, letter to a friend, 1901
"I know of no safe depository of the ultimate powers of the society but the people themselves, and if we think them not enlightened enough to exercise control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion by education."
-- Thomas Jefferson, letter to William C. Jarvis, September 28, 1820
"What's the point of vaccination if it doesn't protect you from the unvaccinated?"
-- Sandy Gottstein
"Who gets to decide what the greater good is and how many will be sacrificed to it?"