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Left brain surgery may lead to greater infection risk

26 May, 2004

A major
difference in the immune system between the opposite halves of the
human brain is reported in a study published in the journal the Annals of Neurology.

Researchers
have found that damage or surgery to the left half of the brain may
make a right-handed person more susceptible to infections and diseases
due to an improperly working immune system.

Study director Dr Kimford J Meador, of Georgetown University Hospital, said:

"These
findings raise the possibility that doctors need to be more aggressive
in protecting patients from infection following strokes or surgery on
the left side of the brain.'

Studies
of animals have shown distinct differences in how the two brain halves
are linked to the immune system and several years ago Meador and his
colleagues found preliminary evidence of similar differences in humans.

In
the present study, the researchers examined how the immune system
responded to surgery on either side of the brain, following the
progress of 22 epilepsy patients who had parts of their brain
surgically removed in an attempt to control their seizures.

Most
patients who had surgery on the left side of their brains experienced
significant decreases in immune function, with the immune system
reducing the numbers of lymphocytes and T-cells. By contrast, patients
who had surgery on the right side of their brains saw the levels of
their lymphocytes and T-cells significantly boosted.

The
researchers note that this may be true only for right-handed patients.
Although they did not have enough left-handed and ambidextrous people
in their study, they state that non-right-handed people could have the
opposite reaction or they might show equivalent responses to right and
left brain injuries.

Dr Meaford added:

"Even
with these results, we and others have examined only a small portion of
possible immune responses in regards to left/right brain influences.
Even more important, exactly how the brain alters immune response is
unclear. Future studies will need to address these issues.'