Immune system variations may underlie
differences in MS between African Americans and Caucasians
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Medical Update Memo
July 23, 2007
Summary
A new report shows differences
in immune system responses between a group
of African Americans
with MS compared with Caucasians. Previous research
had shown that clinical symptoms differ between
these groups, and the current findings may help
to explain why.
Details
Drs. John R. Rinker II,
Anne Cross (Washington University in St. Louis)
and colleagues have
published this study in the July 3 issue
of Neurology (2007;69:68-72).
Dr. Rinker was supported by a 2006-2007 Serono-Pfizer
Clinical Fellowship of the U.S. National MS Society.
Background: Generally,
the risk of MS in African Americans is around
half that of Caucasian
Americans. Researchers have previously reported
significant
differences in the clinical characteristics
of MS in African Americans and Caucasian
Americans: in that study, African Americans
tended to
have
a more aggressive course of disease, were
at higher risk for developing mobility impairments,
were
more likely to develop MS later in life,
and
were at higher risk for having symptoms restricted
to
the optic nerve and spinal cord (Neurology 2004;63[11]:2039-45).
Study and Results: The team sought to determine
if differences in the immune system which
launches an attack on the brain and spinal
cord in MS
underlie these clinical differences. They
reviewed the medical
records of 66 African Americans and 132 Caucasian
Americans with MS for whom results of cerebrospinal
fluid (CSF) tests were available. This test
is often given to help confirm the diagnosis
of
MS. The CSF of people with MS usually contains
elevated
levels of antibodies called IgG, as well
as a specific group of proteins called oligoclonal
bands. These
findings indicate an abnormal immune response
within the central nervous system.
The group found that IgG antibodies in the
spinal fluid were on average 29% higher in
African Americans
than in Caucasian Americans. The study also
confirmed previous reports that African Americans
tended
to need walking aids sooner than Caucasians
(on average, African Americans had MS for
nine years
before needing ambulatory assistance such
as a cane, compared to 17 years for Caucasians).
However,
the study did not find that higher antibody
levels could predict earlier need for ambulatory
assistance.
The authors caution that the results may
be affected by the fact that patients for
whom
CSF samples
were available may have had the test performed
to help diagnose unusual courses of MS such
as very mild or very aggressive forms. They
add
that the challenge facing researchers now
is to understand
how this increased immune response relates
to the differences in clinical symptoms.
ASK MS CODE: 2.3.aa
Adapted from National MS Society website
Disponible en français.
Disclaimer
The Multiple Sclerosis Society of Canada is an independent, voluntary health
agency and does not approve, endorse or recommend any specific product or therapy,
but provides information to assist individuals in making their own decisions.
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