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[JJ World] Do Bacteria or Viruses Cause MS?

Do Bacteria or Viruses Cause MS?

by C.

Article Date: 07-08-05

The origins of multiple sclerosis apparently lie in an abnormal assault by

the body's immune system against certain parts of the central nervous

system,

which include the brain and spinal cord.1

Similar Proteins Targeted?

Though it hasn't been clear as to the cause of this immune system miscue, a

new study from Switzerland suggests that a certain bacterium or virus may

be

the culprit.2 These bacterial infections, the Swiss study team claims,

induce a kind of self-recognition that may contribute to some autoimmune

diseases

such as MS and Guillain-Barre syndrome (GBS).

These organisms produce an infection that may stimulate the production of

antibodies that make up the immune system, as well as immune cells known as

T-cells. The theory is that the immune cells target bacterial proteins that

closely resemble the body's own proteins, leading to crossreactivity with

healthy

tissues.

Alternative Theory

However, in the latest study, Gennaro de Libero, MD, at University Hospital

in Basel, Switzerland, and his associates identified another possible

mechanism. In this case, bacterial infections may promote activation of T

cells that

recognize special molecules present in bacteria and humans known as

glycosphingolipids (gly-koh-sfin-goh-LIH-pids), or GSL. The research team

showed

that infection with some bacteria or even exposure to pieces of the outer

wall

of the bacteria results in an increase in T-cell response to these

molecules.

" This stimulation may contribute to inflammatory responses during bacterial

infections and may predispose individuals to autoimmune diseases, " de

Libero's team wrote. It's an important mechanism that leads to autoreactive

T-cell

activation in the immune system, and may take part in the origins of many

other autoimmune diseases, de Libero explained.

The investigators theorize that although autoreactive T-cells may play a

beneficial role in promoting the response to infection in the body, in the

absence of infection, these T-cells might instead seek out the abundant GSL

molecules found in the central nervous system, resulting in the damage to

tissue

in that part of the body seen in people with _MS_

(http://www.msneighborhood.com/content/understanding_ms/what_is_ms.aspx) .

Another disease in which this mechanism may be found includes Guillain-Barr

syndrome (GBS), " in which the anti-GSL T-cell response may be important, "

de

Libero explained.

No Definite Conclusions Yet

Other research has focused on the possible role of disease-causing

organisms

as an underlying source of MS. For instance, in 2003, Spanish researchers

assessed the levels of antibodies that were associated with three

pathological

organisms in the blood samples taken from a group of people with MS.3

The study team found " a strong association " between antibodies against

human

herpesvirus type 6 (anti-HHV-6), one of the many herpesviruses, and the

early stages of _multiple sclerosis_

(http://www.msneighborhood.com/content/understanding_ms/what_is_ms_1421.aspx)

, particularly in those with the relapsing

form of the disease. Antibodies against Epstein-Barr virus were also linked

with MS in these patients, the study team noted.

In a review paper on the subject,4 doctors at Wayne State University in

Detroit reviewed previous studies that suggested a link between MS and

certain

bacterial or viral infections. However, they found many inconsistent

observations, writing that " no conclusion is possible at this point " .

1. National Multiple Sclerosis Society. What is Multiple Sclerosis?

Available at: http://www.nationalmssociety.org/What%20is%20MS.asp.

2. De Libero G, Moran AP, Gober HJ et al. Bacterial infections promote T

cell recognition of self-glycolipids. Immunity 2005 Jun;22(6):763-72.

3. Villoslada P, Juste C, Tintore M et al. The immune response against

herpesvirus is more prominent in the early stages of MS. Neurology 2003 Jun

24;60(12):1944-8.

4. Swanborg RH, Whittum-Hudson JA, Hudson AP. Infectious agents and

multiple

sclerosis—are Chlamydia pneumoniae and human herpes virus 6 involved? J

Neuroimmunol 2003 Mar;136(1-2):1-8.

is a long-time health journalist and an editor for Priority

Healthcare. His credits include overseeing health news coverage for the

website

of Fox Television's The Health Network, and articles for the New York Post

and

other consumer and trade publications.

_What is MS?_

(http://www.msneighborhood.com/content/understanding_ms/what_is_ms.aspx)

_How MS Makes You Sick_

(http://www.msneighborhood.com/content/understanding_ms/what_is_ms_1421.aspx)

_Disease Course and Progression_

(http://www.msneighborhood.com/content/understanding_ms/what_is_ms_1926.aspx)

_More on Bacteria/Viruses' Possible Role in MS_

(http://www.nationalmssociety.org/Sourcebook-Etiology.asp)

_National Institutes of Health_

(http://www.ninds.nih.gov/disorders/multiple_sclerosis/multiple_sclerosis.htm)