Re: Deficiency of immune system 'peacekeeper' pinpointed in mice as cause of ulc

[Guest guest]

>

> Please help me understand something. The article says...

>

> researchers have linked ulcerative colitis in mice to a deficiency of

> a molecular " peacekeeper " in the immune system, allowing harmful

> bacteria in the large intestine to breach the bowel's protective

> lining and trigger damaging inflammation.

>

> To me a " deficiency of molecular " in the immune system means that if

> the immune system was stronger, the body would not allow ( " allowing

> harmful bacteria in the large intestine " ) to enter our body.

>

> My question is this... why do the doctor's prescribe immune

> suppressing drugs?? Doesn't it just feed into the deficiency?? Am

> I missing something?

The deficient molecule, T-bet, suppresses the immune system's release

of TNF-alpha. When not suppressed, overproduction of TNF-alpha results

in the death of cells lining the intestinal, allowing bacteria to

break through and further stimulate the production of TNF-alpha.

Immune suppressing drugs are an attempt to restore the proper balance

in the immune system. As explained in the article:

" The key to maintaining this mucosal barrier, the scientists

discovered, is the " peacekeeper " activity of T-bet in the dendritic

cells of the intestine's immune system. When T-bet is at normal

levels, the boundary - a kind of demilitarized zone - remains intact

and prevents trouble from pathogenic bacteria. But if T-bet is

insufficient, the dendritic cells overproduce a powerful chemical

called TNF-alpha (tumor necrosis factor-alpha) that triggers

inflammation and causes normal cells to die. In ulcerative colitis,

the T-bet-related excess of TNF-alpha leads to the death of cells

making up the epithelial barrier of the colon, enabling harmful

bacteria to chronically inflame the intestinal wall. "

Hope that helps,

Tim R