I thought this was a good description of P

[jiml]

EDIT By Fred: Mention of website removed.

What is an Autoimmune Disorder?

Your body's immune system is responsible for fighting what is perceived to be foreign invaders threatening your body's health: bacteria, viruses and fungi are just a few examples. Your good health depends partly on two important features of the immune system:

It should be able to recognize all tissues and organs within your body as "self" and therefore exempt them from attack by the immune system.
It should be able to identify foreign invaders as "other" to participate in their destruction and mobilize other parts of the immune system to participate in this attack.
Unfortunately, when you have an autoimmune disease, your body's immune system mistakenly confuses what is "self" with what is "other." Instead of protecting your body, the immune system produces cells and chemicals that attack your own body, causing damage and disease. Rheumatoid arthritis; some types of thyroid diseases; and anemia, lupus, celiac disease and type 1 diabetes are also autoimmune diseases.

Why is Psoriasis an Autoimmune Disorder?

As part of its defense against foreign invaders, your body's bone marrow and thymus gland collaborate to pump out specialized white blood cell warriors called "T cells." Under normal circumstances, T cells are programmed to identify and coordinate an attack on enemy combatants.

When you have psoriasis, T cells mistakenly identify your skin cells as "other" and attack them. This attack injures the skin cells, setting off a cascade of responses in your immune system and in your skin, resulting in skin damage (that is, swelling, reddening and scaling).

In an effort to heal, your skin cells begin reproducing rapidly. Activities that should take a month take place in only days, and abnormally large numbers of new skin cells push their way to the surface of your skin. This occurs so quickly that older skin cells and white blood cells aren't shed quickly enough. These discarded cells pile up on the surface of the skin, creating thick, red plaques with silvery scales on their surface: the hallmark of the classic form of plaque psoriasis.

A good description