1. Autoimmune Diseases:

2. The ability of your immune system to distinguish cells and antigens of your body from foreign cells and antigens is crucial to the fight against viral pathogens invading. In some people, the immune system can not distinguish between the body’s antigens and foreign antigens, causing an autoimmune disease. In an autoimmune disease the body launches an immune response attack against it’s own cells. It confuses it’s own cells for pathogens.

3. In an autoimmune disease, the body can not distinguish between it’s own cells and foreign viruses invading the body. The immune system can not tell the difference between it’s own antigens and antigens from outside the body. This affect may be caused by an incorrect production of antibodies specific to the antigens of the body cells. Antibodies may attack the body’s own tissues instead.

4. Autoimmune diseases affect organs and tissues in various areas of the body. For example, multiple sclerosis (MS) usually strikes people between 20 and 40. MS is generally thought to be an autoimmune disease. In people with MS, the immune system attacks and gradually destroys insulating materials surrounding nerve cells in the brain, in the spinal cord, and the nerves connecting the brain to the eyes.

5. Autoimmune diseases can attack many parts of the body, the list below names several of the most prevalent... Grave’s Disease – affects thyroid gland Multiple Sclerosis (MS) – affects nervous system Rheumatoid Arthritis – attacks joints Lupus – attacks connective tissue, joints, kidneys Type 1 Diabetes – attacks insulin producing cells in pancreas

6. Before 1981, AIDS, or acquired immunodeficiency syndrome, was unknown. Between 1981 and 2000, more than 448,000 Americans died of AIDS. Since than, the total number of people living with HIV in the United States has increased to more than 850,000. AIDS is a disease caused HIV, or the human immunodeficiency virus. AIDS QUILT Washington DC

7. Many scientists think HIV evolved from a virus similar to one that infects nonhuman primates in Africa. A mutation enables HIV to recognize a receptor protein called CD4 on some human cells. HIV usually invades Helper T cells, which began to produce HIV soon after infection. As Helper T cells die, the immune system gradually weakens and becomes overwhelmed by pathogens that normally it could destroy. The body becomes susceptible to other diseases, opportunistic infections, that usually would only cause minor illness in a normal immune system.

8. Antibodies to HIV can be detected in the blood. Someone whose blood contains antibodies to HIV is said to be HIV positive. A diagnosis of AIDS may be based on several criteria, including a Helper T cell count less than 200 cells/mL of blood. The number of T cells in a person who is HIV positive goes down steadily over a period of time after an infection sets in.

9. The time between an HIV infection and the onset of AIDS can exceed 10 years, and the time period is increasing as new treatments for HIV infection are developed. A person with HIV may feel and appear healthy but can infect many other people before the onset of the disease AIDS.

10. In the US, the number of deaths caused by AIDS has dropped from more than 38,000 in 1996 to about 22,000 in 1997, and to about 15,000 in the year 2000. This decrease does not reflect as much a decline in HIV infections, but rather more effective therapies which slow down the disease’s progression and thus death from it.

11. You can become infected with HIV if you come in contact with body fluids, including the blood, of an infected person. The most common method of HIV infection is through sexual contact. Use of a latex condom during sex reduces but does not eliminate the risk of getting HIV. Many people who have been infected with HIV do not even know that they have the disease.

12. HIV can also be passed between drug users who share needles because HIV infected blood often remains in the needle. In the early 80s when the AIDS epidemic first started, many cases occurred where patients became infected through tainted blood donations. Today, blood donations are carefully screened for signs of HIV virus. Another danger however is that pregnant or nursing mothers may pass on the HIV virus to infants through blood or nursing.

13. HIV is not transmitted through the air, on toilet seats, by kissing or handshaking, or by any other medium where HIV-infected white blood cells could not survive. Although HIV has been found in saliva, tears, urine, these body fluids contain too few HIV particles to cause an infection. Mosquitoes and ticks do not transmit HIV because they do not carry HIV-infected white blood cells.

14. Many health problems are caused by inappropriate responses of the immune system. An allergy is the body’s inappropriate response to a normally harmless antigen. Allergy causing antigens include pollen, residue from dust mites, fungal spores, and substances found in some food or drugs. Most allergic responses are merely uncomfortable but a few can be serious enough to endanger life if untreated.

15. Cells exposed to allergy causing antigens release histamine. Histamine causes swelling, redness, increased mucus production, runny nose, itchy eyes, and nasal congestion. Most allergy medicines contain antihistamines, which are drugs that block the action of histamines. Severe allergic reactions, such as asthma, can be life threatening if they are not treated immediately.