The Stem Cell

Scientists have long sought the hematopoietic stem cell, the precursor cell that continuously replenishes the body's entire panoply of blood cells, both red and white. Stem cells represent a small portion of all bone marrow cells (perhaps one in 2,000), and they are even rarer in the bloodstream. In the mouse, implanting just a few purified stem cells can completely restore an immune system that has been experimentally destroyed.

Although the human stem cell has yet to be isolated and purified, scientists have discovered that progenitor cells capable of giving rise to an array of blood cells (if not of actually reproducing themselves) carry the cell surface marker CD34. These cells can be sorted out from marrow and blood with monoclonal antibodies that recognize CD34. In experimental programs, CD34 cells are being tested as long-lived vehicles for gene therapy and as an alternative to bone marrow transplants.

Immunoregulation Research

Research into the delicate and complex checks and balances that regulate the immune response is increasing knowledge of normal and abnormal immune functions. Someday it may be possible to treat diseases such as systemic lupus erythematosus by suppressing parts of the immune system that are overactive and stimulating those that are underactive. Blocking a mechanism such as co-stimulation, by paralyzing T cell responses, may make it possible to prevent graft rejection or to sideline autoimmune diseases, while boosting co-stimulation might help the body rid itself of cells that are infected or cancerous.

What depresses immune response?

• Long term courses of drugs: antacids (reduce nutrient assimilation), antibiotics (destroy friendly bacteria vital to GI immunity), anti-inflammatory drugs like acetaminophen, aspirin and ibuprofen (inhibit white cells that fight infection).
• Long term exposure to second hand smoke, chemicals and pollutants: which put a strain on the body's natural detoxification system and lead to genetic mutations that cause cancer.
• A diet high in chemicalized "foods in a box," so popular today: Your body regularly rejects or ignores these "nonfood" foods. Fake fats like olestra that rob cancer fighting carotenoids are especially disrupting.
• Repeated exposure to allergens: Allergens from foods and chemicals causes the immune system to take a dive because immune defenses are channeled to deal with the allergen rather than to fight infection. (In turn, allergies are usually the result of impaired immunity....a vicious health disrupting circle.)
• A diet high in trans fatty acids, saturated fats or refined sugars: Our food supply is loaded with them today....deep fried foods, fast foods, and almost all snack foods. Trans fatty acids increase LDL (bad) cholesterol and decrease HDL (good) cholesterol, and are found at high levels in women with breast cancer. Saturated fats interfere with prostaglandin E1 which regulates efficient Tcell activity. Sugary foods suppress immune white blood cell activity for a few hours after eating! Eat these foods regularly and your immune system may take a nose dive all day long!
• Low intake of protective, antioxidant and enzyme rich fruits and vegetables: Low nutrient intake not only depletes immunity. It also leads to a poor outlook on life or severe, long lasting depression.
• Excessive dieting depresses interferon activity: Overeating also depresses immune response.
• A lifestyle low on rest: People who overextend themselves may be unusually susceptible to immune system malfunction. Natural killer cell activity is reduced by as much as 28% when sleep is cut by 4 hours in clinical tests performed at U. California at San Diego School of Medicine.
• Having parents who smoke, drink to excess or abuse drugs: Children born to addicted parents have more genetic predisposition to illness and infections.
• Not being breastfed as a child: Breast milk is rich in antibodies, essential fatty acids and interferon that strengthen a child's developing immune system.