This unit examines the relationship between the mind and the immune system. Recent findings have resulted in a new sub- specialty of medicine known as PNI, psychoneuroimmunology. It recognizes the mind-body connection in health and disease.
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I. SUPPORT GROUPS AND BREAST CANCER SURVIVAL
In the mid-1970s, David Spiegel, a psychiatrist at Stanford University led support groups for women being treated for advanced breast cancer that had metastasized to other sites in the body. (My note: when breast cancer is confirmed by tissue biopsy, the primary tumor is removed surgically. Oncologists, the doctors who deal with cancer then frequently prescribe adjuvant chemotherapy and on occasion--radiation to kill cancer cells that may have spread beyond the primary tumor. With breast cancer, if it recurs later, it tends to appear in the lungs, liver, brain, and most frequently--bone. Prognosis is more serious with spread to distant sites--which is called metastasis.)
The focus of Dr. Spiegel's study was to affirm the importance of support groups in dealing with day to day problems. Short term findings demonstrated that the groups were a success; the participation in support groups did improve the women's quality of life.
Years later, he went back to these women's records to disprove a popular contention that emotional factors could influence the course of cancer. To his surprise, the women in support groups survived twice as long as non-support group women. It was evident that states of mind can affect physical health. (My note: being successfully married helps, too. Married people live longer that persons who are single, widowed, or never married. Beyond marriage, it is found that women with supportive women friends do better than loners. Women gain more support from other women than they do from their husbands. Men gain more from female companionship than they do from their male cronies. Pets are helpful, too. Dogs are especially helpful. Persons who are religious do better than the non-religious. Being socially connected helps! )
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II. CONDITIONING THE IMMUNE SYSTEM
Tests on rats by Robert Ader at Rochester University have convincingly shown that aspects of the immune system can, in fact, be conditioned just like Pavlov's dog. You will recall in those classic experiments that the Russian investigator rang a bell when food was given to dogs. Later, when he rang the bell without providing food, the dogs salivated anyway. This learned response is called conditioning.
What Ader did was this: he gave rats the immune-suppressing drug cyclophosphamide along with saccharin-flavored water. In due course, the immune systems of the rats weakened, and some rats died of infection. As part of his study, he then gave surviving rats just the saccharine flavored water. The interesting finding ws that the rat's immune system reacted as though they were getting the cyclophosphamide alone. To his surprise, he discovered that classical conditioning had triggered a learned association between the taste of saccharin and the immune system.
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III. THREE LINES OF EVIDENCE
The evidence can be organized into three categories. First is physiological research. This dates back to Walter Cannon and Hans Selye. Their work is described at length in the McElroy/Townsend text. Cannon discovered the 'fight or flight' response of the autonomic nervous system response to stress during World War I. Selye had studied the physical changes that go along with psychological stress. Epidemiological studies in this field look for relationships between psychosocial factors and patterns of illness in large populations. Studies by the Navy showed that men who had gone through serious life changes--a divorce, a major move, job loss, or the like--had an increased chance of becoming seriously ill within months following these upsets. These observations led to more recent studies of why strong social networks are linked to better health.
A third line of evidence is clinical research. Promising results have been demonstrated in people who have severe coronary heart disease. Actual reversal of atherosclerosis has been demonstrated without the use of medication in groups of people who have made significant life style changes.
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There is now a great deal of evidence for direct connections between the central nervous system and the immune system. Until recently, these parts of the body had been viewed as independent. Nerve endings have now been found in the organs and systems of the immune system. These include the thymus, lymph nodes, spleen, and bone marrow. The immune system cells respond directly to chemical signals produced by the nervous system and released by it into the bloodstream.
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IV. THE IMMUNE SYSTEM AND HOW IT WORKS
This was a difficult unit to prepare for you. The immune system involves advanced complex cellular systems and molecular biology. On the one hand, we need to cover enough to give you the basics. On the other hand, we need to avoid getting lost in detail that really belongs in a biologically oriented medical program. With these thoughts in mind, we begin.
The immune system is a network of cells and organs that work together to defend the body against attacks by 'foreign' invaders. These invaders are primarily germs--tiny infection- causing organisms such as bacteria, viruses, parasites and fungi. It is the immune system's job to keep them out, or seek them out and destroy them.
The organs of the immune system are positioned throughout the body. They are called lymphoid organs because they are the home of the lymphocytes, small white cells that are the key players in the immune system. Lymphocytes are initially produced in the bone marrow. One set of lymphocytes, the T-cells, spend time early in their development in the thymus. There they mature and develop the ability to distinguish between self and nonself. While lymphocytes travel throughout the body, small armies of these cells are kept at the alert in the lymph nodes and the spleen--which have specialized compartments for different kinds of immune system cells. Now, note this sentence well; all of these immunologial organs have now been shown to contain networks of nerve cells, which provide a pathway for the brain and central nervous system to influence immunity.
At the heart of the immune system is the remarkable ability to distinguish between the body's own cells--self--and foreign cells--nonself. Anything that can trigger this immune response is called an antigen. Bacteria, a virus. cells or tissues from another person carry nonself markers and act as antigens. Autoimmune disease results when the immune system can mistake self for nonself and attack the host. Some forms of arthritis and diabetes are autoimmune diseases. So is lupus. In other cases, the immune system response inappropriately to seemingly harmless substances such as ragweed pollen or cat hair. A common result is and allergy. Most autoimmune diseases are far more common in women than in men.
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The immune system and the nervous system are linked in several ways. We have mentioned that nerve endings innervate immune system tissues. Another well known connection involves the adrenal glands. In response to stress messages from the brain, the adrenal glands release hormones into the blood. In addition to helping a person respond to emergencies by mobilizing the body's energy reserves, these 'stress hormones' can stifle the effects of antibodies and lymphocytes. Hormones and other chemicals known to convey messages among nerve cells have been found to 'speak' to cells of the immune system. Indeed, some immune cells are able to manufacture typical nerve cells products, while some lymphokines can transmit information to the nervous system. What is more, the brain may send messages to the immune system by connecting nerves. The immune and nervous systems function together to maintain health and are not the separate entities as was believed for many years.
..... CJ '98
Resources
Goleman, D. and Gurin, J. Mind-Body Medicine. Yonkers: Consumers Union, 1993.
Schindler, L. The Immune System-How it Works. NIH Publication #94-3229, Washington: National Iinstitutes of Health, 1993.