and healing successfully. Conversely, a person can be well (not diseased) but still be unhealthy (cited Newberry et als., 1984). The importance of Weiner's construct between disease and illness in crucial to this argument, as it raises the issue of behaviour as an outcome variable in stress-disease studies (Newberry et als., 1984). The immune system constitutes a major defense against infectious organisms and possibly, to a lesser extent, against cancer. It is now beyond dispute that the immune system is affected by neuroendocrine factors and stress-related psychologic variables (Newberry et als, 1984). For this reason, and because of its role in host resistance to numerous disorders, the immune system has received a great deal of attention as a possible mediator of the stress-disease relationship (Newberry et als, 1984). It is the immune system which protects the body from disease organisms and other foreign bodies, known as antigens. The first line of defense are local barriers such as the skin, peritoneum, etc, and inflammation due to immunoglobulins, or antibodies. If these fail to block or destroy the antigens, the cell-mediated immune and humoral immune responses takes over (Gallagher, Gilder, Nossal and Salvatore, 1995). The cell-mediated responses use sensitised T cells (white blood cells derived in the thymus) to recognise, attach to, and render antigens inactive. Other types of T cells, called helper T cells, aid in production of antibodies by B (bone marrow) cells, and suppressor/cytotoxic T cells, (which inhibit that production), are also essential for proper immune system function. Helper T cells are known as CD4 cells, and suppressor T cells are known as CD8 cells (Kiecolt-Glaser, Cacioppo, Malarkey and Anderson, 1992). Immunocompetence is the degree to which the immune system is active and effective (Rice, 1999), and it is the ineffectiveness of the immune system which is used to measure, in this discussion, the inter...
