Miller 1995b). support an strike against among the body’s very own tissues? What are the type and origin of the misguided immune system cells? It’s been preserved traditionally the fact that central anxious system is certainly exempt from physiological immune system mechanisms. How after that can we describe pathological autoimmune replies occurring inside the central anxious system? Both sets of questions should be answered to be able to understand the pathogenesis of multiple sclerosis convincingly. First, we describe the overall organization from the immune system, talk about systems that bring about autoimmune strike against self after that, and find out which of the mechanisms donate to the pathogenesis of multiple sclerosis. We consider the central anxious system tissue as a host for immune system reactivity. We examine the global circumstances that prevent or enable immune system replies in central anxious program tissue, and then particularly describe the transformed central anxious system agreements in the lesions of multiple sclerosis. The disease fighting capability may be the body’s primary defence power. It must drive back the many environmental microbial organisms and also against potentially cancerous cells arising within tissues of high cellular turnover. The immune system works as a formidable killing machine. It is designed to spot, encircle and neutralize any suspicious structure appearing in the body and threatening its well-being. In this context, suspicious means any material deviating from healthy self tissues. If immune cells lose their ability to distinguish suspicious foreign and intact self components, they may attack and damage normal tissues C and thus cause autoimmune disease. These are not rare and exotic afflictions, but count among the most important problems in clinical medicine. Autoimmune diseases together constitute the third-greatest clinical burden, after cardiovascular diseases and cancer (Nossal 2001). Autoimmunity may affect diverse organs, causing diseases ranging from rheumatoid arthritis, insulin-dependent diabetes mellitus, ulcerative colitis and systemic lupus erythematosus to multiple sclerosis. It should be stressed, however, that the autoimmune concept in multiple sclerosis lacks formal proof. However, it rests on several diverse lines of evidence, which, taken together strongly suggest that immunopathological events, which we presume to be of an autoimmune nature, are responsible for the occurrence and development of the disease. One of the strongest arguments in favour of an immune pathogenesis for multiple sclerosis comes from the morphology of its lesions. As detailed in Chapter TH5487 12, TH5487 the lesion in multiple sclerosis is characterized by perivascular round cell infiltration, and these accumulating lymphocytes spill into the surrounding parenchyma. Active lesions in multiple sclerosis are almost indistinguishable from areas of inflammation seen in diseases of proven autoimmune pathogenesis, especially models of experimentally induced autoimmune encephalomyelitis (EAE; see below). The second line of evidence supporting the autoimmune hypothesis is genetic and rests on the association of disease susceptibility with polymorphic genes that are potentially involved in autoimmune responses (see Chapter TH5487 3). The best-documented example is the major histocompatibility complex (MHC), whose class II products are required for the presentation of autoantigen to T lymphocytes and are, in addition, crucially involved in the development of the immune repertoire. Finally, the autoimmune pathogenesis of multiple sclerosis is endorsed by the relative success Rabbit Polyclonal to GSPT1 of therapies that suppress or modulate the immune response (see Chapter 18). For example, -interferon (IFN-) has a favourable effect in reducing relapse rates and decreasing lesion load as assessed by magnetic resonance imaging (MRI). The same is true for Copaxone (copolymer-1), which diverts myelin-reactive T cells from the pathogenic Th1 (T helper 1) profile to the regulatory Th2 (T helper 2) pattern. Finally, some antibodies that blindfold or eliminate activated T cells were found to be beneficial in clinical trials (von Andrian and Engelhardt 2003). IMMUNE RESPONSES: INNATE AND ADAPTIVE Evolution has provided two protective immune systems, the innate and the adaptive. Both share the ability to identify a potentially harmful external (or internal) structure, and then mount a response designed to neutralize this threat. At the same time, either type of response must be selective, meaning that the destructive potential TH5487 must be directed exclusively to the suspected target, while the body’s own tissues are completely spared. The two immune systems fulfil their tasks admirably well, although they use radically different principles. The innate immune response is phylogenetically old. It acts in worms and insects as well as mammals. It is fully preformed in the healthy organism. Its elements are present in the tissues irrespective of microbial threat. In stark contrast, the more modern adaptive immune system formed much later in evolution. It is only found in vertebrates. Adaptive immune responses only offer protection following a first encounter with a microbial target. This contact leads to a maximal response concentrated on the particular microbe, with the generation of killer cells or.