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Helminthic therapy, an experimental type of immunotherapy, is the treatment of autoimmune diseases and immune disorders by means of deliberate infestation with a helminth or with the ova of a helminth. Helminths are parasitic worms such as hookworms, whipworms, and threadworms that have evolved to live within a host organism on which they rely for nutrients. These worms are members of two phyla; Nematoda, which are primarily used in human helminthic therapy, and Platyhelminths.〔 Helminthic therapy consists of the inoculation of the patient with specific parasitic intestinal nematodes (helminths). A number of such organisms are currently being investigated for their use as treatment including: ''Trichuris suis'' ova (TSO),〔(【引用サイトリンク】title=Ovamed )〕 commonly known as pig whipworm eggs; ''Necator americanus'',〔(【引用サイトリンク】title=Helminthic therapy or worm therapy using human hookworm or whipworm. )〕 commonly known as hookworms; ''Trichuris trichiura'' ova,〔 commonly referred to as human whipworm eggs; ''Hymenolepis diminuta'', commonly known as rat tapeworm, cysticerci, ''Ascaris lumbricoides'' commonly known as human giant roundworm; ''Strongyloides stercoralis''〔〔 commonly known as human roundworm; ''Enterobius vermicularis''〔〔 commonly known as threadworm or seatworm; and ''Hymenolepis nana''〔〔 also known as dwarf tapeworm. Current research targets Crohn's disease, ulcerative colitis, inflammatory bowel disease (IBD), multiple sclerosis, and asthma. Helminthic infection has emerged as one possible explanation for the low incidence of autoimmune diseases and allergies in less developed countries, together with the significant and sustained increase in autoimmune diseases in industrialized countries.〔 == Incidence of autoimmune diseases and parasitic infestation == While it is recognized that there is probably a genetic disposition in certain individuals for the development of autoimmune diseases, the rate of increase in incidence of autoimmune diseases is not a result of genetic changes in humans; the increased rate of autoimmune-related diseases in the industrialized world is occurring in too short a time to be explained in this way. There is evidence that one of the primary reasons for the increase in autoimmune diseases in industrialized nations is the significant change in environmental factors over the last century. Environmental factors include exposure to certain artificial chemicals from industrial processes, medicines, farming, and food preparation. It is posited that the absence of exposure to certain parasites, bacteria, and viruses is playing a significant role in the development of autoimmune diseases in the more sanitized and industrialized Western nations. Lack of exposure to naturally occurring pathogens and parasites may result in an increased incidence of autoimmune diseases. Correlational data has shown the prevalence of helminthic infections to be greatest south of the equator where the rates of autoimmune diseases such as multiple sclerosis are low.〔(【引用サイトリンク】title=Intestinal Worms )〕 This is consistent with the hygiene hypothesis which suggests that helminthic infections protect individuals from developing auto-immune diseases rather than being an agent responsible for inducing them.〔〔 A complete explanation of how environmental factors play a role in autoimmune diseases has still not been proposed. Epidemiological studies such as the meta-analysis by Leonardi-Bee et al.,〔 however, have helped to establish the link between parasitic infestation and their protective role in autoimmune disease development. Genetic research on the interleukin genes (IL genes) shows that helminths have been a major selective force on a subset of these human genes. In other words, helminths have shaped the evolution of at least parts of the human immune system, especially the genes responsible for Crohn's disease, ulcerative colitis, and celiac disease—and provides further evidence that it is the absence of parasites, and in particular helminths, that has likely caused a substantial portion of the increase in incidence of diseases of immune dysregulation and inflammation in industrialized countries in the last century. A systematic approach was used to determine the relative pressure pathogens, such as helminths, viruses or bacteria exerted upon a selection of interleukin genes. Fumagalli et al. (2009) examined 52 globally dispersed human populations along with the diverse levels of pathogen richness, for >650,00 SNPs within 91 IL or IL receptor genes. Helminths were identified as a major selective pressure on a subset of IL genes. Through additional genome-wide association studies the subset of IL genes were associated with the human susceptibility to IBS and coeliac disease. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Helminthic therapy」の詳細全文を読む スポンサード リンク
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