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Chronic granulomatous disease | |
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Classification and external resources | |
Superoxide
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ICD-10 | D71 |
ICD-9 | 288.1 |
OMIM | 306400 233690 233700 |
DiseasesDB | 2633 |
MedlinePlus | 001239 |
MeSH | D006105 |
Chronic granulomatous disease (CGD) (also known as Bridges–Good syndrome, Chronic granulomatous disorder, and Quie syndrome[1]) is a diverse group of hereditary diseases in which certain cells of the immune system have difficulty forming the reactive oxygen compounds (most importantly, the superoxide radical) used to kill certain ingested pathogens.[2] This leads to the formation of granulomata in many organs.[3] CGD affects about 1 in 200,000 people in the United States, with about 20 new cases diagnosed each year.[4][5]
This condition was first discovered in 1950 in a series of 4 boys from Minnesota, and in 1957 was named "a fatal granulomatosus of childhood" in a publication describing their disease.[6][7] The underlying cellular mechanism that causes chronic granulomatous disease was discovered in 1967, and research since that time has further elucidated the molecular mechanisms underlying the disease.[8] In 1986, the x-linked form of CGD was the first disease for which positional cloning was used to identify the underlying genetic mutation.
This section requires expansion. (May 2009) |
Chronic granulomatous disease is the name for a genetically heterogeneous group of immunodeficiencies. The core defect is a failure of phagocytic cells to kill organisms that they have engulfed because of defects in a system of enzymes that produce free radicals and other toxic small molecules. There are several types, including chronic X-linked disease, chronic b-negative disease, X-linked cytochrome b-positive disease, x-linked variant disease, and atypical granulomatous disease.[9]
Classically, patients with chronic granulomatous disease will suffer from recurrent bouts of infection due to the decreased capacity of their immune system to fight off disease-causing organisms. The recurrent infections they acquire are specific and are, in decreasing order of frequency:
Most people with CGD are diagnosed in childhood, usually before age 5.[10] Early diagnosis is important since these people can be placed on antibiotics to ward off infections before they occur. Small groups of CGD patients may also be affected by McLeod syndrome because of the proximity of the two genes on the same X-chromosome.[citation needed]
People with CGD are sometimes infected with organisms that usually do not cause disease in people with normal immune systems. Among the most common organisms that cause disease in CGD patients are:
Patients with CGD can usually resist infections of catalase-negative bacteria. Catalase is an enzyme that catalyzes the breakdown of hydrogen peroxide in many organisms. In organisms that lack catalase (catalase-negative), normal metabolic functions will cause an accumulation of hydrogen peroxide which the host's immune system can use to fight off the infection. In organisms that have catalase (catalase-positive), the enzyme breaks down any hydrogen peroxide that was produced through normal metabolism. Therefore hydrogen peroxide will not accumulate, leaving the patient vulnerable to catalase-positive bacteria.
Most cases of chronic granulomatous disease are transmitted as a mutation on the X chromosome and are thus called an "X-linked trait".[10] The affected gene on the X chromosome codes for the gp91 protein p91-PHOX (p is the weight of the protein in kDa; the g means glycoprotein). CGD can also be transmitted in an autosomal recessive fashion (via CYBA and NCF1) and affects other PHOX proteins. The type of mutation that causes both types of CGD are varied and may be deletions, frame-shift, nonsense, and missense.[14][15]
A low level of NADPH, the cofactor required for superoxide synthesis, can lead to CGD. This has been reported in women who are homozygous for the genetic defect causing glucose-6-phosphate dehydrogenase deficiency (G6PD), which is characterised by reduced NADPH levels.[citation needed]
Phagocytes (i.e., neutrophils and macrophages) require an enzyme to produce reactive oxygen species to destroy bacteria after they ingest the bacteria in a process called phagocytosis, a process known as the respiratory burst. This enzyme is termed "phagocyte NADPH oxidase" (PHOX). This enzyme oxidizes NADPH and reduces molecular oxygen to produce superoxide anions, a reactive oxygen species. Superoxide is then disproportionated into peroxide and molecular oxygen by superoxide dismutase. Finally, peroxide is used by myeloperoxidase to oxidize chloride ions into hypochlorite (the active component of bleach), which is toxic to bacteria. Thus, NADPH oxidase is critical for phagocyte killing of bacteria through reactive oxygen species.
(Two other mechanisms are used by phagocytes to kill bacteria: nitric oxide and proteases, but the loss of ROS-mediated killing alone is sufficient to cause chronic granulomatous disease.)
Defects in one of the four essential subunits of phagocyte NADPH oxidase (PHOX) can all cause CGD of varying severity, dependent on the defect. There are over 410 known possible defects in the PHOX enzyme complex that can lead to chronic granulomatous disease.[3]
The nitroblue-tetrazolium (NBT) test is the original and most widely known test for chronic granulomatous disease.[16][17] It is negative in CGD, meaning that it does not turn blue. The higher the blue score, the better the cell is at producing reactive oxygen species. This test depends upon the direct reduction of NBT to the insoluble blue compound formazan by NADPH oxidase; NADPH is oxidized in the same reaction. This test is simple to perform and gives rapid results, but only tells whether or not there is a problem with the PHOX enzymes, not how much they are affected. A similar test uses dihydrorhodamine (DHR) where whole blood is stained with DHR, incubated, and stimulated to produce superoxide radicals which oxidize DHR to rhodamin in cells with normal function. An advanced test called the cytochrome C reduction assay tells physicians how much superoxide a patient's phagocytes can produce. Once the diagnosis of CGD is established, a genetic analysis may be used to determine exactly which mutation is the underlying cause.[citation needed]
Management of chronic granulomatous disease revolves around two goals: 1) diagnose the disease early so that antibiotic prophylaxis can be given to keep an infection from occurring, and 2) educate the patient about his or her condition so that prompt treatment can be given if an infection occurs.[citation needed]
Physicians often prescribe the antibiotic trimethoprim-sulfamethoxazole to prevent bacterial infections.[18] This drug also has the benefit of sparing the normal bacteria of the digestive tract. Fungal infection is commonly prevented with itraconazole,[19] although a newer drug of the same type called voriconazole may be more effective.[20] The use of this drug for this purpose is still under scientific investigation.
Interferon, in the form of interferon gamma-1b (Actimmune) is approved by the Food and Drug Administration for the prevention of infection in CGD. It has been shown to reduce infections in CGD patients by 70% and to decrease their severity. Although its exact mechanism is still not entirely understood, it has the ability to give CGD patients more immune function and therefore, greater ability to fight off infections. This therapy has been standard treatment for CGD for several years.[21]
Hematopoietic stem cell transplantation from a matched donor is curative although not without significant risk.[22][23]
There are currently no studies detailing the long term outcome of chronic granulomatous disease with modern treatment. Without treatment, children often die in the first decade of life. The increased severity of X-linked CGD results in a decreased survival rate of patients, as 20% of X-link patients die of CGD-related causes by the age of 10, in contrast to an approximate age of 35 in autosomal recessive patients.[24]
CGD affects about 1 in 200,000 people in the United States, with about 20 new cases diagnosed each year.[4][5]
Chronic granulomatous disease affects all people of all races, however, there is limited information on prevalence outside of the United States. One survey in Sweden reported an incidence of 1 in 220,000 people,[25] while a larger review of studies in Europe suggested a lower rate: 1 in 250,000 people.[24]
This section requires expansion. (May 2009) |
This condition was first described in 1954 by Janeway, who reported five cases of the disease in children.[26] In 1957 it was further characterized as "a fatal granulomatosus of childhood".[6][7] The underlying cellular mechanism that causes chronic granulomatous disease was discovered in 1967, and research since that time has further elucidated the molecular mechanisms underlying the disease.[8] Use of antibiotic prophylaxis, surgical abscess drainage, and vaccination led to the term "fatal" being dropped from the name of the disease as children survived into adulthood.
Gene therapy is currently being studied as a possible treatment for chronic granulomatous disease. CGD is well-suited for gene therapy since it is caused by a mutation in single gene which only affects one body system (the hematopoietic system). Viruses have been used to deliver a normal gp91 gene to rats with a mutation in this gene, and subsequently the phagocytes in these rats were able to produce oxygen radicals.[27]
In 2006, two human patients with X-linked chronic granulomatous disease underwent gene therapy and blood cell precursor stem cell transplantation to their bone marrow. Both patients recovered from their CGD, clearing pre-existing infections and demonstrating increased oxidase activity in their neutrophils. However, long-term complications and efficacy of this therapy are unknown.[28]
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リンク元 | 「サイトカイン」「慢性肉芽腫症」「NADPHオキシダーゼ」「CGD」「慢性肉芽腫」 |
関連記事 | 「disease」「chronic」「granulomatous」「granulomatous disease」 |
機能 | サブグループ | サイトカイン | 標的 | 機能 |
炎症性サイトカイン | TNFファミリー | TNF-α | 白血球、上皮細胞 | 活性化 |
インターロイキン | IL-1 | 上皮細胞、リンパ球 | 活性化 | |
IL-6 | 種々の細胞 | 活性化 | ||
IL-8 | 白血球 | 炎症部位遊走 | ||
T細胞の増殖・分化 | インターロイキン | IL-2 | T細胞 | 活性化。増殖 |
IL-4 | T細胞 | 増殖 | ||
Th2細胞 | 分化誘導 | |||
IL-12 | Th1細胞 | 分化誘導 | ||
インターフェロン | IFN-γ | Th2細胞 | 分化抑制 | |
B細胞の増殖・分化 | インターロイキン | IL-2 | B細胞 | 活性化 |
IL-4 | B細胞 | 活性化、増殖、分化 | ||
IL-5 | B細胞 | 活性化、増殖 | ||
IL-6 | B細胞 | 増殖、分化 | ||
TGF-β | B細胞 | 分化(IgA分泌) | ||
アレルギー調節サイトカイン | インターロイキン | IL-3 | 肥満細胞 | 増殖、分化促進 |
IL-4 | B細胞 | IgEクラススイッチ促進 | ||
IL-5 | 好酸球 | 増殖、分化促進 | ||
IL-13 | B細胞 | IgEクラススイッチ促進 | ||
インターフェロン | IFN-γ | B細胞 | IgEクラススイッチ抑制 | |
走化性サイトカイン(ケモカイン) | CCケモカイン | MIP-1 | 好中球 | 遊走 |
MIP-2 | ||||
RANTES | 単球 | |||
CXCケモカイン | IL-8 | 好中球、リンパ球、好塩基球 | ||
SDF-1 | ||||
造血系サイトカイン | SCF | |||
インターロイキン | IL-7 | |||
erythropoietin | ||||
コロニー刺激因子 | GM-CSF | |||
G-CSF | ||||
M-CSF |
agent | clinical uses | |
aldesleukin | interleukin-2 | renal cell carcinoma, metastatic melanoma |
erythropoietin | epoetin | anemias (especially in renal failure) |
filgrastim | granulocyte colony-stimulating factor | recovery of bone marrow |
sargramostim | granulocyte-macrophage colony stimulating factor | recovery of bone marrow |
α-interferon | hepatitis B and C, Kaposi's sarcoma, leukemias, malignant melanoma | |
β-interferon | multiple sclerosis | |
γ-interferon | chronic granulomatous disease | |
oprelvekin | interleukin-11 | thrombocytopenia |
thrombopoietin | thrombocytopenia |
===uptodate
first aid step1 2006 p.89
[★] 慢性肉芽腫症 chronic granulomatous disease
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