This article needs more reliable medical references for verification or relies too heavily on primary sources , specifically: It relies too much on primary sources.(June 2022) |
Anti-AQP4 disease | |
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Other names | Neuromyelitis optica spectrum of diseases |
Anti-AQP4 diseases, are a group of diseases characterized by auto-antibodies against aquaporin 4.
After the discovery of anti-AQP4 autoantibody in neuromyelitis optica, it was found that it was also present in some patients with other clinically defined diseases, including multiple sclerosis variants like optic-spinal MS. [1]
The collection of these condition has been named "anti-AQP4 disease" and "neuromyelitis optica spectrum disorders" (NMSD) and they are expected to respond to the same treatments as standard NMO. [2] [ failed verification ] Some authors propose to use the name "autoimmune aquaporin-4 channelopathy" for these diseases, [3] while others prefer a more generic term "AQP4-astrocytopathy" that includes also problems in AQP4 with a non-autoimmune origin. [4] [1] [5]
After finding the anti-AQP4 autoantibody in cases outside the standard Devic's disease course, the spectrum was expanded. The spectrum is now believed to consist of:
Devic's disease is currently considered a syndrome more than a disease, presenting an overlapping with the wide spectrum of multiple sclerosis in the form of Optic-Spinal MS. [10]
The reason for the presence of anti-AQP4 autoantibodies is currently unknown. Some researchers have pointed out that it could be paraneoplastic. [11] [ non-primary source needed ] It seems also clear that lupus can produce NMO-IgG autoantibodies sometimes, leading to some cases of lupus-derived NMO. [12] [ non-primary source needed ]
AQP4-Ab-negative NMO presents problems for diagnosis. The behavior of the oligoclonal bands respect MS[ clarification needed ] can help to establish a more accurate diagnosis. Oligoclonal bands in NMO are rare and they tend to disappear after the attacks, while in MS they are nearly always present and persistent. [13]
It is important to notice for differential diagnosis that, though uncommon, it is possible to have longitudinal lesions in MS. [14]
Other problem for diagnosis is that AQP4ab in MOGab levels can be too low to be detected. Some additional biomarkers have been proposed. [15] [16]
Currently, there is no cure for Devic's disease, but symptoms can be treated. Some patients recover, but many are left with impairment of vision and limbs, which can be severe.[ citation needed ]
Attacks are treated with short courses of high dosage intravenous corticosteroids such as methylprednisolone IV.[ citation needed ]
Plasmapheresis can be an effective treatment [8] when attacks progress or do not respond to corticosteroid treatment. Clinical trials for these treatments contain very small numbers, and most are uncontrolled, though some report high success percentage. [17]
Until recently, no placebo-controlled trials had established the effectiveness of treatments for the prevention of attacks. Most clinicians agree that long term immunosuppression is required to reduce the frequency and severity of attacks. Commonly used immunosuppressant treatments include azathioprine (Imuran) plus prednisone, mycophenolate mofetil plus prednisone, [18] [ non-primary source needed ] mitoxantrone, intravenous immunoglobulin (IVIG), Rituximab, Soliris and cyclophosphamide. [8] [19]
The disease is known to be auto-antibodies mediated, and (antibody-producing) B-cell depletion has been tried [20] with monoclonal antibodies showing good results. [21] [ non-primary source needed ] Several other disease modifying therapies are being tried. In 2007, Devic's disease was reported to be responsive to glatiramer acetate [18] [ non-primary source needed ] and to low-dose corticosteroids. [22] Use of Mycophenolate mofetil is also currently under research. [23]
Hematopoietic stem cell transplantation (HSCT) is sometimes used in severe cases of NMO. Early data suggested that then-practiced forms of HSCT were very effective only in the short term. [24] However, later study data had most patients thriving, with no relapses within 5 years. [25]
Optic neuritis describes any condition that causes inflammation of the optic nerve; it may be associated with demyelinating diseases, or infectious or inflammatory processes.
Transverse myelitis (TM) is a rare neurological condition wherein the spinal cord is inflamed. The adjective transverse implies that the spinal inflammation (myelitis) extends horizontally throughout the cross section of the spinal cord; the terms partial transverse myelitis and partial myelitis are sometimes used to specify inflammation that affects only part of the width of the spinal cord. TM is characterized by weakness and numbness of the limbs, deficits in sensation and motor skills, dysfunctional urethral and anal sphincter activities, and dysfunction of the autonomic nervous system that can lead to episodes of high blood pressure. Signs and symptoms vary according to the affected level of the spinal cord. The underlying cause of TM is unknown. The spinal cord inflammation seen in TM has been associated with various infections, immune system disorders, or damage to nerve fibers, by loss of myelin. As opposed to leukomyelitis which affects only the white matter, it affects the entire cross-section of the spinal cord. Decreased electrical conductivity in the nervous system can result.
Multiple sclerosis (MS) is an autoimmune disease in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This damage disrupts the ability of parts of the nervous system to transmit signals, resulting in a range of signs and symptoms, including physical, mental, and sometimes psychiatric problems. Symptoms include double vision, vision loss, eye pain, muscle weakness, and loss of sensation or coordination. MS takes several forms, with new symptoms either occurring in isolated attacks or building up over time. In relapsing forms of MS, between attacks, symptoms may disappear completely, although some permanent neurological problems often remain, especially as the disease advances. In progressive forms of MS, bodily function slowly deteriorates once symptoms manifest and will steadily worsen if left untreated.
Neuromyelitis optica spectrum disorders (NMOSD) are a spectrum of autoimmune diseases characterized by acute inflammation of the optic nerve and the spinal cord (myelitis). Episodes of ON and myelitis can be simultaneous or successive. A relapsing disease course is common, especially in untreated patients.
Myelin oligodendrocyte glycoprotein (MOG) is a glycoprotein believed to be important in the myelination of nerves in the central nervous system (CNS). In humans this protein is encoded by the MOG gene. It is speculated to serve as a necessary "adhesion molecule" to provide structural integrity to the myelin sheath and is known to develop late on the oligodendrocyte.
Multiple sclerosis is an inflammatory demyelinating disease of the CNS in which activated immune cells invade the central nervous system and cause inflammation, neurodegeneration, and tissue damage. The underlying cause is currently unknown. Current research in neuropathology, neuroimmunology, neurobiology, and neuroimaging, together with clinical neurology, provide support for the notion that MS is not a single disease but rather a spectrum.
Aquaporin-4, also known as AQP-4, is a water channel protein encoded by the AQP4 gene in humans. AQP-4 belongs to the aquaporin family of integral membrane proteins that conduct water through the cell membrane. A limited number of aquaporins are found within the central nervous system (CNS): AQP1, 3, 4, 5, 8, 9, and 11, but more exclusive representation of AQP1, 4, and 9 are found in the brain and spinal cord. AQP4 shows the largest presence in the cerebellum and spinal cord grey matter. In the CNS, AQP4 is the most prevalent aquaporin channel, specifically located at the perimicrovessel astrocyte foot processes, glia limitans, and ependyma. In addition, this channel is commonly found facilitating water movement near cerebrospinal fluid and vasculature.
Multiple sclerosis and other demyelinating diseases of the central nervous system (CNS) produce lesions and glial scars or scleroses. They present different shapes and histological findings according to the underlying condition that produces them.
Inflammatory demyelinating diseases (IDDs), sometimes called Idiopathic (IIDDs) due to the unknown etiology of some of them, are a heterogenous group of demyelinating diseases - conditions that cause damage to myelin, the protective sheath of nerve fibers - that occur against the background of an acute or chronic inflammatory process. IDDs share characteristics with and are often grouped together under Multiple Sclerosis. They are sometimes considered different diseases from Multiple Sclerosis, but considered by others to form a spectrum differing only in terms of chronicity, severity, and clinical course.
Baló's concentric sclerosis is a disease in which the white matter of the brain appears damaged in concentric layers, leaving the axis cylinder intact. It was described by József Mátyás Baló who initially named it "leuko-encephalitis periaxialis concentrica" from the previous definition, and it is currently considered one of the borderline forms of multiple sclerosis.
Eugène Devic was a French neurologist who was a native of Lyon.
Research in multiple sclerosis may find new pathways to interact with the disease, improve function, curtail attacks, or limit the progression of the underlying disease. Many treatments already in clinical trials involve drugs that are used in other diseases or medications that have not been designed specifically for multiple sclerosis. There are also trials involving the combination of drugs that are already in use for multiple sclerosis. Finally, there are also many basic investigations that try to understand better the disease and in the future may help to find new treatments.
Tumefactive multiple sclerosis is a condition in which the central nervous system of a person has multiple demyelinating lesions with atypical characteristics for those of standard multiple sclerosis (MS). It is called tumefactive as the lesions are "tumor-like" and they mimic tumors clinically, radiologically and sometimes pathologically.
Current standards for diagnosing multiple sclerosis (MS) are based on the 2018 revision of McDonald criteria. They rely on MRI detection of demyelinating lesions in the CNS, which are distributed in space (DIS) and in time (DIT). It is also a requirement that any possible known disease that produces demyelinating lesions is ruled out before applying McDonald's criteria.
Chronic relapsing inflammatory optic neuropathy (CRION) is a form of recurrent optic neuritis that is steroid responsive and dependent. Patients typically present with pain associated with visual loss. CRION is a clinical diagnosis of exclusion, and other demyelinating, autoimmune, and systemic causes should be ruled out. An accurate antibody test which became available commercially in 2017 has allowed most patients previously diagnosed with CRION to be re-identified as having MOG antibody disease, which is not a diagnosis of exclusion. Early recognition is crucial given risks for severe visual loss and because it is treatable with immunosuppressive treatment such as steroids or B-cell depleting therapy. Relapse that occurs after reducing or stopping steroids is a characteristic feature.
MOG antibody disease (MOGAD) or MOG antibody-associated encephalomyelitis (MOG-EM) is an inflammatory demyelinating disease of the central nervous system. Serum anti-myelin oligodendrocyte glycoprotein antibodies are present in up to half of patients with an acquired demyelinating syndrome and have been described in association with a range of phenotypic presentations, including acute disseminated encephalomyelitis, optic neuritis, transverse myelitis, and neuromyelitis optica.
Inebilizumab, sold under the brand name Uplizna, is a medication for the treatment of neuromyelitis optica spectrum disorder (NMOSD) in adults. Inebilizumab is a humanized mAb that binds to and depletes CD19+ B cells including plasmablasts and plasma cells.
Satralizumab, sold under the brand name Enspryng, is a humanized monoclonal antibody medication that is used for the treatment of neuromyelitis optica spectrum disorder (NMOSD), a rare autoimmune disease. The drug is being developed by Chugai Pharmaceutical, a subsidiary of Roche.
Anti-neurofascin demyelinating diseases refers to health conditions engendered by auto-antibodies against neurofascins, which can produce both central and peripheral demyelination. Some cases of combined central and peripheral demyelination (CCPD) could be produced by them.
Brenda Banwell is Chief of the Division of Neurology and Co-Director of the Neuroscience Center, and Professor of Neurology at Children's Hospital of Philadelphia and holder of the Grace R. Loeb Endowed Chair in Neurosciences. She also holds the title of Professor of Pediatrics and Neurology at the Perelman School of Medicine at the University of Pennsylvania.