What is aquaporin-4 antibody test?
Aquaporin-4 receptor (AQP4) and myelin oligodendrocyte glycoprotein (MOG) antibody testing is used for diagnosis and evaluation of neuromyelitis optica (NMO), acute myelitis, spinal cord lesions, autoimmune encephalitis, or NMOSD.
What is NMO negative?
NMO spectrum disorder (NMOSD) is a newly revised nomenclature in which new diagnostic criteria have been developed, including serological testing of serum aquaporin-4 immunoglobulin G (AQP4-IgG) antibodies. Results of a negative antibody will group the patient in a seronegative subgroup.
What is the role of aquaporin-4?
AQP4 plays a critical role in brain and spinal cord water balance, astrocyte migration, neural signal transduction, and neuroinflammation. It is involved in the development, function, and integrity of the interface between the brain and blood and between the brain and cerebrospinal fluid.
Where is aquaporin-4 found?
Aquaporin-4 is the most common aquaporin in the brain, spinal cord, and optic nerve. It is highly expressed in the human body primarily at the end-feet of astrocytes.
What is aquaporin-4 receptor antibody?
Antibodies to aquaporin-4 (called NMO-IgG or AQP4-Ab) constitute a sensitive and highly specific serum marker of neuromyelitis optica (NMO) that can facilitate the differential diagnosis of NMO and classic multiple sclerosis.
Can you have NMO and MS?
MS typically affects the brain as well as the spinal cord and optic nerve. NMO-IgG (anti-AQP4 antibody) is not found in people with MS but is found in 70 percent of those with NMO. In MS, individual episodes are usually mild; their cumulative effect over time may or not not cause progressive disability.
How can you tell the difference between MS and NMO?
In MS, individual episodes are usually mild; their cumulative effect over time may or not not cause progressive disability. In NMO, the opposite is true and therefore early diagnosis is critical; acute episodes are usually severe and – if untreated – can have devastating, irreversible effects on function.
Where is aquaporin-4 specifically expressed in both the CNS and body?
astrocyte end-feet
Aquaporin-4 (AQP4) is the main water channel protein expressed in the central nervous system (CNS). AQP4 is densely expressed in astrocyte end-feet, and is an important factor in CNS water and potassium homeostasis.
What is the physiological role of aquaporins in the eye?
The aquaporins (AQPs) are integral membrane proteins whose main function is to transport water across cell membranes in response to osmotic gradients. At the ocular surface, AQP1 is expressed in corneal endothelium, AQP3 and AQP5 in corneal epithelium, and AQP3 in conjunctival epithelium.
Can NMO be cured?
Neuromyelitis optica is a rare but serious disease that affects the central nervous system. There is no cure but there medicines and treatments may inhibit future disease flares.
What is worse NMO or MS?
Symptoms of NMO are usually severe than multiple sclerosis (MS). The individual episodes in NMO are more serious compared to MS. Their cumulative effect will have debilitating, irreversible effects on nerve functions.
What is idiopathic aquaporin-4 antibody negative (n-LETM)?
Idiopathic isolated N-LETM is not that rare among first-ever LETM, and has many features distinct from P-LETM where astrocytic damage is evident. Idiopathic aquaporin-4 antibody negative longitudinally extensive transverse myelitis Mult Scler. 2015 May;21(6):710-7.doi: 10.1177/1352458514551454. Epub 2014 Oct 10. Authors
What is the prevalence of aquaporin 4 Antibody-Negative NMO?
However, aquaporin 4 antibodies are so far only found in about 70–90% of patients with NMO ( Lennon et al., 2004; Takahashi et al., 2007) and the pathogenesis of disease in these aquaporin 4 antibody-negative patients is currently unclear.
What is aquaporin-4?
Aquaporin-4 (AQP4) is a water channel protein that is most highly, but not exclusively, expressed in the central nervous system.
Is the anti-AQP4 antibody a pathogenic target?
Because the anti-AQP4 antibody bound to a CNS water channel, it raised the possibility that the antibody might be pathogenic and that NMO could be an autoimmune channelopathy. Several lines of evidence suggested that AQP4 is a pathogenic target.