Autoimmune retinopathy

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It is a span of rare autoimmune diseases that initially affect the function of retinal photoreceptor and encompass cancer associated retinopathy, melanoma associated retinopathy and assumed non- paraneoplastic autoimmune retinopathy.

Autoimmune retinopathy (AIR) is a rare disease in which the patient's immune system attacks proteins in the retina, leading to loss of eyesight. The disease is poorly understood, but may be the result of cancer or cancer chemotherapy. The disease is an autoimmune condition characterized by vision loss, blind spots, and visual field abnormalities. It can be divided into cancer-associated retinopathy (CAR) and melanoma-associated retinopathy (MAR).The condition is associated with retinal degeneration caused by autoimmune antibodies recognizing retinal proteins as antigens and targeting them. AIR's prevalence is extremely rare, with CAR being more common than MAR. It is more commonly diagnosed in females (approximately 60% of diagnosed patients are females) in the age range of 50-60.

Types

Cancer-associated retinopathy

A division of AIR, cancer-associated retinopathy is a paraneoplastic syndrome, which is a disorder caused by an immune system response to an abnormality. Autoimmune antibodies target proteins in retinal photoreceptor cells. The proteins targeted as antigenic are recoverin, α‚Äźenolase and transducin. This autoimmune response leads to photoreceptor cell death. It causes progressive vision loss that can lead to blindness. CAR is typically associated with the anti-recoverin antibody.

Melanoma-associated retinopathy

Retinal bipolar cells (cells in retina that transmit signals) react with the antibodies, leading to cell death. Although it is less prevalent than CAR, diagnosed cases of MAR continue to increase while CAR numbers decrease.

Signs and symptoms

Both CAR and MAR share the same symptoms. This is because they are both paraneoplastic syndromes. AIR symptoms are numerous and shared by many other diseases.

Symptoms

Painless Vision Loss

Blind Spots in Vision

Photopsia

Nyctalopia

Scotomas

Dislike/avoidance of light

Loss of contrast sensitivity

Incomplete colour blindness

Decreased night vision

Diagnosis

Diagnosis of AIR can be difficult due to the overlap of symptoms with other disorders.Examination of the fundus (inner surface of eye) can show no results or it can show narrowing of the blood vessels, abnormal colouration of the optic disc, and retinal atrophy.  Fundus examination results are not indicative of autoimmune retinopathy but they are used to initiate the diagnostic process. An electroretinogram (eye test used to see abnormalities in the retina) is used to detect AIR. An abnormal electroretinogram (ERG) with respect to light and dark adaptations indicates AIR. The ERG also allows differentiation between cancer-associated retinopathy and melanoma-associated retinopathy. If the ERG shows cone responses, CAR can be prematurely diagnosed. If the ERG shows a significant decrease in b-wave amplitude, MAR can be prematurely diagnosed.To confirm, analysis for anti-retinal antibodies through Western blotting of serum collected from the patient is done.

Treatment

Due to the difficulty of diagnosis, managing this disease is a challenge. For this reason, there is no established treatment for AIR. Clinicians try to reduce and control the autoimmune system attack to prevent any irreversible retinal damage. Methods of treatment include intravenous immunoglobulin (IVIG), plasmapheresis, and corticosteroids.

Media Contacts,
Managing Editor
Rutherford
Journal of Autoimmune Disorders