Autoimmune retinopathy: a review and summary

A case of autoimmune retinopathy associated with thyroid carcinoma

PURPOSE

To report a case of autoimmune retinopathy (AIR) associated with a thyroid carcinoma.

DESIGN

Case report.

METHOD

A 51-year-old Caucasian woman presented with a rapid decline in vision. Initial visual field and immunohistochemical testing revealed autoimmune retinopathy without an apparent underlying malignancy. Conventional local and systemic immunosuppressive therapies failed to halt the progression.

RESULTS

Rituximab treatments were initiated and a slowing of visual loss was seen. Continued surveillance for malignancy revealed a thyroid adenoma, and later a thyroidectomy revealed a thyroid carcinoma.

CONCLUSIONS

This report highlights the unique presentation of AIR associated with a thyroid carcinoma, the need for continued surveillance for malignancy in cases of AIR, and the possible new use of rituximab for the treatment of AIR.

Loss of lysophosphatidylcholine acyltransferase 1 leads to photoreceptor degeneration in rd11 mice

Retinal degenerative diseases, such as retinitis pigmentosa and Leber congenital amaurosis, are a leading cause of untreatable blindness with substantive impact on the quality of life of affected individuals and their families. Mouse mutants with retinal dystrophies have provided a valuable resource to discover human disease genes and helped uncover pathways critical for photoreceptor function. Here we show that the rd11 mouse mutant and its allelic strain, B6-JR2845, exhibit rapid photoreceptor dysfunction, followed by degeneration of both rods and cones. Using linkage analysis, we mapped the rd11 locus to mouse chromosome 13. We then identified a one-nucleotide insertion (c.420-421insG) in exon 3 of the Lpcat1 gene. Subsequent screening of this gene in the B6-JR2845 strain revealed a seven-nucleotide deletion (c.14-20delGCCGCGG) in exon 1. Both sequence changes are predicted to result in a frame-shift, leading to premature truncation of the lysophosphatidylcholine acyltransferase-1 (LPCAT1) protein. LPCAT1 (also called AYTL2) is a phospholipid biosynthesis/remodeling enzyme that facilitates the conversion of palmitoyl-lysophosphatidylcholine to dipalmitoylphosphatidylcholine (DPPC). The analysis of retinal lipids from rd11 and B6-JR2845 mice showed substantially reduced DPPC levels compared with C57BL/6J control mice, suggesting a causal link to photoreceptor dysfunction. A follow-up screening of LPCAT1 in retinitis pigmentosa and Leber congenital amaurosis patients did not reveal any obvious disease-causing mutations. Previously, LPCAT1 has been suggested to be critical for the production of lung surfactant phospholipids and biosynthesis of platelet-activating factor in noninflammatory remodeling pathway. Our studies add another dimension to an essential role for LPCAT1 in retinal photoreceptor homeostasis.

Melanoma-associated retinopathy: a paraneoplastic autoimmune complication

OBJECTIVES

To study 11 patients with melanoma-associated retinopathy (MAR) to clarify the reliability of various methods of diagnostic testing, to determine the underlying antigenic retinal proteins, and to study the clinical histories and types of associated melanomas.

METHODS

Clinical data were obtained from patients with melanoma who developed marked visual problems. Testing included electroretinography, kinetic visual fields, comparative studies of Western blots, and indirect immunohistologic examination to detect antiretinal antibodies, as well as proteomic studies to identify underlying antigenic retinal proteins.

RESULTS

Patients with MAR typically have rapid onset of photopsias, scotomata, and loss of central or paracentral vision. Ophthalmoscopy seldom shows significant changes early, but electroretinograms are abnormal. Results of Western blots and immunohistologic examination can show antiretinal antibodies but not always. Most patients (9 of 11) had a strong family history of autoimmune disorders. Any type of melanoma (cutaneous, choroidal, ciliary body, or choroidal nevi) may be associated with this paraneoplastic autoimmune reactivity. MAR may precede or follow the diagnosis of melanoma. Patients with MAR have the same antigenic retinal proteins that have been associated with cancer-associated retinopathy. In addition, 2 new antigenic retinal proteins, aldolase A and aldolase C, were found.

CONCLUSIONS

There was a high prevalence of positive family histories of autoimmune disease in patients with MAR. To confirm the disorder, multiple clinical and serum diagnostic techniques (Western blot or indirect immunohistologic examination) are needed. Two newly observed antigenic retinal proteins, aldolase A and aldolase C, are associated with MAR.

A survey of photopsias in self-reported retinitis pigmentosa: location of photopsias is related to disease severity

PURPOSE

To characterize photopsias or light shows in patients self-reporting retinitis pigmentosa and determine associations between their location and patient-reported visual function.

METHODS

One hundred and twenty-seven self-reported patients with retinitis pigmentosa with varying levels of vision completed an anonymous survey on an Internet web site.

RESULTS

One hundred and eighteen (93%) of the respondents reported photopsias. The majority (60%) who experience photopsias have them daily, 48% already had them before being diagnosed with retinitis pigmentosa, and 69% report interference with vision. The proportions noting photopsias mostly peripherally versus centrally were 53% of those reading normal or small print versus 35% requiring magnification (odds ratio, 2.3; 95% confidence interval, 1.0-5.5; P = 0.05); 61% of current drivers versus 41% who stopped or never drove (odds ratio, 2.6; 95% confidence interval, 1.0-6.7; P = 0.04); and 54% of individuals who easily navigate or have only minor difficulty in unfamiliar areas versus 29% of those with great difficulty or needing assistance with mobility (odds ratio, 3.0; 95% confidence interval, 1.2-6.7; P = 0.02).

CONCLUSION

Contrary to common belief that photopsias are associated with end-stage retinal degeneration, they are also commonly reported in earlier stages. The location of photopsias appears to be related to residual photoreceptor function assessed by self-reported performance of daily activities. Clinicians and researchers should be aware of their frequent occurrence and offer reassurance to patients.

Autoimmunity in retinal degeneration: autoimmune retinopathy and age-related macular degeneration

Autoantibody production is associated with a variety of ocular disorders, including autoimmune retinopathy (AIR) and age-related macular degeneration (AMD). A breakdown of immunologic tolerance (ocular immune privilege), including the blood-retinal barrier, anti-immune and anti-inflammatory proteins, and anterior chamber-associated immune deviation may play important roles in these disorders. Although the exact triggers for ocular autoimmunity are unknown, autoimmune targeting of retinal tissue is clearly associated with and may contribute to the pathogenesis of both AIR and AMD. Autoantibody production has long been associated with AIR, a collection of disorders that includes cancer-associated retinopathy, melanoma-associated retinopathy and non-paraneoplastic autoimmune retinopathy. A growing body of evidence indicates that AMD pathogenesis, too, involves ocular inflammation and autoimmunity. Identification and quantification of autoantibodies produced in patients with AIR and AMD may assist with diagnosis, prognosis, and choice of treatments. Animal models that allow investigation of ocular autoimmunity will also be needed to better understand the disease processes and to develop novel therapies. In this review we discuss ocular immune privilege and potential mechanisms of autoimmunity in the eye. We describe how autoimmunity relates to the pathogenesis of AIR and AMD. We explain how the antigen microarray technique is used to detect autoantibodies in patient serum samples, and discuss how current animal models for AMD can be used to investigate autoimmune pathogenesis. Finally, we outline unanswered questions and exciting areas of future study related to autoimmune retinal degeneration.

Molecular biomarkers for autoimmune retinopathies: significance of anti-transducin-alpha autoantibodies

Autoimmune retinopathies (AR) are uncommon retinal degenerations with vision loss associated with unique clinical symptoms and findings and with serum anti-retinal autoantibodies. The experimental and clinical studies corroborate that autoantibodies in high titers can penetrate into the retina affecting function of the target antigens, which leads to retinal dysfunction and degeneration. Anti-recoverin and anti-enolase alpha-enolase autoantibodies were more frequently recognized in AR but autoantibodies with other specificities have also been documented, indicating immunological heterogeneity. Our goal was to examine the associations of anti-retinal autoantibodies with retinopathy in order to identify molecular biomarkers for better diagnosis and prognosis of retinopathies. In these studies we examined 39 patients (10 with cancers) of average age of approximately 57 years old with sudden onset of unexplained progressive vision loss and the presence of circulating serum autoantibodies against 40-kDa retinal protein. The patients presented the retinal phenotype characterized by defects in visual fields and reduced scotopic ERG responses. Anti-40-kDa autoantibodies had specificity to the amino terminus of transducin-alpha. None of the normal subjects' sera had anti-40-kDa autoantibodies. In conclusion, the clinical phenotype of patients with anti-transducin-alpha autoantibodies differed from other phenotypes of AR. These patients, often women at a ratio approximately 2:1, had defects in rod (scotopic) photoreceptor function and typically did not have cancers, whereas the anti-recoverin phenotype is associated with cancer and severe loss of rod and cones function, and anti-enolase retinopathy typically presents with cone dysfunction and is equal in cancer and non-cancer patients. Our studies suggest that anti-transducin autoantibodies can serve as molecular biomarkers for retinal phenotypes and could be used for progression of retinal dysfunction and degeneration.

Autoimmune retinopathy in systemic lupus erythematosus: histopathologic features

The ocular pathology of autoimmune retinopathy is demonstrated in a 62-year-old female patient with systemic lupus erythematosus (SLE) who presented with typical clinical autoimmune retinopathy. Macroscopically, there were multiple depigmented lesions in the peripheral retina and choroid and scattered pigmentary bone-spickling at the equator and periphery. Microscopically, there were generalized loss of photoreceptors and thinning of the outer plexiform layer. Many peripheral retinal vessels were sclerotic and occluded, some surrounded by pigment granules and RPE cells. Cobblestone degeneration was prominent in the periphery. Macrophages were seen in the retina, particularly in areas of photoreceptor degeneration. Rare, scattered T- lymphocytes were present in the retina and choroid, while B-cells were notably absent. The optic nerve showed loss of axons and thickened septae. Serum autoantibodies against normal retinal nuclei were detected. These pathological changes represent both known SLE-associated ocular complications as well as possible features of autoimmune retinopathy secondary to SLE.