Serum IgM in retinitis pigmentosa: a genetic study

A review of the immunologic findings observed in retinitis pigmentosa

Most patients suffering from retinitis pigmentosa (RP) inherit the disorder; however, the immune-pathologic features associated with this disease have yet to be extensively studied. Six reports correlate antiretinal immune activity with vision deterioration in RP patients. Some of these patients have sporadic RP that occurs in excess of expected gene segregation during inheritance. The hypothesis that a primary immune-mediated disease process occurs in this sporadic group is supported by significant associations of RP with autoimmune endocrinopathies and other immune-related conditions or factors; however, no immunologic difference regarding RP family history is reported in the peripheral blood studies of RP patients. Twenty-one percent to 51% of RP patients display antiretinal antibodies, whereas 19-58% have antiretinal lymphocyte reactivity to retinal extract, and 60-85% have activated T cells. Mutations in animal models of RP have been shown to cause endoplasmic reticulum stress that may initiate immunopathology for genetic RP, but oxidative stress also encourages immune cytotoxicity. In addition, necrotic cell death is evident, which promotes inflammatory conditions. We review mechanisms and evidence for an occult inflammation in genetic RP and examine reports of efficacy in retarding RP progression with anti-inflammatory agents in clinical trials.

Retinitis pigmentosa-associated cystoid macular oedema: pathogenesis and avenues of intervention

Hereditary retinal diseases are now the leading cause of blindness certification in the working age population (age 16–64 years) in England and Wales, of which retinitis pigmentosa (RP) is the most common disorder. RP may be complicated by cystoid macular oedema (CMO), causing a reduction of central vision. The underlying pathogenesis of RP-associated CMO (RP-CMO) remains uncertain, however, several mechanisms have been proposed, including: (1) breakdown of the blood-retinal barrier, (2) failure (or dysfunction) of the pumping mechanism in the retinal pigment epithelial, (3) Müller cell oedema and dysfunction, (4) antiretinal antibodies and (5) vitreous traction. There are limited data on efficacy of treatments for RP-CMO. Treatments attempted to date include oral and topical carbonic anhydrase inhibitors, oral, topical, intravitreal and periocular steroids, topical non-steroidal anti-inflammatory medications, photocoagulation, vitrectomy with internal limiting membrane peel, oral lutein and intravitreal antivascular endothelial growth factor injections. This review summarises the evidence supporting these treatment modalities. Successful management of RP-CMO should aim to improve both quality and quantity of vision in the short term and may also slow central vision loss over time.

Cellular immune status in retinitis pigmentosa

Previous reports have suggested a role of cellular and/or humoral immunity in retinitis pigmentosa. Because of the controversial nature of many of these reports, the authors undertook a detailed investigation of cellular and humoral immunity in a well-characterized group of 47 persons with retinitis pigmentosa of various heritability patterns and a similar number of age- and sex-matched controls. The authors found two changes in lymphocyte subsets. Retinitis pigmentosa patients had significantly elevated Leu 3A-positive lymphocytes (CD4 or T-helper cells) and significantly fewer Leu 2A-positive lymphocytes (CD8 or T-suppressor cells) than controls, although the total numbers of T cells did not differ between the two groups. A small but significant number of retinitis pigmentosa patients expressed interleukin 2 (IL-2) antigens on their lymphocytes as compared with none of the controls. The authors saw no differences between the retinitis pigmentosa and control groups in the inducibility and secretion of gamma-interferon or IL-2. Concentrations of immunoglobulins G, A, and M did not differ between the two groups. The link between immune system alterations and the retinitis pigmentosa process remains tenuous.

Autoimmunity in hereditary retinal degenerations. II. Clinical studies: antiretinal antibodies and fluorescein angiogram findings

Testing by indirect immunofluorescence for the detection of antiretinal antibodies and lymphocyte stimulation for cell-mediated immunity to retinal antigens was performed on blood obtained from 59 patients with retinitis pigmentosa (RP) and 29 without RP who had other types of retinal disease. The results from the patients' immunological studies were correlated in a masked fashion with six parameters of the fluorescein angiogram: disc staining, peripapillary oedema, vascular arcade oedema, macular oedema, and focal vascular staining (late phases), and disc telangiectasia (early phases). Significant correlations for both groups together were found for IgG antiretinal antibody reactivity and macular oedema (p less than 0.038) and disc staining (p less than 0.033). The non-RP retinal disease group had more significant correlations, including IgG antiretinal antibody reactivity with vascular arcade oedema (p less than 0.018), disc staining (p less than 0.018), and peripapillary oedema (p less than 0.023); the RP patients had significant correlation with IgG reactivity and arcade oedema (p less than 0.045). With combinations of IgG, IgM, and lymphocyte reactivity various significant correlations were found with the fluorescein angiogram.

Autoimmunity in hereditary retinal degeneration. I. Basic studies

One hundred and sixteen patients with retinitis pigmentosa (RP), 64 patients with other eye diseases, and 36 control subjects with no known eye disease were examined for antiretinal autoimmune activity. Sera were screened by indirect immunofluorescence on normal donor human eye sections to detect antibodies to human retinal antigens. Forty three of 116 RP patients (37%), 21 out of 64 non-RP patients with other eye diseases (33%), and 1 out of 42 controls (2%) had antibodies reacting with donor eye retinal antigens. Lymphocytes were tested by an in vitro transformation assay to detect cell mediated immunity to retinal antigens. Sixteen RP patients (19%), 11 non-RP patients (18%), and four controls (10%) showed lymphocyte sensitisation. Autoimmune responses were detected in many degenerative ocular disorders, but it is not known if they play a contributory pathogenic role.