Anti-retinal antibodies (ARAs) definitely have an effect on many retinal diseases. We have consistently found that elevated ARAs exacerbate the disease or cause additional complications that regress when the antibodies are reduced. For example, cystoid and other forms of retinal edema in patients with retinitis pigmentosa are consistently associated with circulating ARAs. Several studies have demonstrated ARAs in patients with diabetes that may contribute to retinopathy-for example, loss of pericytes or retinal edema;however, whether ARAs plays a role in vision loss in these diseases is unclear. Previous experience with specific retinal diseases has demonstrated that identifying the ARAs in affected patients and illuminating their role in disease processes can lead to the use of effective treatments and methods of assessing disease progression. For instance, in patients with birdshot chorioretinitis, immunosuppressant agents are now used to achieve long-term suppression of antibodies and inflammation. Moreover, most patients with autoimmune retinopathy who have active ARAs regain function with immunosuppression and anti-inflammatory medications. In recent years, through investigations of ARAs in various retinal degenerations, we have discovered several antibodies involved in melanoma-associated retinopathy and we have reconfirmed the presence of several putative antibodies in cancer-associated retinopathy. In reviewing the medical literature on diabetic antibodies, several findings stand out, as they parallel findings in patients with autoimmune retinopathy (AIR). Of note, antibodies to aldolase-C and a-enolase have been found in patients with type 1 diabetes;these ARAs are known to be associated with disease changes in patients with AIR. As a preliminary study, we performed Western blots on serum samples obtained from 38 patients with various types of diabetes retinopathy and 12 healthy controls to look for the presence of ARAs. We found that the patients with diabetes consistently had more antibodies and more intense staining on their Western blots, compared with the controls. In this proposed project, we will test the hypothesis that elevated ARAs cause retinal dysfunctional in patients with diabetes and will determine which antibodies contribute to vision loss. Study participants recruited from our clinic will undergo clinical testing-specifically, dark adaptometry to measure final rod thresholds and standardized electroretinography to measure cone and rod function. Clinical tests will be performed to quantify the extent of any retinal edema and to check for vascular alterations. Functional changes will be compared with immunologic test parameters, including ARAs on Western blots, and retinal targets using patient antibodies with immunohistologic techniques. By correlating different patients'immunoreactive bands with similar staining patterns on immunohistology or identifying the same bands in multiple patients with the same clinical conditions, we will establish which antibodies are affecting the retina. Specific immunoreactive bands will be processed for mass spectrometry, and candidate proteins will be identified and the correct ones confirmed.
Patients with diabetes have increased circulating anti-retinal antibodies (ARAs). In other retinal diseases, ARAs is known to cause serious complications, but their effects in diabetes are unknown. This project will investigate whether eye-related complications of diabetes-including retinal changes such as cystic edema or retinal thickening, or reduced night vision-are related to circulating ARAs. If so, this information could be used by physician-researchers to develop more effective treatments for these conditions and ultimately contribute to preventing major vision loss in patients with diabetes. Thus, the proposed research is relevant to the part of the NEI's mission that pertains to understanding the pathogenesis of diabetic retinopathy and to develop strategies for prevention and improved treatment.
