Birdshot chorioretinopathy

Bilateral juxtapapillary choroidal neovascularization secondary to Birdshot chorioretinopathy-case report

Central vision loss, photopsia, floaters, and macular edema in a highly myopic patient can easily be misinterpreted as high myopia complications. In atypical cases, detailed examination and a thorough diagnostic workup are required to establish the proper diagnosis, which is often beyond the scope of diagnoses initially considered.

ANALYSIS OF THREE-DIMENSIONAL CHOROIDAL VOLUME WITH ENHANCED DEPTH IMAGING FINDINGS IN PATIENTS WITH BIRDSHOT RETINOCHOROIDOPATHY

PURPOSE

To describe changes in three-dimensional choroidal volume and thickness with full raster scans of enhanced depth imaging optical coherence tomography in patients with birdshot retinochoroidopathy.

METHODS

This prospective case series collected spectral domain optical coherence tomography images with the enhanced depth imaging technique from eight eyes of eight patients with birdshot retinochoroidopathy including four active patients (four eyes) and four quiet patients (four eyes). Fifty scans of each patient were manually segmented before automated built-in calibration software was used.

RESULTS

Of all active patients, there were no statistically significant differences in the total choroidal volume and mean central choroidal thickness between the active and inactive phase over 6 months of follow-up. Alterations in choroidal parameters were evident and consistent after amelioration of inflammation, whereas the retinal volume and thickness remained stable. Regarding the eight inactive eyes at 6 months, the mean total choroidal volume and mean central choroidal thickness were significantly less than historical controls (P = 0.03 and P < 0.001, respectively). Persistent suprachoroidal hyporeflective space in two patients was noted despite the fact that clinical inflammation completely subsided at 6 months.

CONCLUSION

Choroidal volume and thickness changes were consistent with inflammation in patients with birdshot retinochoroidopathy. Patients with inactive birdshot retinochoroidopathy have significant reduction in choroidal volume and thickness than do normal patients.

HLA-A29-POSITIVE BIRDSHOT CHORIORETINOPATHY IN AN AFRICAN AMERICAN PATIENT

PURPOSE

To report the first documented case of HLA-A29-positive birdshot chorioretinopathy in an African American patient.

METHODS

A 51-year-old African American woman presented with a 10-year history of photopsia, progressive decrease in visual acuity, metamorphopsia, and new nyctalopia. Both fundi showed evidence of periphlebitis, arterial attenuation, macular edema, and diffuse chorioretinal atrophy.

RESULTS

Fluorescein angiography revealed diffuse vascular leakage, and indocyanine green showed evenly distributed and symmetrical hypofluorescent spots, which were difficult to appreciate on fundoscopy. Workup revealed a positive HLA-A29 and was negative for sarcoid, tuberculosis, and syphilis.

CONCLUSION

Birdshot chorioretinopathy overwhelmingly affects non-Hispanic Caucasians, but there have been rare reported cases in other ethnicities including Hispanics and African Americans. This patient's ethnicity may have contributed to the 10-year delay in diagnosis. To our knowledge, this is the first documented HLA-A29 positive case of birdshot chorioretinopathy in an African American. HLA-A29 may be a useful supportive test in cases with classic clinical presentation in non-Caucasian patients to enable the correct diagnose in a timely manner.

Birdshot uveitis: current and emerging treatment options

Birdshot chorioretinopathy is a relatively uncommon subtype of idiopathic posterior uveitis with distinct clinical characteristics and a strong genetic association with the Human Leukocyte Antigen (HLA)-A29 allele. The diagnosis remains clinical and is based on the presence of typical clinical features, including multiple, distinctive, hypopigmented choroidal lesions throughout the fundus. The long-term visual prognosis of this disorder, however, remains guarded – central visual acuity can be preserved until late in the disease and it is not uncommon for patients to receive inadequate immunosuppressive treatment, leading to a poor long-term outcome in which peripheral retinal damage eventually leads to visual deterioration. Birdshot chorioretinopathy has proven a particularly attractive area of study within the field of uveitis, as it is a relatively easily defined disease with an associated human leukocyte antigen haplotype. Despite this, however, the immune mechanisms involved in its pathogenesis remain unclear, and some patients continue to lose retinal function despite therapy with corticosteroids and conventional immunosuppressive agents. Laboratory research continues to investigate the underlying mechanisms of disease, and clinical research is now being driven to improve the phenotyping and monitoring of this condition as, in the era of so-called personalized medicine, it is becoming increasingly important to identify patients at risk of visual loss early so that they can be treated more aggressively with targeted therapies such as the newer biological agents. This approach requires the formation of collaborative groups, as the relative rarity of the condition makes it difficult for one center to accumulate enough patients for worthwhile studies. Nevertheless, results obtained with newer therapies, such as biological agents directed against particular cytokines or cell-surface receptors, demonstrate ever improving control of the inflammation in refractory cases, providing hope that the outlook for visual function in this condition can only improve.

Interleukin 21, interleukin 23, and transforming growth factor β1 in HLA-A29-associated birdshot retinochoroidopathy

PURPOSE

To determine the peripheral levels of 20 immune mediators in serum samples from patients with birdshot retinochoroidopathy (BSRC).

DESIGN

Single-center prospective case-control study.

METHODS

The serum of 17 BSRC patients during different phases of disease activity and therapy were analyzed with a quantitative multiplex sandwich enzyme-linked immunosorbent assay-based microarray to determine the levels of 20 immune mediators (T cell and proinflammatory). The serum of 12 healthy volunteers was used as controls.

RESULTS

Serum levels of interleukin (IL)-21 (P = .0005), IL-23 (P = .0005), and transforming growth factor (TGF)-β1 (P = .0011) were elevated in BSRC patients with active disease naïve to systemic therapy compared with that of controls. There was no significant difference in the serum levels of immune mediators between controls and BSRC patients who had a current or past history of IMT or who were in remission. The levels of IL-21, IL-23, and TGF-β1 were positively correlated (IL-23/IL-21, r = 0.91; TGF-β1/IL-21, r = 0.97; TGF-β1/IL-23, r = 0.87; for all, P < .0001).

CONCLUSIONS

BSRC patients with active disease naïve to systemic therapy have elevated serum levels of 3 key immune mediators known to promote T helper 17 (Th17) cells in autoimmune disease. Our results suggest that IL-21, IL-23, and TGF-β1 may play an important role in the development of site-specific Th17 cell-mediated inflammation in BSRC, which underscore the importance of systemic therapy and offer new insights into the potential of targeted treatments.

Treatment of cystoid macular edema in a patient with birdshot chorioretinopathy with bevacizumab

PURPOSE

Birdshot chorioretinopathy is currently treated with either systemic immune modulation or intravitreal polytherapy. These regimens pose challenges to the clinician and patient such as adverse effects, chronic treatment and compliance, and failure of therapy. In a patient with birdshot chorioretinopathy and juxtaposed cystoid macular edema, the authors assessed the efficacy of bevacizumab for treatment after systemic therapy had failed.

METHODS

A 48-year-old woman was injected with intravitreal bevacizumab 10 times in her right eye with 4 weeks to 6 weeks intervening between injections. Improvement was monitored by best-corrected visual acuity and ocular coherence tomography.

RESULTS

Visual acuity improved from 20/200 to 20/30 in the right eye, and foveal thickness improved from 638 μm to 200 μm. Visible signs of macular edema and inflammation completely disappeared.

CONCLUSION

Bevacizumab monotherapy may improve visual acuity with resolution of macular edema in patients with birdshot chorioretinopathy that is refractory to traditional systemic therapy.

Intraocular interleukin-17 and proinflammatory cytokines in HLA-A29-associated birdshot chorioretinopathy

PURPOSE

To determine the levels of 23 immune mediators in paired aqueous humor (AqH) and serum samples from patients with birdshot chorioretinopathy (BSCR).

DESIGN

Single-centre case-control study.

METHODS

A multiplex immunoassay was used to determine the levels of 23 immune mediators (T-cell, proinflammatory, and vascular-active mediators) in paired AqH and serum of 16 BSCR patients. The AqH of 11 age-related cataract controls served as controls.

RESULTS

AqH levels of the T-cell mediators interleukin (IL)-2 (P=.044) and IL-17 (P=.039) and proinflammatory mediators IL-1β (P=.032), IL-6 (P=.034), and tumor necrosis factor α (P=.041) were elevated compared with that of age-related cataract controls. The elevated intraocular levels of IL-1β, IL-17, and tumor necrosis factor α in BSCR samples were higher than their concurrent serum levels. A significant positive correlation of intraocular mediators was noted between IL-17 and both IL-2 (r=0.744; P<.0001) and IL-23 (r=0.921; P<.0001) and between IL-2 and IL-23 (r=0.776; P<.0001). AqH levels of vascular-active mediators were not distinct between the groups.

CONCLUSIONS

BSCR patients have elevated intraocular levels of proinflammatory and T cell-associated cytokines. Our results suggest the novel pathogenic concept that BSCR is an autoimmune inflammatory disease restricted to the eye and associated with elevated IL-17.

HLA-B*5901 is strongly associated with methazolamide-induced Stevens-Johnson syndrome/toxic epidermal necrolysis

AIMS

The carbonic anhydrase inhibitor methazolamide infrequently causes Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). An association between these diseases and the HLA-B59 serotype has been suggested in case reports. This study examined the disease-associated B*59 allele and investigated the association of these diseases with other HLA class I alleles.

METHODS

We performed high-resolution HLA-A, -B and -C genotyping in five patients with methazolamide-induced SJS/TEN using a PCR-sequencing-based typing method and analyzed the association between HLA-class I alleles and occurrence of methazolamide-induced SJS/TEN.

RESULTS

B*5901 and Cw*0102 alleles were observed in all patients and A*2402 was observed in four patients. The B*5901 allele showed the strongest association with methazolamide-induced SJS/TEN (p < 0.001; odds ratio: 249.8; 95% CI: 13.4-4813.5), followed by Cw*0102 (p = 0.004; odds ratio: 22.1; 95% CI: 1.2-414.3), when compared with the general population as a control. The frequency of the patients carrying B*5901, Cw*0102 and A*2402 simultaneously was significantly higher than that in the general population (p < 0.001; odds ratio: 110.1; 95% CI: 11.7-1038.6).

CONCLUSION

A strong association was observed between HLA-B*5901 and methazolamide-induced SJS/TEN in Korean patients. HLA-B*5901 may be a useful screening marker for predicting methazolamide-induced SJS/TEN in patients of Korean and Japanese ancestry.

Genetics of birdshot chorioretinopathy

Birdshot chorioretinopathy is a bilateral, posterior uveitis that affects primarily Caucasians. Although the genetic basis of disease is not completely understood, certain factors are known, such as the strong association with human leukocyte antigen (HLA)-A29. However, given the prevalence of the HLA-A29 allele in the general population, if it were the only factor required for disease, many more people would have birdshot chorioretinopathy. It has been suggested that some environmental factor may trigger this disease entity in those who are genetically predisposed based on inheritance of the HLA-A29 allele.

Longitudinal cohort study of patients with birdshot chorioretinopathy. IV. Visual field results at baseline

PURPOSE

To describe visual field parameters at baseline examination of 80 participants in a longitudinal cohort study of birdshot chorioretinopathy and to identify relationships between these parameters and visual acuity, symptoms, clinical findings, and results of laboratory tests.

DESIGN

Single-center cross-sectional study.

METHODS

Standardized Fastpac, full-threshold Humphrey 30-2 (Carl Zeiss Meditec, Dublin, California, USA) visual field studies were performed for both eyes of all patients. A standardized protocol identified foveal threshold and mean deviation, specified categories of total deviation, and assigned visual field pattern descriptors. These parameters were compared with best-corrected visual acuity (BCVA), symptoms, color confusion score (CCS), cataract, vitreous inflammatory reactions, retinal vasculitis, birdshot lesion characteristics, and ocular coherence tomography (OCT) and fluorescein angiography parameters.

RESULTS

Each visual field parameter was closely related to the others, although mean deviation could be abnormal in the presence of a near normal foveal threshold. Mean deviation was related to BCVA, but the correlation was moderate (the Spearman correlation, -0.55; P < .001). It was also related to CCS and the symptoms of blurry vision, poor contrast sensitivity, and nyctalopia. The most common visual field patterns were multiple foci and arcuate defects. Among clinical and laboratory findings, visual field parameters were most closely related to absence of the third highly reflective band on OCT (P < .001).

CONCLUSIONS

Patients with birdshot chorioretinopathy may have a variety of visual field abnormalities, even with normal BCVA. Abnormalities seem to be associated with retinal damage. Automated visual field testing may provide objective measures for monitoring disease activity.