Comparison of Clinical and Immunological Features of Para- and Non-Paraneoplastic Autoimmune Retinopathy in Chinese - A Series of 48 Cases.

PURPOSE: To characterize and compare clinical and immunological features of para(p)-autoimmune retinopathy (AIR) and non-para(np)-AIR and to assess the clinical significance of the presence of serum anti-retinal antibodies (ARAs). METHODS: We retrospectively reviewed 48 Chinese patients with p-AIR or np-AIR who took comprehensive ophthalmic examinations and lab tests of the presence of serum ARAs. RESULTS: p-AIR patients differed from np-AIR patients in terms of disease progression, ocular inflammation, findings of OCT, FFA, and presence of ARAs. No significant difference was found in the band number of serum ARAs between AIR patients and healthy controls. The prevalence of antibodies to recoverin and ɑ-enolase in the sera of p-AIR was significantly higher than that of the healthy individuals. CONCLUSION: While having many similar clinical signs, patients with p-AIR or np-AIR nevertheless displayed unique characteristics. Detection of ARAs subtypes, rather than their quantity, may be helpful in evaluating the conditions in the verified instances.

Serum antiretinal antibodies and cytokine profiling in autoimmune retinopathy and their association with clinical outcomes.

PURPOSE: Autoimmune retinopathy (AIR) is a group of autoimmune retinal diseases that can cause blindness. The purpose of this study is to investigate the profiles of serum antiretinal antibodies (ARAs) and cytokines and their association with disease diagnosis as well as clinical features in AIR. METHODS: The patients with presumed para (p) and non-paraneoplastic (np) AIR diagnosis, the patients with retinitis pigmentosa and bilateral uveitis as disease controls, and healthy subjects were prospectively enrolled. Western blotting and Luminex multiple cytokine assay/enzyme linked immunosorbent assay were used to determine the presence of serum ARAs and the concentration of cytokines, respectively. Kruskal-Wallis or chi square test was applied to compare the profiles of ARA and cytokines among various groups. The multilevel mixed-effect regression was used to investigate the association of ARA or cytokines with clinical features. RESULTS: No significant difference in the band number and subtypes of serum ARAs was found between AIR patients and their controls. AIR patients had higher concentration of serum IFN-ɤ, CXCL9, or CXCL10 than non-AIR controls. A positive correlation was found between increased number of ARAs and elevated TNF-α in np-AIR patients. Elevated pro-inflammatory cytokines or ARA subtypes (antibody against recoverin and α-enolase) were associated with worse retinal functions or anatomy, including visual acuity, visual field, ERG parameters, and central retinal thickness. CONCLUSIONS: The data of our study demonstrate that detection of serum ARAs has limited value in the diagnosis of AIR. Th1-type cytokines/chemokines or specific ARA subtypes are associated with pathogenesis and disease severity of the AIR.

Management of autoimmune retinopathy treated with intravitreal dexamethasone implant.

PURPOSE: The purpose of this study is to evaluate clinical outcomes of autoimmune retinopathy (AIR) in the patients treated with intravitreal dexamethasone implant (IDI). METHOD: Twenty-one eyes of 11 AIR patients treated with at least 1 injection of IDI were retrospectively reviewed. Clinical outcomes before and after treatment, including best corrected visual acuity (BCVA), optic coherence tomography (OCT), fundus autofluorescence (FAF), full-field electroretinography (ff-ERG), and visual field (VF) at last visit within 6 and/or 12 months, were recorded. RESULTS: Among all the patients, 3 had cancer-associated retinopathy (CAR) and 8 had non-paraneoplastic-AIR (npAIR) with mean followed up of 8.52 ± 3.03 months (range 4-12 months). All patients achieved improved or stable BCVA within 6 and/or 12 months after the treatment. Cystoid macular edema (CME) in 2 eyes and significant retinal inflammation in 4 eyes were markedly resolved after single injection. Central retinal thickness (CFT) in all eyes without CME, ellipsoid zone (EZ) on OCT in 71.4% of eyes, ERG response in 55% of eyes, and VF in 50% of eyes were stable or improved within 6 months after treatment. At last visit within 12 months, both BCVA and CFT remained stable in the eyes treated with either single or repeated IDI; however, progression of EZ loss and damage of ERG response occurred in some patients with single IDI. CONCLUSION: Clinical outcomes, including BCVA and parameters of OCT, ERG, and VF, were stable or improved after IDI in a majority of AIR patients. Local treatment of AIR with IDI was a good option to initiate the management or an alternative for the patients' refractory to the systemic therapy but with limited side effect.

One-year efficacy of intravitreal conbercept injection for macular oedema secondary to central retinal vein occlusion in Chinese patients.

PURPOSE: To evaluate intravitreal conbercept injection for treatment of macular oedema secondary to central retinal vein occlusion (CRVO) in Chinese patients during 1-year follow-up in the real-world setting. METHODS: Twenty-seven eyes of 27 patients with macular oedema associated with CRVO were retrospectively reviewed. The eyes received monthly intravitreal conbercept injection (0.5 mg in 50 µl) for 3 months. From then on, the patients were followed up every month and received injection pro re nata (PRN) up to 12 months. The primary outcome measurements included changes of best-corrected visual acuity (BCVA) and central retinal thickness (CRT) from baseline to month 3 and month 12. Other outcome measurements included proportion of patients gaining ≥15 letters in BCVA at month 3 and 12, the mean number of injections and safety concerns. RESULTS: The mean BCVA gain from baseline was 12.7 ± 7.6 letters at month 3 and 14.8 ± 9.6 letters at month 12. The mean CRT reduction from baseline was 374.5 ± 280.7 µm at month 3 and 428.2 ± 241.3 µm at month 12. The proportion of patients who gained ≥15 letters in BCVA was 45.1% at month 3 and 52.9% at month 12. The mean number of injections was 7.6 ± 1.5. No severe local and systemic complications occurred following injection. CONCLUSIONS: Intravitreal conbercept injection by three monthly loading doses followed by PRN treatment regimen was safe and efficacious for patients with macular oedema secondary to CRVO through 1-year follow-up.

Detection of serum anti-retinal antibodies in the Chinese patients with presumed autoimmune retinopathy.

PURPOSE: To explore the presence of serum anti-retinal antibodies (ARAs) in the Chinese patients with presumed autoimmune retinopathy (AIR). METHODS: Twenty-three Chinese patients with presumed AIR, disease controls including 40 RP patients, 22 bilateral uveitis patients, 18 acute zonal outer occult retinopathy (AZOOR) patients, and 30 healthy donors were included. Serum samples of all the subjects were obtained and analyzed for the presence of four ARAs including recoverin, α-enolase, carbonic anhydraseII (CAII), and collapsin response-mediated protein (CRMP)-5 by Western bolt assay. RESULTS: ARAs were present in the serum of either presumed AIR patients, disease control, or healthy donors. One or more ARAs were present in the 78.2% of presumed AIR while they were indicated in the 35.0% of RP patients (p < 0.01) and 33.3% of healthy donors (p < 0.01). The prevalence of ARAs in the bilateral uveitis and AZOOR was 63.3% and 100% respectively. Positive rate of α-enolase antibody present in the presumed AIR, disease control, and healthy donors was 73.9%, 47.5%, and 33.3% respectively. Positive rate of CAII antibody present above groups was 52.1%, 50%, and 33.3% respectively. Recoverin antibody seemed to be specifically present in the serum of patients with cancer-associated retinopathy. CONCLUSION: Presence of serum ARAs including recoverin, α-enolase, CAII, or CRMP-5 in the Chinese patients with presumed AIR occurred significantly more often than RP patients and healthy donors. Seropositivity of ARAs had diagnostic value for the presumed AIR but mere presence was not sufficient for the diagnosis due to identification of them in the healthy controls and other retinal diseases.

Selective Early Glial Reactivity in the Visual Pathway Precedes Axonal Loss, Following Short-Term Cerebrospinal Fluid Pressure Reduction.

Purpose: To examine the early glial reactivity and neuron damage in response to short-term cerebrospinal fluid pressure (CSFp) reduction, as compared with intraocular pressure (IOP) elevation. Methods: The experiment included 54 male Sprague-Dawley rats with elevated translaminar cribrosa pressure difference (TLPD), defined as IOP minus CSFp. These rats underwent either continuous CSF drainage for 6 hours (n = 18), or unilateral IOP elevation to 40 mm Hg for 6 hours (n = 18). For control, 18 normal rats were anesthetized for 6 hours. Orthograde axonal transport was examined by intravitreal injection of 3% rhodamine-ß-isothiocyanate. We also used transmission electron microscopy to display the ultrastructural features of retinal ganglion cell axons in the optic nerve head. Early glial reactivity in the retina, lateral geniculate nucleus (LGN), and superior colliculus (SC) was detected by immunostaining and Western blot for the glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS). We also observed the glial reactivity in the inferior colliculus and hippocampus to rule out possible influences of CSF dynamics and composition. Results: Anterograde staining with 3% rhodamine-ß-isothiocyanate revealed decreased fluorescence intensity of the SC and LGN projected from both lower CSFp and higher IOP eyes. Transmission electron microscopy showed loss of axons from the optic nerve head in the high-IOP group, but not in the low-CSFp group. Compared with the anesthesia control group, GFAP expression was significantly increased in the retina, LGN, and SC, whereas GS expression was only increased in the retina following CSFp reduction. However, their expressions were not significantly elevated in the inferior colliculus and hippocampus. In the high-IOP group, expressions of GFAP and GS were significantly increased in the retina, LGN, and SC. Conclusions: Visual system neurons may be much more sensitive than other nervous tissues. Following short-term CSFp reduction, early glial reactivity may precede axonal loss. Changes of translaminar cribrosa pressure difference in both experimental low-CSFp and high-IOP groups induce selective early glial reactivity. The neuron damage from abnormally low CSFp may be pathogenetically similar to high IOP.

The role of CCR1 expression in the retinal degeneration in rd mice.

PURPOSE: Chemokine receptors are reported to be involved in neuronal cell death and CNS neurodegenerative diseases. The aim of the current study was to investigate the expression of CCR1, a major chemokine receptor for CC chemokines in retinal dystrophy in rd (retinal degeneration) mice and further explore its role in photoreceptor degeneration. MATERIALS AND METHODS: The expression levels of CCR1 mRNA in the whole control and rd retinas at postnatal days (P) 8, 10, 12, 14, 16, and 18 were determined by RT-PCR assay. Location of CCR1 in the retina of rd mice at each age group was studied by immunohistochemical analysis. Expression of CCR1 in the photoreceptor cells and apoptotic cells was determined by double labeling. RESULTS: Expression of CCR1 mRNA was noted in both control and rd retinas at each age group. CCR1-positive cells started to emerge in the outer nuclear layer (ONL) in rd retinas at P8 and reached a peak at P12 and P14. Double labeling of CCR1 with rhodopsin, CD11b, or TUNEL staining showed expression of CCR1 in the photoreceptor cells, rather than in the microglial cells. Partial CCR1 expression was observed in some of the apoptotic photoreceptor cells. CONCLUSIONS: Expression of CCR1 in the photoreceptor cells was increased with the progress of retinal degeneration in rd mice. Activation of CCR1 may play a role in the photoreceptor apoptosis.

Activation of nuclear factor-kappaB during retinal degeneration in rd mice.

PURPOSE: Transcription factors of the nuclear factor-kappa beta (NF-kappaB) family have been demonstrated to play an important role in the regulation of gene expression in the chronic neurodegenerative disorders. The aims of the current study were to investigate the alteration of NF-kappaB activity during retinal degeneration in rd mice and further explore its role in photoreceptor apoptosis. METHODS: Activation of NF-kappaB and its nuclear translocation in the retina of rd mice at postnatal days (P) 8, 10, 12, 14, 16, 18, and 28 were studied by immunohistochemical analysis using NF-kappaB P65 antibody. The amount of NF-kappaB P65 protein and NF-kappaB DNA-binding activity in the whole retina were assessed by western blot analysis and gel shift analysis, respectively. Expression of NF-kappaB in microglial cells labeled with CD11b was determined by double labeling. RESULTS: NF-kappaB P65 nuclear translocation and its DNA binding activity started to increase in the rd retina at P10 and reached a peak at P12. Expressions of P65 remained at high levels from P12 to P18. Double labeling of P65 with CD11 at P14 showed colocalization of P65 in the microglial cells in the outer nuclear layer. CONCLUSIONS: NF-kappaB was activated in the retinal degeneration of rd mice. NF-kappaB modulation may play a role in the retinal degeneration through microglial activation.

Microglial activation in human diabetic retinopathy.

OBJECTIVE: To investigate microglial activation in human diabetic retinopathy. METHODS: Paraffin sections from 21 eyes of 13 patients with diabetic background, preproliferative, or proliferative retinopathies and 10 normal eyes of 9 individuals were studied with immunolabeling of microglia with antibodies against HLA-DR antigen, CD45, or CD68. RESULTS: In the healthy human eyes, ramified microglial cells were scattered in the inner retinal layers. In eyes with diabetic retinopathy, the microglia were markedly increased in number and were hypertrophic at different stages of the disease. These cells clustered around the retinal vasculature, especially the dilated veins, microaneurysms, intraretinal hemorrhages, cotton-wool spots, optic nerve, and retinal and vitreal neovascularization. In some retinas with cystoid macular edema, microglia infiltrated the outer retina and subretinal space. Cells in the epiretinal membrane were also labeled with microglial markers. CONCLUSIONS: Microglia were activated at different stages of human diabetic retinopathy and optic neuropathy. Microglial perivasculitis was a prominent feature of the disease process. CLINICAL RELEVANCE: Activated microglia and microglial perivasculitis may play a role in vasculopathy and neuropathy in diabetic retinopathy.

Activation of microglia and chemokines in light-induced retinal degeneration.

PURPOSE: Microglial cells, which are activated and recruited by chemokines, have been shown to play crucial roles in neuronal degenerations of the central nervous system (CNS). This study investigated the activation and migration of retinal microglial cells and expression of chemokines in retinas in light-induced photoreceptor degeneration in mice. METHODS: Ninety-five Balb/cJ mice were kept in cyclic light for 1 week followed by dark adaptation for 48 h prior to light exposure of 3 h at 3.5 Klux. Animals were enthuanized at various times after light exposure. Terminal deoxynucleotidyl transferase-mediated dUTP nick end label (TUNEL) assay, rat-anti-mouse CD11b and 5D4 antibodies, isolectin-B4, and a chemokine-specific gene array were used to detect DNA fragmentation during retinal degeneration, to label retinal microglial cells, and to determine the expression of retinal chemokines and chemokine receptors, respectively. Reverse-transcriptase coupled polymerase chain reactions (RT-PCRs) were conducted on selected chemokine mRNAs to confirm the gene array findings. RESULTS: After intense light exposure, TUNEL-positive cells were noted in the outer nuclear layer (ONL) of the retina at 3 h, and their presence were noticeably increased at 1 day but declined at 3 days and 7 days after light exposure. In contrast, CD11b- or isolectin-B4-positive cells were seen in the ONL as early as 6 h and their presence increased significantly at 1 day and 3 days after light exposure. These cells displayed a round or ovoid morphology at 6 h and 1 day but assumed a more ameboid configuration at 3 days. By 7 day, the number of the microglial cells declined in the ONL and they became ramified, and were present mostly in the subretinal space. 5D4-positive cells with large cell bodies were only noted at 3 day and 7 day but not earlier. With chemokine-specific gene array analysis, we identified four chemokines and two chemokine receptors showing significant increases in their gene expressions. Among them, monocyte chemoattractant protein-3 (MCP-3), showed a remarkable 4.4 fold increase in its gene expression. RT-PCR confirmed a marked increase of MCP-3 expression in retinas at 3 h to 1 day, and a return to normal at 3 days following light injury. CONCLUSIONS: Retinal chemokines such as MCP-3 and their receptors are involved in the activation and migration of retinal microglia in light-induced retinal degeneration, which in turn modulate the apoptotic loss of photoreceptor cells in the outer retina.

Identification of sequential events and factors associated with microglial activation, migration, and cytotoxicity in retinal degeneration in rd mice.

PURPOSE: To elucidate the role of activated microglia in the photoreceptor apoptosis of rd mice by identifying sequential events and factors associated with microglial activation, migration, and cytotoxicity during retinal degeneration. METHODS: Photoreceptor apoptosis in rd mice at postnatal days (P)8, 10, 12, 14, 16, and 18 was detected by terminal dUTP transferase nick end labeling (TUNEL). Retinal microglia were identified by CD11b antibody. Expression of chemokine mRNA, including monocyte chemoattractant protein (MCP)-1, MCP-3, macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, regulated on activation normal T-cell expressed and secreted (RANTES), interferon-gamma-inducible 10-kDa protein (IP-10), and fractalkine in the retina were examined by reverse transcription-polymerase chain reaction (RT-PCR) assay. Production of tumor necrosis factor (TNF)-alpha in the dystrophic retina was studied by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry analysis. Microglial expression of TNF-alpha was determined by double immunolabeling. RESULTS: Whereas photoreceptor apoptosis in the rd mice started at P10 and reached a peak at P16, activation and migration of microglial cells were observed at P10 and peaked at P14. The expression of MCP-1, MCP-3, MIP-1alpha, MIP-1beta, and RANTES transcripts were noted at P8 and reached a peak at P12. Production of TNF-alpha was noted in the outer nuclear layer (ONL) of the rd mice at P8 and reached a peak at P12. At the peak of microglial activity, TNF-alpha was predominantly expressed in the activated microglial cells in the ONL. CONCLUSIONS: Activation of microglia, as well as expression of their signaling molecules (chemokines) and microglia-derived toxic factor (TNF-alpha), coincides with or precedes the occurrence of photoreceptor apoptosis, suggesting activated microglia play a major role in retinal degeneration in rd mice. The chemokines MCP-1, MCP-3, MIP-1alpha, MIP-1beta, and RANTES are involved in activation and recruitment of the microglia to the degenerating photoreceptor cell layer. TNF-alpha, produced by the activated microglia, may accentuate the photoreceptor cell death.