Diagnostic Utility of MOG Antibody Testing in Cerebrospinal Fluid.

OBJECTIVE: The aim of this study was to assess the diagnostic utility of cerebrospinal fluid (CSF) myelin oligodendrocyte glycoprotein antibodies (MOG-IgG) testing. METHODS: We retrospectively identified patients for CSF MOG-IgG testing from January 1, 1996, to May 1, 2023, at Mayo Clinic and other medical centers that sent CSF MOG-IgG for testing including: controls, 282; serum MOG-IgG positive MOG antibody-associated disease (MOGAD), 74; serum MOG-IgG negative high-risk phenotypes, 73; serum false positive MOG-IgG with alternative diagnoses, 18. A live cell-based assay assessed CSF MOG-IgG positivity (IgG-binding-index [IBI], ≥2.5) using multiple anti-human secondary antibodies and end-titers were calculated if sufficient sample volume. Correlation of CSF MOG-IgG IBI and titer was assessed. RESULTS: The pan-IgG Fc-specific secondary was optimal, yielding CSF MOG-IgG sensitivity of 90% and specificity of 98% (Youden's index 0.88). CSF MOG-IgG was positive in: 4/282 (1.4%) controls; 66/74 (89%) serum MOG-IgG positive MOGAD patients; and 9/73 (12%) serum MOG-IgG negative patients with high-risk phenotypes. Serum negative but CSF positive MOG-IgG accounted for 9/83 (11%) MOGAD patients, and all fulfilled 2023 MOGAD diagnostic criteria. Subgroup analysis of serum MOG-IgG low-positives revealed CSF MOG-IgG positivity more in MOGAD (13/16[81%]) than other diseases with false positive serum MOG-IgG (3/15[20%]) (p = 0.01). CSF MOG-IgG IBI and CSF MOG-IgG titer (both available in 29 samples) were correlated (Spearman's r = 0.64, p < 0.001). INTERPRETATION: CSF MOG-IgG testing has diagnostic utility in patients with a suspicious phenotype but negative serum MOG-IgG, and those with low positive serum MOG-IgG results and diagnostic uncertainty. These findings support a role for CSF MOG-IgG testing in the appropriate clinical setting. ANN NEUROL 2024;96:34-45.

Radiologic Predictors of Visual Outcome in Myelin Oligodendrocyte Glycoprotein-Related Optic Neuritis.

PURPOSE: This study aimed to determine whether magnetic resonance imaging (MRI) biomarkers are associated with visual prognosis in myelin oligodendrocyte protein (MOG)-associated optic neuritis (ON). DESIGN: Cross-sectional analysis. PARTICIPANTS: Patients meeting 2023 international diagnostic criteria for MOG antibody-associated disease who were seen for first episodes of MOG-associated ON at 3 tertiary neuro-ophthalmology practices between January 2017 and July 2023 were enrolled. Patients who received < 3 months of neuro-ophthalmic follow-up and did not demonstrate visual recovery (visual acuity [VA] ≥ 20/20 and visual field mean deviation [VFMD] > -5.0 dB) during this time were excluded. METHODS: Patients underwent contrast-enhanced, fat-suppressed MRI of the brain and orbits within 1 month of symptom onset. MAIN OUTCOME MEASURES: The associations between radiologic biomarkers and poor VA outcome (< 20/40), incomplete VA recovery (< 20/20), and poor VFMD outcome (VFMD < -5.0 dB) were assessed using multivariable logistic regression adjusting for time from symptom onset to treatment and nadir VA or VFMD. Radiologic biomarkers included length of optic nerve enhancement (> 25% vs. < 25%; > 50% vs. < 50%; and > 75% vs. < 75%); degree of orbital, canalicular, and intracranial or chiasmal optic nerve enhancement (mild vs. moderate to severe compared with the lacrimal gland); and absence versus presence of optic nerve sheath enhancement on baseline T1-weighted MRI. RESULTS: A total of 129 eyes of 92 patients (median age, 37.0 years [interquartile range, 20.8-51.3 years]; 65.2% female) were included. Poor VA outcome was seen in 6.2% of patients, incomplete VA recovery was seen in 19.4% of patients, and poor VFMD outcome was seen in 16.9% of patients. Compared with eyes with moderate to severe enhancement, eyes with mild orbital optic nerve enhancement were more likely to have poor VA outcome (odds ratio [OR], 8.57; 95% confidence interval [CI], 1.85-51.14; P = 0.009), incomplete VA recovery (OR, 7.31, 95% CI, 2.42-25.47; P = 0.001), and poor VFMD outcome (adjusting for time to treatment: OR, 6.81; 95% CI, 1.85-28.98; P = 0.005; adjusting for nadir VFMD: OR, 11.65; 95% CI, 1.60-240.09; P = 0.04). Lack of optic nerve sheath enhancement additionally was associated with incomplete VA recovery (OR, 3.86; 95% CI, 1.19-12.85; P = 0.02) compared with the presence of enhancement. These associations remained consistent in subgroup logistic regression analysis of MRIs performed before initiation of treatment but were not seen in pairwise analysis of MRIs performed after treatment. CONCLUSIONS: In eyes with first MOG-associated ON episodes, milder enhancement in the orbital optic nerve was associated with poorer VA and visual field recovery. Prospective and mechanistic studies are needed to confirm the prognostic usefulness of MRI in MOG-associated ON. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Etiologies and Outcomes of Granulomatosis With Polyangiitis-Associated Optic Neuropathy: A Case Series and Review of the Literature.

BACKGROUND: Granulomatosis with polyangiitis (GPA), formerly known as Wegener granulomatosis, is a rare autoimmune disease characterized by inflammation of small- to medium-sized blood vessels (vasculitis). We described the 3 causes of GPA-associated optic neuropathy (compressive, inflammatory, or ischemic) and analyzed initial and final visual acuities (VAs) in each group, which could potentially help prognosticate visual outcomes depending on the etiology of optic neuropathy. METHODS: This was a retrospective chart review of patients who were diagnosed with GPA-associated optic neuropathy and were seen in the Department of Ophthalmology at Mayo Clinic in Rochester, Minnesota. Only patients who met the 2022 American College of Rheumatology/European Alliance of Associations for Rheumatology GPA classification criteria were included. RESULTS: A total of 12 patients with GPA-associated optic neuropathy were identified. The etiology of the optic neuropathy was compressive in 6 patients, inflammatory in 4 patients, and ischemic in 3 patients. One patient had compressive optic neuropathy initially, then presented with GPA-related optic neuritis years later. Four patients in the compressive optic neuropathy group had orbital masses requiring orbitotomy for debulking, and the remaining 2 patients had compression from pachymeningitis. Average logarithm of the minimum angle of resolution (logMAR) VA at optic neuropathy onset was 1.50, 1.50, and 0.67 (Snellen equivalent 20/600, 20/600, and 20/100, respectively). At the last follow-up, average logMAR VA was 0.91, 1.73, and 1.10 (Snellen equivalent 20/160, 20/1,000, and 20/250, respectively) for each group. CONCLUSION: Visual outcomes were variable, with compressive and inflammatory optic neuropathies showing improvement in 4 eyes and worsening in 3 eyes in total. Patients with ischemic optic neuropathy from GPA were either stable or worsened over the course of the disease.

Optic Disc Cupping in Neuromyelitis Optica Spectrum Disorder, Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease, and Multiple Sclerosis and Its Relationship With Optical Coherence Tomography Parameters: A Multicenter Study.

BACKGROUND: Although cupping of the optic nerve is classically a sign of glaucomatous optic neuropathy, it has been shown that cupping can sometimes occur after an episode of optic neuritis (ON). The purpose of this study was to compare cupping in patients after ON from multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), or myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and to investigate the relationship between cupping and retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thinning. METHODS: This was a retrospective cohort involving patients (≥18 years) with ON from 3 institutions. Patients were eligible if they had optical coherence tomography (Cirrus, OCT) performed ≥6 months after a single unilateral ON. The amount of thinning and cupping was estimated from the difference in the OCT parameters between affected and unaffected eyes. Univariable and multivariable regressions were used to investigate the relationship between cupping and ON etiology. Pearson correlation was used to investigate the relationship between cupping and RNFL and GCC. RESULTS: Eighty-six subjects (MS: 35, NMOSD: 26, and MOGAD: 25) were included. There was no significant difference in gender and race between the groups, and most patients (86.1%) were female. Patients with NMOSD were significantly older than patients with MS or MOGAD (P = 0.002). In the univariate model, cupping was significantly higher in the NMOSD group (P = 0.017); however, after adjusting for age, GCC, and RNFL of the affected eye, the difference was no longer statistically significant (P = 0.949). The correlation between cupping asymmetry and RNFL and GCC of the affected eye was inversely strong in patients with MS (R = -0.60 and R = -0.64, respectively), inversely moderate in patients with MOGAD (R = -0.34 and R = -0.40, respectively), and weak in patients with NMOSD (R = -0.03 and R = -0.17, respectively). CONCLUSIONS: Our results demonstrated that cupping after ON is correlated with RNFL and GCC thinning; although cupping was overall greater in the NMOSD group, once adjusted for age, RNFL, and GCC, it did not differ among patients with MS, NMOSD, and MOGAD.

A Comparative Study of Large Language Models, Human Experts, and Expert-Edited Large Language Models to Neuro-Ophthalmology Questions.

BACKGROUND: While large language models (LLMs) are increasingly used in medicine, their effectiveness compared with human experts remains unclear. This study evaluates the quality and empathy of Expert + AI, human experts, and LLM responses in neuro-ophthalmology. METHODS: This randomized, masked, multicenter cross-sectional study was conducted from June to July 2023. We randomly assigned 21 neuro-ophthalmology questions to 13 experts. Each expert provided an answer and then edited a ChatGPT-4-generated response, timing both tasks. In addition, 5 LLMs (ChatGPT-3.5, ChatGPT-4, Claude 2, Bing, Bard) generated responses. Anonymized and randomized responses from Expert + AI, human experts, and LLMs were evaluated by the remaining 12 experts. The main outcome was the mean score for quality and empathy, rated on a 1-5 scale. RESULTS: Significant differences existed between response types for both quality and empathy (P < 0.0001, P < 0.0001). For quality, Expert + AI (4.16 ± 0.81) performed the best, followed by GPT-4 (4.04 ± 0.92), GPT-3.5 (3.99 ± 0.87), Claude (3.6 ± 1.09), Expert (3.56 ± 1.01), Bard (3.5 ± 1.15), and Bing (3.04 ± 1.12). For empathy, Expert + AI (3.63 ± 0.87) had the highest score, followed by GPT-4 (3.6 ± 0.88), Bard (3.54 ± 0.89), GPT-3.5 (3.5 ± 0.83), Bing (3.27 ± 1.03), Expert (3.26 ± 1.08), and Claude (3.11 ± 0.78). For quality (P < 0.0001) and empathy (P = 0.002), Expert + AI performed better than Expert. Time taken for expert-created and expert-edited LLM responses was similar (P = 0.75). CONCLUSIONS: Expert-edited LLM responses had the highest expert-determined ratings of quality and empathy warranting further exploration of their potential benefits in clinical settings.

Clinical Characteristics and Treatment of MOG-IgG-Associated Optic Neuritis.

PURPOSE OF REVIEW: Antibodies against myelin oligodendrocyte glycoprotein (MOG) are associated with a unique acquired central nervous system demyelinating disease-termed MOG-IgG-associated disorder (MOGAD)-which has a variety of clinical manifestations, including optic neuritis, transverse myelitis, acute disseminating encephalomyelitis, and brainstem encephalitis. In this review, we summarize the current knowledge of the clinical characteristics, neuroimaging, treatments, and outcomes of MOGAD, with a focus on optic neuritis. RECENT FINDINGS: The recent development of a reproducible, live cell-based assay for MOG-IgG, has improved our ability to identify and study this disease. Based on contemporary studies, it has become increasingly evident that MOGAD is distinct from multiple sclerosis and aquaporin-4-positive neuromyelitis optica spectrum disorder with different clinical features and treatment outcomes. There is now sufficient evidence to separate MOGAD from other inflammatory central nervous system demyelinating disorders, which will allow focused research on understanding the pathophysiology of the disease. Prospective treatment trials are needed to determine the best course of treatment, and until then, treatment plans must be individualized to the clinical manifestations and severity of disease.

Acute Optic Neuropathy in Older Adults: Differentiating Between MOGAD Optic Neuritis and Nonarteritic Anterior Ischemic Optic Neuropathy.

BACKGROUND AND OBJECTIVES: Myelin oligodendrocyte glycoprotein antibody-associated disease optic neuritis (MOGAD-ON) and nonarteritic anterior ischemic optic neuropathy (NAION) can cause acute optic neuropathy in older adults but have different managements. We aimed to determine differentiating factors between MOGAD-ON and NAION and the frequency of serum MOG-IgG false positivity among patients with NAION. METHODS: In this international, multicenter, case-control study at tertiary neuro-ophthalmology centers, patients with MOGAD presenting with unilateral optic neuritis as their first attack at age 45 years or older and age-matched and sex-matched patients with NAION were included. Comorbidities, clinical presentations, acute optic disc findings, optical coherence tomography (OCT) findings, and outcomes were compared between MOGAD-ON and NAION. Multivariate analysis was performed to find statistically significant predictors of MOGAD-ON. A separate review of consecutive NAION patients seen at Mayo Clinic, Rochester, from 2018 to 2022, was conducted to estimate the frequency of false-positive MOG-IgG in this population. RESULTS: Sixty-four patients with unilateral MOGAD-ON were compared with 64 patients with NAION. Among patients with MOGAD-ON, the median age at onset was 56 (interquartile range [IQR] 50-61) years, 70% were female, and 78% were White. Multivariate analysis showed that eye pain was strongly associated with MOGAD-ON (OR 32.905; 95% CI 2.299-473.181), while crowded optic disc (OR 0.033; 95% CI 0.002-0.492) and altitudinal visual field defect (OR 0.028; 95% CI 0.002-0.521) were strongly associated with NAION. On OCT, peripapillary retinal nerve fiber layer (pRNFL) thickness in unilateral MOGAD-ON was lower than in NAION (median 114 vs 201 µm, p < 0.001; median pRNFL thickening 25 vs 102 µm, p < 0.001). MOGAD-ON had more severe vision loss at nadir (median logMAR 1.0 vs 0.3, p < 0.001), but better recovery (median logMAR 0.1 vs 0.3, p = 0.002). In the cohort of consecutive NAION patients, 66/212 (31%) patients with NAION were tested for MOG-IgG and 8% (95% CI 1%-14%) of those had false-positive serum MOG-IgG at low titers. DISCUSSION: Acute unilateral optic neuropathy with optic disc edema in older adults can be caused by either MOGAD-ON or NAION. Detailed history, the degree of pRNFL swelling on OCT, and visual outcomes can help differentiate the entities and prevent indiscriminate serum MOG-IgG testing in all patients with acute optic neuropathy.

Appropriateness of Ophthalmology Recommendations From an Online Chat-Based Artificial Intelligence Model.

Objective: To determine the appropriateness of ophthalmology recommendations from an online chat-based artificial intelligence model to ophthalmology questions. Patients and Methods: Cross-sectional qualitative study from April 1, 2023, to April 30, 2023. A total of 192 questions were generated spanning all ophthalmic subspecialties. Each question was posed to a large language model (LLM) 3 times. The responses were graded by appropriate subspecialists as appropriate, inappropriate, or unreliable in 2 grading contexts. The first grading context was if the information was presented on a patient information site. The second was an LLM-generated draft response to patient queries sent by the electronic medical record (EMR). Appropriate was defined as accurate and specific enough to serve as a surrogate for physician-approved information. Main outcome measure was percentage of appropriate responses per subspecialty. Results: For patient information site-related questions, the LLM provided an overall average of 79% appropriate responses. Variable rates of average appropriateness were observed across ophthalmic subspecialties for patient information site information ranging from 56% to 100%: cataract or refractive (92%), cornea (56%), glaucoma (72%), neuro-ophthalmology (67%), oculoplastic or orbital surgery (80%), ocular oncology (100%), pediatrics (89%), vitreoretinal diseases (86%), and uveitis (65%). For draft responses to patient questions via EMR, the LLM provided an overall average of 74% appropriate responses and varied by subspecialty: cataract or refractive (85%), cornea (54%), glaucoma (77%), neuro-ophthalmology (63%), oculoplastic or orbital surgery (62%), ocular oncology (90%), pediatrics (94%), vitreoretinal diseases (88%), and uveitis (55%). Stratifying grades across health information categories (disease and condition, risk and prevention, surgery-related, and treatment and management) showed notable but insignificant variations, with disease and condition often rated highest (72% and 69%) for appropriateness and surgery-related (55% and 51%) lowest, in both contexts. Conclusion: This LLM reported mostly appropriate responses across multiple ophthalmology subspecialties in the context of both patient information sites and EMR-related responses to patient questions. Current LLM offerings require optimization and improvement before widespread clinical use.

Visual Outcomes Following Plasma Exchange for Optic Neuritis: An International Multicenter Retrospective Analysis of 395 Optic Neuritis Attacks.

PURPOSE: To evaluate the effectiveness of plasma exchange (PLEX) for optic neuritis (ON). METHODS: We conducted an international multicenter retrospective study evaluating the outcomes of ON following PLEX. Outcomes were compared to raw data from the Optic Neuritis Treatment Trial (ONTT) using a matched subset. RESULTS: A total of 395 ON attack treated with PLEX from 317 patients were evaluated. The median age was 37 years (range 9-75), and 71% were female. Causes of ON included multiple sclerosis (108), myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) (92), aquaporin-4-IgG-positive neuromyelitis optica spectrum disorder (AQP4+NMOSD) (75), seronegative-NMOSD (34), idiopathic (83), and other (3). Median time from onset of vision loss to PLEX was 2.6 weeks (interquartile range [IQR], 1.4-4.0). Median visual acuity (VA) at the time of PLEX was count fingers (IQR, 20/200-hand motion), and median final VA was 20/25 (IQR, 20/20-20/60) with no differences among etiologies except MOGAD-ON, which had better outcomes. In 81 (20.5%) ON attacks, the final VA was 20/200 or worse. Patients with poor outcomes were older (P = .002), had worse VA at the time of PLEX (P < .001), and longer delay to PLEX (P < .001). In comparison with the ONTT subset with severe corticosteroid-unresponsive ON, a final VA of worse than 20/40 occurred in 6 of 50 (12%) PLEX-treated ON vs 7 of 19 (37%) from the ONTT treated with intravenous methylprednisolone without PLEX (P = .04). CONCLUSION: Most ON attacks improved with PLEX, and outcomes were better than attacks with similar severity in the ONTT. The presence of severe vision loss at nadir, older age, and longer delay to PLEX predicted a worse outcome whereas MOGAD-ON had a more favorable prognosis. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Murine corneal transplantation: a model to study the most common form of solid organ transplantation.

Corneal transplantation is the most common form of organ transplantation in the United States with between 45,000 and 55,000 procedures performed each year. While several animal models exist for this procedure and mice are the species that is most commonly used. The reasons for using mice are the relative cost of using this species, the existence of many genetically defined strains that allow for the study of immune responses, and the existence of an extensive array of reagents that can be used to further define responses in this species. This model has been used to define factors in the cornea that are responsible for the relative immune privilege status of this tissue that enables corneal allografts to survive acute rejection in the absence of immunosuppressive therapy. It has also been used to define those factors that are most important in rejection of such allografts. Consequently, much of what we know concerning mechanisms of both corneal allograft acceptance and rejection are due to studies using a murine model of corneal transplantation. In addition to describing a model for acute corneal allograft rejection, we also present for the first time a model of late-term corneal allograft rejection.