A Quality Assessment of Aquaporin-4 & Myelin Oligodendrocyte Glycoprotein Antibody Testing.

BACKGROUND: Accurate anti-aquaporin-4 (AQP4) and anti-myelin oligodendrocyte glycoprotein (MOG) autoantibody assays are needed to effectively diagnose neuromyelitis optica spectrum disorder and MOG antibody-associated disease. A proportion of patients at our centre have been tested for anti-AQP4 and anti-MOG autoantibodies locally, followed by an outsourced test as part of real-world practice. Outsourced testing is costly and of unproven utility. We conducted a quality improvement project to determine the value of outsourced testing for anti-AQP4 and anti-MOG autoantibodies. METHODS: All patients seen by Calgary neurological services who underwent cell-based testing for anti-AQP4 and/or anti-MOG autoantibodies at both MitogenDx (Calgary, AB) and Mayo Clinic Laboratories (Rochester, MN, USA) between 2016 and 2020 were identified from a provincial database. The interlaboratory concordance was calculated by pairing within-subject results collected no more than 365 days apart. Retrospective chart review was done for subjects with discordant results to determine features associated with discordance and use of outsourced testing. RESULTS: Fifty-seven anti-AQP4 and 46 anti-MOG test pairs from January 2016 to July 2020 were analyzed. Concordant tests pairs comprised 54/57 (94.7%, 95%CI 88.9-100.0%) anti-AQP4 and 41/46 (89.1%, 95%CI 80.1-98.1%) anti-MOG results. Discordant anti-AQP4 pairs included two local weak positives (negative when outsourced) and one local negative (positive when outsourced). Discordant anti-MOG pairs were all due to local weak positives (negative when outsourced). CONCLUSION: Interlaboratory discordant results for cell-based testing of anti-AQP4 autoantibodies were rare. Local anti-MOG weak positive results were associated with discordance, highlighting the need for cautious interpretation based on the clinical context. Our findings may reduce redundant outsourced testing.

Relapsing Anti-GAD65-Associated Encephalitis Responsive to Thymoma Resection, Radiation, and Immunomodulatory Therapy.

Herein we describe a case of relapsing anti-GAD65-associated encephalitis which was responsive to the combination of thymoma resection, external beam radiotherapy, and immunomodulatory therapy. The case illustrates the value of remaining vigilant for the possibility of paraneoplastic syndromes in the context of anti-GAD65 antibodies and thymoma. It also illustrates that tumor-directed therapies may offer additional benefit beyond immunomodulatory therapy alone.

Patient-reported outcomes of neurologic and neuropsychiatric symptoms in mild COVID-19: a prospective cohort study.

BACKGROUND: Various neurologic manifestations have been reported in patients with COVID-19, mostly in retrospective studies of patients admitted to hospital, but there are few data on patients with mild COVID-19. We examined the frequency and persistence of neurologic/neuropsychiatric symptoms in patients with mild COVID-19 in a 1-year prospective cohort study, as well as assessment of use of health care services and patient-reported outcomes. METHODS: Participants in the Alberta HOPE COVID-19 trial (hydroxychloroquine v. placebo for 5 d), managed as outpatients, were prospectively assessed 3 months and 1 year after their positive test result. They completed detailed neurologic/neuropsychiatric symptom questionnaires, the telephone version of the Montreal Cognitive Assessment (T-MoCA), the Kessler Psychological Distress Scale (K10) and the EuroQol EQ-5D-3L (measure of quality of life). Close informants completed the Mild Behavioural Impairment Checklist (MBI-C) and the Informant Questionnaire on Cognitive Decline in the Elderly. We also tracked use of health care services and neurologic investigations. RESULTS: The cohort consisted of 198 participants (87 female [43.9%] median age 45 yr, interquartile range 37-54 yr). Of the 179 participants with symptom assessments, 139 (77.6%) reported at least 1 neurologic symptom, the most common being anosmia/dysgeusia (99 [55.3%]), myalgia (76 [42.5%]) and headache (75 [41.9%]). Forty patients (22.3%) reported persistent symptoms at 1 year, including confusion (20 [50.0%]), headache (21 [52.5%]), insomnia (16 [40.0%]) and depression (14 [35.0%]); 27/179 (15.1%) reported no improvement. Body mass index (BMI), a history of asthma and lack of full-time employment were associated with the presence and persistence of neurologic/neuropsychiatric symptoms; female sex was independently associated with both (presence: odds ratio [OR] adjusted for age, race, BMI, history of asthma and neuropsychiatric history 5.04, 95% confidence interval [CI] 1.58 to 16.10). Compared to participants without persistent symptoms, those with persistent symptoms had more hospital admissions and family physician visits, and worse MBI-C scores and less frequent independence for instrumental activities at 1 year (83.8% v. 97.8%, p = 0.005). Patients with any or persistent neurologic symptoms had worse psychologic distress (K10 score ≥ 20: adjusted OR 12.1, 95% CI 1.4 to 97.2) and quality of life (median EQ-5D-3L visual analogue scale rating 75 v. 90, p < 0.001); 42/84 (50.0%) had a T-MoCA score less than 18 at 3 months, as did 36 (42.9%) at 1 year. Participants who reported memory loss were more likely than those who did not report such symptoms to have informant-reported cognitive-behavioural decline (1-yr MBI-C score ≥ 6.5: adjusted OR 15.0, 95% CI 2.42 to 92.60). INTERPRETATION: Neurologic/neuropsychiatric symptoms were commonly reported in survivors of mild COVID-19, and they persisted in 1 in 5 patients 1 year later. Symptoms were associated with worse participant- and informant-reported outcomes. Trial registration: ClinicalTrials.gov, no. NCT04329611.

Neurology of Acute Viral Infections.

As specialists in acute neurology, neurohospitalists are often called upon to diagnose and manage acute viral infections affecting the nervous system. In this broad review covering the neurology of several acute viral infections, our aim is to provide key diagnostic and therapeutic pearls of practical use to the busy neurohospitalist. We will review acute presentations, diagnosis, and treatment of human herpesviruses, arboviruses, enteroviruses, and some vaccine-preventable viruses. The neurological effects of coronaviruses, including COVID-19, are not covered in this review.

Selective localization of Mfn2 near PINK1 enables its preferential ubiquitination by Parkin on mitochondria.

Mutations in Parkin and PINK1 cause early-onset familial Parkinson's disease. Parkin is a RING-In-Between-RING E3 ligase that transfers ubiquitin from an E2 enzyme to a substrate in two steps: (i) thioester intermediate formation on Parkin and (ii) acyl transfer to a substrate lysine. The process is triggered by PINK1, which phosphorylates ubiquitin on damaged mitochondria, which in turn recruits and activates Parkin. This leads to the ubiquitination of outer mitochondrial membrane proteins and clearance of the organelle. While the targets of Parkin on mitochondria are known, the factors determining substrate selectivity remain unclear. To investigate this, we examined how Parkin catalyses ubiquitin transfer to substrates. We found that His433 in the RING2 domain contributes to the catalysis of acyl transfer. In cells, the mutation of His433 impairs mitophagy. In vitro ubiquitination assays with isolated mitochondria show that Mfn2 is a kinetically preferred substrate. Using proximity-ligation assays, we show that Mfn2 specifically co-localizes with PINK1 and phospho-ubiquitin (pUb) in U2OS cells upon mitochondrial depolarization. We propose a model whereby ubiquitination of Mfn2 is efficient by virtue of its localization near PINK1, which leads to the recruitment and activation of Parkin via pUb at these sites.

Quality of life, respiratory symptoms, and health care utilization 1 year following outpatient management of COVID-19: a prospective cohort study.

The long-term impact of COVID-19 among those with mild infections is not well characterized. Among 81 adults who completed online assessments at 3- and 12-months following infection, quality of life scores did not significantly improve over time. Among 62 subjects who also completed telephone interviews, respiratory symptoms or exercise limitation were reported by 42% at a median follow-up of 387 days (IQR 251-402 days). Those with persistent respiratory symptoms scored lower on the EQ-5D visual analog score compared to those without. Persistent respiratory symptoms were associated with a lower likelihood of full-time employment at 1 year (aOR 0.09, 95%CI 0.01-0.91; P = 0.041). In an adjusted linear regression, persistent respiratory symptoms (P = 0.037) and female sex (P = 0.016) were both independent risks for increased visits to a primary care provider. This cohort study demonstrates that respiratory symptoms are frequent at 1 year following COVID-19 and more importantly, are associated with negative impacts on employment, quality of life, and health care utilization. Further research is needed to determine the pathophysiology and risk factors for persistent symptoms as well as optimal management strategies to improve the level of functioning and quality of life.

Hemorrhagic encephalopathy associated with COVID-19.

The mechanisms for neurological complications of COVID-19, the disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), are not yet well understood. We present a critically ill man with a COVID-19-associated hemorrhagic encephalopathy. SARS-CoV-2 RNA was not detected in cerebrospinal fluid (CSF) or blood. CSF analyses suggested dysregulation of pro-inflammatory cytokine pathways, particularly tumor necrosis factor-α and interleukin-6, consistent with a cytokine release syndrome. The patient gradually recovered with supportive care and neurological rehabilitation. Awareness of this clinical entity may facilitate the identification of patients with a potentially remediable cause of encephalopathy in COVID-19.

"Lupus Myelitis" Revisited: A Retrospective Single-Center Study of Myelitis Associated With Rheumatologic Disease.

BACKGROUND AND OBJECTIVES: Previous reports of patients with myelitis associated with rheumatologic disease may have had unrecognized aquaporin-4 (AQP4)-IgG seropositive neuromyelitis optica spectrum disorder (NMOSD) or myelin oligodendrocyte glycoprotein (MOG)-IgG-associated disease (MOGAD). We clinicoradiologically and serologically characterized patients with myelitis associated with rheumatologic disease evaluated in the era of availability of MOG-IgG and more sensitive AQP4-IgG cell-based assays. METHODS: A retrospective cohort (2018-2023) at Johns Hopkins Medicine with diagnoses of myelopathy and rheumatologic comorbidity was identified by electronic medical record (EMR) query. All patients with myelitis unrelated to typical multiple sclerosis (MS) were included and analyzed by chart review. RESULTS: Of 238 patients identified by EMR query, 197 were excluded (148 not meeting prespecified inclusion criteria, 49 had typical MS), resulting in 41 patients for review. The mean age at myelitis onset was 44 ± 15 years; 39 (95%) were female. Rheumatologic diagnoses included 17 (41.5%) with systemic lupus erythematosus (SLE), 10 (24.3%) Sjögren syndrome (SS), 6 (15%) undifferentiated connective tissue disease (UCTD), 5 (12%) combinations of SLE/SS/UCTD with antiphospholipid antibody syndrome, 1 (2.4%) rheumatoid arthritis, 1 (2.4%) psoriatic arthritis, and 1 (2.4%) Behçet disease. 20 patients (49%) were diagnosed with AQP4-IgG seropositive NMOSD, 3 (7%) with MOGAD, and 18 (44%) had "double-seronegative" myelitis. Of these 18, 3 were diagnosed with AQP4-IgG seronegative NMOSD, 1 neuro-Behçet disease, and 14 other (unclassifiable) myelitis. Excluding 1 patient with neuro-Behçet disease, 18 (90%) of 20 AQP4-IgG seropositive patients had longitudinally extensive cord lesions compared with 5 (29%; p < 0.001) of 17 "double-seronegative" patients and 2 (67%) of 3 with MOGAD. "Double-seronegative" patients more commonly had CSF-restricted oligoclonal bands. Functional outcomes did not differ by diagnosis, and most patients received acute immunotherapy at the time of initial myelitis diagnosis with at least partial recovery over a median follow-up of 38 (interquartile range: 9-74) months. DISCUSSION: Approximately half of our rheumatologic disease cohort with myelitis unrelated to MS had AQP4-IgG seropositive NMOSD while MOGAD accounted for a small but clinically relevant proportion of patients. Further research is needed to characterize myelitis etiology in patients who are seronegative for both AQP4-IgG and MOG-IgG.