Screening for autoantibodies in inflammatory neurological syndrome using fluorescence pattern in a tissue-based assay: Cerebrospinal fluid findings from 793 patients

A Mild Phenotype of Overlapping Syndrome With Myelin-Oligodendrocyte Glycoprotein and Glial Fibrillary Acidic Protein Immunoglobulin G: Mimicking Viral Meningitis in a Patient

INTRODUCTION

Glial fibrillary acidic protein (GFAP) astrocytopathy, an autoimmune central nervous system disorder characterized by the development of immunoglobulin G reactive with GFAP, has received growing attention in recent years. It is documented that GFAP-immunoglobulin G and other autoantibodies can be both detected in some patients. However, the coexistence of anti-myelin-oligodendrocyte glycoprotein (MOG) and GFAP antibodies is rarely reported.

CASE

A 45-year-old man presented with headache, fever, backache, dysuria, tremble of hands, numbness of lower limbs, without diplopia, decreased vision, or other manifestations of optic neuritis. He was initially diagnosed with viral meningitis. After antiviral therapy, his headache, fever, and dysuria were improved, but the tremble of his upper limbs and numbness of his lower limbs still existed. A lumbar puncture was further performed and found both anti-GFAP and anti-MOG antibodies in the cerebrospinal fluid. No evidence of other immune disorders or infectious diseases was revealed. Meanwhile, a magnetic resonance scan showed enhancement of spinal pia mater in cervical, thoracic, and lumbar segments. He was then treated with immunoglobulin (intravenous immunoglobulin) therapy (25 g for 5 d), and steroid pulse therapy (methylprednisolone, 1 g for 5 d), followed by a gradual tapering of oral prednisolone.

CONCLUSION

We reported a case of overlapping anti-GFAP and anti-MOG antibody-associated syndrome. This case enriches our understanding of the clinical manifestations of overlapping syndrome and expands the spectrum of this disorder.

A framework for immunofluorescence image augmentation and classification based on unsupervised attention mechanism

Autoimmune encephalitis (AE) is a common neurological disorder. As a standard method for neuroautoantibody detection, pathologists use tissue matrix assays (TBA) for initial disease screening. In this study, microscopic fluorescence imaging was combined with deep learning to improve AE diagnostic accuracy. Due to the inter-class imbalance of medical data, we propose an innovative generative adversarial network supplemented with attention mechanisms to highlight key regions in images to synthesize high-quality fluorescence images. However, securing annotated medical data is both time-consuming and costly. To circumvent this problem, we employ a self-supervised learning approach that utilizes unlabeled fluorescence data to support downstream classification tasks. To better understand the fluorescence properties in the data, we introduce a multichannel input convolutional neural network that adds additional channels of fluorescence intensity. This study builds an AE immunofluorescence dataset and obtains the classification accuracy of 88.5% using our method, thus confirming the effectiveness of the proposed method.

Prevalence of serum MOG antibody and AQP4 antibody in optic neuritis after SARS-CoV-2 infection

Purpose

To evaluate the prevalence of serum myelin oligodendrocyte glycoprotein antibody (MOG-Ab) and aquaporin-4 antibody (AQP4-Ab) in optic neuritis (ON) patients after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection by cell-based indirect immunofluorescence assay (CBA).

Methods

In this prospective case series study, 35 patients clinically diagnosed as ON and laboratory-confirmed SARS-CoV-2 infection from 8 December 2022 to 8 February 2023 were included. All patients' clinical and laboratory data were collected and analyzed.

Results

The mean age of the 35 patients (46 eyes) was 38.2 years (ranging from 6 to 69 years), and 17 cases were female patients. Thirty-three and two cases showed positive SARS-CoV-2 RNA test results before or shortly after ON onset, respectively. ON occurred unilaterally in 24 cases and bilaterally in 11 cases. Ophthalmic examination revealed swollen optic disc in 37 eyes, normal optic disc in 6 eyes, and temporally or wholly paled optic disc in 3 eyes. CBA revealed seropositive MOG-Ab in 10 cases and AQP4-Ab in 2 cases, respectively, of which 2 AQP4-Ab-seropositive cases and 1 MOG-Ab-seropositive case had a past medical history of ON. Most ON patients showed a rapid and dramatic response to pulse steroid therapy. The median of BCVA at the onset and at the last follow-up was 20/500 (ranging from light perception to 20/20) and 20/67 (ranging from counting fingers to 20/20), respectively.

Conclusion

Serum MOG-Ab and AQP4-Ab were detected in 28.6% (10/35) and 5.7% (2/35) ON cases after SARS-CoV-2 infection. SARS-CoV-2 infection may trigger an onset or a relapse of ON, as well as the production of MOG-Ab.

Early autoimmunity and outcome in virus encephalitis: a retrospective study based on tissue-based assay

To explore the autoimmune response and outcome in the central nervous system (CNS) at the onset of viral infection and correlation between autoantibodies and viruses.

METHODS

A retrospective observational study was conducted in 121 patients (2016-2021) with a CNS viral infection confirmed via cerebrospinal fluid (CSF) next-generation sequencing (cohort A). Their clinical information was analysed and CSF samples were screened for autoantibodies against monkey cerebellum by tissue-based assay. In situ hybridisation was used to detect Epstein-Barr virus (EBV) in brain tissue of 8 patients with glial fibrillar acidic protein (GFAP)-IgG and nasopharyngeal carcinoma tissue of 2 patients with GFAP-IgG as control (cohort B).

RESULTS

Among cohort A (male:female=79:42; median age: 42 (14-78) years old), 61 (50.4%) participants had detectable autoantibodies in CSF. Compared with other viruses, EBV increased the odds of having GFAP-IgG (OR 18.22, 95% CI 6.54 to 50.77, p<0.001). In cohort B, EBV was found in the brain tissue from two of eight (25.0%) patients with GFAP-IgG. Autoantibody-positive patients had a higher CSF protein level (median: 1126.00 (281.00-5352.00) vs 700.00 (76.70-2899.00), p<0.001), lower CSF chloride level (mean: 119.80±6.24 vs 122.84±5.26, p=0.005), lower ratios of CSF-glucose/serum-glucose (median: 0.50[0.13-0.94] vs 0.60[0.26-1.23], p=0.003), more meningitis (26/61 (42.6%) vs 12/60 (20.0%), p=0.007) and higher follow-up modified Rankin Scale scores (1 (0-6) vs 0 (0-3), p=0.037) compared with antibody-negative patients. A Kaplan-Meier analysis revealed that autoantibody-positive patients experienced significantly worse outcomes (p=0.031).

CONCLUSIONS

Autoimmune responses are found at the onset of viral encephalitis. EBV in the CNS increases the risk for autoimmunity to GFAP.

Case Report: Optic neuritis as the initial presentation of Orientia tsutsugamushi infection detected by metagenomic next-generation sequencing

Scrub typhus is an acute febrile illness caused by Orientia tsutsugamushi infection, and typically manifested as fever, eschar, lymphadenopathy, rash, and other flu-like signs. Ocular involvement was not uncommon, and mostly occurred at post-fever or recovery stage in scrub typhus cases. We hereby report a case of scrub typhus presenting as unilateral optic neuritis (ON). A 56-year-old man going wild fishing nearly every day complained of a blurred vision and an inferior visual field defect in the right eye two or three days after an insect-bite like shin induration in his left leg. He was diagnosed as ON, and treated with dexamethasone in the local hospital. Unfortunately, his right eye vision progressively deteriorated during steroid therapy. Three days after steroid therapy ceased, he suffered from a high fever and painful subcutaneous masses in the left groin. Peripheral blood test by metagenomic next-generation sequencing (mNGS) was positive for Orientia tsutsugamushi, but negative for other pathogens. The diagnosis was then revised to scrub typhus and ON. His systemic symptoms rapidly disappeared after oral doxycycline and omadacycline therapy. However, his right eye vision continuously deteriorated to hand motion. Further serum tests for aquaporin 4-IgG antibody and myelin oligodendrocyte glycoprotein-IgG antibody were both negative, but for anticardiolipin IgM and beta-2-glycoprotein-I IgM were both positive. The patient's right eye vision gradually improved after doxycycline combined with steroid pulse therapy. Our case indicates that ON in scrub typhus cases may present as a parainfectious inflammation, and that mNGS is a useful and valuable method for early diagnosis of scrub typhus.

Coexistent anti-GFAP and anti-MOG antibodies presenting with isolated meningitis and papillitis: more support for overlapping pathophysiology

Background

Anti-myelin oligodendrocyte glycoprotein (MOG)-associated disorders are heterogeneous and associated predominantly with central nervous system demyelination. Anti-glial fibrillar acidic protein (GFAP) conditions are much rarer and involve meningoencephalomyelitis with papillitis in addition to characteristic imaging findings and are generally a severe condition. Multiple autoantibodies can exist in patients and may support overlapping pathophysiological mechanisms. The co-occurrence of MOG and GFAP antibodies, however, is rare, with only two cases previously reported.

Case

A 53-year-old man presented with headache and fevers, with quick resolution, though with the later development of asymptomatic papillitis. He had a full recovery without the need for immunotherapy. He underwent extensive investigations and was found to have both anti-GFAP and anti-MOG antibodies in the cerebrospinal fluid. Extensive other immunological and infectious investigations were negative. Imaging was largely unremarkable.

Conclusions

This is the third case of overlapping anti-GFAP and anti-MOG antibody-associated syndrome of self-limited lymphocytic meningitis, serving to expand the phenotype. Clinicians should consider testing for GFAP and MOG antibodies in otherwise unexplained meningitis, particularly with associated papillitis. This case may also help provide future insights into the pathophysiology of each condition.

Overlapping syndrome mimicking infectious meningoencephalitis in a patient with MOG and GFAP IgG

Background

Central nervous system overlapping autoimmune syndromes are uncommon, especially with the coexistence of MOG-IgG and GFAP-IgG.

Case presentation

A 23-year-old woman presented with transient convulsions, a loss of consciousness, persistent fever, headache, and vomiting. Cerebrospinal fluid (CSF) analysis revealed elevated cellularity, and magnetic resonance imaging (MRI) showed diffuse leptomeningeal enhancement. She had fever and headache with antiviral and antibiotic treatment for 2 weeks, and she had empirical anti-tuberculosis treatment and oral prednisolone therapy. She was followed for 3 months after presentation with improved symptoms and normal CSF analysis. A 3-month follow-up MRI showed asymmetric lesions in the cerebellum, corona radiata, and white matter with enhancement. The anti-tuberculosis treatment was continued, and steroid therapy was discontinued. After she stopped taking prednisolone, an interrupted headache gradually appeared. MRI at 4 months after presentation revealed a partial reduction in lesions but enlarged areas in the left cerebellum and right parietal white matter and a new lesion in the region of the right ependyma with linear enhancement. Her CSF was positive for anti-myelin oligodendrocyte glycoprotein (MOG) and anti-glial fibrillary acidic protein (GFAP) antibodies using a transfected cell-based assay. She was diagnosed with overlapping syndrome of MOG‑IgG‑associated disease and GFAP astrocytopathy. She received steroid pulse therapy (methylprednisolone, 1 g for 5 days), followed by a gradual tapering of oral prednisolone and the addition of an immunosuppressant (tacrolimus, 3 mg per day). Six months after the initial presentation, she had no symptoms. An MRI showed that the lesions had diminished, and no enhancement was found.

Conclusions

We report a case that was positive for double antibodies, which was initially misdiagnosed as infectious meningoencephalitis. This case broadens the clinical and phenotypic presentation of the overlapping syndrome spectrum.

Evaluation of cell-based and tissue-based immunofluorescent assays for detection of glial fibrillary acidic protein autoantibodies in the cerebrospinal fluid of dogs with meningoencephalitis of unknown origin and other central nervous system disorders

OBJECTIVE

To evaluate whether cell-based and tissue-based immunofluorescent assays (IFAs) run in parallel could be used to detect glial fibrillary acidic protein (GFAP) autoantibodies in the CSF of dogs with meningoencephalitis of unknown origin (MUO) and other CNS disorders.

ANIMALS

15 CSF samples obtained from dogs with presumed MUO (n = 5), CNS disease other than MUO (5), and idiopathic epilepsy (5).

PROCEDURES

All CSF samples underwent parallel analysis with a cell-based IFA that targeted the α isoform of human GFAP and a tissue-based IFA that involved mouse brain cryosections. Descriptive data were generated.

RESULTS

Only 1 CSF sample yielded mildly positive results on the cell-based IFA; that sample was from 1 of the dogs with presumed MUO. The remaining 14 CSF samples tested negative on the cell-based IFA. All 15 CSF samples yielded negative results on the tissue-based IFA.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that concurrent use of a cell-based IFA designed to target the human GFAP-α isoform and a tissue-based IFA that involved mouse tissue cryosections was inadequate for detection of GFAP autoantibodies in canine CSF samples. Given that GFAP autoantibodies were likely present in the CSF samples analyzed, these findings suggested that epitopes differ substantially between canine and human GFAP and that canine GFAP autoantibody does not bind to mouse GFAP. Without a positive control, absence of GFAP autoantibody in this cohort cannot be ruled out. Further research is necessary to develop a noninvasive and sensitive method for diagnosis of MUO in dogs.

Overlapping syndrome of MOG-IgG-associated disease and autoimmune GFAP astrocytopathy

Antibodies against myelin oligodendrocyte glycoprotein (MOG-IgG) have been considered to be closely relevant to an inflammatory demyelinating disease of the central nervous system (CNS). Glial fibrillary acidic protein (GFAP) immunoglobulin G (IgG) has been identified as a biomarker for a novel autoimmune astrocytopathy. However, coexistence of MOG-IgG and GFAP-IgG is extremely unusual and only one patient has been described with simultaneous presence of MOG-IgG in serum and GFAP-IgG in cerebrospinal fluid (CSF). Herein, we reported the first case of overlapping syndrome of MOG-IgG-associated disease (MOG-AD) and autoimmune GFAP astrocytopathy in whom MOG-IgG and GFAP-IgG were detected both in serum and CSF. A 20-year-old male patient was referred to our department with the presentation of decreased vision, diplopia and weakness of right limb with unknown reasons. Magnetic resonance imaging (MRI) revealed multiple intracranial lesions presenting hypointensity on T1-weighted images, hyperintensity on T2-weighted and FLAIR images and patchy contrast enhancement. MOG-IgG and GFAP-IgG were detected both in serum and CSF, and the titers of both antibodies fluctuated with the severity of disease. Treatment strategy employing intravenous methylprednisolone pulse therapy followed by oral prednisone with slow tapering resulted in an improvement of his symptoms and a sustained remission. Coexistence of MOG-IgG and GFAP-IgG with distinct underlying pathogeneses necessitates the recommendations to screen all recognized pathogenic antibodies against CNS antigens when an autoimmune disease is suspected, since it shows great significance for definite diagnosis of disease and treatment strategy options.

Overlapping Clinical Syndromes in Patients with Glial Fibrillary Acidic Protein IgG

OBJECTIVE

The aim of this paper is to report 2 cases with overlapping syndromes in autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy.

METHODS

Antibodies were detected by indirect immunofluorescence assay. Patient data were analyzed retrospectively.

RESULTS

One patient presented with overlapping neuromyelitis optica spectrum disorder (NMOSD) and positive GFAP-IgG and aquaporin-4-IgG. His main symptoms included vision loss, hiccups, fever, headache, and ataxia. High leukocyte count and protein levels were found in cerebrospinal fluid. Brain magnetic resonance imaging (MRI) revealed abnormalities in the hippocampus, midbrain, pons, medulla, and meninges. Characteristic radial enhancing patterns were seen. The other patient was a male with relapsing polychondritis (RP) and positive GFAP-IgG. His main manifestations were meningoencephalitis and dementia. MRI showed extensive abnormalities in the white matter around the ventricles, temporal lobe, and thalamus, with enhancement. Both patients responded well to the treatment with steroids and immunosuppressants.

CONCLUSIONS

Although overlapping syndromes are rare, we report positive GFAP-IgG in 2 cases with NMOSD or RP. Both patients had clinical features of GFAP astrocytopathy, but diagnosis of the condition was very challenging because of the overlapping presentation.