Genome-Wide Association Study Identifies IFIH1 and HLA-DQB1*05:02 Loci Associated With Anti-NMDAR Encephalitis.

BACKGROUND AND OBJECTIVES: Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is a rare autoimmune neurologic disorder, the genetic etiology of which remains poorly understood. Our study aims to investigate the genetic basis of this disease in the Chinese Han population. METHODS: We performed a genome-wide association study and fine-mapping study within the major histocompatibility complex (MHC) region of 413 Chinese patients with anti-NMDAR encephalitis recruited from 6 large tertiary hospitals and 7,127 healthy controls. RESULTS: Our genome-wide association analysis identified a strong association at the IFIH1 locus on chromosome 2q24.2 (rs3747517, p = 1.06 × 10-8, OR = 1.55, 95% CI, 1.34-1.80), outside of the human leukocyte antigen (HLA) region. Furthermore, through a fine-mapping study of the MHC region, we discovered associations for 3 specific HLA class I and II alleles. Notably, HLA-DQB1*05:02 (p = 1.43 × 10-12; OR, 2.10; 95% CI 1.70-2.59) demonstrates the strongest association among classical HLA alleles, closely followed by HLA-A*11:01 (p = 4.36 × 10-7; OR, 1.52; 95% CI 1.29-1.79) and HLA-A*02:07 (p = 1.28 × 10-8; OR, 1.87; 95% CI 1.50-2.31). In addition, we uncovered 2 main HLA amino acid variation associated with anti-NMDAR encephalitis including HLA-DQß1-126H (p = 1.43 × 10-12; OR, 2.10; 95% CI 1.70-2.59), exhibiting a predisposing effect, and HLA-B-97R (p = 3.40 × 10-8; OR, 0.63; 95% CI 0.53-0.74), conferring a protective effect. Computational docking analysis suggested a close relationship between the NR1 subunit of NMDAR and DQB1*05:02. DISCUSSION: Our findings indicate that genetic variation in IFIH1, involved in the type I interferon signaling pathway and innate immunity, along with variations in the HLA class I and class II genes, has substantial implications for the susceptibility to anti-NMDAR encephalitis in the Chinese Han population.

Cerebrospinal fluid uric acid levels associated with disease severity in patients with anti-N-methyl-d-aspartate receptor encephalitis.

INTRODUCTION: Uric acid (UA) is an important natural antioxidant and strong peroxynitrite scavenger, but little is known about central nervous system (CNS) levels of UA in patients with anti-N-methyl-d-aspartate receptor encephalitis (NMDARE). METHODS: Cerebrospinal fluid (CSF) and serum levels of UA were determined in 72 patients with anti-NMDARE and 111 controls with non-inflammatory neurological diseases (NINDs). Serum UA levels were also evaluated in 132 healthy controls (HCs). CSF neuron-specific enolase (NSE) and blood-brain barrier (BBB) index were evaluated in patients with anti-NMDARE. The association of CSF UA levels with anti-NMDARE and its clinical parameters were evaluated in the patients. RESULTS: CSF UA levels were lower in patients with anti-NMDARE than in patients with NINDs, especially in patients with severe impairments (modified Rankin Scale [mRS] scores >3 vs. ≤ 3, p = 0.006). Furthermore, serum UA levels in patients with anti-NMDARE were significantly lower than in patients with NINDs and HCs. CSF UA levels were significantly associated with mRS scores, and serum UA levels in patients with anti-NMDARE. Furthermore, CSF/serum UA ratio was significantly associated with BBB index. CONCLUSIONS: CSF UA levels associated with disease severity and serum UA levels in patients with anti-NMDARE. And CSF/serum UA ratio correlated with BBB index, indicating that CSF and serum UA levels change similarly with BBB permeability in anti-NMDARE patients.

Transfer of patient's peripheral blood mononuclear cells (PBMCs) disrupts blood-brain barrier and induces anti-NMDAR encephalitis: a study of novel humanized PBMC mouse model.

BACKGROUND: Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a severe autoimmune neuropsychiatric disease. Brain access of anti-NMDAR autoantibody through the blood-brain barrier (BBB) is essential for pathogenesis. Most previous animal models limit the investigation of etiologies of BBB damage in patients. METHODS: In this study, we established a novel humanized mouse model of anti-NMDAR encephalitis by intraperitoneal injection of patients' peripheral blood mononuclear cells (PBMCs) into BALB/c Rag2-/-Il2rg-/-SirpαNODFlk2-/- mice. RESULTS: We found that engraftment of patients' PBMCs not only produced potent anti-GluN1 autoantibodies, but also disrupted BBB integrity to allow brain access of autoantibodies, resulting in a hyperactive locomotor phenotype, anxiety- and depressive-like behaviors, cognitive deficits, as well as functional changes in corresponding brain regions. Transcriptome analysis suggested an exaggerated immune response and impaired neurotransmission in the mouse model and highlighted Il-1ß as a hub gene implicated in pathological changes. We further demonstrated that Il-1ß was produced by endothelial cells and disrupted BBB by repressing tight junction proteins. Treatment with Anakinra, an Il-1 receptor antagonist, ameliorated BBB damage and neuropsychiatric behaviors. CONCLUSIONS: Our study provided a novel and clinically more relevant humanized mouse model of anti-NMDAR encephalitis and revealed an intrinsic pathogenic property of the patient's lymphocytes.

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.

Serum neurofilament light chain is associated with disturbed limbic-based functional connectivity in patients with anti-NMDAR encephalitis.

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis shows a predilection for affecting the limbic system, but structural MRI in most patients is usually unremarkable. However, the functional connectivity reorganization of limbic nodes remains unknown. Serum neurofilament light chains (sNfL) are clinically linked with the disease severity and neurological disability of anti-NMDAR encephalitis. However, the relationship between sNfL and limbic-based functional architecture has not been explored. We consecutively recruited 20 convalescent patients with anti-NMDAR encephalitis and 24 healthy controls from March 2018 to March 2021. Resting-state functional MRI metrics, including fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), and atlas-based seed functional connectivity, were analyzed to investigate regional activities and functional connectivity alterations. Correlation analysis among functional connectivity, sNfL, Mini-Mental State Examination (MMSE), and Montreal cognitive assessment outcomes were explored in patients. Compared with those of healthy controls, the fALFF and ReHo were consistently increased in regions of the posterior default mode network (DMN) hub, mainly the bilateral supramarginal gyrus and precuneus, in patients with anti-NMDAR encephalitis (FWE-corrected p < 0.05). Patients demonstrated disturbed functional organization characterized by reduced connectivity of the posterior DMN hub with the sensorimotor cortex and hypoconnectivity of the parahippocampal gyrus (PHG) with the right fusiform gyrus but extensively enhanced thalamocortical connectivity (FWE-corrected p < 0.05). Furthermore, convalescent sNfL showed a positive correlation with enhanced thalamocortical connectivity (r = 0.4659, p = 0.0384). Onset sNfL with an independent linear correlation to convalescent MMSE performance (B coefficient, -0.013, 95% CI, -0.025 ~ -0.002, p = 0.0260) was positively correlated with intra-DMN connectivity (r = 0.8969, p < 0.0001) and limbic-sensory connectivity (r = 0.4866, p = 0.0346 for hippocampus seed and r = 0.5218, p = 0.0220 for PHG seed). Patients with anti-NMDAR encephalitis demonstrated disturbed functional organization with substantial thalamocortical hyperconnectivity, that was positively correlated with convalescent sNfL. Onset sNfL showed a positive correlation with intra-DMN connectivity and limbic-sensory connectivity.

Neutrophil Nanovesicle Protects against Experimental Autoimmune Encephalomyelitis through Enhancing Myelin Clearance by Microglia.

Timely clearance of myelin debris is the premise of neuroinflammation termination and tissue regeneration in multiple sclerosis (MS). Microglia are the main scavengers of myelin debris in MS lesions, but its phagocytic capability is limited in MS patients. Here, we develop neutrophil-derived nanovesicles (NNVs) to enhance the efficiency of myelin debris clearance in microglia for MS therapy. RNA sequencing (RNAseq) results demonstrate that NNVs treatment ameliorates lesional neuroinflammation of experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. Consequently, EAE mice exhibit favorable neurological functions and white matter integrity after NNVs treatment. Specifically, NNVs treatment upregulates the expression of nuclear factor E2-related factor 2 (NRF2) in microglia, as revealed by Assay for Transposase Accessible Chromatin using sequencing (ATACseq). We also demonstrate that NRF2 can activate the transcription of RUBCN (RUN domain and cysteine-rich domain containing Beclin 1-interacting protein), which in turn enhances LC3-associated phagocytosis (LAP) in microglia. As a result, myelin debris engulfed by microglia can be efficiently catabolized in NNVs-treated EAE mice without obvious side effects. Together, this study proves that NNVs can modulate neuroinflammation by clearing myelin debris and is a promising MS treatment strategy.

Myelin oligodendrocyte glycoprotein-associated disease is associated with BANK1, RNASET2 and TNIP1 polymorphisms.

AIM: Here we aimed to compare association of common immune-related genetic variants with three autoimmune central nervous system (CNS) demyelinating diseases, namely myelin oligodendrocyte glycoprotein-associated disease (MOGAD), multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD). METHODS: In this retrospective cross-sectional study, 26 common immune-related single nucleotide polymorphisms were genotyped in 102 patients with MOGAD, 100 patients with MS, 198 patients with NMOSD and 541 healthy control subjects recruited from Guangzhou, China. RESULTS: Among all tested genetic variations, one polymorphism, B cell scaffold protein with ankyrin repeats 1 (BANK1) rs4522865 was associated with multiple disorders, namely MOGAD (OR = 1.94, 95% CI:1.19-3.17, P = 0.0059) and NMOSD (OR = 1.69, 95% CI:1.17-2.45). Besides BANK1 rs4522865, two other non-HLA loci, ribonuclease T2 (RNASET2) rs9355610 (OR = 0.47, 95% CI: 0.26-0.85) and TNFAIP3 interacting protein 1 (TNIP1) rs10036748 (OR = 1.76, 95% CI: 1.16-2.71), were associated with MOGAD. In addition, NMOSD was associated with signal transducer and activator of transcription 4 (STAT4) rs7574865 (OR = 1.58, 95% CI: 1.12-2.24) and general transcription factor Iii (GTF2I) rs73366469 (OR = 1.60, 95% CI:1.12-2.29), while MS was associated with a killer cell lectin like receptor G1 (KLRG1) rs1805673 (OR = 0.61, 95% CI: 0.40-0.94) and T-box transcription factor 21 (TBX21) rs17244587 (OR = 2.25, 95% CI: 1.25-4.06). CONCLUSION: The current study suggests for the first time three non-HLA susceptibility loci for MOGAD. In addition, comparison of association of 26 immune-related polymorphisms with three autoimmune CNS demyelinating diseases demonstrates substantial difference in genetic basis of those disorders.

Cerebrospinal fluid cystatin C levels in patients with anti-NMDAR encephalitis and other neurological diseases.

BACKGROUND: Cystatin C has neuroprotective and immunomodulatory effects on the central nervous system. However, the role of cerebrospinal fluid (CSF) cystatin C in anti-N-methyl-d-aspartate receptor encephalitis (anti-NMDARE) remains unknown. METHODS: In this study, CSF levels of cystatin C were determined in 73 patients with anti-NMDARE; 496 patients with other neurological diseases, comprising 108 with neuromyelitis optica, 77 with multiple sclerosis, 71 with schizophrenia, 68 with cryptococcus meningitis or meningoencephalitis, 43 with tuberculous meningitis or meningoencephalitis, 43 with bacterial meningitis or meningoencephalitis (BM), 35 with Guillain-Barré syndrome, 23 with spinal cord injury (SCI), 14 with amyotrophic lateral sclerosis (ALS), and 14 with idiopathic epilepsy; and 136 control patients with non-inflammatory diseases. The associations of CSF cystatin C with anti-NMDARE and its clinical parameters were evaluated. RESULTS: CSF cystatin C levels were significantly lower in patients with anti-NMDARE than in patients with BM, SCI, and ALS, especially among those with poor functional status (modified Rankin Scale [mRS] ≥4). CSF cystatin C levels were also significantly lower in anti-NMDARE patients with poor functional status (mRS ≥4) than in those with good functional status (mRS <4). CSF cystatin C levels were significantly associated with mRS scores and CSF white blood cell counts in anti-NMDARE patients. CONCLUSIONS: CSF levels of cystatin C are decreased in anti-NMDARE patients and negatively associated with disease severity.

Immunosuppressant and neuromyelitis optica spectrum disorder: optimal treatment duration and risk of discontinuation.

BACKGROUND AND PURPOSE: Preventing relapse by immunosuppressants (ISs) is critical for the prognosis of neuromyelitis optica spectrum disorder (NMOSD); however, the optimal duration of IS treatment is still under discussion. The objective was to explore the optimal duration of IS treatment and the risk of IS discontinuation for NMOSD. METHOD: This cohort study was conducted at a major neurological center that housed the largest NMOSD database in South China. Eligible participants were patients with NMOSD undergoing IS treatment. The main outcome measures were changes in relapse risk based on IS treatment duration, clinical outcomes and predictors of relapse following IS discontinuation. RESULTS: In total, 343 patients were included in this study. The duration of IS treatment was strongly associated with a decrease in relapse risk (hazard ratio [HR] 0.53, p < 0.001). Continuous IS treatment resulted in decreased relapse HRs within 5 years of receiving IS medication, with a mild rebound starting at 5 years. Rituximab reduced the risk of NMOSD relapse to approximately zero within 3 years. The rate of relapse after IS withdrawal was high (77.5%). As opposed to other ISs, a delayed relapse following rituximab withdrawal was observed in this study. Longitudinal extensive transverse myelitis (HR = 2.023, p = 0.006) was associated with a higher risk of relapse after IS discontinuation. CONCLUSIONS: Long-term IS medication for NMOSD is generally suitable. Patients with longitudinal extensive transverse myelitis had a higher risk of relapse after IS discontinuation. Future studies should explore individualized strategies of rituximab maintenance treatment.

Anti-IgLON5 Encephalopathy with Concomitant Herpes Virus Encephalitis.

Anti-IgLON5 encephalopathy is a new and rare autoimmune encephalitis with unclear pathophysiology. In this study, we reported an unusual case of anti-IgLON5 encephalopathy with concomitant herpes virus encephalitis. A 51-year-old man with HLA-DQB1*05:01 and HLA-DRB1*10:01, who suffered from an episode of acute encephalitis, mental disorders, and memory impairment was admitted to our hospital. Human alpha herpes virus 1, human gamma herpes virus 4 (Epstein-Barr virus), and IgLON5-IgG were detected in the cerebrospinal fluid, indicating anti-IgLON5 encephalopathy with concomitant herpes virus encephalitis of this patient. Brain magnetic resonance imaging revealed T2 hyperintensities in the left temporal lobe and enhancement in the hippocampus. A mild sleep disorder was also found by video polysomnography. The patient was then treated with antiviral drugs, intravenous immunoglobulins, methylprednisolone, and protein A immunoadsorption. After treatment, the patient's clinical symptoms were partially improved. This is the first reported case of anti-IgLON5 encephalopathy with concomitant herpes virus encephalitis.

Serum NfL associated with anti-NMDA receptor encephalitis.

INTRODUCTION: Neurofilament light chains (NfL) have been reported as potential markers for neuronal-axonal injury in neuroinflammatory diseases. In the current study, we describe serum NfL levels as a prognostic marker for anti-N-methyl-D-aspartate receptor encephalitis (NMDARE). METHODS: Serum levels of NfL of 64 patients with anti-NMDARE and 84 healthy controls were measured by Simoa. The anti-NMDAR Encephalitis One-Year Functional Status (NEOS) score, Modified Rankin Scale (mRS) scores, and clinical and cerebrospinal fluid parameters were evaluated in patients with anti-NMDARE. Meanwhile, we performed a receiver-operator characteristic analysis to assess the power of the serum NFL in predicting the 1-year functional status. RESULTS: Serum NfL levels were significantly elevated in patients with anti-NMDARE compared to healthy controls (p < 0.001, padjusted < 0.001), especially in patients with severe impairments (mRS > 3 vs ≤ 3, p = 0.035) or with limited response to treatment (vs. favorable outcome, p = 0.011). Serum NFL was positively associated with the initial admission mRS (r = 0.23, p = 0.072) and 1-year mRS (r = 0.29, p = 0.018). The AUC of serum NfL and NEOS score for 1-year poor functional status was 0.697 (95% CI 0.527-0.866, p = 0.011), 0.753 (95% CI 0.616-0.890, p = 0.001), respectively. Furthermore, AUC of the combination of serum NfL and NEOS was 0.815 (95% CI 0.680-0.950, p < 0.001). CONCLUSION: Our findings show that serum NfL levels evaluated in anti-NMDAR encephalitis may be a good predictor of the risk of 1-year poor functional status.

Dysregulated CD40 and CD40 ligand expression in anti-N-methyl-d-aspartate receptor encephalitis.

Anti-N-methyl-d-aspartate receptor encephalitis (anti-NMDARE) is a B cell- and antibody-mediated autoimmune disease which may be regulated by CD40/CD40L signaling pathway. we enrolled anti-NMDARE patients and measured the serum CD40 and CD40L concentrations. The serum concentration of CD40 was decreased, while CD40L was increased in anti-NMDARE patients compared with that of healthy controls. The concentrations of CD40 and CD40L were both elevated in the acute stage of anti-NMDARE and were reduced during remission. Serum CD40L levels were positively correlated with serum CD40 levels. These results revealed that the CD40/CD40L signaling pathway might contribute to the pathogenesis of anti-NMDARE.

Association of serum Gasdermin D with anti-N-methyl-D-aspartate receptor encephalitis.

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an autoimmune disease of the central nervous system. Gasdermin D (GSDMD) is associated with autoimmune disorders and neuroinflammatory disorders, but its role in anti-NMDAR encephalitis is unclear. In this study, we measured serum levels of GSDMD in 42 patients with anti-NMDAR encephalitis and 25 healthy controls. Of the 42 patients, 17 had follow-up evaluation of GSDMD levels and modified Rankin scale (mRS) scores at 3 months. Association of GSDMD with anti-NMDAR encephalitis and its clinical parameters were evaluated. Serum GSDMD levels were significantly higher in patients with anti-NMDAR encephalitis than in healthy controls (p = 0.002, padjusted  = 0.009), especially in males (p = 0.001, padjusted  = 0.022). This was also evident in patients with severe impairment (mRS >3 vs mRS ≤3; p < 0.001). Serum GSDMD was associated with mRS before and after adjustment for age and gender (r = 0.440 and 0.430, p = 0.004 and 0.006, respectively) as well as serum CH50 (r = -0.419 and -0.426, p = 0.011 and 0.012, respectively). Furthermore, 3-month follow-up evaluation revealed that after treatment, anti-NMDAR encephalitis patients had significantly decreased serum GSDMD levels (p = 0.007) and significantly decreased mRS scores (p = 0.002) compared with before treatment. Furthermore, the changes in mRS scores were negatively associated with changes in GSDMD levels, although the associations were not significant (r = -0.222, p = 0.393). Our findings show that serum GSDMD levels are elevated in anti-NMDAR encephalitis and are associated with disease prognosis.

Transfer of PBMC From SSc Patients Induces Autoantibodies and Systemic Inflammation in Rag2-/-/IL2rg-/- Mice.

Objective: The contribution of sustained autologous autoantibody production by B cells to the pathogenesis of systemic sclerosis (SSc) and granulomatosis with polyangiitis (GPA) is not fully understood. To investigate this, a humanized mouse model was generated by transferring patient-derived peripheral blood mononuclear cells (PBMC) into immunocompromised mice. Methods: PBMC derived from patients with SSc and GPA as well as healthy controls (HD) were isolated, characterized by flow cytometry, and infused into Rag2-/-/IL2rg-/- mice. In addition, PBMC from SSc patients treated with rituximab were transferred into mice. Twelve weeks later, human autoantibodies were determined in blood of the recipient mice and affected tissues were analyzed for pathological changes by histology and immunohistochemistry. Results: Mice engrafted with PBMC derived from SSc patients developed autoantibodies such as antinuclear antibodies (ANA) mimicking the pattern of the respective donors. Moreover, cellular infiltrates dominated by B cells were observed in lung, kidney and muscles of the recipient mice. By contrast, PBMC derived from HD or GPA patients survived in recipient mice after transfer, but neither human autoantibodies nor inflammatory infiltrates in tissues were detected. Furthermore, these pathological changes were absent in mice transferred with PBMC from rituximab-treated SSc patients. Conclusion: This humanized mouse model is indicative for cross-reactivity of human lymphocytes to murine autoantigens and argues for a pivotal role of B cells as well as of sustained autoimmunity in the pathogenesis of SSc. It provides a powerful tool to study interstitial lung disease and so far, under-recognized disease manifestations such as myositis and interstitial nephritis.

Infiltration of plasma cells in colorectal adenocarcinoma associated with autoimmune encephalitis.

Paraneoplastic autoimmune encephalitis (PAE) represents a group of rare neurological syndromes associated with neoplastic diseases. Here, we report a case that multiple anti-neuronal antibodies were present in a patient with PAE who developed both small cell lung cancer and colorectal adenocarcinoma. Furthermore, the immunopathological investigation of the colorectal adenocarcinoma revealed the formation of abnormal neuronal antigens and a massive infiltration of plasma cells in the tumor tissue. These findings support the hypothesis that expression of neuronal antigens in neoplasm initiates autoimmune responses in PAE.

Brain histopathological study and prognosis in MOG antibody-associated demyelinating pseudotumor.

Our objective was to examine the brain biopsies by histopathology and investigate the prognosis of patients with myelin oligodendrocyte glycoprotein antibody-associated demyelinating pseudotumor. The clinical, MRI, and histological features of two patients with myelin oligodendrocyte glycoprotein antibody-associated demyelinating pseudotumor were reviewed. Both patients were treated with steroid plus rituximab and followed up. The brain biopsies of both cases revealed T cells, macrophages, and complement-mediated demyelination, which was in accord with multiple sclerosis-like pathology. Moreover, both cases showed favorable response to steroid plus rituximab therapy. Our cases add a new variant to the myelin oligodendrocyte glycoprotein-encephalomyelitis spectrum, which favorably responds to immunotherapy.

HLA class II allele DRB1*16:02 is associated with anti-NMDAR encephalitis.

BACKGROUND AND OBJECTIVE: Aetiology and pathogenesis of anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis, the most common autoimmune encephalitis, is largely unknown. Since an association of the disease with the human leucocyte antigen (HLA) has not been shown so far, we here investigated whether anti-NMDAR encephalitis is associated with the HLA locus. METHODS: HLA loci of 61 patients with anti-NMDAR encephalitis and 571 healthy controls from the Chinese Han population were genotyped and analysed for this study. RESULTS: Our results show that the DRB1*16:02 allele is associated with anti-NMDAR encephalitis (OR 3.416, 95% CI 1.817 to 6.174, p=8.9×10-5, padj=0.021), with a higher allele frequency in patients (14.75%) than in controls (4.82%). This association was found to be independent of tumour formation. Besides disease susceptibility, DRB1*16:02 is also related to the clinical outcome of patients during treatment, where patients with DRB1*16:02 showed a lower therapeutic response to the treatment than patients with other HLA alleles (p=0.033). Bioinformatic analysis using HLA peptide-binding prediction algorithms and computational docking suggested a close relationship between the NR1 subunit of NMDAR and the DRB1*16:02. CONCLUSIONS: This study for the first time demonstrates an association between specific HLA class II alleles and anti-NMDAR encephalitis, providing novel insights into the pathomechanism of the disease.

Serum Bilirubin and Albumin in Anti-N-Methyl-D-Aspartate Receptor Encephalitis.

BACKGROUND AND OBJECTIVE: Low serum levels of bilirubin and albumin are associated with multiple autoimmune diseases, but their role in anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is unknown. METHODS: Serum bilirubin and albumin levels were evaluated in 60 patients with anti-NMDAR encephalitis, 50 cryptococcal encephalitis, and 145 healthy controls (CTLs). Of the 60 anti-NMDAR encephalitis patients, 30 had a follow-up evaluation at 3 months after admission. RESULTS: Serum bilirubin and albumin levels were both significantly lower in anti-NMDAR encephalitis than in CTLs, and serum bilirubin levels were significantly lower in anti-NMDAR encephalitis than in cryptococcal encephalitis. Serum bilirubin levels were significantly lower in patients with psychiatric symptoms, with severe impairment, and with limited responses to treatment than those without psychiatric symptoms, with mild impairment, and with favorable responses to treatment, respectively. A follow-up evaluation of 30 patients revealed that the modified Rankin Scale scores were significantly decreased after treatment. Serum bilirubin significantly associated with serum albumin, and plasma hemoglobin. CONCLUSIONS: Our results revealed for the first time an association between the serum levels of bilirubin in the anti-NMDAR encephalitis. Further studies investigating the role of bilirubin and albumin in anti-NMDAR encephalitis are required.

MicroRNA-142-3p Induces Atherosclerosis-Associated Endothelial Cell Apoptosis by Directly Targeting Rictor.

BACKGROUND/AIMS: Atherosclerosis, a multifactorial chronic disease, is the main cause of death and impairment in the world. Endothelial cells (ECs) apoptosis plays a crucial role in the onset and development of atherosclerosis, whereas the underlying molecular mechanisms are unclear. MicroRNA-142-3p (miR-142-3p) is a well-defined tumor suppressor in several types of cancer, while the role of miR-142-3p in ECs apoptosis and the development of atherosclerosis has yet to be elucidated. Therefore, the present study aimed to investigate the role of miR-142-3p in ECs apoptosis during atherosclerosis and the underlying mechanism. METHODS: Human aortic endothelial cells (HAECs) were treated with oxidized low-density lipoprotein (ox-LDL). The expression level of miR-142-3p was detected using qRT-PCR. Apoptosis was determined via flow cytometry and Caspase-3 activity assay. Prediction of the binding between miR-142-3p and 3'-UTR of Rictor mRNA was performed by bioinformatics analyses and confirmed by a dual luciferase reporter assay. The effects of miR-142-3p on endothelial apoptosis and atherosclerosis were further analyzed in an in vivo model using ApoE-/- mice fed with high-fat diet (HFD). RESULTS: MiR-142-3p expression was substantially up-regulated during the ox-LDL-elicited apoptosis in HAECs. Forced expression of miR-142-3p exacerbated apoptosis in ECs whereas inhibition of miR-142-3p could partly alleviate apoptotic cell death mediated by ox-LDL. Further analysis identified Rictor as a direct target of miR-142-3p, and Rictor knockdown abolished the anti-apoptotic effect of miR-142-3p inhibitor. Moreover, the Akt/endothelial nitric oxide synthase (eNOS) signaling pathway was found to mediate the beneficial effect of miR-142-3p inhibitor on endothelial apoptosis. Finally, systemic treatment with miR-142-3p antagomir attenuated endothelial apoptosis and retarded the progression of atherosclerosis in the aorta of ApoE-/- mice. CONCLUSIONS: Down-regulation of miR-142-3p inhibited ECs apoptosis and atherosclerotic development by up-regulating the expression of Rictor and activating the Akt/eNOS signaling pathway. This indicates that miR-142-3p may be a potential target for the prevention and treatment of atherosclerosis.

Brain Immunohistopathology in a Patient with Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy.

BACKGROUND: Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is a novel meningoencephalomyelitis. However, the pathogenesis of this disease is unclear. We therefore examined a brain biopsy from a patient with autoimmune GFAP astrocytopathy by immunohistopathology. METHODS: We examined brain biopsy sections from a patient with autoimmune GFAP astrocytopathy using hematoxylin and eosin (HE) and Luxol fast blue (LFB) staining, and immunostaining with antibodies for CD4, CD8, CD3, CD20, CD68, CD138, Neu-N, GFAP, myelin oligodendrocyte glycoprotein (MOG), and aquaporin-4 (AQP4). RESULTS: HE staining revealed extensive inflammatory cells (marked lymphocytes) around brain vessels, and LFB showed no signs of demyelination or axon loss. Immunohistochemical analysis showed CD3+ and CD4+ T cells cuffing around brain vessels, accompanied by CD8+ T cells, CD20+ B cells, and CD138+ plasma cells, while some macrophages (CD68+) were scattered throughout the brain parenchyma. There was no loss of AQP4 or MOG expression in this patient, while GFAP was abundantly expressed. CONCLUSIONS: These findings suggest that inflammatory cells, including T cells, B cells, plasma cells, and macrophages, are involved in autoimmune GFAP astrocytopathy. Demyelination and astrocyte loss may not necessarily occur in this disease.