Pathogenic Potential of Eomesodermin-Expressing T-Helper Cells in Neurodegenerative Diseases.

Eomesodermin-expressing (Eomes+) T-helper (Th) cells show cytotoxic characteristics in secondary progressive multiple sclerosis. We found that Eomes+ Th cell frequency was increased in the peripheral blood of amyotrophic lateral sclerosis and Alzheimer's disease patients. Furthermore, granzyme B production by Th cells from such patients was high compared with controls. A high frequency of Eomes+ Th cells was observed in the initial (acutely progressive) stage of amyotrophic lateral sclerosis, and a positive correlation between Eomes+ Th cell frequency and cognitive decline was observed in Alzheimer's disease patients. Therefore, Eomes+ Th cells may be involved in the pathology of amyotrophic lateral sclerosis and Alzheimer's disease. ANN NEUROL 2024;95:1093-1098.

High frequency of HTRA1 AND ABCC6 mutations in Japanese patients with adult-onset cerebral small vessel disease.

BACKGROUND: This study aimed to clarify the frequency and clinical features of monogenic cerebral small vessel disease (mgCSVD) among patients with adult-onset severe CSVD in Japan. METHODS: This study included patients with adult-onset severe CSVD with an age of onset ≤55 years (group 1) or >55 years and with a positive family history (group 2). After conducting conventional genetic tests for NOTCH3 and HTRA1, whole-exome sequencing was performed on undiagnosed patients. Patients were divided into two groups according to the results of the genetic tests: monogenic and undetermined. The clinical and imaging features were compared between the two groups. RESULTS: Group 1 and group 2 included 75 and 31 patients, respectively. In total, 30 patients had NOTCH3 mutations, 11 patients had HTRA1 mutations, 6 patients had ABCC6 mutations, 1 patient had a TREX1 mutation, 1 patient had a COL4A1 mutation and 1 patient had a COL4A2 mutation. The total frequency of mutations in NOTCH3, HTRA1 and ABCC6 was 94.0% in patients with mgCSVD. In group 1, the frequency of a family history of first relatives, hypertension and multiple lacunar infarctions (LIs) differed significantly between the two groups (monogenic vs undetermined; family history of first relatives, 61.0% vs 25.0%, p=0.0015; hypertension, 34.1% vs 63.9%, p=0.0092; multiple LIs, 87.8% vs 63.9%, p=0.0134). CONCLUSIONS: More than 90% of mgCSVDs were diagnosed by screening for NOTCH3, HTRA1 and ABCC6. The target sequences for these three genes may efficiently diagnose mgCSVD in Japanese patients.

Novel partial deletions, frameshift and missense mutations of CSF1R in patents with CSF1R-related leukoencephalopathy.

BACKGROUND AND PURPOSE: Colony-stimulating factor 1 receptor (CSF1R)-related leukoencephalopathy is an adult-onset leukoencephalopathy caused by mutations in CSF1R. The present study aimed to explore the broader genetic spectrum of CSF1R-related leukoencephalopathy in association with clinical and imaging features. METHODS: Mutational analysis of CSF1R was performed for 100 consecutive patients with adult-onset leukoencephalopathy. Sequence and copy number variation (CNV) analyses of CSF1R were performed. The genomic ranges of the deletions were determined by long-read sequencing. Ligand-dependent autophosphorylation of CSF1R was examined in cells expressing the CSF1R mutants identified in this study. RESULTS: CSF1R mutations were identified in 15 patients, accounting for 15% of the adult-onset leukoencephalopathy cases. Seven novel and five previously reported CSF1R mutations were identified. The novel mutations, including three missense and one in-frame 3 bp deletion, were located in the tyrosine kinase domain (TKD) of CSF1R. Functional assays revealed that none of the novel mutations in the TKD showed autophosphorylation of CSF1R. Two partial deletions of CSF1R were identified that resulted in lack of the C-terminal region, including the distal TKD, in two patients. Various clinical features including cognitive impairment, psychiatric symptoms and gait disturbance were observed. Various degrees of the white matter lesions and corpus callosum abnormalities on magnetic resonance imaging and characteristic calcifications on computed tomography were observed as imaging features. CONCLUSIONS: Our results highlight the importance of examining the CNV of CSF1R even when Sanger or exome sequencing reveals no CSF1R mutations. Genetic examination of sequences and CNV analyses of CSF1R are recommended for an accurate diagnosis of CSF1R-related leukoencephalopathy.

MicroRNA-101a regulates microglial morphology and inflammation.

BACKGROUND: Microglia, as well as other tissue-resident macrophages, arise from yolk sac progenitors. Thus, it is likely that the central nervous system environment is critical for the acquisition of a distinct microglial phenotype. Several microRNAs that are enriched in the brain play crucial roles in brain development and may also play a role in the differentiation of microglia. METHODS: To track the differentiation of hematopoietic cells into microglia, lineage-negative bone marrow cells were co-cultured with astrocytes in the absence or presence of microRNAs or their inhibitors. Microglia-like cells were identified as small, round cells that were immunopositive for CD11b, Iba1, CX3CR1, and triggering receptor expressed on myeloid cells (TREM)-2. RESULTS: Five microRNAs (miR-101a, miR-139-3p, miR-214*, miR-218, and miR-1186) were identified as modifiers of the differentiation of bone marrow-derived microglia-like cells. Among them, miR-101a facilitated the differentiation of bone marrow cells into microglia-like cells most potently. Small, round cells expressing CD11b, Iba1, CX3CR1, and TREM-2 were predominant in cells treated by miR-101a. miR-101a was abundantly expressed in non-microglial brain cells. Transfection of miR-101a into microglia significantly increased the production of IL-6 in response to LPS. Finally, miR-101a downregulated the expression of MAPK phosphatase-1. CONCLUSIONS: miR-101a, which is enriched in the brain, promotes the differentiation of bone marrow cells into microglia-like cells.

Development of a culture system to induce microglia-like cells from haematopoietic cells.

AIMS: Microglia are the resident immune cells in the central nervous system, originating from haematopoietic-derived myeloid cells. A microglial cell is a double-edged sword, which has both pro-inflammatory and anti-inflammatory functions. Although understanding the role of microglia in pathological conditions has become increasingly important, histopathology has been the only way to investigate microglia in human diseases. METHODS: To enable the study of microglial cells in vitro, we here establish a culture system to induce microglia-like cells from haematopoietic cells by coculture with astrocytes. The characteristics of microglia-like cells were analysed by flow cytometry and functional assay. RESULTS: We show that triggering receptor expressing on myeloid cells-2-expressing microglia-like cells could be induced from lineage negative cells or monocytes by coculture with astrocytes. Microglia-like cells exhibited lower expression of CD45 and MHC class II than macrophages, a characteristic similar to brain microglia. When introduced into brain slice cultures, these microglia-like cells changed their morphology to a ramified shape on the first day of the culture. Moreover, we demonstrated that microglia-like cells could be induced from human monocytes by coculture with astrocytes. Finally, we showed that interleukin 34 was an important factor in the induction of microglia-like cells from haematopoietic cells in addition to cell-cell contact with astrocytes. Purified microglia-like cells were suitable for further culture and functional analyses. CONCLUSION: Development of in vitro induction system for microglia will further promote the study of human microglial cells under pathological conditions as well as aid in the screening of drugs to target microglial cells.

'Grasshopper sign': the novel imaging of post-COVID-19 myelopathy with delayed longitudinal white matter abnormalities.

Introduction: Recently, there have been a few reports of atypical post-coronavirus disease 2019 (COVID-19) myelopathy manifesting tract-specific lesions similar to those due to vitamin B12 deficiency. However, the precise characteristics of imaging or clinical course remain not well understood. Methods: A retrospective analysis of the clinical and imaging characteristics of four patients who were referred to our hospital with a unique post-COVID-19 myelopathy was performed. Results: Four-to-six weeks following COVID-19 infection in the summer of 2023, four middle-aged men developed paraparesis, hypo/dysesthesia and bladder/bowel disturbance, suggesting myelopathy. Although spinal MRI showed no abnormalities in the early stages, tract-specific longitudinal lesions along the dorsal and lateral columns became apparent as the symptoms progressed. Owing to the lack of MRI findings at the early stage, all cases were challenging to diagnose. However, the patients remained partially responsive to aggressive immunosuppressive therapies, even in the advanced stage. Discussion: We termed these tract-specific longitudinal lesions in the presented case series 'Grasshopper sign' because brain coronal and spine axial MRI findings looked like a grasshopper's antennae and face. Early identification of the characteristic MRI abnormality could allow for early intervention using intensive immunosuppressive therapy, which could improve patient outcomes.

Ratio of lymphocyte to monocyte area under the curve as a novel predictive factor for severe infection in multiple sclerosis.

Background: Individuals with multiple sclerosis (MS) are vulnerable to all types of infection, because MS itself involves immunodeficiency, in addition to involving treatment with immunosuppressants. Simple predictive variables for infection that are easily assessed in daily examinations are warranted. Lymphocyte area under the curve (L_AUC), defined as the sum of serial absolute lymphocyte counts under the lymphocyte count-time curve, has been established as a predictive factor for several infections after allogenic hematopoietic stem cell transplantation. We assessed whether L_AUC could also be a useful factor for predicting severe infection in MS patients. Methods: From October 2010 to January 2022, MS patients, diagnosed based on the 2017 McDonald criteria, were retrospectively reviewed. We extracted patients with infection requiring hospitalization (IRH) from medical records and matched with controls in a 1:2 ratio. Variables including clinical severity and laboratory data were compared between the infection group and controls. L_AUC was calculated along with the AUC of total white blood cells (W_AUC), neutrophils (N_AUC), lymphocytes (L_AUC), and monocytes (M_AUC). To correct for different times of blood examination and extract mean values of AUC per time point, we divided the AUC by follow-up duration. For example, in evaluating lymphocyte counts, we defined the ratio of [L_AUC] to [follow-up duration] as [L_AUC/t]. Multivariate regression analysis was conducted to extract predictive factors associated with IRH. Also, discriminative analysis was conducted using candidate variables from multivariate analysis. Results: The total case-control sample included 177 patients of MS with IRH (n=59) and non-IRH (controls) (n=118). Adjusted odds ratios (OR) for the risk of serious infection in patients with MS with higher baseline expanded disability status scale (EDSS) (OR 1.340, 95% confidence interval [CI] 1.070-1.670, p = 0.010) and lower ratio of L_AUC/t to M_AUC/t (OR 0.766, 95%CI 0.591-0.993, p = 0.046) were significant. Notably, the kind of treatment, including glucocorticoids (GCs), disease-modifying drugs (DMDs) and other immunosuppressants agents, and dose of GCs were not significantly associated with serious infection after correlated with EDSS and ratio of L_AUC/t to M_AUC/t. In discriminative analysis, sensitivity was 88.1% (95%CI 76.5-94.7%) and specificity was 35.6% (95%CI 27.1-45.0%), using EDSS ≥ 6.0 or ratio of L_AUC/t to M_AUC/t ≤ 3.699, while sensitivity was 55.9% (95%CI 42.5-68.6%) and specificity was 83.9% (95%CI 75.7-89.8%), using both EDSS ≥ 6.0 and ratio of L_AUC/t to M_AUC/t ≤ 3.699. Conclusion: Our study revealed the impact of the ratio L_AUC/t to M_AUC/t as a novel prognostic factor for IRH. Clinicians should pay more attention to laboratory data such as lymphocyte or monocyte counts itself, directly presenting individual immunodeficiency, rather than the kind of drug to prevent infection as a clinical manifestation.

Prevalence, Clinical Profiles, and Prognosis of Stiff-Person Syndrome in a Japanese Nationwide Survey.

BACKGROUND AND OBJECTIVES: To elucidate current epidemiologic, clinical, and immunologic profiles and treatments of stiff-person syndrome (SPS) in Japan. METHODS: A nationwide mail survey was conducted using an established method. Data processing sheets were sent to randomly selected departments of internal medicine, neurology, pediatrics, psychiatry, and neurosurgery in hospitals and clinics throughout Japan to identify patients with SPS who were seen between January 2015 and December 2017. RESULTS: Thirty cases were identified as glutamic acid decarboxylase 65 (GAD65)-positive SPS cases on the basis of detailed clinical data of 55 cases. Four patients had α1 subunit of glycine receptor (GlyR) antibodies, and 1 patient had both GAD65 and GlyR antibodies. The total estimated number of patients with GAD65-positive SPS was 140, and the estimated prevalence was 0.11 per 100,000 population. The median age at onset was 51 years (range, 26-83 years), and 23 (76%) were female. Of these, 70% had classic SPS, and 30% had stiff-limb syndrome. The median time from symptom onset to diagnosis was significantly longer in the high-titer GAD65 antibody group than in the low-titer group (13 months vs 2.5 months, p = 0.01). The median modified Rankin Scale (mRS) at baseline was 4, and the median mRS at the last follow-up was 2. Among the 29 GAD65-positive patients with ≥1 year follow-up, 7 received only symptomatic treatment, 9 underwent immunotherapy without long-term immunotherapy, and 13 received long-term immunotherapy such as oral prednisolone. The coexistence of type 1 diabetes mellitus and the lack of long-term immunotherapy were independent risk factors for poor outcome (mRS ≥3) in the GAD65-positive patients (odds ratio, 15.0; 95% CI 2.6-131.6; p = 0.001; odds ratio, 19.8; 95% CI 3.2-191.5; p = 0.001, respectively). DISCUSSION: This study provides the current epidemiologic and clinical status of SPS in Japan. The symptom onset to the diagnosis of SPS was longer in patients with high-titer GAD65 antibodies than in those with low-titer GAD65 antibodies. The outcome of patients with SPS was generally favorable, but more aggressive immunotherapies are necessary for GAD65-positive patients with SPS.

Microbleeds are associated with subsequent hemorrhagic and ischemic stroke in healthy elderly individuals.

BACKGROUND AND PURPOSE: Cerebral microbleeds (MBs) are frequently detected in patients with stroke, especially those who experience intracerebral hemorrhage. However, the clinical significance of MBs in subjects without cerebrovascular disease is still unclear. We performed a prospective study to determine whether the presence of MBs provides useful prognostic information in healthy elderly individuals. METHODS: We tracked 2102 subjects (mean age, 62.1 years) over a mean interval of 3.6 years after they voluntarily participated in the brain checkup system at the Shimane Institute of Health Science. An initial assessment was performed to document the presence of MBs and silent ischemic brain lesions and to map the location of the MBs. During the follow-up period, we obtained information about stroke events that occurred in each subject. RESULTS: MBs were detected in 93 of the 2102 subjects (4.4%). Strokes occurred in 44 subjects (2.1%) during the follow-up period. They were significantly more common among subjects with MBs. Age and hypertension were independent risk factors for MBs. The presence of MBs was more strongly associated with a deep brain hemorrhage (hazard ratio, 50.2; 95% CI, 16.7 to 150.9) than ischemic stroke (hazard ratio, 4.48; 95% CI, 2.20 to 12.2). All hemorrhagic strokes occurred in deep brain regions, and they were associated with MBs located in the deep brain region. CONCLUSIONS: This longitudinal study demonstrated that the presence of MBs can be used to predict hemorrhagic and ischemic stroke, even in healthy elderly individuals.