Novel Neuronal Autoantibodies in Huntington's Disease

Tremendous Fidelity of Vitamin D3 in Age-related Neurological Disorders

Vitamin D3 (VD) is a secosteroid hormone and shows a pleiotropic effect in brain-related disorders where it regulates redox imbalance, inflammation, apoptosis, energy production, and growth factor synthesis. Vitamin D3's active metabolic form, 1,25-dihydroxy Vitamin D3 (1,25(OH)2D3 or calcitriol), is a known regulator of several genes involved in neuroplasticity, neuroprotection, neurotropism, and neuroinflammation. Multiple studies suggest that VD deficiency can be proposed as a risk factor for the development of several age-related neurological disorders. The evidence for low serum levels of 25-hydroxy Vitamin D3 (25(OH)D3 or calcidiol), the major circulating form of VD, is associated with an increased risk of Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), dementia, and cognitive impairment. Despite decades of evidence on low VD association with neurological disorders, the precise molecular mechanism behind its beneficial effect remains controversial. Here, we will be delving into the neurobiological importance of VD and discuss its benefits in different neuropsychiatric disorders. The focus will be on AD, PD, and HD as they share some common clinical, pathological, and epidemiological features. The central focus will be on the different attributes of VD in the aspect of its anti-oxidative, anti-inflammatory, anti-apoptotic, anti-cholinesterase activity, and psychotropic effect in different neurodegenerative diseases.

Novel anti-cytoplasmic antibodies in cerebrospinal fluid and serum of patients with chronic severe mental disorders

OBJECTIVES

There is an emerging role of autoimmune causes related to severe mental disorders (SMD). The clinical approach in patients with chronic SMD and novel anti-central nervous system antibodies is complex.

METHODS

Two corresponding cumulative cases are presented. Cerebrospinal fluid (CSF) and serum were investigated using tissue-based assays.

RESULTS

Both patients suffered from chronic SMD and were negative for well-characterized neuronal antibodies. Patient 1 suffered from a dysexecutive and neurocognitive syndrome with mild abnormalities in automated electroencephalography analysis, elevated CSF protein levels, several serum autoantibodies (including antibodies against endothelial cells), and novel antibodies with a "dotted/scalloped" binding against cytoplasmic structures in CSF. Patient 2 with obsessive-compulsive disorder had left temporal abnormalities on automated magnetic resonance imaging analysis, an elevated CSF/serum albumin quotient, and novel atypical cytoplasmic "spotted" antibody staining in the serum. Patient 1 improved with immunotherapy using high-dose steroids, but patient 2 did not improve under the same treatment.

CONCLUSIONS

The detection of autoantibodies in CSF of chronic SMD may be beneficial in selecting some patients for immunotherapy. The possible impact of novel anti-cytoplasmic antibodies in this context is critically discussed. Further research is needed to establish the underlying pathophysiological processes as well as their diagnostic and therapeutic implications.

Autoantibodies - enemies, and/or potential allies?

Autoantibodies are well known as potentially highly harmful antibodies which attack the host via binding to self-antigens, thus causing severe associated diseases and symptoms (e.g. autoimmune diseases). However, detection of autoantibodies to a range of disease-associated antigens has enabled their successful usage as important tools in disease diagnosis, prognosis and treatment. There are several advantages of using such autoantibodies. These include the capacity to measure their presence very early in disease development, their stability, which is often much better than their related antigen, and the capacity to use an array of such autoantibodies for enhanced diagnostics and to better predict prognosis. They may also possess capacity for utilization in therapy, in vivo. In this review both the positive and negative aspects of autoantibodies are critically assessed, including their role in autoimmune diseases, cancers and the global pandemic caused by COVID-19. Important issues related to their detection are also highlighted.

Cerebrospinal fluid findings in adult patients with obsessive-compulsive disorder: A retrospective analysis of 54 samples

OBJECTIVES

Obsessive-compulsive disorder (OCD) can rarely be associated with immunological aetiologies, most notably in Paediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal Infections and possibly in autoimmune encephalitis. As cerebrospinal fluid (CSF) analysis is a sensitive method for assessing neuroinflammation, this retrospective study analysed basic CSF parameters and well-characterised as well as novel neuronal autoantibodies in OCD to screen for signs of autoimmunity.

METHODS

Basic CSF findings of 54 adult OCD patients suspected of an organic aetiology were retrospectively compared to a control group of mentally healthy patients (N = 39) with idiopathic intracranial hypertension. Further subgroup analysis included testing for well-characterised neuronal IgG autoantibodies and tissue-based assays using indirect immunofluorescence to screen for novel brain autoantibodies.

RESULTS

Elevated protein in the CSF of OCD patients compared to the control group (p = 0.043) was identified. Inflammatory markers (pleocytosis/oligoclonal bands/increased IgG-index) were detected in 7% of all patients with OCD. Well-characterised neuronal autoantibodies were not found in any OCD patient, whereas 6/18 (33%) CSF samples showed binding on mouse brain sections in tissue-based assays (binding to neuropil in the basal ganglia/brainstem, cilia of granule cells, blood vessels, nuclear/perinuclear structures).

CONCLUSIONS

While elevated CSF protein is merely a weak indicator of blood CSF barrier dysfunction, the presence of inflammatory CSF changes and novel brain autoantibodies in CSF may indicate OCD subtypes with inflammatory pathomechanism and supports the hypothesis of a rare "autoimmune OCD" subtype.

Spectrum of Novel Anti-Central Nervous System Autoantibodies in the Cerebrospinal Fluid of 119 Patients With Schizophreniform and Affective Disorders

BACKGROUND

Autoimmune psychosis may be caused by well-characterized anti-neuronal autoantibodies, such as those against the NMDA receptor. However, the presence of additional anti-central nervous system (CNS) autoantibodies in these patients has not been systematically assessed.

METHODS

Serum and cerebrospinal fluid (CSF) from patients with schizophreniform and affective syndromes were analyzed for immunoglobulin G anti-CNS autoantibodies using tissue-based assays with indirect immunofluorescence on unfixed murine brain tissue as part of an extended routine clinical practice. After an initial assessment of patients with red flags for autoimmune psychosis (n = 30), tissue-based testing was extended to a routine procedure (n = 89).

RESULTS

Based on the findings from all 119 patients, anti-CNS immunoglobulin G autoantibodies against brain tissue were detected in 18% (n = 22) of patients (serum 9%, CSF 18%) following five principal patterns: 1) against vascular structures, most likely endothelial cells (serum 3%, CSF 8%); 2) against granule cells in the cerebellum and/or hippocampus (serum 4%, CSF 6%); 3) against myelinated fibers (serum 2%, CSF 2%); 4) against cerebellar Purkinje cells (serum 0%, CSF 2%); and 5) against astrocytes (serum 1%, CSF 1%). The patients with novel anti-CNS autoantibodies showed increased albumin quotients (p = .026) and white matter changes (p = .020) more frequently than those who tested negative for autoantibodies.

CONCLUSIONS

The study demonstrates five novel autoantibody-binding patterns on brain tissue of patients with schizophreniform and affective syndromes. CSF yielded positive findings more frequently than serum analysis. The frequency and spectrum of autoantibodies in these patient groups may be broader than previously thought.