Intrathecal synthesis of oligoclonal IgG in patients with Viliuisk encephalomyelitis: The relationship between oligoclonal bands and clinical features.

Viliuisk encephalomyelitis (VE) is a neurodegenerative disease that afflicts aboriginal people of Yakutia in Siberia with unknown etiology. Oligoclonal IgG bands (OCBs) were discovered in the VE patients (Green et al., 2003). In this study we analysed the association of OCBs with clinical symptoms in 58 VE patients. Positive oligoclonal IgG are associated with a shorter duration of disease (p=0.002), older age of onset (p=0.023) and high frequency of main neurological VE symptoms such as dementia, frontal dysbasia, bulbar disorders, muscle atrophy and centrally caused pelvic disorders. Our results show that the OCBs in VE patients are associated with more severe central nervous system (CNS) damage and may cause secondary complications in the course of the disease.

Communicating hydrocephalus following eosinophilic meningitis is pathogenic for chronic Viliuisk encephalomyelitis in Northeastern Siberia.

BACKGROUND: Viliuisk encephalomyelitis (VE) is an endemic neurological disease in Northeast Siberia and generally considered to be a chronic encephalomyelitis of unknown origin actually spreading in the Sakha (Yakutian) Republic. METHODOLOGY AND PRINCIPLE FINDINGS: In search for the pathophysiology and causative agent of VE, we performed a cross-sectional study on clinical, serological and neuroimaging data on chronic VE patients during two medical expeditions to three villages within the Viliuiski river basin in the Republic of Sakha in 2000 and to the capital Yakutsk in 2006. The severity of the core clinical picture with predominant sensory ataxia, gait apraxia, lower limb spasticity, cognitive impairment and bladder dysfunction correlated with the degree of MRI findings showing enlargement of inner ventricular spaces as in communicating hydrocephalus. Laboratory studies revealed transient eosinophilia during the preceding acute meningitis-like phase, but no ongoing inflammatory process in the CSF. We found immune reactions against Toxocara canis in the majority of chronic VE patients but rarely in controls (P = 0.025; Fisher's exact test). Histological analysis of subacute to subchronic VE brain samples showed eosinophilic infiltrations with no signs of persistent Toxocara canis infection. CONCLUSIONS AND SIGNIFICANCE: Our data showed that pressure by the communicating hydrocephalus as a mechanical factor is the major pathogenic mechanism in chronic VE, most likely triggered by eosinophilic meningitis. There are no signs for an ongoing inflammatory process in chronic VE. The past eosinophilic reaction in VE might be caused by Toxocara ssp. infection and might therefore represent the first hint for an initial cause leading to the development of chronic VE. Our data provide a framework for future studies and potential therapeutic interventions for this enigmatic epidemic neurological disease potentially spreading in Sakha Republic.

Viliuisk encephalomyelitis: intrathecal synthesis of oligoclonal IgG.

Viliuisk encephalomyelitis (VE) is a neurodegenerative disorder expressed as subacute meningo-encephalitis progressing to a more prolonged pan-encephalitic syndrome with a fatal outcome within 1 to 10 years. Some patients survive to a steady state of global dementia and severe spasticity that may last for over 20 years. Multiple micronecrotic foci surrounded by inflammatory infiltrates are observed throughout the cerebral cortex and other gray matter areas. Infectious etiology of VE is strongly suspected, but the causative agent has not been identified. We conducted a search for assays that might be helpful for VE diagnosis and established for the first time that the majority of patients with definite VE show evidence for intrathecal IgG synthesis correlating with the clinical manifestations of the disease. This indicates that the detection of oligoclonal IgG banding in the cerebrospinal fluid is a valuable diagnostic assay for VE. Implications of these findings for a possible etiology of VE are discussed.