Plasma immune markers in an idiopathic REM sleep behavior disorder cohort.

INTRODUCTION: Increasing evidence shows a strong association between idiopathic REM sleep behavior disorder (iRBD) and α-synucleinopathies. Recent studies have indicated an inflammatory mechanism in the pathogenesis of α-synucleinopathies. Whether peripheral inflammatory cytokines are altered in iRBD and can be biomarkers for predicting phenoconversion remains unclear. METHODS: We collected baseline plasma samples from 77 consecutive iRBD patients and 64 age- and sex-matched healthy controls. Ten cytokines were measured: Interferon (IFN)-γ, interleukin (IL)-1ß, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, and tumor necrosis factor (TNF)-α. All iRBD patients underwent clinical assessment tests at baseline, and 75 were prospectively followed and received assessments for parkinsonism or dementia. Cox regression analyses were used to evaluate the predictive value of plasma cytokines in a follow-up period of 6.0 years. RESULTS: TNF-α and IL-10 were significantly elevated in iRBD compared with controls (both p < 0.001). IL-6/IL-10 and IL-8/IL-10 were significantly reduced in iRBD than in controls (p = 0.001, p < 0.001, respectively). After a median follow-up of 3.7 years, 16 iRBD patients developed neurodegenerative synucleinopathies. iRBD patients with higher TNF-α/IL-10 levels were more likely to develop neurodegenerative diseases (adjusted HR 1.07, 95% CI 1.01-1.14). The coexistence of elevated TNF-α/IL-10 and possible mild cognitive impairment predicted an early conversion of iRBD to neurodegenerative synucleinopathies (adjusted HR 4.17, 95% CI 1.47-11.81). CONCLUSIONS: Our study supported the early involvement of peripheral inflammation in prodromal α-synucleinopathy. Plasma cytokines may be predictive of disease conversion in iRBD, while large-scale longitudinal studies are warranted to validate the assumption.

Rapid Eye Movement Sleep Behavior Disorder in Paraneoplastic Cerebellar Degeneration: Improvement with Immunotherapy.

STUDY OBJECTIVES: To report two female patients with paraneoplastic cerebellar degeneration (PCD) related to breast cancer that presented with rapid eye movement-sleep behavior disorder (RBD) and improved sleep symptoms with immunotherapy. METHODS: The two patients were evaluated through clinical scale and polysomnography before and after therapy with intravenous immunoglobulin. RESULTS: RBD was successfully treated with immunotherapy in both patients. Score on the RBD screening questionnaire dropped from 10 to 1 or 0, allied with the normalization of polysomnographic findings. CONCLUSIONS: A marked improvement in RBD after immunotherapy in PCD raises the hypothesis that secondary RBD may be an immune-mediated sleep disorder.

Narcolepsy, REM sleep behavior disorder, and supranuclear gaze palsy associated with Ma1 and Ma2 antibodies and tonsillar carcinoma.

OBJECTIVE: To describe a patient with diencephalic and mesencephalic presentation of a Ma1 and Ma2 antibody-associated paraneoplastic neurological disorder. DESIGN: Case report. SETTING: The Colorado Neurological Institute Movement Disorders Center in Englewood, Colorado, and the Mayo Clinic in Rochester, Minnesota. PATIENT: A 55-year-old man with a paraneoplastic neurological disorder characterized by rapid eye movement sleep behavior disorder, narcolepsy, and a progressive supranuclear palsy-like syndrome in the setting of tonsillar carcinoma. INTERVENTION: Immunotherapy for paraneoplastic neurological disorder, surgery and radiotherapy for cancer, and symptomatic treatment for parkinsonism and sleep disorders. MAIN OUTCOME MEASURES: Polysomnography, multiple sleep latency test, and neurological examination. RESULTS: The cancer was detected at a limited stage and treatable. After oncological therapy and immunotherapy, symptoms stabilized. Treatment with modafinil improved daytime somnolence. CONCLUSIONS: Rapid onset and progression of multifocal deficits may be a clue to paraneoplastic etiology. Early treatment of a limited stage cancer (with or without immunotherapy) may possibly slow progression of neurological symptoms. Symptomatic treatment may be beneficial.

REM sleep behavior disorder and narcoleptic features in anti-Ma2-associated encephalitis.

A 69-year-old man with anti-Ma2 paraneoplastic encephalitis presented with subacute onset of severe hypersomnia, memory loss, parkinsonism, and gaze palsy. A brain magnetic resonance imaging study showed bilateral damage in the dorsolateral midbrain, amygdala, and paramedian thalami. Videopolysomnography disclosed rapid eye movement (REM) sleep behavior disorder, and a Multiple Sleep Latency Test showed a mean sleep latency of 7 minutes and 4 sleep-onset REM periods. The level of hypocretin-1 in the cerebrospinal fluid was low (49 pg/mL). This observation illustrates that REM sleep behavior disorder and narcoleptic features are 2 REM-sleep abnormalities that (1) may share the same autoimmune-mediated origin affecting the brainstem, limbic, and diencephalic structures and (2) may occur in the setting of the paraneoplastic anti-Ma2-associated encephalitis.

Rapid eye movement sleep behavior disorder and potassium channel antibody-associated limbic encephalitis.

Of six patients registered in our center with nonparaneoplastic limbic encephalitis associated with antibodies to voltage-gated potassium channels, the five men had rapid eye movement sleep behavior disorder (RBD) coincident with voltage-gated potassium channel antibody-associated limbic encephalitis onset. In three patients, immunosuppression resulted in resolution of RBD in parallel with remission of the limbic syndrome. RBD persisted in two patients with partial resolution of the limbic syndrome. Our findings suggest that RBD is frequent in the setting of voltage-gated potassium channel antibody-associated limbic encephalitis and can be related to autoimmune-mediated mechanisms. In addition, these observations suggest that impairment of the limbic system may play a role in the pathogenesis of RBD.