Peter O. Behan

Fatigue in neurological disorders

Chronic fatigue is a typical symptom of neurological diseases, and is most disabling in multiple sclerosis, postpoliomyelitis, poststroke, and in chronic fatigue syndrome. Disorders of neuromuscular junction transmission and metabolic diseases cause muscle fatigability, which is characterised by failure to sustain the force of muscle contraction (peripheral fatigue). Fatigue is also seen in diseases that affect the central, peripheral, and autonomic nervous systems (central fatigue). Enhanced perception of effort and limited endurance of sustained physical and mental activities are the main characteristics of central fatigue. Metabolic and structural lesions that disrupt the usual process of activation in pathways interconnecting the basal ganglia, thalamus, limbic system, and higher cortical centre are implicated in the pathophysiological process of central fatigue. A state of pre-existing relative hypocortisolaemia might sensitise the hypothalamic-pituitary-adrenal axis to development of persistent central fatigue after stress. The contributions of physiological, cognitive, and affective changes underlying fatigue are variable, and treatment is largely symptomatic and rehabilitative.

Cytomegalovirus in autoimmunity: T cell crossreactivity to viral antigen and autoantigen glutamic acid decarboxylase

Antigens of pathogenic microbes that mimic autoantigens are thought to be responsible for the activation of autoreactive T cells. Viral infections have been associated with the development of the neuroendocrine autoimmune diseases type 1 diabetes and stiff-man syndrome, but the mechanism is unknown. These diseases share glutamic acid decarboxylase (GAD65) as a major autoantigen. We screened synthetic peptide libraries dedicated to bind to HLA-DR3, which predisposes to both diseases, using clonal CD4+ T cells reactive to GAD65 isolated from a prediabetic stiff-man syndrome patient. Here we show that these GAD65-specific T cells crossreact with a peptide of the human cytomegalovirus (hCMV) major DNA-binding protein. This peptide was identified after database searching with a recognition pattern that had been deduced from the library studies. Furthermore, we showed that hCMV-derived epitope can be naturally processed by dendritic cells and recognized by GAD65 reactive T cells. Thus, hCMV may be involved in the loss of T cell tolerance to autoantigen GAD65 by a mechanism of molecular mimicry leading to autoimmunity.

Postviral fatigue syndrome: persistence of enterovirus RNA in muscle and elevated creatine kinase.

Enterovirus-specific probes have been prepared by reverse transcription of conserved sequences in purified Coxsackie B2 virus genomic RNA and molecular cloning techniques. These probes were used in quantitative slot blot hybridizations to test for the presence of enterovirus-specific RNA in skeletal muscle biopsy specimens from 96 patients who had suffered from the postviral fatigue syndrome myalgic encephalomyelitis for up to 20 years. Biopsy specimens from 20 patients were positive for the presence of virus-specific RNA with hybridization signals more than three standard deviations greater than the mean of the normal muscle controls. Biopsies from the remaining 76 patients were indistinguishable from the controls. These data show that enterovirus RNA is present in skeletal muscle of some patients with postviral fatigue syndrome up to 20 years after onset of disease and suggest that a persistent virus infection has an aetiological role.

The clinical spectrum, diagnosis, pathogenesis and treatment of Hashimoto's encephalopathy (recurrent acute disseminated encephalomyelitis).

Hashimotos encephalopathy may present with a wide variety of different neurological symptoms and signs. These include recurrent severe migrainous headache, psychoses, seizures, ataxia, dementia, stupor and coma. We present a personal series of 18 adult patients with Hashimotos encephalopathy and a review of the literature in this paper. The natural history, laboratory abnormalities and neuroimaging data in these cases favour an immunopathological basis for this syndrome similar to relapsing acute disseminated encephalomyelitis. We suggest that Hashimotos encephalomyelitis should be considered in the differential diagnosis of seizures, coma, atypical migraine and reversible dementia. Serological screening for anti-thyroid antibody should form part of the initial investigations in all relapsing and reversible encephalopathies.

IMMUNOLOGICAL ABNORMALITIES IN PATIENTS WHO HAD THE OCULOMUCOCUTANEOUS SYNDROME ASSOCIATED WITH PRACTOLOL THERAPY

Patients with and without adverse reactions on practolol therapy showed altered immune responses. There was cutaneous anergy to Candida albicans and streptokinase/streptodornase antigens and depression of lymphocyte function in vitro. Anticomplementary activity and a wide range of autoantibodies were found in patients who had received practolol.

Dyslexia, congenital anomalies, and immune disorders: the role of the fetal environment.

Etude de la presence de malformations dans la famille des dyslexiques. Etude de la presence dautoanticorps humoraux chez les meres de dyslexiques

The sad plight of multiple sclerosis research (low on fact, high on fiction): critical data to support it being a neurocristopathy

The literature for evidence of autoimmunity in multiple sclerosis (MS) is analysed critically. In contrast to the accepted theory, the human counterpart of the animal model experimental autoimmune demyelinating disease, experimental allergic encephalomyelitis (EAE), is not MS but a different demyelinating disorder, i.e. acute disseminated encephalomyelitis and acute haemorrhagic leucoencephalitis. Extrapolation of EAE research to MS has been guided largely by faith and a blind acceptance rather than sound, scientific rationale. No specific or sensitive immunological test exists that is diagnostic of MS despite the extensive application of modern technology. Immunosuppression has failed to have any consistent effect on prognosis or disease progression. The available data on MS immunotherapy are conflicting, at times contradictory and are based on findings in animals with EAE. They show predominantly a 30% effect in relapsing/remitting MS which suggests powerful placebo effect. Critical analysis of the epidemiological data shows no association with any specific autoimmune diseases, but does suggest that geographic factors and age at development posit an early onset possibly dependent on environmental influences. Certain neurological diseases are, however, found in association with MS, namely hypertrophic peripheral neuropathy, neurofibromatosis-1, cerebral glioma, glioblastoma multiforme and certain familial forms of narcolepsy. These share a common genetic influence possibly from genes on chromosome 17 affecting cell proliferation. A significant number of these disorders are of neural crest origin, the classical example being abnormalities of the Schwann cell. These and other data allow us to propose that MS is a developmental neural crest disorder, i.e. a cristopathy, implicating glial cell dysfunction with diffuse blood–brain barrier breakdown. The data on transcription factor SOX10 mutations in animals may explain these bizarre clinical associations with MS and the phenotypic variability of such alterations (Cossais et al. 2010). Research directed to the area of neural crest associations is likely to be rewarding.

Detection of immune complexes in polymyositis

There is good evidence to suggest a role for immunological factors in the pathogenesis of polymyositis although the exact mechanism and type of immunological disorder is unknown. The specific cellular and humoral hypersensitivity to muscle antigens described is most likely to represent an epiphenomenon.

Complement abnormalities in polymyositis

Abstract Eight of 19 cases of polymyositis were found to have positive anticomplementary assays with concomitant evidence of complement activation in 6 of these cases. The presence of circulating soluble immune complexes is suggested. These complexes may have a primary role in the pathogenesis of the disease

Antiviral Pathway Activation in Patients with Chronic Fatigue Syndrome and Acute Infection

Gene expression of key enzymes in 2 antiviral pathways (ribonuclease latent [RNase L] and RNA-regulated protein kinase [PKR]) was compared in 22 patients with chronic fatigue syndrome (CFS), 10 patients with acute gastroenteritis, and 21 healthy volunteers. Pathway activation in the group of patients with infections differed significantly from that of the other 2 groups, in whom there was no evidence of upregulation. Therefore, assay of activation is unlikely to provide the basis for a diagnostic test for CFS.