Intrathecal immune response in patients with the post-polio syndrome

Post-polio syndrome is not a dysimmune condition

BACKGROUND

Poliomyelitis is a global disabling disease affecting 12-20 million of people. Post poliomyelitis syndrome (PPS) may affect up to 80% of polio survivors: increased muscle weakness, pain, fatigue, functional decline. It relies on aging of an impaired neuro-muscular system with ongoing denervation processes. A late involvement of humoral or cellular pro-inflammatory phenomena is also suspected.

AIM

To assess the dysimmune hypothesis of PPS by comparing lymphocyte subpopulations and humoral immune factors between PPS patients and controls.

DESIGN

Cross-sectional study.

SETTING

Montpellier University Hospital.

POPULATION

Forty-seven PPS and 27 healthy controls.

METHODS

PPS patients and controls were compared on their lymphocyte subpopulations and humoral immune factors (IL-1β, IL-6, IL-8, IL-17, IL-21, IL-22, IL-23, IFN-γ, TNF-α, GM-CSF, RANTES, MCP1, MIP-3a, IL-10, TGF-β, IL4, IL13). Patients were further compared according to their dominant clinical symptoms. Sample size guaranteed a power >90% for all comparisons.

RESULTS

PPS patients and controls were comparable in gender, age and corpulence. Most patients had lower limb motor sequelae (N.=45, 95.7%), a minority had upper limb motor impairment (N.=16, 34.0%). Forty-five were able to walk (94%), 35/45 with technical aids. The median of the two-minute walking test was 110 meters (interquartile range 55; 132). Eighteen (38%) required help in their daily life. Their quality of life was low (SF36). All described an increased muscular weakness, 40 (85%) a general fatigue, and 39 (83%) muscular or joint pain. Blood count, serum electrolytes, T and B lymphocyte subpopulations and cytokines were comparable between patients and controls, except for creatine phospho kinase that was significantly higher in PPS patients. None of these variables differed between the 20/47 patients whose late main symptoms were pain or fatigue, and other patients.

CONCLUSIONS

Our results suggest that PPS is not a dysimmune disease.

CLINICAL REHABILITATION IMPACT

Our results do not sustain immunotherapy for PPS. Our work suggest that PPS may be mostly linked to physiological age-related phenomena in a disabled neuromuscular condition. Thus, our results emphasize the role of prevention and elimination of aggravating factors to avoid late functional worsening, and the importance of rehabilitation programs that should be adapted to patients' specific conditions.

The Fight against Poliovirus Is Not Over

Poliovirus (PV), the virus that causes both acute poliomyelitis and post-polio syndrome, is classified within the Enterovirus C species, and there are three wild PV serotypes: WPV1, WPV2 and WPV3. The launch of the Global Polio Eradication Initiative (GPEI) in 1988 eradicated two of the three serotypes of WPV (WPV2 and WPV3). However, the endemic transmission of WPV1 persists in Afghanistan and Pakistan in 2022. There are cases of paralytic polio due to the loss of viral attenuation in the oral poliovirus vaccine (OPV), known as vaccine-derived poliovirus (VDPV). Between January 2021 and May 2023, a total of 2141 circulating VDPV (cVDPV) cases were reported in 36 countries worldwide. Because of this risk, inactivated poliovirus (IPV) is being used more widely, and attenuated PV2 has been removed from OPV formulations to obtain bivalent OPV (containing only types 1 and 3). In order to avoid the reversion of attenuated OPV strains, the new OPV, which is more stable due to genome-wide modifications, as well as sabin IPV and virus-like particle (VLP) vaccines, is being developed and offers promising solutions for eradicating WP1 and VDPV.

Effectiveness of Intravenous Immunoglobulin for Management of Pain in Patients with Postpolio Syndrome

Objective

Many patients with postpolio syndrome (PPS) experience pain. In this study, we aimed to review previous studies to investigate the effectiveness of intravenous immunoglobulin (IVIG) for managing pain in patients with PPS. We performed a narrative review.

Methods

In PubMed, we searched for the keywords ((Immunoglobulin OR IVIG) AND (poliomyelitis OR poliomyelitis syndrome)). We included articles in which IVIG was infused in patients with PPS and pain severity was measured before and after treatment.

Results

In the results, five articles (4 randomized controlled trials and 1 prospective observational study) were included in this review. Four of the studies reported that IVIG had a positive pain-reducing effect in patients with PPS. In addition, 4 studies evaluated the outcomes related to muscle strength and function. Of these studies, 3 showed some improvement in measurements for muscle strength and function.

Conclusion

In conclusion, IVIG might be one of the beneficial options for managing pain in PPS. Pain reduction might be responsible for the improvement of muscle strength or function. To confirm the benefits of IVIG in reducing pain, more high-quality studies are required.

Post-polio Syndrome: More Than Just a Lower Motor Neuron Disease

Post-polio syndrome (PPS) is a neurological condition that affects polio survivors decades after their initial infection. Despite its high prevalence, the etiology of PPS remains elusive, mechanisms of progression are poorly understood, and the condition is notoriously under-researched. While motor dysfunction is a hallmark feature of the condition, generalized fatigue, sleep disturbance, decreased endurance, neuropsychological deficits, sensory symptoms, and chronic pain are also often reported and have considerable quality of life implications in PPS. The non-motor aspects of PPS are particularly challenging to evaluate, quantify, and treat. Generalized fatigue is one of the most distressing symptoms of PPS and is likely to be multifactorial due to weight-gain, respiratory compromise, poor sleep, and polypharmacy. No validated diagnostic, monitoring, or prognostic markers have been developed in PPS to date and the mainstay of therapy centers on symptomatic relief and individualized rehabilitation strategies such as energy conservation and muscle strengthening exercise regimes. Despite a number of large clinical trials in PPS, no effective disease-modifying pharmacological treatments are currently available.

Role of Tumor Necrosis Factor Superfamily in Neuroinflammation and Autoimmunity

Tumor necrosis factor superfamily (TNFSF) molecules play an important role in the activation, proliferation, differentiation, and migration of immune cells into the central nervous system (CNS). Several TNF superfamily molecules are known to control alloimmunity, autoimmunity, and immunity. Development of transgenic and gene knockout animals, and monoclonal antibodies against TNFSF molecules have increased our understanding of individual receptor-ligand interactions, and their intracellular signaling during homeostasis and neuroinflammation. A strong clinical association has been observed between TNFSF members and CNS autoimmunity such as multiple sclerosis and also in its animal model experimental autoimmune encephalomyelitis. Therefore, they are promising targets for alternative therapeutic options to control autoimmunity. Although, TNFSF ligands are widely distributed and have diverse functions, we have restricted the discussions in this review to TNFSF receptor-ligand interactions and their role in the pathogenesis of neuroinflammation and CNS autoimmunity.

Post-poliomyelitis syndrome as a possible viral disease

This review summarizes current concepts on post-polio syndrome (PPS), a condition that may arise in polio survivors after partial or complete functional recovery followed by a prolonged interval of stable neurological function. PPS affects 15-20 million people worldwide. Epidemiological data are reported, together with the pathogenic pathways that possibly lead to the progressive degeneration and loss of neuromuscular motor units. As a consequence of PPS, polio survivors experience new weakness, generalized fatigue, atrophy of previously unaffected muscles, and a physical decline that may culminate in the loss of independent life. Emphasis is given to the possible pathogenic role of persistent poliovirus infection and chronic inflammation. These factors could contribute to the neurological and physical decline in polio survivors. A perspective is then given on novel anti-poliovirus compounds and monoclonal antibodies that have been developed to contribute to the final phases of polio eradication. These agents could also be useful for the treatment or prevention of PPS. Some of these compounds/antibodies are in early clinical development. Finally, current clinical trials for PPS are reported. In this area, the intravenous infusion of normal human immunoglobulins appears both feasible and promising.

Enteroviruses as a possible cause of hypertension, dilated cardiomyopathy (DCM) and hypertensive heart failure (HHF) in South western Nigeria

BACKGROUND

Human enteroviruses have long been associated with various diseases of man resulting into a wide range of acute symptoms involving the cardiac and skeletal muscles, central nervous system, pancreas, skin and mucous membranes.

OBJECTIVE

To assess the role of enteroviruses in the etiology of hypertension, DCM and HHF.

METHODS

We obtained stool specimens from 70 subjects comprising 65 patients and 5 controls and isolation was carried out on RD, L20B, HEp-2C and Vero cell lines and identified by neutralization with standard antisera (RIVM). Thirty-six enteroviruses were isolated and identified to be Coxsackieviruses-B5, A9, Echoviruses 1, 6, 7, 9, 11, 12, 22, 30 and Poliovirus type 1 and 3.

RESULTS

Three most frequently occurring enterovirus serotypes which constitute 60.0% of the 30 NPEV typed and 50.0% of all the isolates were Echoviruses, Coxsackie-B5-virus and Coxsackievirus-A9. Echoviruses constituted 50.0% of all the serotypes while Coxsackieviruses-B5 and A9 accounts for the 27.8 % and 5.6% respectively. Enteroviral isolation rate was higher in age groups 51 years and above. The percentage of study subjects who had Coxsackie-B5-viruses and echoviruses was significantly (P<0.05) higher in cases of hypertension, HHF and DCM than in control subjects. Coxackie-B5-virus, Echovirus-6 and Echovirus-11 were found in both study locations.

CONCLUSION

The findings of this study showed that Enteroviruses may likely be involved in the etiology of hypertension, DCM and HHF. Further studies would therefore be necessary for the prevention and control of these diseases.

Demyelination and other neurological adverse events after anti-TNF therapy

Tumor necrosis factor (TNF) α inhibitors are an essential therapeutic option for several inflammatory diseases, like rheumatoid arthritis, spondyloarthropathies and inflammatory bowel diseases. As TNFα antagonists have become increasingly utilized, there have been a number of reports of neurological adverse events in patients receiving anti-TNFα therapy. The frequency of central nervous system adverse events after initiation of anti-TNFα therapy is unknown. However, questions have been raised about a possible causal association. Although several hypotheses have been proposed in an attempt to explain the possible relationship between TNFα antagonist and demyelination, none is considered to be adequate. Thus, in this report we deal with the implication of TNFα in multiple sclerosis and we discuss the possible relationship of TNFα antagonist and demyelinating diseases.

Intravenous immunoglobulin treatment of the post-polio syndrome: sustained effects on quality of life variables and cytokine expression after one year follow up

BACKGROUND

Expression of inflammatory cytokines in cerebrospinal fluid (CSF) has led to the hypothesis of intrathecal chronic inflammation to explain the denervation observed in post-polio syndrome (PPS). It has been shown that therapy with intravenous immunoglobulin (IVIG) improves physical performance and dampens down the inflammatory process at 6 months in PPS patients. We here examined the effects of IVIG on cytokine expression and clinical outcome one year after IVIG treatment.

METHODS

From a previous study with 135 PPS patients included, 41 patients were further evaluated before un-blinding for one year (21 placebo and 20 treated with IVIG, Xepol® 50 mg/ml), and were assessed for clinical variables by performing the Short Form-36 survey (SF-36) questionnaire assessment, the 6 minute walk distance test (6MWT) and registering pain level by Visual Analogue Scale (VAS) after IVIG treatment. A separate cohort of 37 PPS patients went through lumbar puncture (LP) at baseline and 20 patients, treated with IVIG, repeated the LP one year later. Thirty patients affected with other neurological diseases (OND) were used as control group. Inflammatory cytokines TNF, TGFβ, IFNγ, IL-23, IL-13 and IL-10 were measured in blood cells and CSF cells with RT-PCR.

RESULTS

Scores of the physical components of SF-36 were significantly higher at the one year follow up time-point in the IVIG-treated patients when compared to baseline as well as to the control subjects. Pain VAS score and 6MWT improved significantly in the IVIG-treated patients when compared with baseline Relative expression of TNF and IFN-γ in both PBMCs and CSF from PPS patients were increased compared to OND subjects at baseline (p < 0.05). One year after IVIG-treatment a decreased expression of IFN-γ and IL23 was found in CSF of PPS patients, while anti-inflammatory IL-13 was increased (p < 0.05).

CONCLUSIONS

IVIG has effects on relevant QoL variables and inflammatory cytokines up to one year in patients with PPS. This gives a basis for scheduling IVIG in upcoming trials with this therapy.

Restless legs syndrome--theoretical roles of inflammatory and immune mechanisms

Theories for restless legs syndrome (RLS) pathogenesis include iron deficiency, dopamine dysregulation and peripheral neuropathy. Increased prevalence of small intestinal bacterial overgrowth (SIBO) in controlled studies in RLS and case reports of post-infectious RLS suggest potential roles for inflammation and immunological alterations. A literature search for all conditions associated with RLS was performed. These included secondary RLS disorders and factors that may exacerbate RLS. All of these conditions were reviewed with respect to potential pathogenesis including reports of iron deficiency, neuropathy, SIBO, inflammation and immune changes. A condition was defined as highly-associated if there was a prevalence study that utilized an appropriate control group. Small case reports were recorded but not included as definite RLS-associated conditions. Fifty four diseases, syndromes and conditions have been reported to cause and/or exacerbate RLS. Of these, 38 have been reported to have a higher prevalence than age-matched controls, 9 have adequate sized reports and have general acceptance as RLS-associated conditions and 7 have been reported in case report form. Overall, 42 of the 47 RLS-associated conditions (89%) have also been associated with inflammatory and/or immune changes. In addition, 43% have been associated with peripheral iron deficiency, 40% with peripheral neuropathy and 32% with SIBO. Most of the remaining conditions have yet to be studied for these factors. The fact that 95% of the 38 highly-associated RLS conditions are also associated with inflammatory/immune changes suggests the possibility that RLS may be mediated or affected through these mechanisms. Inflammation can be responsible for iron deficiency and hypothetically could cause central nervous system iron deficiency-induced RLS. Alternatively, an immune reaction to gastrointestinal bacteria or other antigens may hypothetically cause RLS by a direct immunological attack on the central or peripheral nervous system.

Shared molecular and functional frameworks among five complex human disorders: a comparative study on interactomes linked to susceptibility genes

BACKGROUND

Genome-wide association studies (gwas) are invaluable in revealing the common variants predisposing to complex human diseases. Yet, until now, the large volumes of data generated from such analyses have not been explored extensively enough to identify the molecular and functional framework hosting the susceptibility genes.

METHODOLOGY/PRINCIPAL FINDINGS

We investigated the relationships among five neurodegenerative and/or autoimmune complex human diseases (Parkinson's disease--Park, Alzheimer's disease--Alz, multiple sclerosis--MS, rheumatoid arthritis--RA and Type 1 diabetes--T1D) by characterising the interactomes linked to their gwas-genes. An initial study on the MS interactome indicated that several genes predisposing to the other autoimmune or neurodegenerative disorders may come into contact with it, suggesting that susceptibility to distinct diseases may converge towards common molecular and biological networks. In order to test this hypothesis, we performed pathway enrichment analyses on each disease interactome independently. Several issues related to immune function and growth factor signalling pathways appeared in all autoimmune diseases, and, surprisingly, in Alzheimer's disease. Furthermore, the paired analyses of disease interactomes revealed significant molecular and functional relatedness among autoimmune diseases, and, unexpectedly, between T1D and Alz.

CONCLUSIONS/SIGNIFICANCE

The systems biology approach highlighted several known pathogenic processes, indicating that changes in these functions might be driven or sustained by the framework linked to genetic susceptibility. Moreover, the comparative analyses among the five genetic interactomes revealed unexpected genetic relationships, which await further biological validation. Overall, this study outlines the potential of systems biology to uncover links between genetics and pathogenesis of complex human disorders.

Update on current and emerging treatment options for post-polio syndrome

Post-polio syndrome (PPS) refers to the clinical deterioration experienced by many polio survivors several decades after their acute illness. The symptoms are new muscle weakness, decreased muscle endurance, fatigue, muscle pain, joint pain, cold intolerance, and this typical clinical entity is reported from different parts of the world. The pathophysiology behind PPS is not fully understood, but a combination of distal degeneration of enlarged motor units caused by increased metabolic demands and the normal aging process, in addition to inflammatory mechanisms, are thought to be involved. There is no diagnostic test for PPS, and the diagnosis is based on a proper clinical workup where all other possible explanations for the new symptoms are ruled out. The basic principle of management of PPS lies in physical activity, individually tailored training programs, and lifestyle modification. Muscle weakness and muscle pain may be helped with specific training programs, in which training in warm water seems to be particularly helpful. Properly fitted orthoses can improve the biomechanical movement pattern and be energy-saving. Fatigue can be relieved with lifestyle changes, assistive devices, and training programs. Respiratory insufficiency can be controlled with noninvasive respiratory aids including biphasic positive pressure ventilators. Pharmacologic agents like prednisone, amantadine, pyridostigmine, and coenzyme Q10 are of no benefit in PPS. Intravenous immunoglobulin (IVIG) has been tried in three studies, all having positive results. IVIG could probably be a therapeutic alternative, but the potential benefit is modest, and some important questions are still unanswered, in particular to which patients this treatment is useful, the dose, and the therapeutic interval.

Identification of novel candidate protein biomarkers for the post-polio syndrome - implications for diagnosis, neurodegeneration and neuroinflammation

Survivors of poliomyelitis often develop increased or new symptoms decades after the acute infection, a condition known as post-polio syndrome (PPS). The condition affects 20-60% of previous polio patients, making it one of the most common causes of neurological deficits worldwide. The underlying pathogenesis is not fully understood and accurate diagnosis is not feasible. Herein we investigated whether it was possible to identify proteomic profile aberrations in the cerebrospinal fluid (CSF) of PPS patients. CSF from 15 patients with well-defined PPS were analyzed for protein expression profiles. The results were compared to data obtained from nine healthy controls and 34 patients with other non-inflammatory diseases which served as negative controls. In addition, 17 samples from persons with secondary progressive multiple sclerosis (SPMS) were added as relevant age-matched references for the PPS samples. The CSF of persons with PPS displayed a disease-specific and highly predictive (p=0.0017) differential expression of five distinct proteins: gelsolin, hemopexin, peptidylglycine alpha-amidating monooxygenase, glutathione synthetase and kallikrein 6, respectively, in comparison with the control groups. An independent ELISA confirmed the increase of kallikrein 6. We suggest that these five proteins should be further evaluated as candidate biomarkers for the diagnosis and development of new therapies for PPS patients.

THE RECOMBINATION OF HUMAN ENTEROVIRUS 71

In 1998, the enterovirus (EV) infections outbreak in Taiwan caused 78 fatalities. Since then, EV infections have continuously posed a threat to the public. Among the 64 serotypes of enteroviruses known to infect human, the enterovirus 71(EV71) is suspected to be the major cause for severe cases. In this study, we estimate the recombination point of enterovirus 71 vp1 by using the method of Likelihood Analysis of Recombination in DNA. The datasets of enterovirus 71 DNA sequences are available in GenBank. After careful cross validation, eight candidate sequences are chosen to advance analysis, including 2734TAI98, TW227298, 1423SIN98 and other five DNA sequences as well. Then, the construction of the phylogeny trees (neighbor-joining trees will be used in this paper) would support for recombination in EV71 virus. In these two methods, the breakpoint was found to be in similar position, demonstrating that a single recombination event occurred prior to the divergence of these two strains.

Enteroviruses and postviral fatigue syndrome

Postviral fatigue syndrome (PFS) occurs both in epidemics and sporadically. Many of the original epidemics were related to poliomyelitis outbreaks which either preceded or followed them. The core clinical symptoms are always the same: severe fatigue made worse by exercise, myalgia, night sweats, atypical depression and excessive sleep. The other common symptoms include dysequilibrium disorders and irritable bowel syndrome. We have detected enteroviral genome sequences in muscle biopsies from cases of PFS, using specific enteroviral oligonucleotide primers in the polymerase chain reaction (PCR). In addition, whole virus particles can be demonstrated in PCR-positive muscle, using solid-phase immuno-electron microscopy. An increase in the number and size of muscle mitochondria was found in 70% of PFS cases, suggesting an abnormality in metabolic function. Evidence of hypothalamic dysfunction was present, particularly involving 5-hydroxytryptamine metabolism. A putative model of PFS, based on persistent enteroviral infection in laboratory mice, revealed resolving inflammatory lesions in muscle with, however, a marked increase in the production of certain cytokines in the brain. This model may help to explain the pathogenesis of PFS.

Post-polio syndrome: clinical manifestations and cerebrospinal fluid markers

Post-polio syndrome (PPS) refers to a constellation of new neurological, musculoskeletal and general symptoms occurring in survivors of poliomyelitis decades after acute paralytic and nonparalytic disease. The common manifestations of PPS include generalized, central and peripheral fatigue, muscle weakness and musculoskeletal pain. The pathogenesis of PPS remains obscure. Three prevailing hypotheses have been advanced: stress-induced degeneration of surviving neurons, persistent poliovirus replication or virus reactivation and immune-mediated damage. The diagnosis of PPS is based on medical history and clinical examination, since no specific diagnostic tests are available. In the light of recent studies demonstrating a partial beneficial effect of intravenous immunoglobulin, this article will focus on cerebrospinal fluid biomarkers reflecting disease activity and pathogenic processes in PPS.

Post-polio syndrome patients treated with intravenous immunoglobulin: a double-blinded randomized controlled pilot study

Post-polio syndrome (PPS) is characterized by new muscle weakness, atrophy, fatigue and pain developing several years after the acute polio. Some studies suggest an ongoing inflammation in the spinal cord in these patients. From this perspective, intravenous immunoglobulin (IvIg) could be a therapeutic option. We performed a double-blinded randomized controlled pilot study with 20 patients to investigate the possible clinical effects of IvIg in PPS. Twenty patients were randomized to either IvIg 2 g/kg body weight or placebo. Primary endpoints were changes in pain, fatigue and muscle strength 3 months after treatment. Surrogate endpoints were changes in cerebrospinal fluid (CSF) cytokine levels. Secondary endpoints were pain, fatigue and isometric muscle strength after 6 months. Patients receiving IvIg reported a significant improvement in pain during the first 3 months, but no change was noted for subjective fatigue and muscle strength. CSF levels of tumour necrosis factor-alpha (TNF-alpha) were increased compared with patients with non-inflammatory neurological disorders. In conclusion, in this small pilot study no effect was seen with IvIg treatment on muscle strength and fatigue, however IvIg treated PPS patients reported significantly less pain 3 months after treatment. TNF-alpha was increased in the CSF from PPS patients. The results are promising, but not conclusive because of the low number of patients studied.

Virology of the post-polio syndrome

The three poliovirus serotypes (PVs) cause acute paralytic poliomyelitis. Decades after being hit by polio, survivors may develop a condition known as post-polio syndrome (PPS). PPS is characterized by extreme fatigue, progressing muscular weakness and chronic pain. The pathogenesis is unclear and, thus, empirical therapies are employed. PVs are known to be able to persist in infected host cells both in vitro and in vivo. The understanding of PV genomes has made it possible to set up sensitive and specific molecular tests capable of detecting minute amounts of virus in samples from PPS patients. Current data indicate that complete PV genomes (or genomic fragments) remain present, decades after acute paralysis, in the CNS of these patients. Virus persistence is hypothesized to bring about chronic inflammation, immune-mediated injury and decreased expression of neurotrophic factors. Establishing a pathogenetic link between PV persistence and PPS would be extremely relevant to the development of an etiologic therapy aimed at virus eradication.

Physical therapist management following rotator cuff repair for a patient with postpolio syndrome

BACKGROUND AND PURPOSE

Postpoliomyelitis sequelae, such as gait instability and progressive weakness, predispose people with postpolio syndrome to secondary disabilities. With aging, people who depend on their upper extremities to accommodate lower-extremity deficits may anticipate overuse injuries. The purpose of this case report is to describe the use of mobilization and exercise in postoperative rehabilitation of rotator cuff surgery on a patient with postpolio syndrome.

CASE DESCRIPTION

A 48-year-old woman with postpolio syndrome had rotator cuff surgical repair followed by physical therapy intervention. Maitland mobilization and mild functional exercises were chosen to avoid triggering fatigue.

OUTCOMES

Measurements taken preoperatively, before and after physical therapy intervention, and 2 years after intervention showed return to independent status with excellent retention.

DISCUSSION

No fatigue or overuse weakness was encountered. This is the first case report to document physical therapy following rotator cuff repair in a patient with postpolio syndrome.

Sporadic amyotrophic lateral sclerosis: a hypothesis of persistent (non-lytic) enteroviral infection

Because of recently reported reverse transcriptase polymerase chain reaction evidence of enterovirus in sporadic amyotrophic lateral sclerosis (SALS) and because of newly available anti-enteroviral drugs binding enteroviral capsids, it is reasonable to re-formulate an enteroviral hypothesis of SALS using recent advances in molecular virology. Viral persistence is non-lytic and non-cytopathic infection that evades host's immune surveillance. Enteroviruses are known to cause persistent as well as lytic infection both in vitro and in vivo. Both virion as well as host factors modulate between persistent and lytic infection. Apoptosis, or programmed cell death, is a process of active non-necrotic cell death. It has complex interplay with viruses and may be either promoted or opposed by them. Apoptosis is a major factor in motor neuron death in SALS. Viral tropism is the process by which viruses select and propagate to target cells. It is controlled by capsid conformation and surface receptors on host cells. Enteroviruses have a region on their capsids known as the canyon which docks on such receptors. Docking induces conformational changes of the capsid and genome release. Poliovirus, tropic for motor neurons, docks on the poliovirus receptor, about which much is known. The virus penetrates the motor system focally after crossing either the blood-muscle or the blood-brain barriers. It propagates bidirectionally along axons and synapses to contiguous motor neurons, upper as well as lower, which sequester infection and create avenues for spread over long distances. If chronic and persistent rather than acute and lytic, such viruses trafficking in a finite system of non-dividing cells and inducing apoptosis would cause cell death that summates linearly rather than exponentially. Taken together, these explain signature clinical features of SALS - focal onset weakness, contiguous or regional spread of weakness, confinement to upper and lower motor neurons, and linear rates of progression. The hypothesis predicts the following testable investigations: 1) viral detection may be possible by applying amplification technology to optimally acquired nervous tissue processed by laser microdissection; 2) genetic susceptibility factors such as cell surface receptor polymorphisms may combine with sporadic exposure and chance penetration of the motor system in SALS; 3) a transgenic animal model might be created by inserting such genetic factors into an animal host and inoculating intramuscularly rather than intracerebrally biochemical fractions of SALS motor neurons at vulnerable periods in the developmental life cycle of the transgenic host; and 4) continual long-term administration of anti-enteroviral agents called capsid-binding compounds which stabilize capsids and prevent genome release might be efficacious.

Poliovirus, pathogenesis of poliomyelitis, and apoptosis

Poliovirus (PV) is the causal agent of paralytic poliomyelitis, an acute disease of the central nervous system (CNS) resulting in flaccid paralysis. The development of new animal and cell models has allowed the key steps of the pathogenesis of poliomyelitis to be investigated at the molecular level. In particular, it has been shown that PV-induced apoptosis is an important component of the tissue injury in the CNS of infected mice, which leads to paralysis. In this review the molecular biology of PV and the pathogenesis of poliomyelitis are briefly described, and then several models of PV-induced apoptosis are considered; the role of the cellular receptor of PV, CD155, in the modulation of apoptosis is also addressed.

Prior poliomyelitis—IvIg treatment reduces proinflammatory cytokine production

The postpolio syndrome (PPS) is characterized by progressive disabilities decades after recovery from the acute paralytic disease. There are reports on intrathecal inflammatory reactions in PPS, including increased expression of cytokines by cerebrospinal fluid (CSF) mononuclear cells (CSF-MC). This is potentially of relevance for the clinical condition. We here explored if cytokine expression in the CSF of PPS patients could be modulated by high-dose intravenous immunoglobulins (IvIg). The expression of TNF-alpha, IFN-gamma, IL-10 and IL-4 mRNAs was measured by real-time RT-PCR in CSF and peripheral blood mononuclear cells (PBMC) of 16 PPS patients before, and 6-8 weeks after IvIg treatment, and in 26 patients with noninflammatory other neurological diseases (OND). TNF-alpha, IFN-gamma and IL-10 CSF mRNA levels were elevated in samples from untreated persons with PPS compared to OND. Upon IvIg treatment, IFN-gamma and TNF-alpha mRNA levels were dramatically reduced, while IL-10 remained unchanged. Placebo-controlled studies are now warranted to evaluate if IvIg treatment also has any effects on the clinical manifestations of PPS.

Characteristics of radiogenic lower motor neurone disease, a possible link with a preceding viral infection

OBJECTIVE

To investigate the pathogenesis of the rare radiogenic lower motor neurone disease (LMND) on the basis of a meta-analysis of the published case histories.

MATERIALS AND METHODS

The authors reviewed 47 well-documented radiogenic LMND cases from the English literature.

RESULTS

The disease typically occurs following the irradiation of radiosensitive cancers situated near the spinal cord. It arises predominantly (46 cases) in the lower extremities; only one case involved the upper extremities. There is a male predominance (male:female ratio 7.8:1), and the patients are characteristically young (13-40 years, with four exceptions). An overdose does not seem to be a particular risk factor for the development of the disease, as total dose, fraction size and biologically effective dose are typically below 50 Gy, 2 Gy and 128 Gy2, respectively, which are regarded as safe doses. Other risk factors (chemotherapy, operations, etc) have been identified only rarely. Radiogenic LMND is manifested in an apparently random manner, 4-312 (mean 48.7) months after the completion of radiotherapy.

DISCUSSION

The complete lack of a dose-effect relationship argues strongly against a pure radiogenic nature of the pathological process. The latency period is typically several years and it varies extremely, which excludes a direct and complete causal relationship between radiotherapy and LMND. As the interaction of ionizing radiation with living tissues is highly unspecific, thus a selective motor injury due to irradiation alone, without comparable effects on the sensory and vegetative fibers, seems improbable.

CONCLUSIONS

On analogy with the viral motor neurone diseases, we suppose that radiogenic LMND may be preceded by viral (enterovirus/poliovirus) infection. Based on the meta-analysis, it is suggested that irradiation may be only a single component of the set of factors jointly resulting in the clinical state regarded as radiogenic LMND.

Le syndrome post-poliomyélitique

Postpoliomyelitis syndrome is a clinical syndrome characterized by late progression of symptoms, neuromuscular weakness, fatigue and pain, several (more than 20) Years after acute anterior poliomyelitis. In the United States, where it has been mainly described, frequency is estimated between 20 and 30p.100 in patients with sequelae of poliomyelitis. Although the cause is still unknown, postpoliomyelitis syndrome is likely due to degeneration and dysfunction of terminal axons of enlarged post-polio units, with a possible role of inflammatory reaction driven by persistence of the polio virus. Due to lack of specific therapy, rational therapeutic approaches are symptomatic, including exercise, reassurance and life-strategies for fatigue.

Post-polio syndrome and total health status in a prospective hospital study

New loss of function among patients with previous polio is frequently reported and has several causes. All patients referred to the Department of Neurology, Haukeland University Hospital, Bergen, for 13 months during 2000-2001 with diagnosis late effects of polio were examined prospectively to identify their symptoms and loss of function. Eighty-five patients aged 47-91 years with mean of 61 years were included. The most common complaints were pain (44%), muscular weakness (27%), and fatigue (16%). Muscular weakness occurred in lower limbs in 75%, in respiratory muscles in only 5%. Walking in stairs was impaired in 72% and outdoor walking in 65%. Seventeen patients (19%) reported no loss of function. Post-polio syndrome was diagnosed in 26% of the patients. Polio-related loss of function including cervical and lumbosacral radiculopathies, mononeuropathies and degenerative joint disease were found in an additional 53%. Eleven patients (13%) had distinct non-polio-related disorders that caused new loss of function. The remaining 8% had a stable condition. In conclusion, the majority of polio patients who seek hospital, experience a new loss of function because of polio-related disorders. A careful neurological examination is necessary to identify the correct diagnosis and treatment.

Prior poliomyelitis-evidence of cytokine production in the central nervous system

In order to study the role of a possible inflammatory reaction in the post-polio syndrome (PPS) four key cytokines were determined by means of mRNA expression in mononuclear cells from cerebrospinal fluid (CSF) and peripheral blood of 13 patients. Data were compared with those of samples from eight non-inflammatory control persons. The PPS-patients displayed increased numbers of CSF cells expressing mRNA for TNF-alpha (p<0.02), IFN-gamma (p<0.02), IL-4 (p<0.001) and IL-10 (p<0.05), in comparison to the non-inflammatory controls. As positive controls, samples from patients with Multiple Sclerosis (MS) were examined. We conclude that there is a chronic intra CNS expression of inflammatory cytokines in PPS, in the range of that in MS, a well known neuroinflammatory disease. However, the pathogenic significance of this is unclear.

Restriction of poliovirus RNA replication in persistently infected nerve cells

The aetiology of post-polio syndrome may involve persistence of poliovirus (PV) in the CNS. PV persists in the CNS of infected paralysed mice for over a year after the acute phase of paralytic poliomyelitis. However, infectious PV particles cannot be recovered from homogenates of CNS from paralysed mice after the acute phase of disease, indicating that PV replication is restricted. To identify the molecular mechanism by which PV replication is limited, PV RNA synthesis was analysed by estimating the relative level of genomic (plus-strand) and complementary (minus-strand) PV RNA in the CNS of persistently infected mice. PV RNA replication decreased during the 6 months following onset of paralysis, due mainly to inhibition of plus-strand RNA synthesis. Thus, restriction of PV RNA synthesis may contribute to persistence by limiting virus replication in the mouse CNS. Interestingly, viral RNA replication was similarly inhibited in neuroblastoma IMR-32 cell cultures persistently infected with PV. This in vitro model thus shows that cellular factors play a role in the inhibition of viral RNA synthesis.

Transgenic expression of replication-restricted enteroviral genomes in heart muscle induces defective excitation-contraction coupling and dilated cardiomyopathy

Numerous studies have implicated Coxsackievirus in acute and chronic heart failure. Although enteroviral nucleic acids have been detected in selected patients with dilated cardiomyopathy, the significance of such persistent nucleic acids is unknown. To investigate the mechanisms by which restricted viral replication with low level expression of Coxsackieviral proteins may be able to induce cardiomyopathy, we generated transgenic mice which express a replication-restricted full-length Coxsackievirus B3 (CVB3) cDNA mutant (CVB3DeltaVP0) in the heart driven by the cardiac myocyte-specific myosin light chain-2v (MLC-2v) promoter. CVB3DeltaVP0 was generated by mutating infectious CVB3 cDNA at the VP4/VP2 autocatalytic cleavage site from Asn-Ser to Lys-Ala. Cardiac-specific expression of this cDNA leads to synthesis of positive- and negative-strand viral RNA in the heart without formation of infectious viral progeny. Histopathologic analysis of transgenic hearts revealed typical morphologic features of myocardial interstitial fibrosis and in some cases degeneration of myocytes, thus resembling dilated cardiomyopathy in humans. There was also an increase in ventricular atrial natriuretic factor mRNA levels, demonstrating activation of the embryonic program of gene expression typical of ventricular hypertrophy and failure. Echocardiographic analysis demonstrated the presence of left ventricular dilation and decreased systolic function in the transgenic mice compared with wild-type littermates, evidenced by increased ventricular end-diastolic and end-systolic dimensions and decreased fractional shortening. Analysis of isolated myocytes from transgenic mice demonstrate that there is defective excitation-contraction coupling and a decrease in the magnitude of isolated cell shortening. These data demonstrate that restricted replication of enteroviral genomes in the heart can induce dilated cardiomyopathy with excitation-contraction coupling abnormalities similar to pressure overload models of dilated cardiomyopathy.

Low-level expression of a mutant coxsackieviral cDNA induces a myocytopathic effect in culture: an approach to the study of enteroviral persistence in cardiac myocytes

BACKGROUND

Enteroviral ribonucleic acids have been identified in heart muscle of a subset of patients with myocarditis and dilated cardiomyopathy as well as in a mouse model of persistent coxsackievirus B3 (CVB3) infection, suggesting that persistent viral infection along with activation of an immune response may contribute to the pathogenesis of ongoing cardiac disease and dilated cardiomyopathy in certain patients. It is still not known whether persistence of the viral genome contributes to the pathogenesis of dilated cardiomyopathy.

METHODS AND RESULTS

To determine whether low-level enteroviral gene expression similar to that observed with viral persistence can induce myocytopathic effects without formation of infectious virus progeny, the full-length infectious cDNA copy of CVB3 was mutated at the VP0 maturation cleavage site. This prevented formation of infectious virus progeny. In myocytes transfected with this mutated cDNA copy of the viral genome, both positive- and negative-strand viral RNAs were detected, demonstrating that there was replication of the viral genome by the RNA-dependent RNA polymerase. The level of viral protein expression was found to be below limits of detection by conventional methods of protein detection, thus resembling restricted virus replication. Nonetheless, the CVB3 mutant was found to induce a cytopathic effect in transfected myocytes, which was demonstrated by inhibition of cotransfected MLC-2v luciferase reporter activity and an increase in release of lactate dehydrogenase from transfected cells.

CONCLUSIONS

This study demonstrates that restricted replication of enteroviral genomes in myocytes in a pattern similar to that observed in hearts with persistent viral infection can induce myocytopathic effects without generation of infectious virus progeny.

Poliovirus vaccine vectors elicit antigen-specific cytotoxic T cells and protect mice against lethal challenge with malignant melanoma cells expressing a model antigen

Recombinant polioviruses expressing foreign antigens may provide a convenient vaccine vector system to induce protective immunity against diverse pathogens. Replication-competent chimeric viruses can be constructed by inserting foreign antigenic sequences within the poliovirus polyprotein. When inserted sequences are flanked by poliovirus protease recognition sites the recombinant polyprotein is processed to mature and functional viral proteins plus the exogenous antigen. It previously has been shown that poliovirus recombinants can induce antibody responses against the inserted sequences but it is not known whether poliovirus or vaccine vectors derived from it can elicit effective cytotoxic T lymphocyte (CTL) responses. To examine the ability of the recombinant poliovirus to induce CTL responses, a segment of the chicken ovalbumin gene, which includes the H2-Kb-restricted CTL epitope SIINFEKL, was cloned at the junction of the P1 and P2 regions. This recombinant virus replicated with near wild-type efficiency in culture and stably expressed high levels of the ovalbumin antigen. Murine and primate cells infected with the recombinant virus appropriately processed the SIINFEKL epitope and presented it within major histocompatibility complex class I molecules. Inoculation of mice with recombinant poliovirus that expresses ovalbumin elicits an effective specific CTL response. Furthermore, vaccination with these recombinant poliovirus induced protective immunity against challenge with lethal doses of a malignant melanoma cell line expressing ovalbumin.

[Amyotrophic lateral sclerosis and herpes virus. Report of an unusual case: a cause or casual association?]

OBJECTIVE

To present a curious case of amyotrophic lateral sclerosis (ALS).

CASE

A forty-seven year old man claimed of paresis in the arms since four years. The electrical study of the muscles and nerves diagnosis was ALS, type Vulpian-Bernardt. The cerebrospinal fluid study revealed an inflammatory process and the positivity of immulogical reactions for Herpes simplex I. The blood-brain barrier study showed the possibility that immunological response for Herpes simplex I was produced in the spinal fluid space. A magnetic resonance suggested cystic myelopathy of cervical spinal cord expanding from C2 to C4. The patient received endovenous acyclovir for 21 days. Until two months after the medication we did not submit the patient to other subsidiary examinations.

DISCUSSION

Until now there is no specific drug treatment for ALS. The notion that there is a "syndrome of ALS" related with various causes may help to treat some patients.

Molecular typing of enteroviruses: current status and future requirements. The European Union Concerted Action on Virus Meningitis and Encephalitis

Human enteroviruses have traditionally been typed according to neutralization serotype. This procedure is limited by the difficulty in culturing some enteroviruses, the availability of antisera for serotyping, and the cost and technical complexity of serotyping procedures. Furthermore, the impact of information derived from enterovirus serotyping is generally perceived to be low. Enteroviruses are now increasingly being detected by PCR rather than by culture. Classical typing methods will therefore no longer be possible in most instances. An alternative means of enterovirus typing, employing PCR in conjunction with molecular genetic techniques such as nucleotide sequencing or nucleic acid hybridization, would complement molecular diagnosis, may overcome some of the problems associated with serotyping, and would provide additional information regarding the epidemiology and biological properties of enteroviruses. We argue the case for developing a molecular typing system, discuss the genetic basis of such a system, review the literature describing attempts to identify or classify enteroviruses by molecular methods, and suggest ways in which the goal of molecular typing may be realized.

A pilot study to determine the efficiency of lightweight carbon fibre orthoses in the management of patients suffering from post-poliomyelitis syndrome

OBJECTIVES

To assess the usage of carbon fibre orthoses in assisting post-polio syndrome patients who reported advancing weakness and difficulty in maintaining their independent ambulatory status.

DESIGN AND INTERVENTIONS

Carbon fibre orthoses that are 30% lighter than metal braces were constructed.

SUBJECTS

Thirty patients who complained of difficulty in maintaining their ambulation using long-leg braces were provided with lightweight orthoses.

RESULTS

Seventy per cent of the patients reported satisfaction with their braces. There were, however, problems in construction and use.

CONCLUSIONS

Ambulation can be preserved in some patients who report advancing weakness because of post-polio syndrome.

Persistent echovirus infection of mouse cells expressing the viral receptor VLA-2

Mouse cells are not susceptible to infection with echovirus 1 (EV-1) because they lack the viral receptor, human VLA-2. Two mouse fibroblast cell lines, L cells and 3T3 cells, were made susceptible to EV-1 infection after transformation with cDNAs of human VLA-2. After EV-1 infection, L cell transformants of human VLA-2 (alpha2beta1 L cells) develop cytopathic effect (CPE) as expected, while 3T3 cell transformants of human VLA-2 (alpha2beta1 3T3 cells) or the alpha2 subunit of human VLA-2 (alpha2 3T3 cells) become persistently infected. The distinct outcome is not a result of differential virus growth on these transformants because one-step growth curve analysis reveals little difference in EV-1 replication in both cell lines. In addition, 3T3 cell transformants expressing the poliovirus receptor (Pvr 3T3 cells) are lysed during poliovirus infection, suggesting that 3T3 cells are not intrinsically resistant to CPE caused by enterovirus infection. The results of limit dilution assays indicate that all EV-1-infected alpha2 3T3 cells produce infectious virus. All EV-1-infected alpha2 3T3 cells remain viable after EV-1 infection, and the kinetics of cell growth were not altered. FACS analysis reveals that receptor down-regulation is not involved in the establishment of persistent infection. Furthermore, inhibition of host protein synthesis was not observed in EV-1-infected alpha2 3T3 or alpha2beta1 L cells. Since alpha2beta1 L cells are lysed by EV-1 infection, these findings suggest that virus-induced translation inhibition is not a determinant of cell killing.

Persistent poliovirus infection in mouse motoneurons

Poliovirus (PV) is the causal agent of paralytic poliomyelitis. Many survivors of the acute disease, after decades of clinical stability, develop new muscular symptoms called postpolio syndrome. It has been hypothesized that the persistence of PV in the spinal cord is involved in the etiology of this syndrome. To investigate the ability of PV to persist in the spinal cord after the onset of paralysis, we exploited a mouse model in which most animals inoculated with a mouse-adapted mutant survived after the onset of paralysis. Light microscopy and ultrastructural immunohistochemical studies and reverse transcription followed by nested PCR performed on spinal cord from paralyzed mice demonstrated that PV persisted in the mouse spinal cord for at least 12 months after the onset of paralysis. This mouse model provides a new tool for studying poliomyelitis evolution after the onset of paralysis.

Poliomyelitis

1996 is polio awareness year. This paper reviews the clinical syndrome of acute paralytic poliomyelitis and its sequelae. We discuss epidemiological studies of the syndrome of late functional deterioration many years after the acute infection and the current hypotheses of the pathophysiology of such disorders. Recent evidence has suggested that potentially treatable factors may be implicated in the majority of such patients and it is therefore important to exclude such disorders before attributing late functional deterioration to progressive post-polio muscular atrophy.

Persistent poliovirus infection of human fetal brain cells

It has been suggested that poliovirus (PV), the causative agent of poliomyelitis, could persist in surviving patients. We have previously shown that PV can persistently infect some human cell lines in vitro, particularly neuroblastoma cell lines. We report here an ex vivo model in which PV can persistently infect primary cultures of human fetal brain cells. Two mutations involving capsid residues 142 of VP2 and 95 of VP1 were repeatedly selected during the persistent infections. These residues are located in capsid regions known to be involved in interactions between PV and its receptor. During the first week after infection, viral antigens were found in cells of both the neuronal and glial lineages. In contrast, 2 weeks after infection, viral antigens were detected almost exclusively in cells of the neuronal lineage. They were detected predominantly in cells expressing a marker of early commitment to the neuronal lineage, MAP-5, particularly in neuroblasts. Viral antigens were also found in immature progenitors expressing a neuroepithelium marker, nestin, and in cells expressing a marker of postmitotic neurons, MAP-2. The presence of viral antigens in postmitotic neurons suggests that PV can persist in neurons of patients who have survived poliomyelitis.

Evidence of presence of poliovirus genomic sequences in cerebrospinal fluid from patients with postpolio syndrome

The postpolio syndrome (PPS) is characterized by new neuromuscular symptoms occurring 30 to 40 years after the acute episode of poliomyelitis paralysis. The presence of the poliovirus RNA genome in the cerebrospinal fluid from 10 patients with PPS and from 23 control patients was sought by using reverse transcription and a PCR specific for polioviruses and/or other enteroviruses. Poliovirus-specific genomic sequences in the 5' untranslated region and in the capsid region (VP1) were detected by reverse transcription PCR in 5 of 10 patients with PPS but in none of the control patients. Sequencing confirmed the presence of mutated poliovirus sequences. This finding suggests persistent viral infection in the central nervous system related to the presence of poliovirus genomes.