Normal serum levels of immune complexes in postpolio patients

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.

Increased cerebral integrity metrics in poliomyelitis survivors: putative adaptation to longstanding lower motor neuron degeneration

BACKGROUND

Post-polio syndrome (PPS) has been traditionally considered a slowly progressive condition that affects poliomyelitis survivors decades after their initial infection. Cerebral changes in poliomyelitis survivors are poorly characterised and the few existing studies are strikingly conflicting.

OBJECTIVE

The overarching aim of this study is the comprehensive characterisation of cerebral grey and white matter alterations in poliomyelitis survivors with reference to healthy- and disease-controls using quantitative imaging metrics.

METHODS

Thirty-six poliomyelitis survivors, 88 patients with ALS and 117 healthy individuals were recruited in a prospective, single-centre neuroimaging study using uniform MRI acquisition parameters. All participants underwent standardised clinical assessments, T1-weighted structural and diffusion tensor imaging. Whole-brain and region-of-interest morphometric analyses were undertaken to evaluate patterns of grey matter changes. Tract-based spatial statistics were performed to evaluate diffusivity alterations in a study-specific whiter matter skeleton.

RESULTS

In contrast to healthy controls, poliomyelitis survivors exhibited increased grey matter partial volumes in the brainstem, cerebellum and occipital lobe, accompanied by increased FA in the corticospinal tracts, cerebellum, bilateral mesial temporal lobes and inferior frontal tracts. Polio survivors exhibited increased integrity metrics in the same anatomical regions where ALS patients showed degenerative changes.

CONCLUSIONS

Our findings indicate considerable cortical and white matter reorganisation in poliomyelitis survivors which may be interpreted as compensatory, adaptive change in response to severe lower motor neuron injury in infancy.

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.

The Neonatal Fc Receptor (FcRn): A Misnomer?

Antibodies are essential components of an adaptive immune response. Immunoglobulin G (IgG) is the most common type of antibody found in circulation and extracellular fluids. Although IgG alone can directly protect the body from infection through the activities of its antigen binding region, the majority of IgG immune functions are mediated via proteins and receptors expressed by specialized cell subsets that bind to the fragment crystallizable (Fc) region of IgG. Fc gamma (γ) receptors (FcγR) belong to a broad family of proteins that presently include classical membrane-bound surface receptors as well as atypical intracellular receptors and cytoplasmic glycoproteins. Among the atypical FcγRs, the neonatal Fc receptor (FcRn) has increasingly gained notoriety given its intimate influence on IgG biology and its ability to also bind to albumin. FcRn functions as a recycling or transcytosis receptor that is responsible for maintaining IgG and albumin in the circulation, and bidirectionally transporting these two ligands across polarized cellular barriers. More recently, it has been appreciated that FcRn acts as an immune receptor by interacting with and facilitating antigen presentation of peptides derived from IgG immune complexes (IC). Here we review FcRn biology and focus on newer advances including how emerging FcRn-targeted therapies may affect the immune responses to IgG and IgG IC.

Is Tolerance Broken in Autoimmunity?

Autoimmune diseases are classified into about 80 different types based on their specificity related to system, organ and/or tissue. About 5% of the western population is affected by this anomaly, but its worldwide incidence is unknown. Autoimmune diseases are heterogeneous in nature and clinical manifestations range from benign disorders to life-threatening conditions. Autoimmunity strikes at any stage of life, but age and/or gender also play role in onset of some of these anomalies. The autoimmune pathogenesis is initiated by the origination of autoantigens, which leads to the development of autoantibodies followed by auto-immunogenicity and the ultimate onset of autoimmunity. There is a lack of suitable therapies to treat autoimmune diseases, because mechanisms involved in the onset of these anomalies were poorly understood. Present therapies are limited to symptomatic treatment and come with severe side effects. Here, I described the molecular mechanisms and cellular events involved in the initiation of autoimmunity and proposed better strategies to modulate such molecular and cellular anomalies, which will help in preventing and/or controlling autoimmune pathogenesis and ultimately aid in enhancing the quality of life.

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.