HIV-1 clade-C-associated "ALS"-like disorder: first report from India

Association between motor neuron disease and HIV infection: A systematic review of case reports

BACKGROUND

Motor neuron disease (MND) is a well-known group of neurodegenerative diseases, with amyotrophic lateral sclerosis (ALS) being the most common form. Since 1985, a possible association between MND/ALS and HIV infection has been described.

METHODS

We performed a systematic review of case reports and case series involving people living with HIV with MND/ALS through PubMed, Bireme, Embase, and Lilacs databases. The risk of bias was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Tool for Case Reports.

RESULTS

We analyzed 36 articles presenting 88 cases. The mean age was 41.6 years. Antiretroviral therapy (ART) was used by 89.8% and riluzole by 16.9%. First signs and symptoms were similarly present on cervical/upper (25%) and lumbosacral/lower limbs (23.9%), mostly with fasciculations (69.8%) and hyperreflexia (58.8%). MND had a progressive course in 32.9% patients and a clinical improve in 54.6% following ART. The mean survival of the 32 patients who died was 12.3 months and the mean survival of the living patients was 62 months. Respiratory failure was the main cause of death (35.7%).

CONCLUSIONS

MND/ALS may present differently in the people living with HIV as a rapidly progressive disease in younger people but with the potential to improve weakness and survival through antiretroviral therapy.

Contribution of CNS and extra-CNS infections to neurodegeneration: a narrative review

Central nervous system infections have been suggested as a possible cause for neurodegenerative diseases, particularly sporadic cases. They trigger neuroinflammation which is considered integrally involved in neurodegenerative processes. In this review, we will look at data linking a variety of viral, bacterial, fungal, and protozoan infections to Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis and unspecified dementia. This narrative review aims to bring together a broad range of data currently supporting the involvement of central nervous system infections in the development of neurodegenerative diseases. The idea that no single pathogen or pathogen group is responsible for neurodegenerative diseases will be discussed. Instead, we suggest that a wide range of susceptibility factors may make individuals differentially vulnerable to different infectious pathogens and subsequent pathologies.

Retroviral Elements in Pathophysiology and as Therapeutic Targets for Amyotrophic Lateral Sclerosis

The study of the role of retroviruses in amyotrophic lateral sclerosis (ALS) dates back to the 1960s shortly after transposable elements themselves were first discovered. It was quickly realized that in wild mice both horizontal and vertical transmissions of retroviral elements were key to the development of an ALS-like syndrome leading to the postulate that endogenous retroviruses (ERVs) contribute significantly to the pathogenicity of this disease. Subsequent studies identified retroviral reverse transcriptase activity in brains of individuals with ALS from Guam. However, except for a single study from the former Soviet Union, ALS could not be transmitted to rhesus macaques. The discovery of an ALS-like syndrome in human immunodeficiency virus (HIV) and human T cell leukemia virus infected individuals led to renewed interest in the field and reverse transcriptase activity was found in the blood and cerebrospinal fluid of individuals with sporadic ALS. However, exogenous retroviruses could not be found in individuals with ALS which further reinforced the possibility of involvement of a human ERV (HERV). The first demonstration of the involvement of a HERV was the discovery of the activation of human endogenous retrovirus-K subtype HML-2 in the brains of individuals with ALS. The envelope protein of HML-2 is neurotoxic and transgenic animals expressing the envelope protein develop an ALS-like syndrome. Activation of HML-2 occurs in the context of generalized transposable element activation and is not specific for ALS. Individuals with HIV-associated ALS show a remarkable response to antiretroviral therapy; however, antiretroviral trials in ALS down-regulate HML-2 without ameliorating the disease. This highlights the need for specific drugs to be developed against HML-2 as a novel therapeutic target for ALS. Other approaches might include antisense oligonucleotides, shRNA targeted against the envelope gene or antibodies that can target the extracellular envelope protein. Future clinical trials in ALS should consider combination therapies to control these ERVs.

Immunity in amyotrophic lateral sclerosis: blurred lines between excessive inflammation and inefficient immune responses

Despite wide genetic, environmental and clinical heterogeneity in amyotrophic lateral sclerosis, a rapidly fatal neurodegenerative disease targeting motoneurons, neuroinflammation is a common finding. It is marked by local glial activation, T cell infiltration and systemic immune system activation. The immune system has a prominent role in the pathogenesis of various chronic diseases, hence some of them, including some types of cancer, are successfully targeted by immunotherapeutic approaches. However, various anti-inflammatory or immunosuppressive therapies in amyotrophic lateral sclerosis have failed. This prompted increased scrutiny over the immune-mediated processes underlying amyotrophic lateral sclerosis. Perhaps the biggest conundrum is that amyotrophic lateral sclerosis pathogenesis exhibits features of three otherwise distinct immune dysfunctions-excessive inflammation, autoimmunity and inefficient immune responses. Epidemiological and genome-wide association studies show only minimal overlap between amyotrophic lateral sclerosis and autoimmune diseases, so excessive inflammation is usually thought to be secondary to protein aggregation, mitochondrial damage or other stresses. In contrast, several recently characterized amyotrophic lateral sclerosis-linked mutations, including those in TBK1, OPTN, CYLD and C9orf72, could lead to inefficient immune responses and/or damage pile-up, suggesting that an innate immunodeficiency may also be a trigger and/or modifier of this disease. In such cases, non-selective immunosuppression would further restrict neuroprotective immune responses. Here we discuss multiple layers of immune-mediated neuroprotection and neurotoxicity in amyotrophic lateral sclerosis. Particular focus is placed on individual patient mutations that directly or indirectly affect the immune system, and the mechanisms by which these mutations influence disease progression. The topic of immunity in amyotrophic lateral sclerosis is timely and relevant, because it is one of the few common and potentially malleable denominators in this heterogenous disease. Importantly, amyotrophic lateral sclerosis progression has recently been intricately linked to patient T cell and monocyte profiles, as well as polymorphisms in cytokine and chemokine receptors. For this reason, precise patient stratification based on immunophenotyping will be crucial for efficient therapies.

Amyotrophic Lateral Sclerosis-like Syndrome after Chikungunya

Amyotrophic lateral sclerosis (ALS)-like syndrome refers to a group of conditions whose outcome is similar to that of amyotrophic lateral sclerosis, but with different characteristics in the initial phase and response to therapy. The involvement of an earlier age group, the subacute course, and the stabilization or improvement of the clinical condition during the treatment are most important. There is still no evidence of an association between amyotrophic lateral sclerosis-like syndrome and chikungunya (CHK) infection in the literature. This report was intended to review this syndrome and present a case that occurred after the epidemic of CHK in Pernambuco in 2016. CHK is a fast-onset febrile illness characterized by intense asthenia, arthralgia, myalgia, headache, and skin rash. Reports range from encephalitis, optic neuritis, myeloradiculitis to Guillain-Barré syndrome, generating drastic sequelae such as mental deficiency, blindness, and persistent paralysis. This is the first case report of a possible association of ALS-like syndrome and chikungunya infection. CHK infection may cause ALS-like syndrome. There is a need for further research in this field to develop therapies for neurological complications such as that of CHK.

Acute lower motor neuron syndrome and spinal cord gray matter hyperintensities in HIV infection

Objective:

To describe a novel manifestation of lower motor neuron disease in patients with well-controlled HIV infection.

Methods:

A retrospective study was performed to identify HIV-positive individuals with acute, painful lower motor neuron diseases.

Results:

Six patients were identified with HIV and lower motor neuron disease. Two patients met the inclusion criteria of well-controlled, chronic HIV infection and an acute, painful, unilateral lower motor neuron paralytic syndrome affecting the distal portion of the upper limb. These patients had segmental T2-hyperintense lesions in the central gray matter of the cervical spinal cord on MRI. One patient stabilized and the second patient improved with immunomodulatory therapy.

Conclusions:

This newly described syndrome expands the clinical spectrum of lower motor neuron diseases in HIV.

Evidence for peripheral immune activation in amyotrophic lateral sclerosis

There is evidence of the activity of immune system in the spinal cords of patients with amyotrophic lateral sclerosis (ALS), however; few studies to date have explored the status of peripheral immune response in ALS patients. Blood samples from 284 ALS patients and 217 aged-match controls were evaluated, and parameters of T cell subset, humoral immunity, and complement system activation were observed. CD4+ T lymphocytes and circulating immune complexes (CICs) were significantly decreased, and component C3 was significantly increased in ALS patients compared with normal controls. Patients with severe or moderate impairment had a higher CD4+ T cell percentage and a lower IgG levels when compared to those with mild impairment. There was an inverse correlation between CD4 T cell percentage and both revised ALS Functional Rating Scale (ALSFRS-R) score and disease duration, but the correlation was positive between IgG level and both ALSFRS-R score and disease duration among ALS patients. These correlations were gender-specific. This investigation demonstrated the existence of peripheral immune abnormalities in ALS patients.

Amyotrophic lateral sclerosis-like presentation in a HIV-positive patient

There has been several reports of an MND like syndrome in HIV-1 infection, however the data is still sparse. Furthermore, HIV-associated amyotrophic lateral sclerosis (ALS) syndrome differs from the classical ALS in some key aspects.. A 44-year-old male presented with a history of insidious onset and gradually progressive asymmetric weakness of lower limbs. He also complained of thinning in both legs, the left leg more than the right since 1 year along with spontaneous twitching of muscles in both the thighs. On neurological examination, the assessment of higher mental functions was normal. There were no cranial nerve deficits. Motor power was grade 5/5 (Medical Research Council scale) in both the upper limbs and 4+ at hips and knees bilaterally, 5 at right ankle, and 4+ at left ankle. All the deep tendon reflexes were brisk with extensor planter responses. There were no cerebellar signs or sensory deficits. HIV-1 was reactive in enzyme-linked immunosorbent assay. Electrophysiological studies were conducted per the MND protocol.None of the nerves studied showed an abnormal drop in compound muscle action potential amplitude with proximal stimulation. There was evidence of diffuse spontaneous activity, which manifests as fibrillation and fasciculation potentials in most muscles tested . Overall there seems to be sufficient evidence to implicate HIV as a potential cause of an ALS-like disorder, but one must also consider the possibility of coincidental HIV infection in patients who have sporadic ALS.

Retroviruses and amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive, invariably fatal neurologic disorder resulting from upper and lower motor neuron degeneration, which typically develops during the sixth or seventh decade of life, and is diagnosed based on standard clinical criteria. Its underlying cause remains undetermined. The disease may occur with increased frequency within certain families, often in association with specific genomic mutations, while some sporadic cases have been linked to environmental toxins or trauma. Another possibility, first proposed in the 1970s, is that retroviruses play a role in pathogenesis. In this paper, we review the published literature for evidence that ALS is associated either with infection by an exogenous retrovirus or with the expression of human endogenous retroviral (HERV) sequences in cells of the central nervous system. A small percentage of persons infected with the human immunodeficiency virus-1 (HIV-1) or human T cell leukemia virus-1 (HTLV-1) develop ALS-like syndromes. While HTLV-1 associated ALS-like syndrome has several features that may distinguish it from classical ALS, HIV-infected patients may develop neurological manifestations that resemble classical ALS although it occurs at a younger age and they may show a dramatic improvement following the initiation of antiretroviral therapy. However, most patients with probable or definite ALS show no evidence of HIV-1 or HTLV-1 infection. In contrast, recent reports have shown a stronger association with HERV, as analysis of serum samples, and postmortem brain tissue from a number of patients with a classical ALS has revealed significantly increased expression of HERV-K, compared to controls. These findings suggest that endogenous retroviral elements are involved in the pathophysiology of ALS, but there is no evidence that they are the primary cause of the syndrome.

Alterations of T cell subsets in ALS: a systemic immune activation?

INTRODUCTION

There is evidence that immunological factors may involved in pathogenetic mechanisms of amyotrophic lateral sclerosis (ALS). Few studies to date have explored the status of the systemic immune response in patients with ALS.

PATIENTS AND METHODS

In order to examine whether systemic immune activation is observed in patients with ALS, we measured the number of T cell subsets by flow cytometry in 36 patients with ALS and 35 normal controls.

RESULTS

CD8 cytotoxic T cells and natural killer (NK) T cells were significantly increased in our patients with ALS compared with the control group (P = 0.02 and P = 0.04, respectively). Treg cells were significantly reduced compared with normal controls (P = 0.01). Treg cells were also negatively correlated with progression of the disease (P = 0.017).

CONCLUSIONS

Our results suggest a systemic immune activation in patients with ALS. The high production of CD8(+) T and NKT cells may suggest an immunological reaction to some unknown or undetected endogenous proteins or viruses. A probably dual (neurodestructive or neuroprotective) inflammatory function of Treg cells cannot be excluded.

No evidence of HIV pol gene in spinal cord tissues in sporadic ALS by real-time RT-PCR

An association of retroviruses and especially HIV has been reported in SALS, but CNS tissues have not been directly tested. To be valid, direct testing should be performed in light of the highly variable distribution of neuropathology from one patient to another and the degradable nature of RNA viruses. We aimed to seek direct evidence of retrovirus and especially HIV in SALS by real-time RT-PCR. We tested 20 SALS spinal cords in our repository specifically created for RNA preservation. We extracted RNA from anterior horns and surrounding tissue scrape from each sample and validated RNA quality. We indexed our search to neuropathologic degeneration and tested multiple areas in many of the nervous systems. We used real-time RT-PCR to a highly conserved region in the highly conserved pol gene and established the lowest limit of detection using a positive control. HIV-1 pol gene sequence was not detected in any of the 20 SALS nervous systems. Our assay was able to detect down to 60 viral copy numbers. In conclusion, we could not find direct evidence of retroviral/HIV activity in SALS CNS to support a relationship. However, our method could miss novel retroviruses with non-homology in the pol gene.

Flail arm-like syndrome associated with HIV-1 infection

During the last 20 years at least 23 cases of motor neuron disease have been reported in HIV-1 seropositive patients. In this report we describe the clinical picture of a young man with HIV-1 clade C infection and flail arm-like syndrome, who we were able to follow-up for a long period. We investigated and prospectively monitored a 34-year-old man with features of flail arm syndrome, who developed the weakness and wasting 1 year after being diagnosed with HIV-1 infection after a routine blood test. He presented in 2003 with progressive, symmetrical wasting and weakness of the proximal muscles of the upper limb of 2 years' duration. He had severe wasting and weakness of the shoulder and arm muscles. There were no pyramidal signs. He has been on HAART for the last 4 years and the weakness or wasting has not worsened. At the last follow-up in July 2007, the patient had the same neurological deficit and no other symptoms or signs of HIV-1 infection. MRI of the spinal cord in 2007 showed characteristic T2 hyperintense signals in the central part of the spinal cord, corresponding to the central gray matter. Thus, our patient had HIV-1 clade C infection associated with a 'flail arm-like syndrome.' The causal relationship between HIV-1 infection and amyotrophic lateral sclerosis (ALS)-like syndrome is still uncertain. The syndrome usually manifests as a lower motor neuron syndrome, as was seen in our young patient. It is known that treatment with antiretroviral therapy (ART) stabilizes/improves the condition. In our patient the weakness and atrophy remained stable over a period of 3.5 years after commencing HAART regimen.

Elevated levels of transcripts encoding a human retroviral envelope protein (syncytin) in muscles from patients with motor neuron disease

Retroviral components of both exogenous and endogenous origins have been associated with nervous system diseases in both animals and humans. In the present study, the levels of transcripts from elements in the human endogenous retrovirus (HERV) W family were determined in muscle biopsies from patients with motor neuron disease (MND) and control subjects. Transcripts from the HERV-W element on chromosome 7q21.2 encoding syncytin and from the SOD1 gene were detected at elevated levels in biopsies from the most affected muscles from MND patients compared to biopsies from control individuals. According to a recent study, syncytin is expressed in microglia in normal brain and can be up-regulated in macrophages/microglia during inflammation. Although syncytin may have cytotoxic effects, it is therefore more likely that the present findings reflect a macrophage response in the muscles undergoing neurogenic atrophy than a primary pathogenetic event in MND.

Adaptive immune neuroprotection in G93A-SOD1 amyotrophic lateral sclerosis mice

Background

Innate neuroimmune dysfunction is a pathobiological feature of amyotrophic lateral sclerosis (ALS). However, links, if any, between disease and adaptive immunity are poorly understood. Thus, the role of T cell immunity in disease was investigated in human G93A superoxide dismutase 1 (SOD1) transgenic (Tg) mice and subsequently in ALS patients.

Methods and Findings

Quantitative and qualitative immune deficits in lymphoid cell and T cell function were seen in G93A-SOD1 Tg mice. Spleens of Tg animals showed reductions in size, weight, lymphocyte numbers, and morphological deficits at terminal stages of disease compared to their wild-type (Wt) littermates. Spleen sizes and weights of pre-symptomatic Tg mice were unchanged, but deficits were readily seen in T cell proliferation coincident with increased annexin-V associated apoptosis and necrosis of lymphocytes. These lymphoid deficits paralleled failure of Copolymer-1 (COP-1) immunization to affect longevity. In addition, among CD4⁺ T cells in ALS patients, levels of CD45RA⁺ (naïve) T cells were diminished, while CD45RO⁺ (memory) T cells were increased compared to age-matched caregivers. In attempts to correct mutant SOD1 associated immune deficits, we reconstituted SOD1 Tg mice with unfractionated naïve lymphocytes or anti-CD3 activated CD4⁺CD25⁺ T regulatory cells (Treg) or CD4⁺CD25⁻ T effector cells (Teff) from Wt donor mice. While naive lymphocytes failed to enhance survival, both polyclonal-activated Treg and Teff subsets delayed loss of motor function and extended survival; however, only Treg delayed neurological symptom onset, whereas Teff increased latency between disease onset and entry into late stage.

Conclusions

A profound and progressive immunodeficiency is operative in G93A-SOD1 mice and is linked to T cell dysfunction and the failure to elicit COP-1 neuroprotective immune responses. In preliminary studies T cell deficits were also observed in human ALS. These findings, taken together, suggest caution in ascribing vaccination outcomes when these animal models of human ALS are used for study. Nonetheless, the abilities to improve neurological function and life expectancy in G93A-SOD1 Tg mice by reconstitution with activated T cells do provide opportunities for therapeutic intervention.

Alsin and the molecular pathways of amyotrophic lateral sclerosis

Autosomal recessive mutations in the ALS2 gene lead to a clinical spectrum of motor dysfunction including juvenile onset amyotrophic lateral sclerosis (ALS2), primary lateral sclerosis, and hereditary spastic paraplegia. The 184-kDa alsin protein, encoded by the full-length ALS2 gene, contains three different guanine-nucleotide-exchange factor-like domains, which may play a role in the etiology of the disease. Multiple in vitro biochemical and cell biology assays suggest that alsin dysfunction affects endosome trafficking through a Rab5 small GTPase family-mediated mechanism. Four ALS2-deficient mouse models have been generated by different groups and used to study the behavioral and pathological impact of alsin deficiency. These mouse models largely fail to recapitulate hallmarks of motor neuron disease, but the subtle deficits that are observed in behavior and pathology have aided in our understanding of the relationship between alsin and motor dysfunction. In this review, we summarize recent clinical and molecular reports regarding alsin and attempt to place these results within the larger context of motor neuron disease.

Formation of multinucleated giant cells and microglial degeneration in rats expressing a mutant Cu/Zn superoxide dismutase gene

BACKGROUND

Microglial neuroinflammation is thought to play a role in the pathogenesis of amyotrophic lateral sclerosis (ALS). The purpose of this study was to provide a histopathological evaluation of the microglial neuroinflammatory response in a rodent model of ALS, the SOD1G93A transgenic rat.

METHODS

Multiple levels of the CNS from spinal cord to cerebral cortex were studied in SOD1G93A transgenic rats during three stages of natural disease progression, including presymptomatic, early symptomatic (onset), and late symptomatic (end stage), using immuno- and lectin histochemical markers for microglia, such as OX-42, OX-6, and Griffonia simplicifolia isolectin B4.

RESULTS

Our studies revealed abnormal aggregates of microglia forming in the spinal cord as early as the presymptomatic stage. During the symptomatic stages there was prominent formation of multinucleated giant cells through fusion of microglial cells in the spinal cord, brainstem, and red nucleus of the midbrain. Other brain regions, including substantia nigra, cranial nerve nuclei, hippocampus and cortex showed normal appearing microglia. In animals during end stage disease at 4-5 months of age virtually all microglia in the spinal cord gray matter showed extensive fragmentation of their cytoplasm (cytorrhexis), indicative of widespread microglial degeneration. Few microglia exhibiting nuclear fragmentation (karyorrhexis) indicative of apoptosis were identified at any stage.

CONCLUSION

The current findings demonstrate the occurrence of severe abnormalities in microglia, such as cell fusions and cytorrhexis, which may be the result of expression of mutant SOD1 in these cells. The microglial changes observed are different from those that accompany normal microglial activation, and they demonstrate that aberrant activation and degeneration of microglia is part of the pathogenesis of motor neuron disease.

Mice deficient in the ALS2 gene exhibit lymphopenia and abnormal hematopietic function

One form of juvenile onset autosomal recessive amyotrophic lateral sclerosis (ALS2) has been linked to the dysfunction of the ALS2 gene. The ALS2 gene is expressed in lymphoblasts, however, whether ALS2-deficiency affects periphery blood is unclear. Here we report that ALS2 knockout (ALS2(-/-)) mice developed peripheral lymphopenia but had higher proportions of hematopoietic stem and progenitor cells in which the stem cell factor-induced cell proliferation was up-regulated. Our findings reveal a novel function of the ALS2 gene in the lymphopoiesis and hematopoiesis, suggesting that the immune system is involved in the pathogenesis of ALS2.

Sporadic amyotrophic lateral sclerosis as an infectious disease: A possible role of cyanobacteria?

The available epidemiological data for amyotrophic lateral sclerosis (ALS) support an infectious etiology and lead us to propose a new hypothesis. We examined older epidemiological data concerning categories of the population with increased incidence (aged people, people living in rural areas, farmers, breeders), more recent epidemiological reports regarding Italian soccer players, AIDS patients, people living in highly polluted areas, and reports of cases of conjugal and pregnancy-associated ALS. The toxic and infectious hypotheses lead us to suggest a role for cyanobacteria in the production of endogenous beta-N-methylamino-L-alanine. Infection from a cyanobacterium, or another ubiquitous bacterium having similar characteristics, may be the missing clue to the etiology of ALS. We speculate that ubiquitous bacteria secreting toxic amino acids and "colonizing" tissues and organs in the human body might be the common element linking motor neuron diseases in Guam to sporadic ALS in the rest of the world.

ALS syndrome in patients with HIV-1 infection

BACKGROUND

A viral etiology of amyotrophic lateral sclerosis (ALS) has been proposed because of the selective vulnerability of motor neurons to certain viruses. During the last 20 years, at least 19 cases of ALS or ALS-like disease have been reported in HIV-1 (HIV) seropositive individuals.

OBJECTIVE

To describe two cases of clinically definite ALS in patients with HIV infection and to review the previously reported cases of HIV-associated ALS syndrome.

SETTING

A multidisciplinary ALS center and Neuro-AIDS clinic at a tertiary care university hospital.

PATIENTS/DESIGN

We investigated and prospectively monitored two patients who had developed clinically definite ALS by El Escorial criteria several years after acquiring the HIV infection. The previously reported cases of ALS or ALS-like disease in patients with HIV infection were reviewed for comparison and contrast with the characteristics of sporadic ALS.

RESULTS

The clinical course of ALS in our two HIV seropositive individuals mirrored that of classical sporadic ALS. A review of previously described 19 patients with ALS syndrome revealed clinically definite ALS in 4 cases and clinically probable or possible ALS in 15. ALS commenced at different stages of the HIV disease; in 7 patients, HIV infection was discovered contemporaneously with diagnosis of ALS. CD4+ T cell count ranged from 2 to 560 cells/mm3. Three (1 definite ALS) of the fatal cases were studied at autopsy and all exhibited pathology outside the motor neuron pool. Unlike our patients, 7 of 8 patients with HIV-associated ALS syndrome receiving HAART demonstrated at least partial recovery of their motor deficit.

CONCLUSIONS

ALS-like syndrome can occur in association with HIV infection; however, the causal relationship remains uncertain. Patients with ALS syndrome related to HIV infection are generally younger in age and often demonstrate pathology outside the motor neuron system. Patients with HIV-associated ALS syndrome may improve following antiretroviral therapy. An aggressive HAART regimen to reduce viral load should be pursued in all such cases.