Carolina Rosadas

Neurological complications in dengue infection: a review for clinical practice

Dengue is an important global public health problem. The World Health Organization estimates that 2/5 of entire world population are in risk of dengue infection. Almost 50 millions cases occur annually, with at least 20 thousand deaths. The etiological agent of this acute febrile disease is a single-strand positive-sense RNA virus of Flavivirus genus. It is an arboviral disease transmitted by Aedes sp. mosquitoes (Aedes aegypti and A. albopictus). Most infected individuals present asymptomatic infection, but some may develop clinical signs. Therefore, a wide spectrum of illness can be observed, ranging from unapparent, mild disease, called dengue fever, to a severe and occasionally fatal dengue hemorrhagic fever/dengue shock syndrome. Currently, neurological manifestations related to dengue infections are increasingly been observed and appears as a challenge for medical practice. In this study the neurological complications of dengue infection will be reviewed, focusing a better understanding of the disease for the clinical practice.

Validation of a quantitative real-time PCR assay for HTLV-1 proviral load in peripheral blood mononuclear cells

The objective of this study was to validate a TaqMan real-time PCR assay for HTLV-1 proviral load detection in peripheral blood mononuclear cells. TARL-2 cells were used to generate a standard curve. Peripheral blood mononuclear cell gDNA from 27 seropositive and 23 seronegative samples was analyzed. The sensitivity, specificity, accuracy, precision, dynamic range of the standard curve and qPCR efficiency were evaluated. All of the positive samples amplified the target gene. All of the negative samples amplified only the control gene (β-actin). The assay presented 100% specificity and sensibility. The intra- and inter-assay variability was 2.4% and 2.2%, respectively. The qPCR efficiency, slope and correlation coefficients (r2) were all acceptable. The limit of detection was 1 copy/rxn. This assay can reliably quantify HTLV-1 proviral load.

Advances and new insights in the neuropathogenesis of dengue infection

Dengue virus (DENV) infects approximately 390 million persons every year in more than 100 countries. Reports of neurological complications are more frequently. The objective of this narrative review is to bring up the advances in the dengue neuropathogenesis. DENV can access the nervous system through blood-brain barrier disturbance mediated by cytokine. The blood-cerebrospinal fluid (CSF) barrier seems to be also involved, considering the presence of the virus in the CSF of patients with neurological manifestations. As for neurotropism, several studies showed the presence of RNA and viral antigens in brain tissue and CSF in humans. In murine model, different virus mutations were associated to neurovirulence. Despite the advances in the dengue neuropathogenesis, it is still necessary to determine a more appropriate animal model and increase the number of cases of autopsy. The detection of neurovirulence markers may contribute to establish a prognosis, the disease control and vaccine development.

Temporal lesions and widespread involvement of white matter associated with multi-organ inflammatory disease in human T-lymphotropic virus type 1-associated myelopathy/tropical spastic paraparesis (HAM/TSP)

Human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic inflammatory disease of the spinal cord, characterized by spastic paraparesis, back pain, and sphincter disorders. Involvement of multiple organs and encephalopathy are uncommon in HAM/TSP. Nonspecific small white matter lesions of unknown etiology, mainly in the periventricular and subcortical regions, have been found on brain magnetic resonance imaging of HAM/TSP patients. Bitemporal lesions have rarely been described. We report the case of a 54-year-old woman diagnosed with HAM/TSP who presented subclinical cognitive deficits associated with bitemporal and widespread white matter lesions. The cerebrospinal fluid (CSF) was inflammatory (blood-CSF barrier dysfunction, intrathecal synthesis of total and HTLV-1 IgG). The proviral load was higher in cerebrospinal fluid than in peripheral blood mononuclear cells. The neurological picture was complicated by multi-organ inflammatory disease (Hashimotos thyroiditis, uveitis, anemia, and chronic renal failure). This case highlights the potential multisystem inflammatory nature of HTLV-1 infection, with a wide spectrum of manifestations. In cases of HAM/TSP with multi-organ inflammatory disease, encephalic involvement should be investigated, even in the absence of clinical manifestations. Also bitemporal lesions can be the consequence of intense and diffuse inflammation associated with HTLV-1 infection.

Carpal tunnel syndrome after chikungunya infection

Chikungunya virus (CHIKV) is an arbovirus of the Togaviridae family, genus Alphavirus. It has attracted increasing attention in the last decade for its global spread and large number of epidemics. Infection with CHIKV causes debilitating inflammatory rheumatism. Carpal tunnel syndrome (CTS) is a focal neuropathy frequently associated with compression of the median nerve in the wrist and rheumatic disorders. A case of CHIKV infection with severe arthritis and CTS in a 41-year-old Brazilian woman is reported. The patient had a history of fever (38.5–40 8C), followed by severe pain and swelling in her right knee, with difficulty performing a flexion movement. The pain intensity increased within 24 h and spread to the knee, wrist, fingers, and feet. One week later, stiffness and constant tingling began in the left hand, which was relieved with movement. The cramp was more frequent at night and was associated with a cold sensation in the tips of the left fingers. At that time, the patient complained of pain in the shoulder joints, with greater intensity on the left side, and stiffness in the neck. She had no history of other comorbidities. Forty-five days after the onset of symptoms, there was a bilateral decreased tactile sensitivity at the thenar eminence, as well as an inability of both thumb opponency and bending of the last two phalanges of the left index finger (Figure 1). Routine blood analysis was normal. RT-PCR was negative for Zika virus (ZIKV) and CHIKV in serum and urine, and for dengue

HTLV-1 ORF-I Encoded Proteins and the Regulation of Host Immune Response: Viral Induced Dysregulation of Intracellular Signaling.

The human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus associated with both proliferative and inflammatory disorders. This virus causes a persistent infection, mainly in CD4+ T lymphocyte. The ability to persist in the host is associated with the virus capacity to evade the immune response and to induce infected T-cell proliferation, once the HTLV-1 maintains the infection mainly by clonal expansion of infected cells. There are several evidences that ORF-I encoded proteins, such as p12 and p8, play an important role in this context. The present study will review the molecular mechanisms that HTLV-1 ORF-I encoded proteins have to induce dysregulation of intracellular signaling, in order to escape from immune response and to increase the infected T-cell proliferation rate. The work will also address the impact of ORF-I mutations on the human host and perspectives in this study field.

First report of persistent dengue-1-associated autoimmune neurological disturbance: neuromyelitis optica spectrum disorder

Dengue virus (DENV) causes immune-mediated diseases. Neurological involvement represents a severe condition that is rarely observed in DENV-1 infection. Neuromyelitis optica (NMO)/NMO spectrum disorders (NMOSD) are idiopathic immune-mediated demyelinating syndromes of the central nervous system. We report a 17-year-old female with oligosymptomatic DENV-1 viremia, diagnosed as NMOSD. Magnetic resonance imaging showed spinal cord and brainstem lesions. Antibody for aquaporin 4 was negative. DENV-1 RNA infection was detected by serial RT-PCR and confirmed by phylogenetic analysis in serum. Although there are some reports of NMO post-dengue infection, there are not any published accounts of NMOSD with coexistent and persistent DENV-1 infection.

Relevance of retrovirus quantification in cerebrospinal fluid for neurologic diagnosis.

Different human retroviruses, such as Human Immunodeficiency Virus (HIV) and Human T-cell Lymphotropic Virus (HTLV), can cause neurologic infection. However, a definitive diagnosis may be hampered by several factors. Quantification of the viral or proviral load in cerebrospinal fluid (CSF) may be helpful in the diagnosis of nervous system disorders due to retroviral infection and may influence the treatment approach. The present work discusses retrovirus infection and neurologic impairment, as well as the usefulness of the determination of the HIV and HTLV proviral or viral load in cerebrospinal fluid in cases of neurologic disorder, in light of recent advances in this field. This study also discusses the different molecular techniques for quantifying the proviral load (real-time quantitative PCR, droplet digital PCR, and semi-nested real-time reverse transcription PCR) that are currently available.

First report of HTLV-1 truncated p12 protein in Brazil

HTLV-1 infects approximately 5–10 millions of individuals in the world and the majority of them remain lifelong asymptomatic carriers (AC). However, up to 5% of HTLV-1 patients may present inflammatory neurological or proliferative disorders as HTLV-1associated myelopathy / tropical spastic paraparesis (HAM/TSP) and adult T-cell leukemia (ATL), respectively. In HAM/ TSP, the spinal cord inflammation, leads to a chronic disabling disturbance. In ATL, HTLV induces T-cell proliferation and transformation, with a lethal consequence to the host. High proviral load is associated with disease progression. However, factors that may influence viral replication are unclear. Some viral encoded proteins, such as p12, induces infected T-cell proliferation and stimulates immune evasion. Previous studies demonstrated that mutations in p12 may influence the HTLV-1 infection outcome. Here, we identified, at the first time, a HTLV-1 strain with a premature stop codon in p12 infecting an individual from Brazil, presenting a very low proviral load. We hypothesize if this mutation would have a protective role against HTLV-1 replication. Genomic DNA was extracted from peripheral blood mononuclear cells (PBMCs) of an asymptomatic individual that is followed in the Neuroinfection outpatient clinic (HUGG/UNIRIO). The patient was a Brazilian Caucasian, 53 years old, female, married, with no family history of HTLV-1 infection, blood transfusion or drug abuse. The HTLV-1 infection was detected by ELISA and Western Blot fifteen years ago, when the patient was tested for blood donation. The HTLV-1 proviral load was 0.03 copies of Tax/100 PBMCs (TaqMan Real Time PCR). For DNA extraction QIAamp DNA mini kit (Quiagen, CA) was used. Nested polymerase chain reaction (n-PCR) was performed in order to amplify p12 and LTR. The PCR product was purified using Illustra GFX PCR DNA and Gel band purification kit (GE HealthCare) and directly sequenced using ABI model 373A automated DNA sequencer and the manufacturer’s Dye Terminator FS Kit instructions. The electropherogram was analyzed by Chromas Lite 2.1 (Thechnelysium) (Fig. 1). The p12 sequence was aligned and translated on BioEdit editor (North Carolina State University). The analyzed sequence (HUGGRJ25) presented a mutation (Fig. 1) that resulted in a premature stop codon at position 82 (Genbank accession number: KR337634) (Fig. 2). The phylogeny on LTR (634bp) showed that the sequence belongs to HTLV-1aA subtype (GenBank accession number KR337613). Truncated p12 proteins had already been identified in AC, HAM/TSP and ATL individuals from Argentina, Japan as also as in Simian T Lymphotropic virus (STLV). In this set of sequences two truncated p12 proteins were observed: the major group presented 87 residues and the other 81 residues. Our truncated p12 sequence belongs to the later type. One patient from Japan with a truncated protein (with the stop codon at position 82) was a HAM/TSP and presented a high proviral load. This is the first report of a truncated protein in a HTLV-1aA from Brazil. In fact, we evaluated a large set of p12 sequences available in GenBank from 76 new HTLV-1 complete genome sequences from Brazil and none presented a premature stop codon at p12 protein. Moreover, Ig~ nez et al (2005) analyzed 26 ORF-I sequences from Brazil (20 from AC, and 6 from HAM/TSP) and also did not find any individual carrying a provirus with a truncated p12. In a very interesting study, ORFI sequences of 160 HTLV-1 infected individuals from different areas of the world (including Brazil) were

Psychogenic movement disorder in human T-lymphotropic virus type 1 associated myelopathy

Human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic inflammatory disorder of the spinal cord. Acute cases of HAM/TSP and those complicated by movement disorders are rarely reported. Otherwise, psychiatric disturbances are very frequent in infected patients. It can evolve to psychogenic disorders. The case of a 46-year-old woman with acute HAM/TSP complicated by depression and psychogenic movement disorders (chorea of the hands and dystonia-like facial symptoms) is reported. Brain magnetic resonance imaging revealed non-specific small white matter lesions. The involuntary movements arose suddenly and disappeared when the patient was distracted. Two years of psychotherapy and psychiatric follow-up induced complete remission of the symptoms. The association of psychogenic movement disorders and HAM/TSP, increasing the range of neurological manifestations associated with HTLV-1, is related here. Early diagnosis of psychogenic movement disorders is very important to improve the prognosis and treatment of the two conditions, thereby improving the quality of life of HAM/TSP patients and avoiding irreversible sequelae.