Association of HLA and T-cell receptor gene polymorphisms with Semple rabies vaccine-induced autoimmune encephalomyelitis

Post-vaccinal distemper-like disease in two dog litters with confirmed infection of vaccine virus strain

Modified live canine distemper virus (CDV) vaccines are widely used and considered both safe and effective. Although there are occasional literature reports of suspected vaccine-induced disease, there are none where the vaccine strain has been identified in affected tissues. Here we describe two such cases in different litters. In litter A, five of ten puppies presented with fever, anorexia, vomiting, and diarrhea a few days post-vaccination. Four puppies died or were euthanized, and autopsy revealed atypical necrosis of the lymphoid tissue. In litter B, two of five puppies developed typical neurological signs some months post-vaccination and autopsy revealed encephalitis. In all cases, affected organs tested positive for CDV on immunohistochemistry, and CDV RNA extracted from the lesions confirmed the presence of vaccine strain. Since multiple puppies from each litter were affected, it cannot be excluded without further studies that some undiagnosed inherited immunodeficiency disorder may have been involved.

COVID-19 Vaccine-Induced Lichenoid Eruptions-Clinical and Histopathologic Spectrum in a Case Series of Fifteen Patients with Review of the Literature

Lichen planus is a distinctive mucocutaneous disease with well-established clinical and histopathologic criteria. Lichenoid eruptions closely resemble lichen planus and may sometimes be indistinguishable from it. Systemic agents previously associated have included medications, viral infections and vaccines. Sporadic case reports of lichen planus and lichenoid reactions associated with COVID-19 vaccines have recently emerged. Herein, we review the world literature (31 patients) and expand it with a case series of 15 patients who presented with vaccine-induced lichenoid eruption (V-ILE). The spectrum of clinical and histopathologic findings is discussed with emphasis on the subset whose lesions manifested in embryologic fusion lines termed lines of Blaschko. This rare Blaschkoid distribution appeared in seven of the 46 patients studied. Of interest, all seven were linked to the mRNA COVID-19 vaccines. We believe that all lichenoid eruptions should be approached with a heightened index of suspicion and patients should be specifically questioned with regards to their vaccination history. When diagnosed early in its course, V-ILE is easily treated and resolves quickly in almost all patients with or without hyperpigmentation. Additional investigative studies regarding its immunopathology and inflammatory signaling pathways may offer insight into other Th1-driven autoimmune phenomena related to COVID-19 vaccination.

Development of High-Throughput Screening Assay for Antihantaviral Therapeutics

Humans acquire hantavirus infection by the inhalation of aerosolized excreta of infected rodent hosts. There is no treatment for hantavirus diseases at present. Therapeutic intervention during early stages of viral infection can improve the outcome of this zoonotic viral illness. The interaction between an evolutionary conserved sequence at the 5' terminus of hantaviral genomic RNA and hantavirus nucleocapsid protein plays a critical role in the hantavirus replication cycle. This unique interaction is a novel target for therapeutic intervention of hantavirus disease. We developed a very sensitive, tractable, and cost-effective fluorescence-based assay to monitor the interaction between the nucleocapsid protein and the target RNA sequence. The assay was optimized for high-throughput screening of chemical libraries to identify molecules that interrupt this RNA-protein interaction. The assay was validated using a library of 6880 chemical compounds. This validation screen demonstrated the reproducibility and validity of required statistical criteria for high-throughput screening. The assay is ready to use for high-throughput screening of large chemical libraries to identify antihantaviral therapeutic molecules and can be amenable to similar targets in other viruses.

Guillain-barré syndrome following influenza vaccination: causal or coincidental?

In 1976, the emergence of a new swine-origin influenza virus prompted concerns about an impending influenza pandemic. Although the outbreak never materialized, the epidemiological link between Guillain-Barre syndrome, a potentially severe peripheral nerve disorder, and the influenza vaccines developed against this virus caught public health officials, clinicians, and the public by surprise. Subsequently, a great deal of scrutiny has been placed on the possible risk of other formulations of influenza vaccine causing this adverse event. Several epidemiologic and biological assessments have been performed in subsequent years to assess this risk, yet considerable uncertainty remains among health care providers about the possible association. The development and rapid implementation of vaccines against the pandemic 2009 A(H1N1) influenza virus once again highlighted this issue. This article reviews the evidence for and against the association of the 1976 influenza vaccines and subsequent seasonal influenza vaccines with the development of Guillain-Barré syndrome.

Arenaviruses and hantaviruses: from epidemiology and genomics to antivirals

The arenaviruses and hantaviruses are segmented genome RNA viruses that are hosted by rodents. Due to their association with rodents, they are globally widespread and can infect humans via direct or indirect routes of transmission, causing considerable human morbidity and mortality. Nevertheless, despite their obvious and emerging importance as pathogens, there are currently no effective antiviral drugs (except ribavirin which proved effective against Lassa virus) with which to treat humans infected by any of these viruses. The EU-funded VIZIER project (Comparative Structural Genomics of Viral Enzymes Involved in Replication) was instigated with an ultimate view of contributing to the development of antiviral therapies for RNA viruses, including the arenaviruses and bunyaviruses. This review highlights some of the major features of the arenaviruses and hantaviruses that have been investigated during recent years. After describing their classification and epidemiology, we review progress in understanding the genomics as well as the structure and function of replicative enzymes achieved under the VIZIER program and the development of new disease control strategies.

Epidemiologic investigation of immune-mediated polyradiculoneuropathy among abattoir workers exposed to porcine brain

Background

In October 2007, a cluster of patients experiencing a novel polyradiculoneuropathy was identified at a pork abattoir (Plant A). Patients worked in the primary carcass processing area (warm room); the majority processed severed heads (head-table). An investigation was initiated to determine risk factors for illness.

Methods and Results

Symptoms of the reported patients were unlike previously described occupational associated illnesses. A case-control study was conducted at Plant A. A case was defined as evidence of symptoms of peripheral neuropathy and compatible electrodiagnostic testing in a pork abattoir worker. Two control groups were used - randomly selected non-ill warm-room workers (n = 49), and all non-ill head-table workers (n = 56). Consenting cases and controls were interviewed and blood and throat swabs were collected. The 26 largest U.S. pork abattoirs were surveyed to identify additional cases. Fifteen cases were identified at Plant A; illness onsets occurred during May 2004–November 2007. Median age was 32 years (range, 21–55 years). Cases were more likely than warm-room controls to have ever worked at the head-table (adjusted odds ratio [AOR], 6.6; 95% confidence interval [CI], 1.6–26.7), removed brains or removed muscle from the backs of heads (AOR, 10.3; 95% CI, 1.5–68.5), and worked within 0–10 feet of the brain removal operation (AOR, 9.9; 95% CI, 1.2–80.0). Associations remained when comparing head-table cases and head-table controls. Workers removed brains by using compressed air that liquefied brain and generated aerosolized droplets, exposing themselves and nearby workers. Eight additional cases were identified in the only two other abattoirs using this technique. The three abattoirs that used this technique have stopped brain removal, and no new cases have been reported after 24 months of follow up. Cases compared to controls had higher median interferon-gamma (IFNγ) levels (21.7 pg/ml; vs 14.8 pg/ml, P<0.001).

Discussion

This novel polyradiculoneuropathy was associated with removing porcine brains with compressed air. An autoimmune mechanism is supported by higher levels of IFNγ in cases than in controls consistent with other immune mediated illnesses occurring in association with neural tissue exposure. Abattoirs should not use compressed air to remove brains and should avoid procedures that aerosolize CNS tissue. This outbreak highlights the potential for respiratory or mucosal exposure to cause an immune-mediated illness in an occupational setting.

Novel vaccines to human rabies

Rabies, the most fatal of all infectious diseases, remains a major public health problem in developing countries, claiming the lives of an estimated 55,000 people each year. Most fatal rabies cases, with more than half of them in children, result from dog bites and occur among low-income families in Southeast Asia and Africa. Safe and efficacious vaccines are available to prevent rabies. However, they have to be given repeatedly, three times for pre-exposure vaccination and four to five times for post-exposure prophylaxis (PEP). In cases of severe exposure, a regimen of vaccine combined with a rabies immunoglobulin (RIG) preparation is required. The high incidence of fatal rabies is linked to a lack of knowledge on the appropriate treatment of bite wounds, lack of access to costly PEP, and failure to follow up with repeat immunizations. New, more immunogenic but less costly rabies virus vaccines are needed to reduce the toll of rabies on human lives. A preventative vaccine used for the immunization of children, especially those in high incidence countries, would be expected to lower fatality rates. Such a vaccine would have to be inexpensive, safe, and provide sustained protection, preferably after a single dose. Novel regimens are also needed for PEP to reduce the need for the already scarce and costly RIG and to reduce the number of vaccine doses to one or two. In this review, the pipeline of new rabies vaccines that are in pre-clinical testing is provided and an opinion on those that might be best suited as potential replacements for the currently used vaccines is offered.

Immunogenetics of drug-induced skin blistering disorders. Part II: Synthesis

The overall immunopathogenesis relevant to a large series of disorders caused by a drug or its associated hyperimmune condition is discussed based upon examining the genetics of severe drug-induced bullous skin problems (sporadic idiosyncratic adverse events including Stevens–Johnson syndrome and Toxic epidermal necrolysis). New results from an exemplar study on shared precipitating and perpetuating inner causes with other related disease phenotypes including aphtous stomatitis, Behçets, erythema multiforme, Hashimoto’s thyroiditis, pemphigus, periodic fevers, Sweet’s syndrome and drug-induced multisystem hypersensitivity are presented. A call for a collaborative, wider demographic profiling and deeper immunotyping in suggested future work is made.

A chimpanzee-origin adenovirus vector expressing the rabies virus glycoprotein as an oral vaccine against inhalation infection with rabies virus

Rabies has the highest fatality rate of all human viral infections and the virus could potentially be disseminated through aerosols. Currently licensed vaccines to rabies virus are highly effective but it is unknown if they would provide reliable protection to rabies virus transmitted through inhalation, which allows rapid access to the central nervous system upon entering olfactory nerve endings. Here we describe preclinical data with a novel vaccine to rabies virus based on a recombinant replication-defective chimpanzee-origin adenovirus vector expressing the glycoprotein of the Evelyn Rokitniki Abelseth strain of rabies virus. This vaccine, termed AdC68rab.gp, induces sustained central and mucosal antibody responses to rabies virus after oral application and provides complete protection against rabies virus acquired through inhalation even if given at a moderate dose.

Acute hemorrhagic leukoencephalitis: neuroimaging features and neuropathologic diagnosis

A case of biopsy-proven acute hemorrhagic leukoencephalitis is reported. The early computed tomography scans showed extensive bilateral hypodensities with mass effects and foci of microhemorrhages. Bilateral asymmetric hyperintensities in the mesiotemporal and frontal lobes and massive edema were found on T2-weighted and fluid-attenuated inversion recovery magnetic resonance images in a pattern classic for herpes simplex encephalitis. This fulminant demyelinating disease progresses to coma and death within days. Early diagnosis with neuroimaging studies and rapid correlation with the clinical findings of this disease are vital for the institution of potentially lifesaving treatments.

The role of immune responses in the pathogenesis of rabies

In the absence of treatment, infection with a variety of rabies virus strains most often results in a lethal outcome. This can be averted by prompt immunization following exposure demonstrating that the development of anti-rabies viral immunity prior to extensive infection of neurons is protective. Otherwise it might be expected that immune clearance of the virus would result in neurological sequelae. Thus, the capacity of a rabies virus to induce a protective immune response is a major, negative determinant of its pathogenicity and highly pathogenic rabies viruses have characteristics that avoid triggering protective immune responses. On the other hand, there is evidence that certain aspects of immunity may contribute to the pathogenesis of rabies under certain circumstances. The relationship between rabies virus and the immune system of the host is the focus of this review.

Human rabies: a disease of complex neuropathogenetic mechanisms and diagnostic challenges

Rabies is inevitably fatal and presents a horrifying clinical picture. Human rabies can manifest in either encephalitic (furious) or paralytic (dumb) forms. The brainstem is preferentially involved in both clinical forms, though there are no clinical signs of brainstem dysfunction. Differences in tropism at the inoculation site or the CNS, in the route of spread, or in the triggering of immune cascades in the brainstem may account for clinical variation. Rabies still poses diagnostic problems, particularly the paralytic form, which closely resembles Guillain-Barré syndrome, or when a patient is comatose and cardinal signs may be lacking. Molecular methods allow reliable detection of rabies-virus RNA in biological fluids or tissue before death. Deviations from the recommendations on prophylaxis of the World Health Organization lead to unnecessary loss of life. To date, attempts to treat human rabies have been unsuccessful.

B-cell responses to myelin basic protein and its epitopes in autoimmune encephalomyelitis induced by Semple rabies vaccine

Semple rabies vaccine is composed of rabies virus-infected sheep or goat brain inactivated with phenol and is administered daily after exposure for 14-21 days. Semple rabies vaccine-induced autoimmune encephalomyelitis (SAE) has clinico-pathological findings of demyelination similar to experimental autoimmune encephalomyelitis (EAE) caused by injection of central nervous system tissue or purified myelin proteins into experimental animals and frequently studied as a model for the human demyelinating disease, multiple sclerosis (MS). T-cell-mediated immune responses play a major role in induction of EAE, and antibody responses enhance disease severity. We studied the antibody responses to myelin basic protein (MBP) in 24 Thai patients with SAE and 77 control individuals to define the linear epitopes in human MBP that are encephalitogenic. Antibody levels were assessed by ELISA using native human MBP or synthetic MBP peptides of 20 amino acids. The major B-cell epitope was MBP61-80 and a minor epitope was MBP106-140 in SAE while in MS the major B-cell epitope is MBP84-96. MBP61-80-specific IgG1 and IgG3 levels were significantly higher in patients than controls while IgG2 and IgG4 were not. The data support the hypothesis that autoreactive Th1 cells induce SAE. The difference in B-cell epitope recognition may be due to differences in the genetic backgrounds of the populations studied or may reflect underlying differences in the pathogenesis of SAE and MS.