Fatal Enterovirus-related Myocarditis in a Patient with Devic’s Syndrome Treated with Rituximab

Enteroviruses are a frequent source of infection and among the most common central nervous system viral pathogens. Enteroviruses – in particular, the Coxsackie B viruses – are a known cause of myocarditis. Rituximab is a genetically engineered chimeric anti-CD20 monoclonal antibody. Many reports in the literature suggest a higher risk of infection following repeated rituximab therapy, including viral infection. However, observations of enterovirus-related myocarditis in the context of rituximab treatment are scarce. The authors describe the case of a patient with neuromyelitis optica spectrum disorder who developed severe and fatal enterovirus-related myocarditis after rituximab therapy with a difficult differential diagnosis of autoimmune or giant-cell myocarditis. This case highlights the importance of complete diagnostic workup in difficult cases of myocarditis, including endomyocardial biopsies.

Up-to-date approaches to forecast of epidemiological situation with incidence of enteroviral meningitis

This work evaluates the results of long-term dynamic monitoring of non-polio enteroviruses (NPEV) circulation in the indicator subpopulation in Yekaterinburg (children aged 3 to 6 years old), isolation of this group of viruses from specimens of sewage and the spectrum of causative agents detected in the liquor of patients with enteroviral meningitis (EVM). We established a high comparability rate of Coxsackie B and ECHO virus serotypes etiologically significant in EVM and isolated from healthy carriers. NPEV detected in sewage waters over the observation period were presented mainly by Coxsackie B viruses (84.0 %), while ECHO viruses (75.6 %) dominated among the causative agents of EVM. A conclusion was made about low informative value of the sewage study results for evaluation and forecast of the EVM epidemic situation as well as about the rationale for including the screening studies of NPEV circulation in the indicator subpopulation into the system of virological and molecular genetic monitoring.

Genetic Susceptibility of the Host in Virus-Induced Diabetes

Enteroviruses, especially Coxsackie B viruses, are among the candidate environmental factors causative of type 1 diabetes. Host genetic factors have an impact on the development of virus-induced diabetes (VID). Host background, in terms of whether the host is prone to autoimmunity, should also be considered when analyzing the role of target genes in VID. In this review, we describe the genetic susceptibility of the host based on studies in humans and VID animal models. Understanding the host genetic factors should contribute not only to revealing the mechanisms of VID development, but also in taking measures to prevent VID.

Enterovirus infections

Enteroviruses are single-stranded, positive-sense RNA viruses comprising poliomyelitis viruses (3 types), coxsackie A viruses (23 types), coxsackie B viruses (6 types), and echoviruses (33 types). They have recently been reclassified into four human enterovirus species (A–D) on the basis of sequence comparisons. Transmission is by the faeco-oral route, with marked seasonal peaks of infection in areas of temperate climate, but infections occurring all year round in tropical regions. Following transmission, enteroviruses undergo a first round of replication in cells of the mucosal surfaces of the gastrointestinal tract and in gut-associated lymphoid cells, followed by viraemia, which leads to infection of distant organs (brain, spinal cord, meninges, myocardium, muscle, skin, and so on), where lesions might be produced. Shedding of virus occurs from throat and faeces for many weeks.

RESEARCH OF BIOLOGICAL PROPERTIES OF ENTEROVIRUS STRAINS ASSOCIATED WITH ISCHEMIC STROKE

Introduction: The research of biological properties of enteroviruses associated with ischemic stroke (IS) allows us to identify their intratypic differences. The aim: to identify genetic markers of strains of enteroviruses associated with IS. Materials and methods: 11 strains of enteroviruses isolated from the serum of patients with IS were identified in the virus neutralization test. Genetic markers of isolated strains (Abent, marker S, marker rct40) were determined. Results: Eleven strains of enteroviruses were isolated from the serum of patients with IS. Eight viruses: Coxsackie B viruses (serotypes 2, 3, 4) and ECHO viruses (serotypes 6, 9, 27 (two strains), 29) were identified in these strains. Other three strains of enteroviruses were unidentified. Different combinations of genetic markers were found. Seven strains of enteroviruses (Coxsackie B2, B3, ECHO 6, ECHO 9, ECHO 27 (two strains) and one unidentified virus) had virulence markers: Abent–, rct40+ and S−. Three strains (Coxsackie B4, ECHO 29, one unidentified virus) had markers: Abent–, rct40+, S+. Another one unidentified virus had markers: Abent+, rct40+, S –. Conclusions: All 11 isolates of enteroviruses associated with IS had rct40+ marker, 10 of the 11 isolates had marker Abent– and 8 of 11 isolates had marker S–. The research of genetic markers allows to perform typic and intratypic differentiation of strains of enteroviruses associated with the IS.

Serological and Molecular Biological Studies of Parvovirus B19, Coxsackie B Viruses, and Adenoviruses as Potential Cardiotropic Viruses in Bulgaria

Background:Inflammatory diseases of the heart (myocarditis, pericarditis) are commonly caused by viruses. Among the human cardiotropic viruses, parvovirus B19, Coxsackie B viruses, and adenoviruses play a leading role.Aim:The aim of the present study was to determine the presumptive causative role of parvovirus B19, Coxsackie B viruses, and adenoviruses in the development of myocarditis, pericarditis and dilated cardiomyopathy by demonstrating the presence of specific antiviral antibodies or viral DNA in patients’ serum samples.Materials and methods:We tested serum samples collected between 2010 and 2014 from 235 patients with myocarditis (n=108), pericarditis (n=79), myopericarditis (n=19), dilated cardiomyopathy (n=7), and fever of unknown origin accompanied by cardiac complaints (n=22). The mean age of patients with the standard deviation was 33 ± 18 years. Serological and molecular methods (ELISA for specific IgM/IgG antibodies to parvovirus B19 and IgM antibodies to Coxsackie B viruses and adenoviruses, and PCR for detection of parvovirus B19 in serum samples, respectively) were used in the study.Results:Of all tested 235 serum samples, in 60 (25.5%) positive results for at least one of the three tested viruses were detected. Forty out of these 235 serum samples (17%) were Coxsackie B virus IgM positive. They were found in 17% (18/108) of the patients with myocarditis, in 15% (12/79) of those with pericarditis, in 16% (3/19) of those with myopericarditis and in 32% (7/22) in those with fever of unknown origin. The 63 Coxsackie B virus IgM negative patient’s serum samples were tested by ELISA for presence of adenovirus IgM antibodies. Such were found in 4 patients with pericarditis and in 2 patients with fever of unknown origin. Every IgM negative sample (n=189) for Coxsackie B and adenovirus was further tested by ELISA for parvovirus B19 IgM/IgG antibodies. B19-IgM antibodies were detected in 14 patients (7.4%). The percentages for B19-IgM antibodies was 8% (7/90), 5% (3/63) and 31% (4/13) in the patients affected with myocarditis, pericarditis, and fever of unknown origin, respectively. Protective B19-IgG antibodies were found in 108 (57%) of the samples. A B19-PCR signal was detected in all the patients who were B19-IgM positive, and in only 1 patient with positive B19-IgG result, the latter presenting with dilated cardiomyopathy.Conclusion:The present study shows the involvement of Coxsackie B, parvovirus B19 and adenoviruses in the development of inflammatory diseases of the heart (myocarditis and pericarditis). It is the first ever study in the country that simultaneously analyzes the prevalence of the three major human cardiotropic viruses.

The Coxsackievirus and Adenovirus Receptor: Glycosylation and the Extracellular D2 Domain Are Not Required for Coxsackievirus B3 Infection

ABSTRACTThe coxsackievirus and adenovirus receptor (CAR) is a member of the immunoglobulin superfamily (IgSF) and functions as a receptor for coxsackie B viruses (CVBs). The extracellular portion of CAR comprises two glycosylated immunoglobulin-like domains, D1 and D2. CAR-D1 binds to the virus and is essential for virus infection; however, it is not known whether D2 is also important for infection, and the role of glycosylation has not been explored. To understand the function of these structural components in CAR-mediated CVB3 infection, we generated a panel of human (h) CAR deletion and substitution mutants and analyzed their functionality as CVB receptors, examining both virus binding and replication. Lack of glycosylation of the CAR-D1 or -D2 domains did not adversely affect CVB3 binding or infection, indicating that the glycosylation of CAR is not required for its receptor functions. Deletion of the D2 domain reduced CVB3 binding, with a proportionate reduction in the efficiency of virus infection. Replacement of D2 with the homologous D2 domain from chicken CAR, or with the heterologous type C2 immunoglobulin-like domain from IgSF11, another IgSF member, fully restored receptor function; however, replacement of CAR-D2 with domains from CD155 or CD80 restored function only in part. These data indicate that glycosylation of the extracellular domain of hCAR plays no role in CVB3 receptor function and that CAR-D2 is not specifically required. The D2 domain may function largely as a spacer permitting virus access to D1; however, the data may also suggest that D2 affects virus binding by influencing the conformation of D1.IMPORTANCEAn important step in virus infection is the initial interaction of the virus with its cellular receptor. Although the role in infection of the extracellular CAR-D1, cytoplasmic, and transmembrane domains have been analyzed extensively, nothing is known about the function of CAR-D2 and the extracellular glycosylation of CAR. Our data indicate that glycosylation of the extracellular CAR domain has only minor importance for the function of CAR as CVB3 receptor and that the D2 domain is not essential per se but contributes to receptor function by promoting the exposure of the D1 domain on the cell surface. These results contribute to our understanding of the coxsackievirus-receptor interactions.