Attempts to isolate virus from human trigeminal and facial ganglions

Herpes virus hominis type 1 was isolated from the trigeminal ganglion (ganglion semilunare, gasservian) in three out of 20 randomly selected autopsies. Two of the three patients had been treated with immunosuppressive or cytostatic agents. Clinical signs of herpes infection were not observed during the previous 6 months. No virus was isolated from the facial ganglion (geniculate ganglion) in the same 20 cases. The findings are discussed in relation to the viral etiology of acute peripheral facial palsy.     

Association of Streptococcus bovis Bacteremia with Bowel Disease

We reviewed the medical records of 19 patients who had Streptococcus bovis bacteremia. Eight patients had diverticulosis, four had benign adenomatous colonic polyps, and three had adenocarcinomas of the gastrointestinal tract. Laboratory workers and clinicians should be aware of the association of S. bovis bacteremia and gastrointestinal disease.     

Immunity induced shortly after DNA vaccination of rainbow trout against rhabdoviruses protects against heterologous virus but not against bacterial pathogens.

It was recently reported that DNA vaccination of rainbow trout fingerlings against viral hemorrhagic septicaemia virus (VHSV) induced protection within 8 days after intramuscular injection of plasmid DNA. In order to analyse the specificity of this early immunity, fish were vaccinated with plasmid DNA encoding the VHSV or the infectious haematopoietic necrosis virus (IHNV) glycoprotein genes and later challenged with homologous or heterologous pathogens. Challenge experiments revealed that immunity established shortly after vaccination was cross-protective between the two viral pathogens whereas no increased survival was found upon challenge with bacterial pathogens. Within two months after vaccination, the cross-protection disappeared while the specific immunity to homologous virus remained high. The early immunity induced by the DNA vaccines thus appeared to involve short-lived non-specific anti-viral defence mechanisms.     

Human herpesvirus type 6 reactivation after haematopoietic stem cell transplantation

Human herpesvirus type 6 (HHV6) is known to reactivate after hematopoetic stem cell transplantation (HSCT) and has been suggested to be associated with increased mortality and severe clinical manifestations, including graft versus host disease (GvHD). The exact etiological role of HHV6 reactivation in increased morbidity and mortality after HSCT remains unclear. This review will focus on the current available evidence of HHV6 reactivation after HSCT and its immuno-modulatory capacities, with particular emphasis on the severe complication GvHD. At present, no effective specific antiviral treatment for HHV6 reactivation has been identified. The currently available antiviral agents are outlined, as well as possible future strategies for the treatment of HHV6 reactivation. Non-toxic, specific treatment or prevention of HHV6 reactivation might improve the safety and efficacy of the HSCT procedure.     

Estimating the relative frequency of leukodystrophies and recommendations for carrier screening in the era of next‐generation sequencing

Leukodystrophies are a heterogeneous group of heritable disorders characterized by abnormal brain white matter signal on magnetic resonance imaging (MRI) and primary involvement of the cellular components of myelin. Previous estimates suggest the incidence of leukodystrophies as a whole to be 1 in 7,000 individuals, however the frequency of specific diagnoses relative to others has not been described. Next generation sequencing approaches offer the opportunity to redefine our understanding of the relative frequency of different leukodystrophies. We assessed the relative frequency of all 30 leukodystrophies (associated with 55 genes) in more than 49,000 exomes. We identified a relatively high frequency of disorders previously thought of as very rare, including Aicardi Goutières Syndrome, TUBB4A‐related leukodystrophy, Peroxisomal biogenesis disorders, POLR3‐related Leukodystrophy, Vanishing White Matter, and Pelizaeus‐Merzbacher Disease. Despite the relative frequency of these conditions, carrier‐screening laboratories regularly test only 20 of the 55 leukodystrophy‐related genes, and do not test at all, or test only one or a few, genes for some of the higher frequency disorders. Relative frequency of leukodystrophies previously considered very rare suggests these disorders may benefit from expanded carrier screening.     

Antigen presentation is a function of all B cell subpopulations separated on the basis of size

Purified splenic B cells from nonimmune mice were separated by counterflow centrifugal elutriation into 6 subpopulations containing cells of discrete sizes ranging from 119 to 200 μm³. B cells of each subpopulation were competent to process and present a native globular protein antigen, cytochrome c, to a cytochrome c-specific T cell hybrid. In all cases, the B cells' antigen-presenting function was radiation sensitive and did not require T cells or T cell products, since B cells fixed with paraformaldehyde effectively presented a carboxyl-terminal peptide fragment of cytochrome c containing the T cell determinant. Furthermore, the antigen-presenting function of B cells of each subpopulation was augmented by treatment with submitogenic doses of the F(ab')₂ fragment of rabbit anti-mouse Ig antibodies, in that 10-30-fold fewer B cells were required and higher maximal T cell responses were achieved, indicating that B cells of all sizes are capable of being regulated in their antigen presentation function through their surface Ig. In addition, B cells of each subpopulation responded to soluble factors present in the supernatants of activated T cells as evidenced by an increase in volume and by the uptake of [³H]thymidine. These results indicate that B cells, regardless of size, are able to participate in at least two essential phases of T cell-dependent antibody responses, initiating the interaction by processing and presenting antigen to helper T cells and responding to soluble helper factors secreted by activated T cells.     

No evidence for chromosomal mosaicism in multiple tissues of 10 patients with 45 XO Turner syndrome

Why the frequency of spontaneous abortions among monosomy X conceptuses is 98 % while the postnatal course of Turner syndrome is relatively benign has not been understood. One explanation could be that mosaicism for a euploid cell line confers viability and that those 2 % of 45, XO zygotes surviving in utero have some degree of mosaicism. We thus reasoned that if the non-mosaic 45, XO karyotype is lethal, a thorough study of living Turner syndrome patients might reveal a much higher frequency of mosaicism than the 30–40 % reported. Ten adult women with a 45 , XO leukocyte karyotype were investigated, looking at five tissue types from all three germ layers: buccal mucosa and hair from ectoderm, urinary epithelium from endoderm and ectoderm, and lymphocytes and skin fibroblasts from mesoderm. We were unable to confirm mosaicism in these patients, although in 2 out of 10 there was the suggestion of a small percentage of euploid cells in skin and blood karyotypes.