The newer herpesviruses are being increasingly recognized as significant opportunistic pathogens in organ transplant recipients. M., Lescott, T., Kelly, D. Antigenic and genetic differentiation of the two putative types of human herpesvirus 6. One theory, commonly referred to as the hygiene hypothesis, postulates that the improved living standard, which in its turn reduces the incidence of childhood infections, might be one important factor. B., Macmahon, E. HHV-6 variant characterization was carried out in 10 HT FNA samples, determining that all specimens harbored HHV-6 Variant A. It has been associated with numerous drugs and infectious agents, including members of the Herpes virus family such as herpes simplex virus (HSV), cytomegalovirus (CMV) and varicella-zoster virus (VZV) (3-6).
Diagnosis and treatment of CMV infection is currently more advanced than for HHV-6 and HHV-7 [1, 3]. Acyclovir is specific for herpesviruses because it requires the virally encoded thymidine kinase (TK) to add the alpha phosphate to the analog, giving rise to acyclovir monophosphate (ACVMP), which is then sequentially phosphorylated by cellular enzymes to acyclovir triphosphate (ACVTP) (9, 12) (). However, controversy abounds regarding the precise role of HHV-6 and HHV-7 in the post-transplant setting. All HHVs encode TK or a protein kinase that phosphorylates acyclovir (8). J Virol 1999 ; 73 : 9655-8. In IgE-mediated allergies, the allergic individual mounts an IgE-antibody response to proteins in foodstuffs, pollens, animal dander, etc. V.
We also report that HHV-6 infects thyroid cells, inducing de novo expression of HLA-II surface antigens. She had extensive orolabial and genital mucosal surface denudement and complete epidermal detachment of at least 10% of the skin surface of her chest, abdomen, back and face consistent with SJS/TENS (Toxic Epidermal Necrolysis Syndrome) based on standard classification (1). He started pre-emptive therapy with IV ganciclovir according to the EBMT (the European Group for Blood and Marrow Transplantation) standards [6, 7]. Acyclovir is an anti-HIV-1 drug. Most infections in transplant recipients are due to HHV-6B; isolation of HHV-6A from blood samples is distinctly rare in transplant patients. Shown is the prodrug acyclovir, a herpesvirus-specific nucleoside analog. 13.
via inhalation or ingestion, minute amounts of intact protein allergen are taken up into the circulation, reach the mast cells and bind to the IgE antibodies. 76 (F. Thyroid cells infected with human cytomegalovirus were shown to act as antigen presenting cells and therefore might be involved in autoimmunity , patients with Graves’ disease display a higher frequency of EBV-infected B cells secreting antibody to TSH-R , and AITD patients have elevated antibody titers against EBV antigens . quantified levels of HHV in tonsil samples used in HIV-1 infection assays and found HHV-6 present in all samples where acyclovir inhibited HIV-1 replication (17). Our patient’s HHV-6 serology was IgG positive in the blood and negative in the CSF (at the moment of diagnosis and after treatment) and IgM negative in every specimen. To further study the herpesvirus dependence of acyclovir inhibition of HIV-1 replication, we used a single-round HIV-1 infectivity assay capable of detecting individual infection events in primary CD4+ T cells (19, 31, 35). Besides directly infecting cells, HHV-6 is a powerful inducer of cytokines, e.g.
We studied cord cells because of the high prevalence of HHV-6 and -7 infections in healthy adults (2). Wilborn F, Schmidt CA, Lorenz F, et al. Hoyte, C.