Involvement of human herpesvirus-6 variant B in classic Hodgkin's lymphoma via DR7 oncoprotein.

PURPOSE: Hodgkin's lymphoma (HL) is associated with the presence of EBV in Reed-Sternberg (RS) cells in ∼40% of cases. Here, we studied the presence of human herpesvirus type 6 (HHV-6) variant B in RS cells of HL patients and correlated results with clinical parameters. We then examined the implication of HHV-6 DR7B protein in cell deregulation. EXPERIMENTAL DESIGN: HHV-6 DR7B protein was produced in a Semliki Forest virus system. Polyclonal antibodies were then generated and used for immunochemical HHV-6 localization in HL biopsies. Binding between DR7B and p53 was studied using a double-hybrid system. Transactivation of NFκB was observed after transient transfection using reporter gene assays. We looked for Id2 factor expression after stable transfection of the BJAB cell line by reverse transcription-PCR and Western blot analysis. RESULTS: HHV-6 was more common in nodular sclerosis subtype HL, and DR7B oncoprotein was detected in RS cells for 73.7% of EBV-negative patients. Colocalization of EBV and HHV-6 was observed in RS cells of doubly infected patients. DR7B protein bound to human p53 protein. p105-p50/p65 mRNA expression and activation of the NFκB complex were increased when DR7B was expressed. Stable expression of DR7B exhibited a strong and uniform expression of Id2. A slightly higher percentage of remission was observed in patients with RS cells testing positive for DR7B than in those testing negative. CONCLUSIONS: Collectively, these data provide evidence for the implication of a novel agent, HHV-6, in cases of nodular sclerosis HL.

Drug reaction with eosinophilia and systemic symptoms (DRESS): a multiorgan antiviral T cell response.

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe, drug-induced reaction that involves both the skin and the viscera. Evidence for reactivation of herpes family viruses has been seen in some DRESS patients. To understand the immunological components of DRESS and their relationship to viral reactivation, we prospectively assessed 40 patients exhibiting DRESS in response to carbamazepine, allopurinol, or sulfamethoxazole. Peripheral blood T lymphocytes from the patients were evaluated for phenotype, cytokine secretion, and repertoire of CD4+ and CD8+ and for viral reactivation. We found Epstein-Barr virus (EBV), human herpes virus 6 (HHV-6), or HHV-7 reactivation in 76% of the patients. In all patients, circulating CD8+ T lymphocytes were activated, exhibited increased cutaneous homing markers, and secreted large amounts of tumor necrosis factor-alpha and interferon-gamma. The production of these cytokines was particularly high in patients with the most severe visceral involvement. In addition, expanded populations of CD8+ T lymphocytes sharing the same T cell receptor repertoire were detected in the blood, skin, liver, and lungs of patients. Nearly half of these expanded blood CD8+ T lymphocytes specifically recognized one of several EBV epitopes. Finally, we found that the culprit drugs triggered the production of EBV in patients' EBV-transformed B lymphocytes. Thus, cutaneous and visceral symptoms of DRESS are mediated by activated CD8+ T lymphocytes, which are largely directed against herpes viruses such as EBV.

Amoxicillin-induced flare in patients with DRESS (Drug Reaction with Eosinophilia and Systemic Symptoms): report of seven cases and demonstration of a direct effect of amoxicillin on Human Herpesvirus 6 replication in vitro.

Amoxicillin is known to induce exanthema in patients with EBV-induced infectious mononucleosis. It is widely recognized that the reactivation of herpesviruses, including HHV-6 (Human Herpesvirus 6) and EBV (Epstein Barr virus) is associated with DRESS (Drug Reaction with Eosinophilia and Systemic Symptoms). We report 7 cases of amoxicillin-induced flare in patients with DRESS induced by other drugs and investigate whether amoxicillin may have a direct effect on HHV-6 replication in vitro. 7 cases of DRESS with amoxicillin-induced flare were retrospectively analysed. The influence of amoxicillin on HHV-6 HST strain replication was studied in vitro in a human T lymphoblastoid MT4 cell line. The viral replication was quantified by immunofluorescence assay and by real-time polymerase chain reaction (PCR). Comparisons were performed using the Student's t test. Amoxicillin-induced flare was observed in 7 patients with DRESS induced by other drugs. In two cases HHV-6 reactivation was studied and was demonstrated by PCR. Amoxicillin neither modified cell viability nor cell proliferation for the range of tested concentrations. Amoxicillin increased the replication of HHV-6 at 25 microg*mL-1 and 50 microg*mL-1. Amoxicillin may induce a flare of DRESS, possibly by acting directly on herpesvirus replication.