Marinella Portolani

HHV-6A in Syncytial Giant-Cell Hepatitis

Syncytial giant-cell hepatitis is a rare but severe form of hepatitis that is associated with autoimmune diseases, drug reactions, and viral infections. We used serologic, molecular, and immunohistochemical methods to search for an infectious cause in a case of syncytial giant-cell hepatitis that developed in a liver-transplant recipient who had latent infection with variant B of human herpesvirus 6 (HHV-6B) and who had received the organ from a donor with variant A latent infection (HHV-6A). At the onset of the disease, the detection of HHV-6A (but not HHV-6B) DNA in plasma, in affected liver tissue, and in single micromanipulated syncytial giant cells with the use of two different polymerase-chain-reaction (PCR) assays indicated the presence of active HHV-6A infection in the patient. Expression of the HHV-6A-specific early protein, p41/38, but not of the HHV-6B-specific late protein, p101, was demonstrated only in liver syncytial giant cells in the absence of other infectious pathogens. The same markers of HHV-6A active infection were documented in serial follow-up samples from the patient and disappeared only at the resolution of syncytial giant-cell hepatitis. Neither HHV-6B DNA nor late protein was identified in the same follow-up samples from the patient. Thus, HHV-6A may be a cause of syncytial giant-cell hepatitis.

Phenotypic characteristics and tendency to apoptosis of peripheral blood mononuclear cells from HIV+ long term non progressors

The aim of this study was to analyze (i) phenotype, (ii) in vitro spontaneous and induced apoptosis, (iii) glutathione (GSH) intracellular content and (iv) inhibitors of apoptosis of potential therapeutical use in peripheral blood mononuclear cells (PBMC) from HIV+ long term non progressors (LTNP), in comparison with progressors (HIV+P) and seronegative controls (HIV−). Three groups of subjects were studied: 15 HIV+P (patients losing >150 CD4+/year), 9 LTNP (subjects infected by HIV for at least 7 years without clinical and immunological signs of progression, with a mean of 898 CD4+/μL) and 18 HIV−. All subjects were living in a large community for former drug addicts, and were matched for age and sex. We used flow cytometry for analyzing PBMC phenotype and apoptosis; high performance liquid chromatography for measuring intracellular GSH content. PBMC phenotype of LTNP shared characteristics with those of both HIV− and HIV+P. Indeed, LTNP showed a normal number CD4+ cells (an inclusion criteria), but significantly increased numbers of CD8+ lymphocytes, activated T cells, CD19+, CD5+ B lymphocytes and CD57+ cells, as well as a decrease in CD19+, CD5− B lymphocytes and CD16+ cells. In LTNP, spontaneous apoptosis was similar to that of HIV− and significantly lower than that of HIV+P. Adding interleukin-2 (IL-2) or nicotinamide (NAM) significantly decreased spontaneous apoptosis in LTNP and HIV+P. Pokeweed mitogen-induced apoptosis was also similar in LTNP and HIV−, but significantly lower than that of HIV+P. In HIV+P, but also in LTNP, spontaneous apoptosis was inversely correlated to the absolute number and percentage of CD4+ cells and directly correlated to the number and percentage of activated T cells present in peripheral blood. GSH intracellular content was greatly decreased in PBMC from HIV+P and slightly, but significantly, reduced in LTNP. Adding 2-deoxy-D-ribose, an agent provoking apoptosis through GSH depletion, to quiescent PBMC resulted in similar levels of massive cell death in the three groups. This phenomenon was equally prevented in the three groups by N-acetyl-cysteine but not by IL-2. A complex immunological situation seems to occur in LTNP. Indeed, PBMC from LTNP are characterized by a normal in vitro tendency to undergo apoptosis despite the presence of a strong activation of their immune system, unexpectedly similar to that of HIV+P. Our data suggest that NAM and IL-2 are possible candidates for reducing spontaneous apoptosis in HIV infection.

Selenite inhibition of Coxsackie virus B5 replication: implications on the etiology of Keshan disease.

Keshan disease is a cardiomyopathy of unknown origin reported in some areas of China. Because of epidemiologic features, this disease was ascribed to an infectious agent, likely a Coxsackie virus, but it has also been thought to depend on selenium deficiency, mainly because selenite is effective in its prophylaxis. We examined the hypothesis that pharmacological activity of selenite on Coxsackie virus growth was associated with prevention of Keshan disease. We studied the antiviral effects of three selenium compounds on Coxsackie virus B5 replication: five microM selenite reduced viral replication, whilst 10 microM selenate and selenomethionine did not exhibit any antiviral activity. The inhibitory activity of selenite on viral replication was due to its toxicity following its interaction with thiols, as that activity could be blocked by dithiothreitol, a sulfhydryl-protecting agent known to reverse several toxic effect of selenite. Zinc, another inhibitor of selenite toxicity, also counteracted the antiviral effect of selenite. The selenium compounds showed only limited activity against herpes simplex 1 virus and IHD strain of vaccinia virus. A direct inhibitory effect of selenite on Coxsackie virus replication might explain the efficacy demonstrated by this compound in the prophylaxis of Keshan disease.

Middle cerebral artery thrombosis in course of parvovirus B19 infection in a young adult: A new risk factor for stroke?

Previous infection, both of bacterial and viral origin, is reported to represent an independent risk factor for ischemic stroke in children and young adults. The authors describe the case of an immunocompetent young woman who developed a middle cerebral artery thrombosis and stroke in course of a recurrence of human parvovirus B19 (PVB19) infection. A previously healthy 25-year-old woman developed right ataxic hemiparesis, 5 days after the onset of a flulike syndrome. Magnetic resonance imaging of the brain revealed acute multiple left frontal-parietal ischemic lesions. Conventional and magnetic resonance angiograms revealed a stenosis in the left middle cerebral artery. Nested polymerase chain reaction detected PVB19-specific DNA sequences in the cerebrospinal fluid and blood, and serology showed high titers of high avidity immunoglobulin G against PVB19. After 10 days, the patient’s recovery was nearly complete. One month later, PVB19 disappeared from the serum, whereas it persisted in the peripheral blood mononuclear cells. This case report suggests that PVB19 infection may play a trigger role in the development of ischemic stroke, and that it should be considered in the screening of infectious risk factors for cerebrovascular diseases in young adults.

A study of childhood febrile convulsions with particular reference to HHV-6 infection : pathogenic considerations

Most febrile convulsions (FC) in infants occur during a viral infection, particularly in children of less than 3 years of age; human herpesvirus 6 (HHV-6) has an important pathogenic role. To evaluate the link between this and other viruses and FC, a group of 65 children (mean age 18.46 months, SD±9.19) with a first episode of simple FC (G1) was compared with 24 children (mean age 19.29 months, SD±13.17) with a febrile syndrome but without FC (G2). Virological study showed the following infection: HHV-6 in 23/65 of G1 and in 12/24 of G2, adenoviruses (ADV) in 9/65 of G1 and in 0/24 of G2, syncytial respiratory virus (SRV) in 3/28 of G1 and in 0/2 of G2, HSV-1 in 6/65 of G1 and in 1/24 of G2, cytomegalovirus (CMV) in 2/65 of G1 and in 0/24 of G2 and HHV-7 in 1/42 of G1 and in 1/13 of G2. Children in G1, statistically compared with G2, were significantly more likely to have a family history of FC and circulating granulocytes, while IgM and α2-globulin were less probable. Some cytokines (IL1β, TNFβ and GM-CSF) were found in 24 children in G1 and 12 in G2; no differences were found between the two groups. In the light of our data and of the recent literature, the possibility that the cytokines may act on the nervous system cannot be excluded. Among the HHV-6-infected children, those suffering from convulsions were statistically more likely to have a family history of FC and IgM, while IgA were less likely. In G1, 57 cases were followed up over 2 years: 9 of them had a second episode of FC. Virological diagnosis at the first episode of FC revealed HHV-6 infection in 3 cases, 2 of these being due to viral reactivation. We underline the important role of HHV-6 infection in FC and postulate a relationship between family history and the immunity of the patient; this is confirmed by the loss of statistical significance in the reduction of IgM in G1 compared with G2 with no family history of FC. The reactivation of FC by HHV-6 is a possibility to be borne in mind; an increased number of cases would be needed to confirm this hypothesis.

GROWTH OF HUMAN HERPESVIRUS 6 IN HEPG2 CELLS

HepG2 cells, a well differentiated liver cell line, were shown to be permissive for both human herpesvirus 6 (HHV-6) A and B strains by three independent methods of analysis: detection of viral antigens, viral DNA sequences and infectious virus. HepG2 cell infection with HHV-6 resulted in functional damage as shown by the increased release in the culture medium of some hepatocyte markers. Cells surviving the acute infection were serially passaged without showing cytopathic effect, but, some months later, HHV-6 DNA was still present in the cells and virus induction with a phorbol ester was successful. A possible pathogenetic role of HHV-6 in liver diseases is discussed. Experiments of HepG2 infection with human herpesvirus 7 (HHV-7) were also carried out. The lack of an efficient virus replication suggested a difficulty for HHV-7 to infect hepatic cells.

Risk of sporadic amyotrophic lateral sclerosis associated with seropositivity for herpesviruses and echovirus-7

We examined the association between risk of sporadic amyotrophic lateral sclerosis (ALS) and seroprevalence of antibodies to echovirus-7 (echo-7) and herpesviruses 6, 7, and 8 through a population-based case–control study. We enrolled in a northern Italy area 20 newly diagnosed ALS cases and 20 referents. Risk of ALS was higher in subjects seropositive for echo-7 when we used the immunofluorescent assay, while little increase was noted with the neutralization test. Considering the different characteristics of these two serological assays, these results suggest an association between disease risk and infection with enterovirus (EV) family members (not specifically echo-7). ALS risk was slightly associated with seropositivity of human herpesvirus-6 (odds ratio: 3.2; p = 0.102) and more strongly with human herpesvirus-8 seropositivity (odds ratio: 8.4, p = 0.064), though these point estimates were statistically unstable due to the limited number of observed cases. The findings of this study warrant further investigation in larger studies of the possible etiologic role of EV or herpesvirus infection in sporadic ALS.

Does HPV play a role in the etiopathogenesis of ameloblastoma? An immunohistochemical, in situ hybridization and polymerase chain reaction study of 18 cases using laser capture microdissection.

Ameloblastomas are epithelial tumors of odontogenic origin, biologically characterized by local recurrence. Among different etiologic factors, HPV infection has been recently postulated to be somehow involved in ameloblastoma etiopathogenesis. To address this issue, we studied 18 ameloblastomas by means of immunohistochemistry, in situ hybridization (conventional and amplified), polymerase chain reaction and nested-polymerase chain reaction analyses using laser capture microdissection in order to detect the occurrence of HPV in this setting. No evidence of HPV infection was detected by morphological examination, immunohistochemistry, in situ hybridization and conventional polymerase chain reaction, while nested-polymerase chain reaction showed a weak positive band in two cases. However, the subsequent restriction enzyme analysis carried out from the nested-polymerase chain reaction amplification products of these two samples excluded the presence of HPV subtypes 16, 18, 31, 33, 35, 52, and 58. The search for HPV 6 and 11 in the same specimens was also negative. In conclusion, our data do not support an etiopathogenetic evidence for HPV in ameloblastoma.

Epstein–Barr virus DNA in cerebrospinal fluid from an immunocompetent man with herpes simplex virus encephalitis

Herpes simplex virus 1 meningo-encephalitis was ascertained in a 63-year-old immunocompetent man. To determine the duration of the persistence of herpesvirus DNA in the central nervous system, the cerebrospinal fluid was periodically monitored by polymerase chain reaction for 53 days. In addition to HSV-1, Epstein-Barr virus DNA was detected in the cerebrospinal fluid 9 days after disease onset. The possible meaning of the Epstein-Barr virus DNA finding is discussed.

Search for herpesvirus DNA in cerebrospinal fluid of HIV patients with brain disorders: prevalence of cytomegalovirus DNA findings.

A study was carried out to search for the presence of the seven human herpesvirus DNAs in cerebrospinal fluid from 52 human immunodeficiency virus-infected patients with brain disorders. Cytomegalovirus DNA was the most prevalent with 12 positive samples; Epstein-Barr virus and varicellazoster DNAs were detected in three and two samples, respectively, while no sample was positive for the DNA of the other herpesviruses.