Reactivation of human herpesvirus 6 by infection of human herpesvirus 7

We have attempted to reactivate human herpesvirus 6 (HHV-6) by infection with HHV-7 using childhood exanthem subitum patients in vitro. Peripheral blood mononuclear cells (PBMCs) were collected from children who had a history of exanthem subitum(ES) by HHV-6 and were infected by human herpesvirus 7 (HHV-7) in vitro. The antigen positive rate to HHV-6 started to increase 7 days after the infection and reached a maximum by Day 15 using an immunofluorescence antibody test. The copy number of HHV-6 DNA also increased in the samples in 10 days after infection in vitro. No antigen or increase in DNA was detected in PBMCs, that were mock-infected or infected with supernatant of stock virus after ultracentrifugation, suggesting that an infection by HHV-7 is necessary to reactivate HHV-6. In the paired sera samples during the acute and the convalescent phases of ES, seven to ten bands, that were specific for HHV-6, were recognized in samples from the acute phase, and at least 5 dominant polypeptides were found more intensively after HHV-7 infection.     

Reactivation of human herpesvirus 6 (HHV-6) infection in patients with connective tissue diseases

BackgroundLittle is known about the involvement of human herpesviruses 6 and 7 (HHV-6 and HHV-7) in autoimmune connective tissue diseases (ACTD).ObjectiveTo determine the prevalence of active infection with HHV-6 and HHV-7 in patients with ACTD.Study designThe presence and quantity of HHV-6 DNA was determined by quantitative real-time PCR in a cross-sectional study of serum, peripheral blood mononuclear cells, and tissues obtained from 58 ACTD patients and 38 healthy subjects (HS). Specific anti-HHV-6 antibody titer was also measured.ResultsHHV-6 serum viremia occurred in a significantly higher proportion of ACTD patients compared to HS [26/58 (44.8%) vs. 1/38 (2.6%), p = 0.001] with the highest reactivation frequency [7/10 (70%)] observed in patients with scleroderma. Moreover, HHV-6 in serum was associated with ACTD activity (22/38 vs. 4/20, p < 0.05). Higher titers of HHV-6 antibodies were found in ACTD patients than in HS, although HHV-6 seroprevalence among patients with ACTD and HS was similar. HHV-7 viremia was not detected in any patients or HS controls.ConclusionThe frequent reactivation of HHV-6 in scleroderma and other ACTD, especially when active, suggests that HHV-6 may play a role in the pathogenesis of these diseases.     

Epidemiology of human herpesvirus 6 (HHV-6) infection in pregnant and nonpregnant women.

BACKGROUND: Human herpesvirus 6 (HHV-6) is a ubiquitous virus primarily associated with benign conditions such as febrile syndromes and exanthem subitum (roseola infantum). Sexual, horizontal, and vertical transmission have been suggested. Little information is available regarding HHV-6 infection in women of reproductive age. OBJECTIVE: Describe epidemiology of HHV-6 infection in pregnant and nonpregnant women. STUDY DESIGN: The study sample consisted of 569 women, age 18-45, who attended a university family planning clinic (nonpregnant, n=224) and two obstetrics clinics (pregnant [first trimester], n=345) in San Antonio, TX between October 1995 and May 1998. Blood and a vaginal swab, as well as sociodemographic information, were collected from each participant. Plasma was tested for HHV-6 IgG antibodies using a standard immunofluorescence assay (IFA). Lysed material from vaginal swabs was tested for HHV-6 DNA by polymerase chain reaction (PCR). Products were screened by enzyme-linked immunosorbent assay and positive tests were confirmed by repeat PCR followed by Southern analysis. PCR-positive samples were subtyped using an established method. RESULTS: All subjects were HHV-6 antibody positive. Geometric mean titers of HHV-6 antibodies were significantly higher among nonpregnant versus pregnant women. Moreover, a higher proportion of nonpregnant versus pregnant women had antibody titers >/=160 and >/=320. This association persisted even after adjusting for a number of sociodemographic and clinical factors. Low rates of HHV-6 shedding in the genital tract were observed for both groups (pregnant, 7/297 [2.0%]; nonpregnant, 8/214 [3.7%]). Of 14 samples subtyped, four (29%) were subtype A. CONCLUSION: The present study showed that 100% of the study sample was infected with HHV-6. Higher HHV-6 antibody titers, however, were noted in nonpregnant women. Both groups shed virus at low rates in the genital tract. HHV-6 subtype A was identified more commonly than previously reported. Further longitudinal studies are required to assess the consequences of maternal HHV-6 infection.     

Improving diagnosis of primary cytomegalovirus infection in pregnant women using immunoblots

Human cytomegalovirus (CMV) is the most common infectious cause of mental disability in newborns of developed countries. Transmission of CMV from mother to baby is more frequent in maternal primary infection, although CMV reactivation causes more congenital infections overall. Current diagnostic tests for distinguishing primary and reactivation CMV have problems with interpretation and immunoblots may assist with diagnosis. Sera from 60 pregnant women were analyzed using conventional serology in parallel with a commercial immunoblot assay (using Recomblot, Mikrogen Diagnostik). Comparison of detection of CMV IgG, IgM, IgG avidity in maternal primary infection showed the immunoblot relative to conventional serology had sensitivity and specificity of 100% for IgG identification. The detection of IgM on immunoblot showed sensitivity of 75%, specificity of 62.5%, positive predictive value (PPV) of 81.8% and negative predictive value (NPV) of 52.6%. The immunoblot IgG avidity assay had sensitivity of 94.1%, with a PPV of 100% when identifying low avidity serum samples, and sensitivity of 100% with a PPV of 97.1% for high avidity serum samples. Overall agreement between conventional serology (IgM, IgG avidity) and immunoblot (IgM, IgG avidity) for detection of primary CMV infection was 65%. Although the immunoblot is effective in detecting IgG and determining IgG avidity, it showed no significant benefits in performance or utility as a first line diagnostic technique for IgM or primary CMV infection in pregnant women. J. Med. Virol. 85:315–319, 2013. © 2012 Wiley Periodicals, Inc.     

Human herpesvirus 6 and human herpesvirus 7 in chronic fatigue syndrome.

We analyzed lymphocytes of patients with chronic fatigue syndrome (CFS) for the presence of human herpesvirus 6 (HHV-6) and HHV-7 DNA. HHV-7 was present in over 80% of CFS patients and healthy controls, while the prevalence of HHV-6 variant A increased significantly in CFS cases (22 versus 4%; P = 0.05).     

Prevalence, risk factors and virological profile of chronic hepatitis B virus infection in pregnant women in India

A large program was conducted by the Government of India to study the prevalence and profile of chronic hepatitis B virus (HBV) infection and its risk factors in pregnant women attending a tertiary care hospital in India. From September 2004 to December 2008 consecutive pregnant women attending the antenatal clinic were screened and those found positive for HBsAg were enrolled. Healthy non‐pregnant women of child‐bearing age, who presented for blood donation during the same period, served as controls. Women with symptoms of liver disease or those aware of their HBsAg status were excluded. Of the 20,104 pregnant women screened, 224 (1.1%) and of the 658 controls, 8 (1.2%) were HBsAg positive (P = ns). Previous blood transfusions and surgery were significant risk factors for infection with HBV. Of the women who were HBsAg positive, the ALT levels were normal in 54% of the women and HBV DNA levels were above 2,000 IU/ml in 71% of women. The median HBV DNA levels were higher in women who were HBeAg positive compared to the HBeAg negative group. The most common HBV genotype was D (84%) followed by A + D and A (8% each). In conclusion, the prevalence of HBsAg positivity among asymptomatic pregnant women in North India is 1.1% with 71% having high HBV DNA levels. These women may have a high risk of transmitting infection to their newborns. J. Med. Virol. 83:962–967, 2011. © 2011 Wiley‐Liss, Inc.     

Human herpesviruses 6 and 7 in cervixes of pregnant women.

We looked for human herpesvirus 6 (HHV-6) and HHV-7 genomes in the cervixes of pregnant women in the late stages of their pregnancies. Of 72 samples collected with cervical swabs and amplified by nested PCR, we found that 14 (19.4%) and 2 (2.7%) contained detectable HHV-6 and HHV-7 genomes, respectively. The two samples in which HHV-7 DNA was detected also contained HHV-6 genomes. Hybridization of HHV-6 DNA amplified by PCR with variant-specific probes revealed that all of these DNA samples belonged to variant type B. These results indicated that HHV-6 and/or HHV-7 exists in the cervixes of infected women in late pregnancy and may cause perinatal infection.     

Efficient identification of inherited chromosomally integrated human herpesvirus 6 using specimen pooling

BackgroundHuman herpesvirus 6 (HHV-6) has a unique ability to integrate into chromosomal telomeres. Vertical transmission via germ cell integration results in offspring with inherited chromosomally integrated (ci)HHV-6 in all nucleated cells, affecting ∼1% of the population.ObjectivesInherited ciHHV-6 may be a direct or indirect mediator of human disease, but efficient identification of affected individuals is a fundamental roadblock to larger studies exploring the clinical importance of this condition.Study designA group testing strategy was designed to efficiently identify individuals with inherited ciHHV-6. DNA was extracted from 2496 cellular samples from hematopoietic cell transplant (HCT) donor–recipient pairs. Pools of 12 samples were screened for HHV-6 DNA with quantitative (q)PCR. Individual samples from high positive pools were tested with qPCR, and high positive individual samples were tested for inherited ciHHV-6 using droplet digital (dd)PCR to determine HHV-6 DNA copies/cellular genome.ResultsThirty-one pools had high positive HHV-6 DNA detection with >10³ HHV-6 DNA copies/μg. Each pool had one sample with >10⁴ copies/μg HHV-6 DNA. Inherited ciHHV-6 was confirmed by ddPCR in every high positive sample (>10³ HHV-6 DNA copies/μg), yielding a prevalence of 1.5% in HCT recipients and 0.96% in donors. We performed 580 qPCR tests to screen 2496 samples for inherited ciHHV-6, a 77% reduction in testing.ConclusionsInherited ciHHV-6 can be efficiently identified by specimen pooling coupled with modern molecular techniques. This algorithm can be used to facilitate cost-effective identification of patients with inherited ciHHV-6, thereby removing a major hurdle for large-scale study of its clinical impact.     

Carriage of group B Streptococcus in pregnant women and newborns: a 2-year study at Perugia General Hospital

Objective: To study the prevalence of group B Streptococcus (GBS) colonization in pregnant women and their newborns at Perugia General Hospital.
Method: The number of mother-child pairs examined was 2300. Vaginal swabs were collected from the mothers at delivery, and auricular and pharyngeal swabs and gastric aspirate from the newborns at birth. Maternal risk factors for GBS disease, including premature delivery, intrapartum fever, prolonged rupture of membranes and multiple births, were evaluated.
Results: Maternal and neonatal colonization rates were 11.3% and 4.6%, respectively. GBS was isolated in 41.5% of the neonates born to colonized mothers and in 0.1% of those born to non-colonized mothers. No significant difference was observed in vertical transmission rates in the presence or absence of maternal risk factors. The external auditory canal was the most frequent (93.5%) and heavily colonized body site. Type Ib was the most common serotype among GBS isolates from mothers and babies. C surface protein was not detected in serotype V and VIII isolates, but was frequent in all other serotypes. Early-onset disease was observed in 0.4/1000 live births.
Conclusions: The prevalence of maternal and neonatal colonization at Perugia General Hospital was similar to that obtained in other studies performed in Italy. The external auditory canal was confirmed as the most reliable body site to be sampled for the detection of neonates exposed to maternal GBS colonization.     

Prospective study of human herpesvirus 6, human herpesvirus 7, and cytomegalovirus infections in human immunodeficiency virus-positive patients.

Blood samples from human immunodeficiency virus (HIV)-positive patients were monitored for cytomegalovirus (CMV), human herpesvirus 6 (HHV-6), and HHV-7 by PCR. We detected CMV in 17% of the patients, HHV-6 in 6%, and HHV-7 in 3%. The viral loads of CMV were significantly higher than those of HHV-6 (P = 0.007) or HHV-7 (P = 0.01). Detection of CMV and HHV-6 was associated with low and high CD4 counts, respectively.     

Latent infection of human herpesvirus 7 in CD4(+) T lymphocytes

To determine the cell populations in peripheral blood that are infected latently with human herpesvirus 7 (HHV-7), the real-time polymerase chain reaction (PCR) was used to determine the quantities of viral DNA in adherent and non-adherent cells from 71 healthy volunteers. Real-time PCR, which detected the U31 gene of HHV-7, was developed to measure viral load. The majority of non-adherent cells (14/16; 87.5%) contained HHV-7 DNA, while most of the adherent cells did not (1/16; 6.3%). HHV-7 viral load in non-adherent cells was significantly higher than that in adherent cells (P < 0.0001). Then, HHV-7 DNA load was compared between the CD4-positive and -negative cell fractions derived from the non-adherent cells of 26 healthy adults. As in the previous experiment, only 2 (7.7%) of the 26 adherent cell specimens contained small amounts of HHV-7 DNA (27.7 copies/1 x 10(6) cells and 208.7 copies/1 x 10(6) cells). In contrast, 88.5% of CD4(+) T cell samples (23/26 specimens) were positive for HHV-7 DNA, ranging from 0.4 to 3,542.8 copies/1 x 10(6) cells. Viral DNA was detected in only 3 (11.5%) of the 26 CD4(-) T cell specimens, with 8.4, 63.5, and 74.1 copies/1 x 10(6) cells. HHV-7-positive DNA loads were significantly higher in the CD4(+) T cells than those observed in the CD4(-) T cells (P = 0.0005). The relationship between HHV-7 viral loads in non-adherent cells and those in saliva was investigated. Comparison of HHV-7 DNA load between blood CD4(+) T cells and saliva revealed that the HHV-7 DNA load in saliva correlated with that present in CD4(+) T cells (r = 0.415; P = 0.0174).     

Real-time PCR determination of human herpesvirus 6 antiviral drug susceptibility

A quantitative real-time PCR assay was developed to determine the antiviral drug susceptibility of human herpesvirus 6 (HHV-6). After short-term culture of the virus, HHV-6 isolates’ susceptibility to the antiviral ganciclovir (GCV) was determined by measuring the HHV-6 variant B (HHV-6B) DNA levels in culture supernatants and infected cells using real-time PCR. A total of 12 well-characterized GCV-sensitive or -resistant strains and clinical isolates were used. This new assay with real-time PCR readout permitted the rapid (3 days), objective, and reproducible determination of HHV-6 drug susceptibilities with no need for stringent control of the initial multiplicity of infection. Furthermore, the real-time PCR assay results showed good correlation (r_s = 0.95) with those from the conventional TCID₅₀ (50% tissue culture infecting dose) reduction assay (TRA). Thus, the real-time PCR assay described in this report was found to be a suitable quantitative method for determining the susceptibility of HHV-6 to antiviral drugs. It is faster and simpler than the TRA, and it is amenable to use in the routine diagnostic virology laboratory.     

Human herpesvirus type 6 and human herpesvirus type 7 infections of the central nervous system

In developing guidelines for the improved management of herpesvirus infections of the central nervous system (CNS), the International Herpes Management Forum (IHMF) has considered human herpesvirus (HHV) type 6 and type 7 disease. Although HHV-6 is generally asymptomatic, it has been associated with exanthema subitum, febrile convulsions and encephalitis in infants and immunocompromised adults and may play a role in multiple sclerosis, Guillain-Barre syndrome and acute disseminated encephalomyelitis. As HHV-6 is present in the brain tissue of healthy individuals, its role as an aetiological agent in CNS disorders is unclear. While polymerase chain reaction (PCR) is a method useful for diagnosis of other viral CNS infections, it has no value for diagnosing HHV-6. HHV-7 has not been shown to cause a specific disease but is associated with febrile convulsions and has been implicated as a cause of encephalitis. Ganciclovir and foscarnet, either alone or in combination, may be used for the management of HHV-6-related neurological disease. Although ganciclovir is unlikely to be effective against HHV-7-related CNS disease, foscarnet may be useful but prospective trials are needed.     

Human herpesvirus 6 and human herpesvirus 7 infections in renal transplant recipients and healthy adults in Turkey

Summary We explored the prevalence of human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7) infections in 16 renal transplant recipients and 16 healthy controls by virus isolation, serology, polymerase chain reaction (PCR) followed by dot blot hybridization. HHV-6 variant A was isolated from one renal transplant recipient. Seven patients (44%) and six controls (38%) had HHV-6 variant B DNA in their peripheral blood mononuclear cells. The prevalence of HHV-7 DNA was found to be the same in patients and controls (19%).     

Isolation of human herpesvirus 7 from an infant with febrile syndrome

A viral isolate obtained from peripheral blood lymphocytes of an infant with a nonspecific febrile syndrome was identified as human herpes-virus 7 (HHV-7) on the basis of PCR analysis of its DMA with one set of primers specific for HHV-7. The correlation of HHV-7 with the febrile episode affecting the infant is suggested. © 1995 Wiley-Liss, Inc.     

Molecular study of human herpesvirus 6 and 8 involvement in coronary atherosclerosis and coronary instability

Several lines of evidence suggest the involvement of infectious agents in the pathogenesis of atherosclerosis. Furthermore, a correlation between infection‐driven inflammatory burden and acute manifestation of coronary artery disease has been hypothesized. The aim of this work was to assess whether human herpesvirus (HHV)‐6 and HHV‐8, two DNA viruses with a distinct tropism for endothelium and lymphocytes, may be associated with coronary instability. An age‐ and gender‐matched cross‐sectional study was undertaken in 70 patients with testing of plasma HHV‐6 and HHV‐8 DNA load in different cardiovascular clinical settings: 29 patients with acute myocardial infarction, 21 patients with stable coronary artery disease, and 20 patients without coronary and carotid artery atherosclerosis subjected to cardiac valve replacement. In all patients, HHV‐6 and HHV‐8 plasma DNA was tested by using highly sensitive, calibrated quantitative real‐time PCR assays which employ a synthetic DNA calibrator to adjust for DNA extraction and amplification efficiency. HHV‐8 viremia was undetectable in all three groups. HHV‐6 viremia was detected in a substantial fraction of the samples examined (18.6%) without significant differences among the three groups (ST segment elevation myocardial infarction: 17.2%; stable coronary artery disease: 14.3%; patients without coronary and carotid artery atherosclerosis: 25%). Furthermore, no significant differences in plasma HHV‐6 load were observed amongst the three groups of patients. These findings indicate that coronary instability is not associated specifically with active HHV‐6 or HHV‐8 infection. However, an unusually high rate of active HHV‐6 infection was documented among patients without atherosclerosis admitted to hospital with cardiac disease. J. Med. Virol. 84:1961–1966, 2012. © 2012 Wiley Periodicals, Inc.     

Controlled study of human herpesvirus 6 detection in acquired immunodeficiency syndrome-associated non-Hodgkin's lymphoma

Human herpesvirus 6 (HHV-6) is a recently identified lymphotropic herpesvirus, which has been isolated from patients with acquired immunodeficiency syndrome (AIDS) or lymphoproliferative diseases. Two variants A and B of HHV-6 have been described, variant B being more common in children with exanthema subitum. HHV-6 infection was studied in cases of AIDS-associated non-Hodgkin's lymphoma (NHL), and in three control populations in order to evaluate the possible etiologicai role of HHV-6 in this lymphoproliferative disease. Tumor specimens from various organs were obtained from 27 patients with AIDS-associated NHL and 20 human immunodeficiency virus (HlV)-seronegative patients with NHL. Lymph node specimens were obtained from four HIV-seropositive and nine HIV-seronegative patients with lymph node follicular hyperplasia. A specific polymerase chain reaction (PCR) was used to detect HHV-6 DNA. Subsequently HHV-6 variant was identified by using variant-specific PCR. Human cytomegalovirus (CMV) infection was detected in parallel by means of specific PCR. HHV-6 DNA was detected in 12 of 27 tumor tissues (44%), including 8 of 15 lymph node specimens (53%) from patients with AIDS-associated NHL. The corresponding values in HIV-seronegative patients with NHL were 35% (7/20) and 36% (5/14), respectively. Lymph node specimens were positive for HHV-6 in two of four (50%) HIV-seropositive and five of nine (55%) HIV-seronegative patients with follicular hyperplasia. Variant A was detected in two cases of AIDS-associated NHL, variant B in one case, and both variants in six cases. The distribution of HHV-6 variants exhibited a similar pattern in the three control groups. CMV was only detected in 3 of 27 tumor tissues (11%) from patients with AIDS-associated NHL. The prevalence of HHV-6 DNA and the distribution of its variants did not differ significantly among the four populations studied. HHV-6 was more prevalent than CMV, a closely related herpesvirus. Most cases of HHV-6 infection involved both HHV-6 variants A and B. These results do not support strongly that HHV-6 infection is closely associated with the occurrence of NHL in AIDS patients but demonstrate that mixed HHV-6 infections are more common than previously assumed. © 1995 Wiley-Liss, inc.