Human Herpesvirus 6 DNA Research Articles

Large-scale analysis of viral nucleic acid spectrum in temporal lobe epilepsy biopsies.

Chronic inflammatory processes are important promotors of temporal lobe epilepsy (TLE) development. Based on human herpesvirus 6 (HHV-6) DNA detection in brain tissue from patients with TLE, an association of persistent viral infection with TLE has been discussed. Individual studies reported increased HHV-6 DNA in patients with clinical signs of previous inflammatory brain reaction, that is, febrile seizures or meningoencephalitis. However, detection rates vary considerably between different studies. Here we performed a large-scale analysis of viral DNA/RNA spectrum in high-quality TLE biopsies. In addition to all Herpesviridae, we addressed potentially relevant neurotropic RNA viruses. DNA and RNA were extracted from 346 fresh-frozen tissue samples removed by epilepsy surgery. Real-time polymerase chain reaction (PCR) and nested PCR were performed for Herpesviridae and RNA viruses, respectively. Clinical data were analyzed for earlier signs of inflammatory brain reactions. Fresh-frozen hippocampal tissue samples from patients without chronic central nervous system (CNS) disease served as controls (n = 62). Seven previous PCR studies with overall 178 TLE patients were additionally analyzed regarding a correlation of clinical parameters and HHV-6 detection. PCR revealed HHV-6B DNA in 34 specimens (9.8%) from TLE patients. HHV-6B DNA was also present in eight control samples (12.9%; p > 0.05), but showed a lower virus concentration (p < 0.001). Other herpesviruses and RNA viruses were virtually absent. In patients with clinical signs of previous brain inflammation, HHV-6B DNA was observed in 15.0%, whereas only 6.3% of the samples from patients without febrile seizures or meningoencephalitis were positive for HHV-6B DNA (p < 0.05). A meta-analysis of the eight HHV-6 PCR studies revealed similar results. This biopsy-based study shows no differences in frequency of HHV-6B DNA detection between TLE patients and controls. These results do not support the hypothesis of a persistent HHV-6B infection as a major pathogenetic factor in TLE. However, the higher virus load in TLE patients and the increased detection rate of HHV-6B DNA in patients with previous inflammatory brain reactions require further investigations.

Quantitative polymerase chain reaction for detection of human herpesvirus-7 infection in umbilical cord blood donors.

Umbilical cord blood (UCB) has been a reasonable alternative to granulocyte colony-stimulating factor-mobilized peripheral blood or bone marrow, as a source of hematopoietic stem cells with a lower risk of graft-versus-host disease. In immunocompromised hosts after transplantation, the risk of viral infection in adults, especially with beta-herpesviruses such as human herpesvirus-7 (HHV-7), may be increased. This virus in immunocompromised patients can be reactivated from latency and converted to an active phase. Therefore, light-upon-extension real-time polymerase chain reaction (PCR) was developed to assess the prevalence and load of HHV-7 in the plasma and buffy coat of donors. About 825 UCB samples under standard protocol from donors were collected. Then, DNA from plasma and buffy coat was extracted and quantitative real-time PCR was performed with light-upon-extension primers. Overall, HHV-7 was detected in 3.64% (30/825) of UCB donors. HHV-7 DNA was detected in 26 (3.2%) buffy coat samples (latent infection), and only 4 (0.48%) of them were positive for HHV-7 DNA in plasma samples (active infection); the mean HHV-7 viral load was 1.31×10(1) copies/mL in latent infection, and 1.94×10(5) copies/mL in active infection. We suggest that real-time PCR in plasma and buffy coat could be a useful method to detect active and latent HHV-7 infection in UCB donors and determine its role in subsequent transmission events.

Association of Mycosis Fungoides and Large Plaque Parapsoriasis with Human Herpes Virus 8

Background: The association of the human herpes virus 8 (HHV-8) with Mycosis fungoides (MF) and large plaque parapsoriasis (LPP) has been assessed previously and contradictory results were reported. Although it was investigated in different countries and different ethnic groups, there was no study concerning Iranian population with these lymphoproliferative diseases. Objectives: We aimed to assess the association of HHV-8 with MF and LPP in biopsy samples of Iranian patients with these lymphoproliferative conditions. Patients and Methods: Paraffin-embedded samples from patients who were diagnosed by histopathological examination as MF or LPP were assessed by real-time polymerase chain reaction (RT-PCR) in a molecular epidemiology case-control study. Primerdesign Genesig kit for HHV-8 Genomes was used to extract total DNA. Samples from chronic dermatitis were used as control; five samples from patients with kaposi sarcoma were used as positive control in PCR. Results: The investigated samples consisted of 13 patient with MF, 10 patients with LPP, and 23 patients with chronic dermatitis; the diagnosis of these skin conditions were confirmed histopathologically. The RT-PCR could not detect HHV-8 DNA sequence in any of the examined samples, ie. MF, LPP, and chronic dermatitis. The PCR results for all kaposi sarcoma samples were positive for HHV-8 genome. Conclusion: There was no association between HHV-8 and MF or LPP in Iranian population. This is in accordance with most of the reports from different countries.

Serum levels of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinases-1 in human herpesvirus-6-infected infants with or without febrile seizures.

Human herpesvirus-6 (HHV-6) is a cause of exanthema subitum and, sometimes, of febrile seizures. However, the pathogenesis of febrile seizures associated with HHV-6 infection remains unclear. We investigated serum matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1) levels in infants with HHV-6 infection. Serum levels of both MMP-9 and TIMP-1 were significantly higher in infants with HHV-6 infection than in controls. Serum TIMP-1 levels were significantly higher in infants with febrile seizures than in infants without febrile seizures. Serum MMP-9/TIMP-1 ratios were significantly lower in infants with febrile seizures than in infants without febrile seizures. In infants with HHV-6 infection, positive correlations were found between serum MMP-9 concentrations and the white blood cells (WBC) count, and between serum TIMP-1 concentrations and the WBC count. Positive correlations were also found between the amounts of HHV-6 DNA and the ratios of MMP-9/TIMP-1 in infants with HHV-6 infection. In conclusion, we suggest that high serum levels of MMP-9 and TIMP-1 in infants with HHV-6 infection may induce dysfunction of the blood-brain barrier, eventually causing febrile seizures.

Detection of human herpesvirus 6 in cerebrospinal fluid of children with possible encephalitis.

Background:Encephalitis is swelling and inflammation of brain, usually due to viral infection. Viral encephalitis symptoms could be fever, headache, altered level of consciousness, and seizures.Objectives:The aim of this study was detection of human herpesvirus-6 (HHV-6) DNA in cerebrospinal fluid (CSF) of patients with symptoms of possible acute encephalitis and without typical signs or symptoms of roseola infantum, using real-time polymerase chain reaction (PCR).Patients and Methods:We studied children two years old or younger, admitted to the pediatric emergency ward with encephalitis-like symptoms. Our evaluation included detection of HHV-6 in CSF of these patients. After DNA extraction, real-time PCR was performed with primers and a probe specific for the U22 open reading frame of both HHV-6A and B.Results:From a total of 114 patients, HHV-6 was detected in 10 (8.8%), 90% of which were boys with mean age 7.7 months and median of 7.5 months. No significant differences were found in clinical presentations and laboratory findings between the patients positive and negative for HHV-6. All the children had complete recovery without neurological deficit or death.Conclusions:According to this research and prevalence of HHV-6 in children, evaluation of CSF (detecting the HHV-6 DNA by PCR) is recommended in patients younger than 13 months with possible encephalitis.

Risk Factors for Human Herpesvirus 6 Reactivation and its Relationship With Syndrome of Inappropriate Antidiuretic Hormone Secretion After Stem Cell Transplantation in Pediatric Patients

There have been several reports on the reactivation of human herpesvirus 6 (HHV6) after stem cell transplantation (SCT) in adults, which sometimes induces severe illness. Few reports exist on pediatric patients; therefore, we retrospectively examined HHV6 reactivation after SCT in children. We reviewed 80 patients with a median age of 6 years. We analyzed HHV6 DNA serum samples from the patients before SCT and at 20 and 40 days after SCT using polymerase chain reaction. We also analyzed the relationship between HHV6 reactivation and the syndrome of inappropriate antidiuretic hormone secretion (SIADH). At 20 days after SCT, 35.0% of serum samples were positive for HHV6 DNA. The median viral load was 3.1×10 copies/mL serum. Multivariate analysis showed cord blood transplantation as the only risk factor for HHV6 reactivation. HHV6 reactivation occurs in 59.4% of 32 patients who underwent cord blood transplantation and in 18.8% of 48 patients who underwent SCT from other sources. Among the 14 patients with SIADH, 78.6% experienced HHV6 reactivation. Among the 66 patients without SIADH, only 25.8% had HHV6 reactivation. This result was statistically significant (P<0.001). This analysis revealed that HHV6 reactivation occurs in many children. In addition, HHV6 reactivation plus SIADH should prompt evaluation for central nervous system disease.

Herpesvirus Genome Integration into Telomeric Repeats of Host Cell Chromosomes.

It is well known that numerous viruses integrate their genetic material into host cell chromosomes. Human herpesvirus 6 (HHV-6) and oncogenic Marek's disease virus (MDV) have been shown to integrate their genomes into host telomeres of latently infected cells. This is unusual for herpesviruses as most maintain their genomes as circular episomes during the quiescent stage of infection. The genomic DNA of HHV-6, MDV, and several other herpesviruses harbors telomeric repeats (TMRs) that are identical to host telomere sequences (TTAGGG). At least in the case of MDV, viral TMRs facilitate integration into host telomeres. Integration of HHV-6 occurs not only in lymphocytes but also in the germline of some individuals, allowing vertical virus transmission. Although the molecular mechanism of telomere integration is poorly understood, the presence of TMRs in a number of herpesviruses suggests it is their default program for genome maintenance during latency and also allows efficient reactivation.

A case of bilateral human herpes virus 6 panuveitis with genomic viral DNA integration.

BackgroundWe report a rare case of bilateral panuveitis from human herpes virus 6 (HHV-6) with genomic viral DNA integration in an immunocompromised man.FindingsA 59-year-old man with history of multiple myeloma presented with altered mental status, bilateral eye redness, and blurry vision. Examination revealed bilateral diffuse keratic precipitates, 4+ anterior chamber cell, hypopyon, vitritis, and intraretinal hemorrhages. Intraocular fluid testing by polymerase chain reaction (PCR) was positive for HHV-6. The patient was successfully treated with intravitreal foscarnet and intravenous ganciclovir and foscarnet. Despite clinical improvement, his serum HHV-6 levels remained high, and it was concluded that he had HHV-6 chromosomal integration.ConclusionsHHV-6 should be considered in the differential for infectious uveitis in immunocompromised hosts who may otherwise have a negative work-up. HHV-6 DNA integration may lead to difficulties in disease diagnosis and determining disease resolution.

Prevalence of herpesviruses at onset of idiopathic nephrotic syndrome.

Idiopathic nephrotic syndrome (INS) is likely a primary immune disorder, but viruses might also be involved in the mechanisms of the disease. Here, we investigate the link between herpesvirus infection and the first manifestation of INS in children. A prospective, multicentre, and population-based case-control study called NEPHROVIR included 164 patients, aged 6 months to 15 years old, newly diagnosed with INS, and 233 controls matched for gender, age, and period of sample. The analysis was done on 124 patients and 196 controls. Epstein-Barr virus (EBV), cytomegalovirus (CMV), human herpesvirus-6 (HHV-6), and human herpesvirus-7 (HHV-7) DNA prevalence at diagnosis were assessed from whole peripheral blood samples, as well as EBV and CMV viral load and seroprevalence. EBV DNA was significantly more prevalent in cases than in controls (50.8 vs 29.1 %; OR = 2.6; p = 0.0002), with no difference in viral load. A significant difference was also found for CMV (11.3 vs 3.6 %; p = 0.02) and HHV-7 (83 vs 72 %; p = 0.02) DNA prevalence between cases and controls. There were significantly more EBV and CMV recent infections or reactivations based on VCA-IgM and CMV IgM in cases than controls, while there were no differences in IgG seroprevalence. The prevalence of positive EBV DNA detection and recent infection or reactivation is higher in children at onset of INS compared to a population matched for age, gender, and time of sampling.

Delayed primary HHV-7 infection and neurologic disease.

Primary human herpesvirus 7 (HHV-7) infection occurs almost universally during the first 5 years of life and is rarely accompanied by central nervous system (CNS) symptoms such as febrile seizures. The present retrospective study investigated the role of primary HHV-7 infection in CNS disease in children, including adolescents. The study included all children who had neurologic disease aged younger than 18 years seen at the Hospital for Sick Children, Toronto, Canada, between April 1, 1998 and December 31, 2011, whose cerebrospinal fluid (CSF) was found by polymerase chain reaction to contain HHV-7 DNA. Where sera were available, HHV-7 IgG antibody titers and avidity were measured to differentiate primary from past infection. HHV-7 DNA was detected in the CSF of 57 (1.9%) of the 2972 children tested. In 3 adolescents primary HHV-7 infection (low avidity IgG) was confirmed as the cause of neurologic disease, 2 who had encephalitis and 1 who had Guillain-Barré syndrome. Eighteen children had possible HHV-7 disease (no alternative cause identified and indeterminate antibody result or serum not available), 7 encephalitis, 8 meningitis, and 3 demyelinating disorders. HHV-7 disease was excluded in 36 children on the basis of past infection (high IgG avidity) and/or an alternative cause. Primary HHV-7 infection delayed into adolescence can cause serious neurologic disease. HHV-7 DNA in CSF alone is insufficient to prove an etiologic association. Combining CSF polymerase chain reaction with serology is essential to prove primary infection when investigating HHV-7 CNS disease.

Presence of HHV-6 genome in spermatozoa in a context of couples with low fertility: what type of infection?

Human herpesvirus-6 (HHV-6) is a betaherpesvirus whose genome may integrate into human chromosomes. Chromosomally integrated HHV-6 (ciHHV-6) may be transmitted vertically from parents to children. HHV-6 DNA has been detected in semen, but its integrated or extrachromosomal status has not yet been characterised. The aim of this study was to determine the prevalence of HHV-6 DNA and to search for ciHHV-6 forms in spermatozoa purified from semen obtained from subjects explored for low fertility. A total of 184 sperm samples were purified using PureSperm(®) . HHV-6 viral load and species identification were performed by real-time polymerase chain reaction. Of 179 sperm specimens analysed, three were positive for HHV-6 (1.7%). Two samples (1.1%) had viral loads of 680232 and 2834075copies per million spermatozoa, compatible with loads expected for a ciHHV-6 form. The viral load of the third positive sample (73684copies per million spermatozoa) was lower than would be expected for ciHHV-6 infection, implying that the HHV-6 DNA detected in spermatozoa corresponds mainly to ciHHV-6. However, viral DNA may also be detected at a low level that is not in favour of the presence of ciHHV-6. Further studies are necessary to determine the origin of detected viral genomes.

Oral HHV-8 replication among women in Mombasa, Kenya

Human herpesvirus-8 (HHV-8) replication in the oropharynx may play an important role in HHV-8 transmission and contribute to the development of Kaposi sarcoma (KS) in some individuals. Studies in the United States and Europe report high rates of HHV-8 DNA detection in saliva of HHV-8 infected men, but little is known about the natural history of HHV-8 among persons in sub-Saharan Africa, where prevalence of HHV-8 infection and KS is greatest. To address this gap, this study evaluated oral HHV-8 replication in a cohort of 40 HHV-8 seropositive Kenyan women. Study clinicians collected daily oral swabs from participants for up to 30 consecutive days, and swab samples were tested for HHV-8 DNA using quantitative, real-time polymerase chain reaction. HHV-8 was detected at least once in 27 (68%) participants, and the overall shedding rate was 23%. On days with HHV-8 detection, mean HHV-8 quantity was 4.5 log10 copies/ml. Among HIV-infected women, CD4 count ≥500 cells/mm(3) versus <500 cells/mm(3) was associated with higher HHV-8 copy number (4.8 log10 copies/ml vs. 3.4 log10 copies/ml; coef 1.2 [95% CI, 0.5-1.9]; P = 0.001) and a higher HHV-8 shedding rate (49% vs.12%; RR, 4.2 [95% CI, 0.8-21.4]; P = 0.08). No other factors were associated with HHV-8 shedding rate or copy number. The study demonstrates high rates and quantity of HHV-8 in the oropharynx of HHV-8 seropositive African women. These findings support the observation that oral replication is an essential feature of HHV-8 infection, with likely implications for HHV-8 transmission and KS pathogenesis.

Low prevalence of human herpesvirus-6 and varicella zoster virus in blood of multiple sclerosis patients, irrespective of inflammatory status or disease progression

Herpesviruses, including human herpesvirus-6 and varicella zoster virus, have been implicated in the disease aetiology of multiple sclerosis. These viruses are capable of reactivation, reminiscent of the relapsing-remitting nature of multiple sclerosis. However, viral DNA has also been reported present in healthy controls, often at similar prevalence rates. This study aimed to determine whether prevalence could be associated with different stages of activity of the disease as well as the inflammatory status of the patients. Polymerase chain reaction assays were used to screen for human herpesvirus-6 and varicella zoster virus DNA in blood from 31 Caucasian patients with multiple sclerosis and 30 healthy age, sex and race matched control subjects. The patients were screened for inflammation using C-reactive protein as a marker and were also categorized according to their remitting/relapsing status. Results were positive for human herpesvirus-6 in blood from only one patient (3.2%) and human herpesvirus-6 DNA was not present in any control subjects. Varicella zoster virus was not detected in either the patients or control subjects. Similar to some other studies we saw an absence or very low viral positivity in blood from both patients and controls. These findings were irrespective of relapse episodes, increased inflammatory status or duration of the disease. Results therefore do not support a causative role for either human herpesvirus-6 or varicella zoster virus in the disease aetiology of multiple sclerosis, but rather that prevalence in patients may be linked to that of the general population.

Analysis of human herpes virus 6 infections with a quantitative, standardized, commercial kit in pediatric stem cell transplant recipients after transplantation.

BACKGROUND AND OBJECTIVESThe aim of the study was to assess the incidence and clinical relevance of active Human Herpes Virus 6 (HHV6) infections in pediatric patients after allogeneic stem cell transplantation.DESIGN AND SETTINGSRetrospective analysis of samples prospectively collected at Akdeniz University Medical Faculty Hospital, Antalya, Turkey, between May 2006 and July 2007 from 15 pediatric patients with allogeneic hematopoietic stem cell transplantation (HSCT).SUBJECTS AND METHODSA commercial quantitative real-time polymerase chain reaction kit was used to analyze plasma samples collected from 15 pediatric allogeneic HSCT recipients.RESULTSHHV6 DNA was found positive in 8 (53%) patients. HHV6 DNA levels above 1000 copies/mL were found only in 2 patients and they were also consecutively positive for HHV6 DNA. Age at transplantation, use of ATG, and receiving grafts other than HLA identical siblings increased the risk, with a statistically significant difference, of having HHV6 reactivation with levels exceeding 1000 copies/mL (P values, respectively, P=.03, .001, .025). Active HHV6 infections with HHV6 viremia levels higher than 1000 copies/mL were associated with subsequent delayed platelet engraftment (P=.001), acute graft versus host disease (P=.001), skin rash, and fever of unknown origin.CONCLUSIONMore than half of pediatric allogeneic HSCT patients develop active HHV6 infection, and especially in patients with high viremic loads, the infection can result in serious clinical situations. A clinically significant cutoff value for viremia seems to be necessary to predict serious clinical complications.

Detection of Herpes Viruses by Multiplex and Real-Time Polymerase Chain Reaction in Bronchoalveolar Lavage Fluid of Patients with Acute Lung Injury or Acute Respiratory Distress Syndrome

Background: Human herpes viruses (HHVs) are important pathogens in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Rapid and efficient diagnostic tools are needed to detect HHVs in the lung in ALI/ARDS patients. Objectives: This study aimed to evaluate the usefulness of multiplex and real-time polymerase chain reaction (PCR) analysis of bronchoalveolar lavage fluid (BALF) for detecting HHV reactivation in ALI/ARDS patients. Methods: Between August 2008 and July 2012, eighty-seven BALF samples were obtained from ALI/ARDS patients with unknown etiology and analyzed for HHVs. The types of HHVs in the BALF samples were determined using qualitative multiplex PCR followed by quantitative real-time PCR. Results: Multiplex PCR identified herpes simplex virus type 1 (HSV-1) (n = 11), Epstein-Barr virus (EBV) (n = 16), cytomegalovirus (CMV) (n = 21), HHV type 6 (HHV-6) (n = 2), and HHV-7 (n = 1) genomic DNA in 35 (40%) of the BALF samples, including 14 (16%) samples containing 2 or 3 HHV types. CMV and EBV reactivation was rare in immunocompetent patients, whereas reactivation of HSV-1 was predominantly observed in intubated patients regardless of their immune status. Overall, HHVs were almost exclusively found in patients with immunosuppression or endotracheal intubation. Real-time PCR detected 0.95-1.59 × 10⁶ copies of viral DNA/μg human genome DNA, and HSV-1 (n = 4), CMV (n = 9), and HHV-6 (n = 1) were identified as potentially pathogenic agents. Conclusions: The implementation of multiplex and real-time PCR of BALF was feasible in ALI/ARDS patients, which allowed efficient detection and quantification of HHV DNA.

High seroprevalence of human herpesvirus 8 infection in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that is associated with genetic and environmental factors and microbial infection. With respect to microbial infection, the Epstein-Barr virus (EBV) has been a widely discussed issue in recent decades. Human herpesvirus 8 (HHV-8) belongs to the same γ-herpesvirus subfamily as EBV and is closely related to it. Until now, only one paper has reported the prevalence of HHV-8 infection in SLE patients. The goal of this study was to detect the prevalence of HHV-8 infection in SLE patients to elucidate the relationship between HHV-8 and SLE. We assessed the seroprevalence of HHV-8 in SLE patients by immunofluorescence assay. In addition, we quantified the HHV-8 DNA in peripheral blood mononuclear cells (PBMCs) from SLE patients by real-time polymerase chain reaction (PCR). The prevalence of HHV-8 antibodies in SLE and normal controls was 57.8% (26/45) and 19.2% (5/26), respectively. These data were highly significant (P = 0.001). No HHV-8 DNA was detected by real-time PCR in SLE patients' PBMCs. In addition, we analyzed the prevalence of HHV-8 infection in patients with rheumatoid arthritis and ankylosing spondylitis. There was no significant difference between the patients and normal controls. A high seroprevalence of HHV-8 infection was found in patients with SLE. The negative DNA load and high seropositive rate indicate that most patients might have latent infection.

Human herpesvirus-6 and cytomegalovirus DNA in liver donor biopsies and their correlation with HLA matches and acute cellular rejection

Herpesvirus reactivation is common after liver transplantation. ObjectiveAnalyze the presence of cytomegalovirus (HCMV) and human herpesvirus-6 (HHV-6) DNA in liver donor biopsies, seeking to better understand issues involving human donor leukocyte antigens (HLA)-A, B and DR, as well as correlations with acute cellular rejection. MethodsFifty-nine liver transplantation patients were investigated for the presence of HCMV and HHV-6 DNA in liver donor biopsies, using the Nested-PCR technique. The clinical donor information and HLA matches were obtained from the São Paulo State Transplant System. The recipients’ records regarding acute cellular rejection were studied. ResultsSeven (11.8%) biopsies were positive for HCMV DNA and 29 (49%) were positive for HHV-6 DNA. In 14 donors with HLA-DR 15 nine had HHV-6 DNA positive liver biopsy with a tendency for significant association (p=0.09), 22 recipients developed acute cellular rejection and 9/22 were positive for HLA-DR 15 (p=0.03; χ2=4.51), which was statistically significant in univariate analysis and showed a tendency after multivariate analysis (p=0.08). ConclusionHHV-6 DNA was prevalent in liver donors studied as well as HLA-DR 15. These findings suggest that patients with HLA-DR 15 in liver donor biopsies develop more rejection after liver transplantation.

Human herpesvirus 8+ polyclonal IgMλ B‐cell lymphocytosis mimicking plasmablastic leukemia/lymphoma in HIV‐infected patients

Multicentric Castleman disease (MCD) is a distinct lymphoproliferative disorder characterized by inflammatory symptoms, lymphadenopathy, splenomegaly, and cytopenia. Kaposi's sarcoma-associated herpesvirus (KSHV), also called human herpesvirus-8 (HHV-8), is the cause of virtually all cases of MCD occurring in patients with HIV infection. MCD lesions characteristically contain HHV-8-infected polyclonal IgMλ plasmablasts. A high frequency of HHV-8-related non-Hodgkin lymphoma has been reported in these patients. We now report on three patients who presented with severe symptoms of MCD, extreme splenomegaly, and rapid expansion of B-cell lymphocytosis (44-81%) attributable to circulating HHV-8 positive plasmablasts. The circulating plasmablastic cells shared the phenotype (IgMλ, CD19+, CD20- CD138-) of HHV-8-infected cells from MCD lesions, mimicking the leukemic phase of large B-cell lymphoma occurring in HHV-8-related MCD. These patients displayed a very high HHV-8 viral load in blood (>7 logs HHV-8 DNA copies/ml) and high levels of serum vIL-6, the viral homolog of human interleukin 6. Serum IL-6 and IL-10 were also abnormally elevated. HHV-8-infected cells were demonstrated by immunoglobulin gene rearrangement analysis, to be polyclonal and likely represent an expansion of HHV-8-infected cells similar to those found in MCD lesions. Thus, the spectrum of HHV-8-related plasmablastic lymphoproliferative disorders in patients with HIV infection is expanded to include HHV-8+ polyclonal IgMλ B-cell lymphocytosis. At onset, this lymphoproliferative disorder may mimic plasmablastic leukemia/lymphoma. Recognizing this unusual complication may have important implications in treatment decision avoiding unnecessary toxicity to the patients.

Human Herpes Virus-6 and Human Herpes Virus -7 in Pityriasis Rosea

**Mersin University School of Medicine, Department of Biostatistics, Mersin, Turkey Objective: The etiology of pityriasis rosea (PR) remains unknown despite numerous investigations. In recent years, human herpes virus-6 (HHV-6) and HHV-7 were accused as causative agents in PR. The aim of this study was to evaluate the possible role of HHV6 and HHV-7 in the pathogenesis of PR. Methods: Twenty three PR patients and 23 healthy blood donors as a control group were included in the study. Polymerase chain reaction (PCR) with specific primers for HHV-6 and HHV-7 DNA sequences was performed on the serum samples of 23 active PR patients and controls, and also the lesional skin biopsies from 11 PR patients. Additionally, serum levels of IgM antibodies againts HHV-7 were detected by using indirect immunofluorescence test on the serum samples of all of the study population. Results: No statistically significant differences were detected between PR patients and controls regarding all serum results. Conclusion: These findings do not support a primary etiological role for HHV-6 and HHV-7 in PR as in some previous studies.

Acute Hepatitis With Periportal Confluent Necrosis Associated With Human Herpesvirus 6 Infection in Liver Transplant Patients

To correlate human herpesvirus 6 (HHV-6) viral load with pathologic features in graft acute hepatitis of unknown origin. Liver frozen samples from 26 patients with graft hepatitis of unknown origin were available for HHV-6 DNA quantification. In 10 (38.5%) of 26 liver samples, HHV-6 DNA was detectable, with a median viral load of 3.84 log10 copies/10⁶ cells. Confluent periportal necrosis was observed in 4 of 10 patients and associated with high viral load. These 4 patients responded to antiviral therapy. Mild unspecific hepatitis was observed in 4 patients with low intragraft viral load and in 2 patients with high viral load in a context of deep immunosuppression. Patients with HHV-6-negative graft hepatitis disclosed lobular necrotico-inflammatory activity without periportal necrosis. Our study provides data supporting the pathogenic role of HHV-6 for liver allografts. The presence of confluent periportal necrosis could be a clue for prompt diagnosis of HHV-6-induced graft hepatitis.