Human Herpes Virus Type 6 Infection Research Articles

Human herpesvirus type 6 in patients with systemic lupus erythematosus.

Infectious agents are considered one of the possible etiological factors of systemic lupus erythematosus (SLE). It has been suggested that human herpesvirus type 6 (HHV-6) may trigger autoimmune disorders, but few studies have been conducted on the relationship between this virus and autoimmune diseases, especially SLE. The present study aimed to compare the frequency of HHV-6 infection between SLE patients and healthy individuals. Serum samples were collected from 60 healthy people and 60 SLE patients referred to the rheumatology clinic of Shahid-Beheshti Hospital, Kashan, Iran, from January 2020 to January 2021. The following data were collected from the medical records of patients: sex; age; duration of disease; SLE clinical manifestations; and disease activity. After the extraction of viral DNA from samples, a nested polymerase chain reaction (PCR) test was performed to detect HHV-6. HHV-6 was detected in 12 SLE patients (20%) and in 8 healthy individuals (13.3%). A significant correlation was not obtained between SLE and the presence of HHV-6 (P = 0.09). There was no correlation between musculoskeletal involvements, skin lesions, renal manifestations, and hematological manifestations with the presence of HHV-6 (P>0.05). HHV-6 was detected more frequently in patients with active lupus than in patients with quiescent disease, but this difference was not significant (P=0.08). Although patients with SLE had a higher prevalence of HHV-6 compared with healthy people, there is no strong link between HHV-6 infection and SLE. Future research is necessary because this data does not support the hypothesis that human herpesvirus 6 plays a role in the pathogenesis of SLE.

Human herpesvirus type 6 reactivation after haploidentical hematopoietic cell transplantation with post-transplant cyclophosphamide and antithymocyte globulin: risk factors and clinical impact

Human herpesvirus type 6 (HHV6) reactivation after haploidentical hematopoietic cell transplantation (HCT) with post-transplant cyclophosphamide (PT-Cy) has been scarcely studied, especially when antithymocyte globulin (ATG) is added to the graft-versus-host disease (GvHD) prophylaxis. We conducted a retrospective cohort study in 100 consecutive patients receiving haploidentical HCT with PT-Cy. We systematically monitored HHV6 DNA loads in blood samples on a weekly basis using quantitative PCR until day +100. The 100-day cumulative incidence of HHV6 reactivation was 54%. Clinically significant HHV6 infections were rare (7%), associated with higher HHV6 DNA loads, and had favorable outcomes after antiviral therapy. The main risk factor for HHV6 reactivation was a low absolute lymphocyte count (ALC) < 290/µL on day +30 (68% versus 40%, p = 0.003). Adding ATG to PT-Cy did not increase the incidence of HHV6 reactivation (52% with ATG versus 79% without ATG, p = 0.12). Patients experiencing HHV6 reactivation demonstrated delayed platelet recovery (HR 1.81, 95% CI 1.07-3.05, p = 0.026), higher risk of acute grade II-IV GvHD (39% versus 9%, p < 0.001) but similar overall survival and non-relapse mortality to the other patients. In conclusion, our findings endorse the safety of combining ATG and PT-Cy in terms of the risk of HHV6 reactivation and infection in patients undergoing haploidentical HCT. Patients with a low ALC on day +30 face a higher risk of HHV6 reactivation and may require careful monitoring.

The Association of HHV-6 and the TNF-α (-308G/A) Promotor with Major Depressive Disorder Patients and Healthy Controls in Thailand.

Major depressive disorder (MDD) is a silent global health problem that can lead to suicide. MDD development is suggested to result from numerous risk factors, including genetic factors. A precise tool for MDD diagnosis is currently not available. Recently, inflammatory processes have been identified as being strongly involved in MDD development and the reactivation of human herpesvirus type 6 (HHV-6), upregulating cytokines such as TNF-α, which are associated with MDD. Therefore, this study aimed to determine the association of HHV-6 with genetic factors, especially TNF-α mutation, in MDD patients and their relatives compared to healthy controls. The Patient Health Questionnaire (PHQ-9) was used to evaluate MDD status, and 471 oral buccal samples were investigated for HHV-6 infection and viral copy number by qPCR. TNF-α (-308G/A) gene mutation and the cytokines TNF-α, IL-6, and IL-10 were analyzed by high-resolution melting (HRM) analysis and enzyme-linked immunosorbent assay (ELISA). Whole-exome sequencing of buccal samples was performed to analyze for genetic factors. The results showed significantly higher HHV-6 positivities and viral loads in MDD patients (15/59 (25.67%) and 14,473 ± 16,948 copies/µL DNA) and their relatives (blood relatives 17/36 (47.22%) and 8146 ± 5656 copies/µL DNA); non-blood relatives 7/16 (43.75%) and 20,721 ± 12,458 copies/µL DNA) compared to the healthy population (51/360 (14.17%) and 6303 ± 5791 copies/µL DNA). The TNF-α (-308G/A) mutation showed no significant difference. Surprisingly, 12/26 (46.15%) participants with the TNF-α (-308G/A) mutation showed HHV-6 positivities at higher rates than those with wild-type TNF-α (-308G) (70/267 (26.22%)). HHV-6-positive participants with TNF-α (-308G/A) showed higher levels of TNF-α, IL-6, and IL-10 than those of negative control. Exome analysis revealed that common mutations in immune genes were associated with depression. Therefore, this study unveiled the novel association of inflammatory gene TNF-α (-308G/A) mutations with HHV-6 reactivation, which could represent a combined risk factor for MDD. This result could induce further research on MDD development and clinical applications.

Detection of human herpesvirus 6 in pediatric CSF samples: causing disease or incidental distraction?

Interpretation of human herpesvirus type 6 (HHV6) detection in the cerebrospinal fluid (CSF) of children can be complex; the virus can cause acute infection, reactivation, or can be inherited chromosomally integrated (iciHHV6). Our objectives were to determine the prevalence of HHV6 including iciHHV6 in CSF and compare the clinical and laboratory characteristics with and without iciHHV6 in our patient population. Overall, the prevalence of HHV6 and iciHHV6 was 2.4% and 0.85%, respectively. Children with iciHHV6 were significantly younger and less likely to present with fever. Septic infants (≤60 days) accounted for 65.2% (15/23) of the iciHHV6 patients. Patients with iciHHV6 had higher viral loads in CSF and whole blood. Twenty-one (91.3%) patients with iciHHV6 and 12 (33.3%) without ici-HHV6 were determined to have an incidental detection of HHV6 not associated with presenting symptoms. Molecular detection of HHV6 in CSF is not always associated with HHV6 infection and may represent iciHHV6 particularly in infants evaluated for sepsis.

VEGETATIVE REACTIVITY OF CHILDREN WITH STREPTOCOCCAL TONSILITIS ON THE BACKGROUND OF HERPES VIRAL INFECTION

Streptococcal infection in children, its complications and adverse long-term consequences remain an urgent problem in pediatrics. Scientists continue to search for factors that shape the course of the disease. One of them is the timely and adequate response of the autonomic nervous system, which provides both short-term and long-term strategic adaptation of the organism. Violations of this adaptation can lead to the presence of comorbid conditions, which are increasingly common. The share of children is growing. infected with the herpes virus group, including human herpes virus type 6 (HHV-6).
 
 The aim of the work was to study the state of vegetative reactivity (VR) of children with streptococcal tonsillitis on the background of HHV-6 infection. In 68 children aged 4 - 15 years with tonsillitis of streptococcal etiology of moderate severity, vegetative reactivity was determined by cardiointervalography (CIG) followed by analysis of heart rate variability (CP) depending on the presence or absence of concomitant HHV-6 type of infection. The studies were performed in the acute period of the disease and in the period of early convalescence. The control group consisted of 20 healthy children, similar in age and sex. Static processing of the obtained results was performed using Excel and Statistica 6.0 using parametric and non-parametric research methods.
 
 Results.
 In the acute period of streptococcal tonsillitis in children of both groups there was a decrease in the humoral component in the regulation of the system and the level of activity of the parasympathetic ANS, as evidenced by a decrease in Mo and ΔX, independent of background, p> 0.05. There was an activation of the influence of the sympathetic link of the VNS, increased the degree of centralization of heart rate control in all patients, and this was confirmed by an increase in AMO and IN. Prior to the convalescence period, CIG parameters were restored only in patients without concomitant VGL-6 infection, and the interrelationships of the sympathetic and parasympathetic links of the VNS were restructured with increasing role of the latter. In patients with concomitant VGL-6 infection, the values ​​of ΔX and IN differed significantly from the control group, p˂0.05. Thus, in children with streptococcal tonsillitis on the background of HHV-6 infection, there was a decrease in the level of functioning of the sympathetic VNS, but complete recovery did not occur, indicating instability of adaptation processes, depletion of the parasympathetic VNS, which hides the possibility of failure of adaptation, recurrence of the disease and / or chronicity, the development of secondary disorders of the cardiovascular system.
 Conclusions.
 The acute period of streptococcal tonsillitis is accompanied by stress of the sympathetic VNS, the severity of which does not depend on the presence of concomitant herpes virus infection. In the period of convalescence of streptococcal tonsillitis in the presence of children with HHV-6 infection there is no complete recovery of autonomic reactivity, among which the most informative are ΔX and IN.

Expression analysis of apoptotic and survival genes in blood leukocytes of children with various forms of HHV-6 infection

Despite that human herpes virus type 6 (HHV-6) is extremely spread worldwide, molecular mechanisms of behind HHV-6 infection pathogenesis remain largely unexplored. No molecular markers were found linked to unfavorable course of HHV-6 infection which could allow to ease up selecting proper therapy and preventing development of complications. The aim of the study was to analyze expression of apoptosis and survival-related genes in blood leukocytes from 7–17-year-old children upon various forms of HHV-6 infection. The analysis was carried out by using DNA microarrays developed by us allowing to assess changes in expression level both of individual mRNAs and total gene set (-Σ). It was shown that during the acute phase of HHV-6 infection mRNA level was shifted toward pro-apoptotic factors. In the convalescence phase, most altered mRNA levels returned to normal. We have identified a set of mRNAs and genes whose expression level was significantly changed in acute disease phase. According to available data, these factors play an important role in regulation of studied signaling pathways. In order to search for HHV-6-associated factors, which markedly affect disease pattern of severe herpesvirus mixed infection, we analyzed significant changes of mRNA and genes expression levels in patients with severe HHV-6+EBV+CMV mixed infection and EBV+CMV mixed infection of moderate severity compared with healthy donors. The levels of 5 mRNAs (FAF1-NM_007051, DAPK2-NM_014326, CASP8AP2-NM_001137667, CASP8-NM_033356, BTK-NM_001287345) and 3 genes (FAS-Σ, Puma/BBC3-Σ, ITCH-Σ) were significantly increased in severe mixed infection comorbid with HHV-6 (EBV+CMV+HHV-6) but without HHV-6 (EBV+CMV) compared with healthy donors. Most of detected factors belong to Fas-mediated apoptosis pathway, and may be considered as candidate prognostic development factors of severe herpes virus infection involving HHV-6. This study profoundly extends existing understanding on molecular pathogenesis of HHV-6 infection involving apoptosis and pro-survival signaling pathways. Marked changes of mRNA and gene levels most likely contributed to the pathogenesis of HHV-6 as well as severe HHV-6+EBV+CMV mixed infection.

Detection of Human Herpes Virus type-6 in Patients Undergoing Hemodialysis

Aim: To investigate the epidemiology of human herpes virus type-6 (HHV-6) among hemodialysis (HD) patients. Materials & methods: DNA was extracted from plasma samples of 149 patients undergoing HD with no history of organ transplantation from 2011 to 2013. Presence of HHV-6 was investigated by using real-time PCR. Results: Diabetes (36.2%) and hypertension (28.8%) were two major factors for HD. The HHV-6 DNA was identified in eight patients (5.37%). Conclusion: This study is one of the few reports of HHV-6 infection among HD patients. In HD patient population, it is critical to improve standards of infection control in dialysis and expand treatment coverage. Furthermore, studies on clinical implications of HHV-6 infection in HD patients are crucial.

THE RESULTS OF LONG-TERM STUDY OF HERPESVIRUS INFECTION AT THE DEPARTMENT OF INFECTIOUS DISEASES IN CHILDREN OF RUSSIAN NATIONAL RESEARCH MEDICAL UNIVERSITY

As a result of many years of research, the role of Herpesviridae IV, V and VI types in the structure of various pathologies in children (with infectious mononucleosis (MI), CNS damage, long-term subfebrile syndrome, vasculitis syndrome, hepatitis, etc.) has been proven. MI is a polyethological disease associated with the Epstein-Barr virus (EBV), cytomegalovirus (CMV) and human herpesvirus type 6 (HHV6), occurring in mono(58%) and mixed infections in various combinations of herpesviruses (42%). Clinical manifestations of MI are typical and do not depend on etiology. With CMV and HHV6 IM, the response to heterophilic antibodies is always negative. Markers of herpesvirus infections were detected in 87% of children observed with neurological pathology. Children with diagnoses such as convulsive syndrome, epilepsy, neuropathy need a comprehensive examination (ELISA, PCR, Indirect immunofluorescence reaction) to identify markers of active replication of herpes viruses, with an emphasis on the detection of HHV6. In 44% of cases, the role of active herpesvirus infection in the etiology of prolonged subfebrile fever in children was proven, with mixed forms (78%) prevailing over monoinfection (22%). To identify the active forms of herpesvirus infection, it is important to detect the markers of viral replication. For EBV, this is the DNA of the virus in the blood, a smear from the tonsils and saliva, antigens of the complete assembly of EBV in blood lymphocytes, antibodies to the capsid antigen (VCA) of IgM and IgG classes, and IgG to the early (EA) antigen. With CMV infection, complete virus assembly antigens (pp65 and pp72) in blood lymphocytes and/or DNA of the virus in the blood, virus DNA in saliva and urine, antibodies to the IgM class virus and high IgG class titer in the blood. With HHV6 infection, the DNA of the virus in the blood, a smear from tonsils and saliva, complete antigens of HHV6 in blood lymphocytes, specific IgM and/or IgG antibodies are 2—4 times higher than the diagnostic values.

Herpesvirus infections in hematopoietic stem cell transplant recipients seropositive for human cytomegalovirus before transplantation.

Viral infections are a major cause of morbidity and mortality after hematopoietic stem cell transplantation (HSCT). The effect of herpesvirus infections in human cytomegalovirus (HCMV)-seropositive (IgG-positive/IgM-negative) HSCT recipients remains poorly understood. The risk factors associated with Epstein-Barr virus (EBV), HCMV, and human herpes virus type 6 (HHV-6) infections after HSCT, both alone and in combination, were investigated in this study. Peripheral blood specimens were collected from 44 HSCT recipients and examined for viral DNA using quantitative fluorescence PCR assays. Risk factors for EBV, HCMV, and HHV-6 infections were analyzed by binary logistic regression, and relationships between these viruses were analyzed using the Chi-square test. EBV, HCMV, and HHV-6 were detected in 50%, 45.45%, and 25% of HCMV-seropositive (IgG-positive/IgM-negative) HSCT recipients, respectively. Male sex (p=0.007) and conditioning regimens including anti-thymocyte globulin (ATG) (p=0.034) were strongly associated with an increased risk of EBV infection. Graft-versus-host disease (GVHD) prophylaxis with corticosteroids was a risk factor for both EBV (p=0.013) and HCMV (p=0.040) infections, while EBV infection (p=0.029) was found to be an independent risk factor for HHV-6 infection. Pre-existing HHV-6 infection was associated with lower rates of HCMV infection (p=0.002); similarly, pre-existing HCMV infection was protective against HHV-6 infection (p=0.036). HCMV-seropositive (IgG-positive/IgM-negative) HSCT recipients exhibited a high rate of herpesvirus infections, particularly EBV. ATG and male sex were strongly associated with an increased risk of EBV infection. GVHD prophylaxis with prednisone was found to affect both EBV and HCMV infections. Prior infection with EBV was shown to promote HHV-6 infection. Taken together, these data highlight the need for active monitoring of herpesvirus infections in patients undergoing HSCT.

Acute Alithiasic Cholecystitis and Human Herpes Virus Type-6 Infection: First Case.

A three-year-old male child presented with erythematous maculopapular nonpruritic generalized rash, poor feeding, vomiting, and cramping generalized abdominal pain. He was previously healthy and there was no family history of immunologic or other diseases. On examination he was afebrile, hemodynamically stable, with painful palpation of the right upper quadrant and positive Murphy's sign. Laboratory tests revealed elevated inflammatory markers, elevated aminotransferase activity, and features of cholestasis. Abdominal ultrasound showed gallbladder wall thickening of 8 mm with a positive sonographic Murphy's sign, without gallstones or pericholecystic fluid. Acute Alithiasic Cholecystitis (AAC) was diagnosed. Tests for underlying infectious causes were negative except positive blood specimen for Human Herpes Virus Type-6 (HHV-6) by polymerase chain reaction. With supportive therapy the child became progressively less symptomatic with gradual improvement. The child was discharged on the sixth day, asymptomatic and with improved analytic values. Two months later he had IgM negative and IgG positive antibodies (1/160) for HHV-6, which confirmed the diagnosis of previous infection. In a six-month follow-up period he remains asymptomatic. To the best of our knowledge, this represents the first case of AAC associated with HHV-6 infection.

Human Herpes Virus 6 Infection in 54 Patients after Allogeneic Hematopoietic Stem Cell Transplantation: Clinical Manifestations and Outcome

▪BACKGROUND: Human herpesvirus type 6 (HHV-6) is increasingly recognized as an opportunistic and potentially life-threatening pathogen in recipients of allogeneic hematopoietic stem cell transplantation (AlloSCT). HHV-6 is a member of the beta herpesvirus subfamily (genus Roseolovirus). HHV-6 infection is recognized as the cause of a febrile disease and exanthem subitum in early childhood. Approximately 60% of solid organ transplant and 40% of patients after alloSCT experienced HHV-6 reactivation. Reported clinical manifestations of HHV-6 infection in transplanted patients are skin rash, interstitial pneumonia, bone marrow suppression and encephalitis. Moreover, some clinical reports suggest that HHV-6 can facilitate the occurrence of severe clinical complications of alloSCT, increasing transplant-related mortality.METHODS: From January 2009 to February 2013, we retrospectively evaluated 54 consecutive adult patients (median age 50 years) who developed positivity to HHV-6 after alloSCT for high-risk hematological malignancies. Stem cell donors were family haploidentical (37), HLA identical sibling (8), unrelated volunteer (6), cord blood (3). The viral load was determined by quantitative PCR (Nanogen Advanced Diagnostic S.r.L) in cell-free body fluids such as plasma, bronchoalveolar lavage (BAL), cerebrospinal fluid (CSF), bone marrow (BM) aspirates or in gastrointestinal biopsies.RESULTS: Median time from alloSCT to HHV-6 reactivation was 34 days (range: 0-705). Thirty-one patients presented HHV-6 positive in plasma, 9/54 in BM, 33/54 in gut biopsies or BAL, 7/54 in CSF. At the time of viral positivity all pts were receiving acyclovir as viral prophylaxis except five. Twenty-nine patients had acute graft versus host disease (GvHD). Twenty-two out of these twenty-nine patients experienced a grade III-IV acute GvHD, requiring high dose steroids in twenty-six cases. A concomitant CMV positivity was detected in 15/54 patients. The median absolute count of CD3+ lymphocytes was 207 cells/mcl. In 52/54 cases we reported HHV-6 clinical manifestations: fever (43), skin rash (22), hepatitis (19), diarrhoea (24), encephalitis (10), BM suppression (18), delayed engraftment (11). HHV-6 positivity led to antiviral pharmacological treatment in 37/54 cases, using as first choice therapy foscarnet. Amongst the total fifty-four patients with documented HHV-6 positivity thirty-one solved the clinical event. However the mortality rate was relatively high in this population (overall survival (OS) ±SE at 1 year after HHV-6 reactivation was 38% ± 7%), mainly related to severe infections or GvHD.A better OS is significantly associated with CD3+ cells ≥200/mcl at the time of HHV-6 reactivation (fig 1) (OS at 1 year 63% compared to 11% for patients with CD3 <200/mcl; HR: 0.27, 95% CI 0.12-0.54, p=0.0002). The overall survival of these patients was also positively affected by the absence of acute GvHD grade III-IV at time of viral reactivation (HR: 0.03, 95% CI 1.08-4.03, p=0.03) and by the complete disease remission at time of HSCT (HR:0.26, 95% CI 0.07-0.89, p=0.03). In this analysis the overall survival was not significantly influenced by steroids administration (HR: 1.36, 95% CI 0.71-2.60, p=0.36), time after alloSCT (HR: 1.30, 95% CI 0.51-3.33, p=0.59), type of antiviral prophylaxis (HR: 1.02, 95% CI 0.45-2.33, p=0.96), plasma viral load (HR:1.18, 95% CI 0.51-2.76, p=0.69) and organ involvement (HR:1.14, 95% CI 0.59-2.20, p=0.70).CONCLUSIONS: This retrospective study confirms a correlation of HHV-6 with high morbidity and mortality rates after alloSCT, thus suggesting a regular HHV-6 monitoring in alloSCT recipients. The regular monitoring of HHV-6 DNA, using a real-time PCR assay, may be useful for identifying active HHV-6 infection and for the introduction of a pre-emptive treatment, possibly reducing the incidence of the most severe clinical complications. Despite HHV-6 detection typically occurred early after alloSCT, a better immune reconstitution has the potential to improve clinical outcome. [Display omitted] DisclosuresBonini:MolMed S.p.A.: Consultancy.

The Role of Human Herpesvirus Type-6 (HHV-6) in Convulsions Seen in Children at Korle-Bu Teaching Hospital, Accra

Background: Since the isolation of HHV-6 in 1986, extensive investigation has revealed it to be ubiquitous and responsible for the majority of cases of a common febrile rash illness of infants known as roseola. Other clinical associations including seizure disorders, encephalitis and meningitis have also been stated in various publications. Objective: The aim of the study is to find out if there is any association between HHV-6 infection and the convulsions prevailing at the Child Health Department of the Korle-Bu Teaching Hospital, Accra-Ghana. Methods and Results: Children admitted into the Department of Child Health with episode of convulsions were recruited after informed consent had been sought from subjects. Cerebrospinal fluid (CSF) and Plasma were obtained from patients. PCR directed at the detection of the large tegument protein (LTP) gene in the SIE strain of the HHV-6 in Plasma and CSF from patients was done. The mean age of study subjects was 37.44 months with 53 (64.6%) being males. There was a significant relationship between the convulsions and fever (P

Human herpesvirus type 6 DNAemia and infection following allogeneic stem cell transplantation with a focus on long-term outcome

Cases of human herpesvirus type 6 (HHV-6) infection and disease were retrospectively analysed in a cohort of 97 allogeneic haematopoietic stem cell transplantation (allo-SCT) patients in Gothenburg, Sweden (1997-2001). Altogether 54 of 97 (56%) patients were tested for HHV-6. HHV-6 DNAemia was detected in 15 of the tested patients at a median of 76 (range 24-387) days after SCT. Nine of these patients were treated against HHV-6 infection and disease for a total of 11 treatment episodes. The morbidity associated with HHV-6 DNAemia following allo-SCT was in most cases moderate. The overall 1-y survival among the patients with HHV-6 DNAemia was 11/15 (73%) and the 5-y survival was 10/15 (67%), which was not significantly different from the whole cohort.

Chromosomal integration of the HHV‐6 genome in a patient with nodular sclerosis Hodgkin lymphoma

Chromosomal integration of the <scp>HHV</scp>‐6 genome in a patient with nodular sclerosis Hodgkin lymphoma

Human Herpes Virus Type 6 Can Cause Skin Lesions at the BCG Inoculation Site Similar to Kawasaki Disease

Kawasaki Disease (KD) is acute, febrile, multisystem vasculitis of early childhood, the detailed mechanism of which is still unclear. Skin symptoms occur in KD, such as edema of the hands and feet with subsequent desquamation and redness at the inoculation site of bacillus Calmette-Guerin (BCG). The change at the BCG inoculation site has been considered as a specific feature of KD, although its mechanism is not fully understood. We present an 11-month-old boy who developed fever with redness of the BCG site due to infection with human herpes virus type 6 (HHV6). At the age of 3 months, the patient received BCG. His fever remitted 7 days after the onset of skin redness, with sequential desquamation at the BCG site and extremities, which is not a common feature of HHV6 infection that typically lasts for 3 days. The final diagnosis was exanthema subitum. Characteristically, the HHV6 infection in our patient appeared to be associated with the invigoration of the T cell system, as represented by the elevated serum levels of soluble interleukin-2 receptor (3,490 U/ml vs. normal range 145-519 U/ml). This patient clearly showed redness and crusting at the BCG inoculation site, suggesting that HHV6 infection might cause skin changes similar to those of KD via an unknown mechanism. In addition, we suggest that the activation of the T cell system may account for the skin lesions in KD, characterized by redness and subsequent crusting of the BCG inoculation site and desquamation of the extremities.

Life-threatening human herpes virus-6 infection in early childhood: Presenting symptom of a primary immunodeficiency?

To report two previously healthy children with a life-threatening course of human herpes virus type 6 (HHV-6) infection and prolonged pediatric intensive care treatment. Case reports. A 16 bed pediatric intensive care unit at a tertiary care children's hospital. Two children with life-threatening HHV-6 disease. Both children were mechanically ventilated because of respiratory failure. A detailed viral and immunologic workup was performed and treatment with antiviral medication started. Polymerase chain reaction assays of plasma, cerebrospinal fluid, bronchoalveolar lavage, and lung biopsies yielded HHV-6 in both patients. Immunophenotyping and lymphocyte stimulation tests with both mitogens and antigens indicated an immunodeficiency in both patients. HHV-6 infection should be considered in infants and young children with respiratory failure or meningo-encephalitis without clear causative agent or failure to respond to empirical treatment. A thorough immunologic workup and early start with antiviral therapy in any patient with a life-threatening course of HHV-6 infection is mandatory, because a severe HHV-6 infection can be the first indication of a primary immunodeficiency.

Role of Human Herpesvirus 6 Infection in Young Brazilian Children With Rash Illnesses

Human herpesvirus type 6 (HHV-6) has been shown to infect almost all children by 4 years of age. Primary infection causes an undifferentiated febrile illness, with approximately 30% of children exhibiting the classic clinical manifestations of exanthem subitum. Even with typical clinical presentation, exanthem subitum is frequently misdiagnosed as measles or rubella. Our aim was to describe the frequency and clinical manifestations of HHV-6 infection in children less than 4 years of age enrolled in a study designed to define the etiology of rash diseases. The study was conducted between January 1998 and December 2006 at a general hospital and a large primary health care unit from Niterói, Rio de Janeiro, Brazil. Sera from 223 children, in whom measles, rubella, dengue fever, and parvovirus B19 infections were excluded, were studied for anti-HHV-6 antibodies using an indirect immunofluorescence test. Demographic and clinical data of those patients were described. Ninety-seven (43.5%) of the children had evidence of primary HHV-6 infection. The age of onset peaked at 6-11 months and 75% of the HHV-6 infection occurred in children between 6 and 17 months. Only 21% of the HHV-6 cases had a typical roseola-like illness and 73% and 46%, respectively, fulfilled the clinical criteria of measles and rubella suspected case. Our study confirms the importance of HHV-6 infection in young children and highlights the difficulties of diagnosing a rash illness on clinical grounds alone.

Optimization of the Sybr Green real time PCR for the detection of Human Herpes Virus type 6 (HHV-6)

HHV-6 is the etiological agent of Exanthem subitum which is considered the sixth most frequent disease in infancy. In immuno-compromised hosts, reactivation of latent HHV-6 infection may cause severe acute disease. We developed a Sybr Green Real Time PCR for HHV-6 and compared the results with nested conventional PCR. A 214 pb PCR derived fragment was cloned using pGEM-T easy from Promega system. Subsequently, serial dilutions were made in a pool of negative leucocytes from 10-6 ng/microL (equivalent to 2465.8 molecules/microL) to 10-9 (equivalent to 2.46 molecules/microL). Dilutions of the plasmid were amplified by Sybr Green Real Time PCR, using primers HHV3 (5' TTG TGC GGG TCC GTT CCC ATC ATA 3)'and HHV4 (5' TCG GGA TAG AAA AAC CTA ATC CCT 3') and by conventional nested PCR using primers HHV1 (outer): 5'CAA TGC TTT TCT AGC CGC CTC TTC 3'; HHV2 (outer): 5' ACA TCT ATA ATT TTA GAC GAT CCC 3'; HHV3 (inner) and HHV4 (inner) 3'. The detection threshold was determined by plasmid serial dilutions. Threshold for Sybr Green real time PCR was 24.6 molecules/microL and for the nested PCR was 2.46 molecules/microL. We chose the Real Time PCR for diagnosing and quantifying HHV-6 DNA from samples using the new Sybr Green chemistry due to its sensitivity and lower risk of contamination.

Prevalence and distribution of HSV-1, VZV, and HHV-6 in human cranial nerve nuclei III, IV, VI, VII, and XII.

The etiology of idiopathic cranial nerve palsies often remains unresolved. It has been hypothesised that viral reactivation of herpesviruses in the corresponding nuclei in the brainstem is the cause. We investigated the distribution of herpes simplex virus type 1 (HSV-1) and varicella zoster virus (VZV) in nuclei that are associated with peripheral sensory ganglia [oculomotor (nIII), facial (nVII) nuclei] and in nuclei that are not associated with peripheral sensory ganglia [trochlear (nIV), abducens (nVI), and hypoglossal (nXII) nuclei] of five human brainstems. Samples of the cranial nerve nuclei and adjacent control tissue were taken from histological sections after precise identification of every single nucleus and control tissue. DNA and RNA amplification methods were used to determine the prevalence and distribution of HSV-1 and VZV. The distribution of human herpes virus type 6 (HHV-6) was also determined and served as a control, since HHV-6 infection has never been associated with idiopathic cranial nerve palsies. HSV-1 was distributed at random in all cranial nerve nuclei and control tissue, whereas VZV DNA was not detected in any of the samples examined. Surprisingly, HHV-6 was present in almost all samples where HSV-1 was also present, however, the latency associated transcript (LAT) of HSV-1 was not found in any of the samples positive for HSV-1 DNA. The absence of LAT in the samples positive for HSV-1 and the distribution of HSV-1 and HHV-6 do not support the hypothesis that idiopathic cranial nerve palsies result from viral reactivation in the brainstem nuclei.

Frequent seizures with elevated interleukin-6 at the eruptive stage of exanthema subitum

A 15-month-old girl developed frequent seizures at the eruptive stage of exanthema subitum. The eruption persisted for 2 weeks. Serum immunoglobulin G antibody to human herpes virus type 6 (HHV-6) increased markedly. Interleukin-6 was elevated whereas HHV-6 deoxyribonucleic acid was not detected in cerebrospinal fluid. These findings suggest that immune-mediated reactions after HHV-6 infection rather than direct action of active HHV-6 are responsible for frequent seizures in this case.