Yoshiki Kawamura

Different characteristics of human herpesvirus 6 encephalitis between primary infection and viral reactivation

BACKGROUND Pathogenesis of human herpesvirus 6 (HHV-6) encephalitis, in particular difference between HHV-6 encephalitis at the time of primary infection and reactivation remains unclear. OBJECTIVES To elucidate the mechanism of HHV-6 encephalitis at the time of primary infection and reactivation. STUDY DESIGN Twenty-two HHV-6 encephalitis patients at the time of primary infection, 6 febrile convulsion (FC) patients caused by HHV-6 infection, and 14 FC patients without HHV-6 infection (non HHV-6 FC) were enrolled. Additionally, 7 stem cell transplant recipients with HHV-6 encephalitis and eight adult controls were also enrolled in this study. Cerebrospinal fluid (CSF) HHV-6 DNA copy numbers and biomarkers levels were compared. RESULTS Low copy number of CSF HHV-6 DNA was detected in 7 of the 22 patients with HHV-6 encephalitis in primary infection, whereas all seven CSF samples collected from post-transplant HHV-6 encephalitis patients contained high viral DNA copy numbers (P<0.001). CSF concentrations of IL-6 (P=0.032), IL-8 (P=0.014), MMP-9 (P=0.004), and TIMP-1 (P=0.002) were significantly higher in patients with HHV-6 encephalitis in primary infection than non-HHV-6 FC. CSF IL-6 (P=0.008), IL-8 (P=0.015), and IL-10 (P=0.019) concentrations were significantly higher in patients with post-transplant HHV-6 encephalitis than adult controls. CONCLUSION The present study suggests that the characteristics of HHV-6 encephalitis are different between HHV-6 encephalitis at the time of primary infection and reactivation in transplant recipients.

Cytokine and chemokine responses in the blood and cerebrospinal fluid of patients with human herpesvirus 6B-associated acute encephalopathy with biphasic seizures and late reduced diffusion

Acute encephalopathy with biphasic seizures and late reduced diffusion has become increasingly common among various types of human herpesvirus 6B (HHV‐6B) encephalitis at the time of primary viral infection. The aim of the present study is to explore the pathophysiology of HHV‐6B‐associated acute encephalopathy with biphasic seizures and late reduced diffusion. Five cytokines and five chemokines were measured in serum and cerebrospinal fluid (CSF) obtained from 12 HHV‐6B‐associated acute encephalopathy with biphasic seizures and late reduced diffusion patients and 19 control exanthem subitum (without complications) patients. Serum interleukin (IL)‐10 (P = 0.007) and IL‐8 (P = 0.025) were significantly higher in the patients with the disease than controls. Serum IL‐1β (P = 0.034) and monocyte chemoattractant protein (MCP)‐1 (P = 0.002) were significantly higher in the controls than patients with the disease. In patients with the disease, IL‐10 (P = 0.012), regulated on activation normal T cell expressed and secreted (RANTES; P = 0.001), and monokine induced by interferon γ (MIG; P = 0.001) were significantly higher in serum than CSF, meanwhile IL‐6 (P = 0.034), IL‐8 (P = 0.034), and MCP‐1 (P = 0.001) were significantly higher in CSF than serum. Additionally, serum IL‐10 was significantly higher in the disease patients with sequelae than those without sequelae (P = 0.016). Several cytokines and chemokines may be associated with the pathogenesis of acute encephalopathy with biphasic seizures and late reduced diffusion. Moreover, the regulation of cytokine networks appears to be different between peripheral blood (systemic) and central nervous system. J. Med. Virol. 86:512–518, 2014.

Development of quantitative RT-PCR assays for detection of three classes of HHV-6B gene transcripts†‡

The monitoring of active human herpesvirus 6 (HHV‐6) B infection is important for distinguishing between the reactivation and latent state of the virus. The aim of this present study is to develop a quantitative reverse transcription polymerase chain reaction (RT‐PCR) assay for diagnosis of active viral infection. Primers and probes for in house quantitative RT‐PCR methods were designed to detect the three kinetic classes of HHV‐6B mRNAs (U90, U12, U100). Stored PBMCs samples collected from 10 patients with exanthem subitum (primary HHV‐6B infection) and 15 hematopoietic stem cell transplant recipients with HHV‐6B reactivation were used to evaluate reliability for testing clinical samples. Excellent linearity was obtained with high correlation efficiency between the diluted RNA (1–100 ng/reaction) and Ct value of each gene transcript. The U90 and U12 gene transcripts were detected in all of the peripheral blood mononuclear cells (PBMCs) samples collected in acute period of primary HHV‐6B infection. Only one convalescent PBMCs sample was positive for the U90 gene transcript. Additionally, the reliability of HHV‐6B quantitative RT‐PCRs for diagnosis of viral reactivation in hematopoietic transplant recipients was evaluated. Relative to virus culture, U90 quantitative RT‐PCR demonstrated the highest assay sensitivity, specificity, positive predictive value, and negative predictive value. Thus, this method could be a rapid and lower cost alternative to virus culture, which is difficult to perform generally, for identifying active HHV‐6B infection. J. Med. Virol. 84:1388–1395, 2012.

Serum biomarker kinetics with three different courses of HHV-6B encephalitis

Human herpesvirus-6B (HHV-6B) encephalitis can clinically manifest as hemorrhagic shock and encephalopathy syndrome (HSES), acute encephalopathy with biphasic seizures and late reduced diffusion (AESD), and acute necrotizing encephalopathy (ANE). To compare the underlying pathophysiology, we measured several biomarkers of interest in patients with these three different courses. Based on their clinical course and neuroimaging analysis, Cases 1, 2 and 3 were diagnosed as HSES, AESD, and ANE, respectively. HHV-6B was isolated from peripheral blood obtained during the acute phase in all three patients, and was detected in the cerebrospinal fluid of Cases 2 and 3. In Case 1, a marked increase in levels of several serum cytokines (IL-1β, IL-6, and IL-10) and chemokines (IL-8, MIG, MCP-1, and IP-10) was observed at disease onset. Subsequently, serum cytokine levels gradually became undetectable and chemokine levels stabilized by day 11 of illness. In Case 2, only two cytokines (IL-6 and IL-10) were slightly elevated at disease onset. In Case 3, the kinetics appeared to follow an up-and-down pattern. Additionally, in all three patients, TIMP-1 concentrations remained high during the observation period, and MMP-9 decreased quickly a few days after disease onset, and then returned to normal level.

Pathogenic Role of Human Herpesvirus 6B Infection in Mesial Temporal Lobe Epilepsy

BACKGROUND Human herpesvirus 6B (HHV-6B) is the causative agent for exanthem subitum. HHV-6B was associated with mesial temporal sclerosis (MTS), leading to mesial temporal lobe epilepsy (MTLE). In this study, we sought to elucidate the pathogenic role of HHV-6B in patients with MTLE. METHODS Seventy-five intractable MTLE patients, including 52 MTS patients and 23 non-MTS patients, were enrolled in this study. Resected hippocampus, amygdala, and mixed samples of amygdala and uncus samples were examined by real-time polymerase chain reaction (PCR) and reverse-transcriptase PCR to detect viral DNA and messenger RNA (mRNA), respectively. Host gene expressions, including neural markers, were measured using the TaqMan Gene Expression Assay. RESULTS Detection of HHV-6 DNA was higher in MTS patients than non-MTS patients (median/interquartile range: 19.1/0-89.2 vs 0.0/0.0-0.0 copies/µg DNA; P = .004). HHV-6B viral DNA was determined in 12/27 HHV-6 DNA-positive samples, and no HHV-6B mRNA were detected in all samples. In MTS patients, expression of monocyte chemotactic protein-1 (P = .029) and glial fibrillary acidic protein (P = .043) were significantly higher in the amygdala samples with HHV-6 DNA than those without viral DNA. CONCLUSIONS This study suggests that HHV-6B may play an important role in the pathogenesis of MTS via modification of host gene expression.

Demonstration of type II latency in T lymphocytes of Epstein–Barr Virus‐associated hemophagocytic lymphohistiocytosis

Epstein–Barr virus (EBV) is the most common infectious cause of non‐genetic hemophagocytic lymphohistiocytosis (HLH). To investigate EBV‐infected lymphocytes and immune dysfunction in EBV‐associated HLH, blood samples from a 6‐year‐old boy were longitudinally analyzed using molecular techniques. EBV‐positive lymphocytes were detected as CD5+, CD8+, and/or HLA DR+ lymphocytes on Day 25 of the disease, mostly disappearing thereafter. CD8+ cells specific for lytic antigen BRLF1 were detected, but cells specific for latent antigens EBNA3 and LMP2 were not. EBV genes EBNA1, LMP1, LMP2, EBER1, BARTs were detected, suggesting a latency type II gene expression pattern in this case. Pediatr Blood Cancer 2013;60:326–328.

Nationwide survey of rotavirus-associated encephalopathy and sudden unexpected death in Japan

BACKGROUND Rotavirus can cause severe complications such as encephalopathy/encephalitis and sudden unexpected death. The incidence of rotavirus-associated encephalopathy/encephalitis or sudden unexpected death remains unknown. To clarify the clinical features of rotavirus-associated encephalitis/encephalopathy and sudden unexpected death, we conducted a nationwide survey in Japan. METHOD A two-part questionnaire was designed to determine the number of the cases and the clinical features of severe cases of rotavirus infection, including encephalitis/encephalopathy and sudden unexpected death, between 2009 and 2011. RESULT Of the 1365 questionnaires sent to hospitals, 963 (70.5%) were returned and eligible for analysis. We determined 58 cases of rotavirus-associated encephalitis/encephalopathy and 7 cases of sudden unexpected death. These patients were diagnosed with rotavirus infection by immunochromatography. Although 36/58 (62.1%) encephalitis/encephalopathy patients had no sequelae, 15/58 (25.9%) patients had neurological sequelae, and 7/58 (12.1%) patients had fatal outcomes. Pleocytosis was observed in 9/40 (22.5%) patients and cerebrospinal fluid protein levels were elevated in only 4/40 (10%) patients. Elevated lactate dehydrogenase (LDH) (>500 IU/L) or acidemia (pH<7.15) were related to a poor prognosis. CONCLUSION We estimate that annual cases of rotavirus-associated encephalitis/encephalopathy and sudden unexpected death were 44.0 and 4.9 cases in Japan, respectively. Elevated LDH (>500 IU/L) or acidemia (pH<7.15) were related to a poor prognosis of the encephalitis/encephalopathy.

Virological analysis of inherited chromosomally integrated human herpesvirus-6 in three hematopoietic stem cell transplant patients.

We analyzed 3 hematopoietic stem cell transplant (HSCT) recipients with inherited chromosomally integrated human herpesvirus‐6 (inherited CIHHV‐6). Cases 1 (inherited CIHHV‐6A) and 2 (inherited CIHHV‐6B) were inherited CIHHV‐6 recipients. Case 3 received bone marrow from a donor with inherited CIHHV‐6B. Following HSCT, HHV‐6B was isolated from Case 1. HHV‐6A and ‐6B messenger RNAs were detected in Cases 1 and 3.

Cytokine and chemokine responses in pediatric patients with severe pneumonia associated with pandemic A/H1N1/2009 influenza virus.

Severe pneumonia and leukocytosis are characteristic, frequently observed, clinical findings in pediatric patients with pandemic A/H1N1/2009 influenza virus infection. The aim of this study was to elucidate the role of cytokines and chemokines in complicating pneumonia and leukocytosis in patients with pandemic A/H1N1/2009 influenza virus infection. Forty‐seven patients with pandemic A/H1N1/2009 influenza virus infection were enrolled in this study. Expression of interleukin (IL)‐10 (P = 0.027) and IL‐5 (P = 0.014) was significantly greater in patients with pneumonia than in those without pneumonia. Additionally, serum concentrations of interferon‐γ (P = 0.009), tumor necrosis factor‐α (P = 0.01), IL‐4 (P = 0.024), and IL‐2 (P = 0.012) were significantly lower in pneumonia patients with neutrophilic leukocytosis than in those without neutrophilic leukocytosis. Of the five serum chemokine concentrations assessed, only IL‐8 was significantly lower in pneumonia patients with neutrophilic leukocytosis than in those without leukocytosis (P = 0.001). These cytokines and chemokines may play important roles in the pathogenesis of childhood pneumonia associated with A/H1N1/2009 influenza virus infection.

Posterior reversible encephalopathy syndrome in a child with post-transplant HHV-6B encephalitis.

Posterior reversible encephalopathy syndrome in a child with post-transplant HHV-6B encephalitis