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Tetsushi Yoshikawa

Publications and source records attributed to Tetsushi Yoshikawa.

At least 19 recordsLinked to original sources
PubMed2026

A Patient-Derived iPSC-Based Model Reveals Neural Lineage-Specific Transcription of Endogenous HHV-6B.

BACKGROUND: Endogenous human herpesvirus 6 (eHHV-6), in which the entire viral genome is integrated into human chromosomes, is present in approximately 1% of the population and has been associated with various clinical conditions, including neurological disorders. However, its biological significance remains unclear due to the lack of appropriate experimental models. METHODS: We established a patient-derived induced pluripotent stem cell (iPSC)-based tissue culture model using lymphoblastoid cell lines from individuals with eHHV-6B. iPSCs retaining the integrated viral genome were generated and subsequently differentiated into neural stem cells (NSCs). Viral gene expression was evaluated by RT-qPCR under basal conditions and following chemical stimulation. RESULTS: The integrated HHV-6B genome was transcriptionally silent in iPSCs but exhibited spontaneous low-level expression of the immediate-early gene U90 and the late gene U100 in NSCs. Chemical stimulation further enhanced U90 expression, whereas induction of U100 did not reach statistical significance. These findings indicate preferential activation of early viral transcriptional programs in neural lineage cells. CONCLUSIONS: Neural lineage cells provide a permissive environment for expression of eHHV-6B transcripts. This patient-derived iPSC-based model provides a platform for investigating the biological significance of neural lineage-specific eHHV-6 transcripts and may facilitate interpretation of HHV-6 DNA detection in patients with eHHV-6 by enabling studies of cell type-dependent viral transcription.

endogenous HHV-6↗
PubMed2026

Comprehensive Viral Detection and Profiling of Plasma Cell-Free RNA in Patients With Suspected Hemophagocytic Lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is a severe, rapidly progressive disease. While viral infection is considered a common etiology of pediatric HLH, specific causative viruses other than the Epstein-Barr virus (EBV) have been rarely identified. This study utilized metagenomic next-generation sequencing (NGS) to identify potential causative pathogens in plasma samples from 17 pediatric patients with suspected HLH. Additionally, one case each of confirmed EBV- and cytomegalovirus (CMV)-associated HLH was analyzed for methodological validation. Plasma cell-free RNA (cfRNA) profiling was performed using NGS data to assess the host transcriptome response. Significant viral reads of human herpesvirus-6B, human herpesvirus-7, and Hubei reo-like virus (HRLV) 14 were detected using metagenomic NGS in one patient each. Plasma cfRNA profiles from five patients with viral infection (including EBV and CMV) were compared to those of 14 patients without viral infection. By comparing the two patient groups, 1053 differentially expressed genes were identified. The gene ontology (GO) term of "adaptive immune response" (GO: 0002250) was significantly enriched among upregulated genes in the virus-positive group. Furthermore, an isolated cluster consisting specifically of mitochondrial RNAs, was identified in the upregulated genes of the virus-positive group. Using metagenomic NGS, several candidate viral pathogens were identified in patients with suspected infection-related HLH. The viral genome of HRLV 14, previously undetected in human clinical samples, was identified in one patient. The results from plasma cfRNA profiling suggest that mitochondrial RNAs may reflect the underlying pathogenesis of virus-associated HLH and have potential utility as disease biomarkers.

Humans↗
PubMed2025

Plasma Proteomic Profiles of Pediatric Patients With Human Herpesvirus 6B Encephalitis Following Umbilical Cord Blood Transplantation.

Human herpesvirus 6B (HHV-6B) encephalitis is a rare but severe complication of hematopoietic cell transplantation. This study investigated the pathogenesis of HHV-6B encephalitis by comparing plasma proteomic profiles of four pediatric patients with HHV-6B encephalitis to three with asymptomatic HHV-6B reactivation following umbilical cord blood transplantation (UCBT). Plasma proteomic profiling was conducted using liquid chromatography-mass spectrometry. Overall, 260 proteins were identified and quantified in plasma samples. At the onset of HHV-6B encephalitis and asymptomatic reactivation, 20 and 24 proteins, respectively, were significantly upregulated compared to their respective pre-onset levels. Of these, 11 proteins were uniquely upregulated in HHV-6B encephalitis. S100-A9 and S100-A8 were the most and second-most upregulated proteins in HHV-6B encephalitis, respectively. Elevated plasma S100A8/A9 heterodimer levels were confirmed via enzyme-linked immunosorbent assay in three of the four patients with HHV-6B encephalitis. Pathway analysis identified neutrophil degranulation as the most enriched category among upregulated proteins in HHV-6B encephalitis. Additionally, proteins related to the protein-lipid complex remodeling pathway were more prominently upregulated in HHV-6B encephalitis than in asymptomatic reactivation. Proteomic analysis revealed distinct plasma protein profiles between HHV-6B encephalitis and asymptomatic HHV-6B reactivation in pediatric UCBT recipients. The inflammatory response mediated by S100A8/A9 proteins may play a critical role in the pathogenesis of HHV-6B encephalitis. These findings indicate that proteomic analysis may provide novel insights into the host response to HHV-6B reactivation and the subsequent development of HHV-6B encephalitis.

Humans↗
PubMed2006

Rapid detection of Epstein-Barr virus DNA by loop-mediated isothermal amplification method.

BACKGROUND: The loop-mediated isothermal amplification (LAMP) method is a novel technique for the amplification of specific DNA sequences. OBJECTIVES: To establish the LAMP method for amplifying Epstein-Barr virus (EBV) DNA and to examine its reliability for the detection of EBV DNA in clinical specimens. STUDY DESIGN: Sera from 108 patients, who were initially suspected of primary EBV infection, were tested by the EBV LAMP method, and the results were compared with those of the real-time PCR assay. Serological examination was regarded as the standard diagnostic method. RESULTS: To diagnose primary EBV infection, the sensitivity of LAMP was 86.4% and the specificity was 100%. The sensitivity of the real-time PCR assay was 84.1% and the specificity was 98.4%. Longitudinal analysis showed that the detection rate of EBV DNA in serum by the LAMP method decreased with time in accordance with the decrease of the EBV load. EBV DNA could not be detected in serum 40 days after onset of symptoms. CONCLUSIONS: These results indicate that the sensitivity and specificity of the LAMP method are comparable to those of real-time PCR and that detecting EBV DNA in serum by this method is potentially useful for diagnosing primary EBV infection.

Child, Preschool↗
PubMed2006

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).

Adult↗
PubMed2006

Time course characteristics of human herpesvirus 6 specific cellular immune response and natural killer cell activity in patients with exanthema subitum.

The time-course of cell-mediated immunity in exanthema subitum is not well documented. The lymphoproliferative response to purified human herpesvirus 6 (HHV-6) antigen and to phytohemagglutinin was measured and natural killer (NK) cell activities determined in three consecutive specimens obtained biweekly from 18 young children and infants with exanthema subitum. Virus isolation and PCR detection of virus DNA and determination of neutralization antibody to HHV-6 and -7 were also carried out. The magnitude of the HHV-6 specific lymphoproliferative response varied; however, in most cases the time course kinetics revealed a low response in the acute phase with a subsequent gradual increase. In contrast, NK cell activities were high in the acute phase and declined gradually during convalescence. The lymphoproliferative response to phytohemagglutinin did not show a consistent trend in kinetics of time; however, dynamic changes in activity were observed in patients during the acute and convalescent periods. The results suggest that NK cells play a major role in resolving acute phase infection while specific lymphocyte activity develops later. The cause of the delayed development of HHV-6 specific lymphoproliferative response is unknown. The lymphoproliferative response to phytohemagglutinin ratios implied that HHV-6 infection has some impact on host T-cell immunity during the course of exanthema subitum.

Cell Proliferation↗
PubMed2006

Pneumonia with marked pleural effusion caused by Aspergillus infection.

We present a case of pneumonia with marked pleural effusion caused by Aspergillus infection in a 2-year-old Japanese girl with Down's syndrome. The patient was previously diagnosed with acute myeloid leukemia, developing the pneumonia during induction treatment. Although no pathogens could be isolated from any clinical specimens, 135,000 copies/mL of Aspergillus DNA were detected in the pleural fluid using real time polymerase chain reaction. The copy numbers of DNA decreased rapidly after appropriate antifungal treatment.

Aspergillosis↗
PubMed2006

Drug-induced hypersensitivity syndrome due to mexiletine hydrochloride associated with reactivation of human herpesvirus 7.

It has been suggested that reactivation of human herpesvirus 6 (HHV-6) infection may be involved in the pathogenesis of drug-induced hypersensitivity syndrome. We report a 45-year-old Japanese man who developed a generalized papuloerythematous rash, fever, hepatitis, lymphadenopathy and lymphocytosis with an increased number of atypical lymphocytes. He was diagnosed with DIHS due to mexiletine hydrochloride based on laboratory data, results of a patch test and the clinical course of his complaint, and was treated with systemic steroids. In order to determine whether HHV-6 or -7 was associated with the patient's disease, serological assays and PCR were carried out. Significant increases in antibody titers against HHV-6 and -7 were observed from day 12 to 24. From PCR analysis, none of the peripheral blood mononuclear cells or skin tissue samples contained HHV-6 DNA. All samples, however, were found to contain HHV-7 DNA. Reactivation of HHV-7 could be responsible for drug-induced hypersensitivity syndrome.

Anti-Arrhythmia Agents↗
PubMed2006

Human herpesvirus 6 reactivation in trichloroethylene-exposed workers suffering from generalized skin disorders accompanied by hepatic dysfunction.

Idiosyncratic generalized skin disorders resembling serious drug hypersensitivities have reportedly occurred after occupational exposure to trichloroethylene. However, factors associated with the disorders remain unknown except for trichloroethylene exposure. This study aimed at clarifying whether infectious diseases contributed to the development of rash or hepatitis in patients with trichloroethylene-related generalized skin disorders. Fifty-nine patients consecutively hospitalized between March 2002 and December 2003 and 59 healthy exposed workers selected on an age-matched basis in the patients' factories were enrolled in the study. Information on possible risk factors for rash and hepatitis was collected with structured checklists. Antibody titers were measured for hepatitis A, B and C viruses, Mycoplasma pneumoniae, herpes simplex viruses 1 and 2, Epstein-Barr virus, cytomegalovirus, human herpesvirus 6, measles and rubella virus. Thirty-six cases (59%) showed exfoliative dermatitis, 17 (28%) erythema multiforme, 4 (7%) Stevens-Johnson syndrome, and 4 (7%) toxic epidermal necrolysis. Before the onset of rash, 16 (27%) cases had received medication prescribed for the preceding fever, a main first symptom of the disorders. Marked increases in anti-human herpesvirus 6 IgG titer (> or =256), which indicated viral reactivation, were noted in 14 (25%) patients, while no abnormal increase was detected in the controls (p<0.001). Anti-measles IgM titer was positive in 2 (7%) cases but not in the controls (p=0.49). The involvement of other known risk factors of rash or hepatitis was ruled out. These results suggest that part of trichloroethylene-related generalized cutaneous disorders occurring in China and drug-induced hypersensitivity syndrome overlap in terms of human herpesvirus 6 reactivation.

Adolescent↗
PubMed2005

Development of the loop-mediated isothermal amplification method for rapid detection of cytomegalovirus DNA.

Cytomegalovirus (CMV) loop-mediated isothermal amplification (LAMP) was performed on DNA extracted from CMV (AD-169)-, herpes simplex virus (HSV) 1 (KOS)-, HSV-2 (186)-, varicella-zoster virus (Oka-vaccine)-, human herpesvirus (HHV)-6 A (U1102)-, HHV-6 B (Z29)-, and HHV-7 (RK)-infected cells. Although amplified CMV demonstrated typical ladder patterns, no LAMP product was detected in reactions performed with other viral DNAs. The sensitivity of the CMV LAMP was 500 copies/tube, as determined by either agarose gel electrophoresis or turbidity assay. To determine whether CMV LAMP could be used for quantitative analysis of viral DNA, threshold times, defined as the time (in seconds) to reach the threshold level (0.1), were measured by amplification of serial dilutions of the plasmid DNA. The standard curve exhibited a correlation coefficient of 0.944, a slope of -208.1, and a y-intercept of 3261.4. Following these initial validation experiments, we analyzed 180 samples collected serially from 20 pediatric hematopoietic stem cell transplant recipients. Detection of CMV DNA in whole blood (WB) was tested by CMV LAMP and real-time polymerase chain reaction (PCR). When >500 copies/tube (>5000 copies/200 microl of WB) was defined as positive for CMV infection, the sensitivity, specificity, positive predictive value, and negative predictive values of the CMV LAMP were 80.0, 98.9, 66.7, and 99.4%, respectively.

Child↗
PubMed2005

Analysis of shedding of 3 beta-herpesviruses in saliva from patients with connective tissue diseases.

BACKGROUND: Whether an association exists between infection with beta -herpesviruses and connective tissue diseases remains unclear, as are the mechanisms for the regulation of these infections in the salivary glands. METHODS: Human herpesvirus (HHV)-7 was isolated and viral DNA was quantified by real-time polymerase chain reaction (PCR) in serially collected saliva samples, to determine whether viral load correlated with infectivity. Then, to examine the role played by beta -herpesviruses in connective tissue diseases, cytomegalovirus, HHV-6, and HHV-7 DNA loads were examined by real-time PCR in serially collected saliva samples from 21 patients with connective tissue diseases. RESULTS: Although subjects with frequent HHV-7 shedding were more likely to have a high viral load than were other subjects, high viral loads were detected in saliva samples from a portion of the subjects with low viral shedding rates. No significant difference between the quantity of HHV-7 DNA in saliva samples from which active virus was isolated and that amplified from samples without detectable virus was observed. Patients with adult-onset Still disease consistently had high HHV-7 DNA loads, in contrast to patients with other connective tissue diseases (P=.0003) and healthy adults (P=.0224). The mean HHV-6 (P=.012) and HHV-7 (P<.0001) DNA loads in patients with connective tissue diseases were lower than those in healthy adults. CONCLUSION: These data suggest that a number of host factors in patients with adult-onset Still disease may function to accelerate HHV-7 replication in the salivary glands.

Adult↗
PubMed2005

Rapid detection of herpes simplex virus DNA in cerebrospinal fluid: comparison between loop-mediated isothermal amplification and real-time PCR.

Loop-mediated isothermal amplification (LAMP) is a novel nucleic acid amplification method that amplifies DNA with high specificity, efficiency, and speed under isothermal conditions. To evaluate the usefulness of LAMP for diagnosing central nervous system infection with herpes simplex virus (HSV), we compared the LAMP method with real-time PCR, using samples that were previously tested by nested PCR. We examined 69 cerebrospinal fluid (CSF) samples from patients suspected of having HSV infection of the central nervous system. The results of the real-time PCR analysis and nested PCR assay were in complete accord. When nested PCR was regarded as standard, the sensitivity of LAMP was 81%, the specificity was 100%, the positive predictive value was 100%, and the negative predictive value was 90%. Although further improvement is necessary for the wide spread use, the LAMP method might be applicable to diagnosis of HSV infection of the central nervous system.

Adolescent↗
PubMed2005

HHV-6 and 7 DNA loads in lung tissues collected from patients with interstitial pneumonia.

The aim of this study is to determine whether human herpesvirus 6 (HHV-6) and HHV-7 might play an important role in causing interstitial pneumonia in patients who have not undergone transplantation. HHV-6 and HHV-7 DNAs were quantitated by real-time polymerase chain reaction (PCR) in paraffin embedded lung tissues collected from 24 patients having the disease. Control tissues (without fibrosis) were also collected from 19 of the 24 patients. Statistical analysis was carried out by the Wilcoxon signed rank test or the Mann-Whitney U-test. HHV-6 DNA was detected in 3 (12.5%) of the 24 target tissues and 3 (15.8%) of the 19 control tissues, respectively. In contrast, HHV-7 DNA was detected in 19 (79.2%) of the 24 target tissues and 11 (57.9%) of the 19 control tissues. Neither HHV-6 DNA load (P = 0.6395) nor HHV-7 DNA load (P = 0.5966) in target tissues differed between males and females. Neither HHV-6 DNA load (P = 0.9589) nor HHV-7 DNA load (P = 0.7419) in target tissues differed between cases with and without underlying collagen disease. While HHV-6 DNA load did not differ between the target and control tissues (P > 0.9999), the HHV-7 DNA load was significantly higher in the target tissue than in the control tissue (P = 0.0298). This study suggests that HHV-7 may play an important role in causing interstitial pneumonia in patients who are not transplant recipients.

Adult↗
PubMed2005

Comparison of loop-mediated isothermal amplification, real-time PCR, and virus isolation for the detection of herpes simplex virus in genital lesions.

This study compares herpes simplex virus (HSV) type-specific loop-mediated isothermal amplification (LAMP) with virus isolation and real-time PCR. Genital tract specimens were obtained from 25 patients with genital lesions; two swab samples were collected from the vulva and cervix of each patient, for a total of 50 specimens. After culturing, 10 of 50 (20%) samples were positive for HSV-1 and 12 of 50 (24%) samples were positive for HSV-2. None of the patients excreted both HSV-1 and HSV-2 virus. An original HSV type-specific LAMP assay (30 min reaction) was compared with virus isolation and HSV type-specific real-time PCR. Viral DNA was detected by LAMP in 9 of 10 HSV-1 isolated samples and 11 of 12 HSV-2 isolated samples. No viral DNA was detected in samples without virus isolation. Thus, if virus isolation was used as the standard method, the LAMP protocol was highly sensitive and specific. In comparing LAMP to real-time PCR, viral DNA was detected by the LAMP method in 9 of 12 HSV-1 DNA positive samples and 11 of 18 HSV-2 DNA positive samples. If real-time PCR was used as the standard method, then, sensitivity of the LAMP method (in particular, for HSV-2) was low. Taking this into consideration, the LAMP reaction was extended to 60 min. This led to an increase in sensitivity, resulting in an additional one and three samples testing positive for HSV-1 LAMP and HSV-2 LAMP, respectively, compared to the original LAMP protocol. Therefore, the sensitivity of the LAMP method increased to about 80%.

Adult↗
PubMed2005

Severe acute tonsillitis caused by Rothia dentocariosa in a healthy child.

A 4-year-old Japanese girl developed a sore throat and high fever. Her tonsils were enlarged, red and covered with a thick white membrane. There was marked leukocytosis (26,600 leukocytes per mm) and elevated C-reactive protein levels (23.3 mg/dL). Rothia dentocariosa was recovered from the throat swab; many Gram-positive cocci were observed in the smear from the pseudomembrane covering the tonsil.

Actinomycetaceae↗