The Epstein-Barr virus pol catalytic subunit physically interacts with the BBLF4-BSLF1-BBLF2/3 complex

The Epstein-Barr virus (EBV)-encoded replication proteins that account for the basic reactions at the replication fork are thought to be the EBV Pol holoenzyme, consisting of the BALF5 Pol catalytic and the BMRF1 Pol accessory subunits, the putative helicase-primase complex, comprising the BBLF4, BSLF1, and BBLF2/3 proteins, and the BALF2 single-stranded DNA-binding protein. Immunoprecipitation analyses using anti-BSLF1 or anti-BBLF2/3 protein-specific antibody with clarified lysates of B95-8 cells in a viral productive cycle suggested that the EBV Pol holoenzyme physically interacts with the BBLF4-BSLF1-BBLF2/3 complex to form a large complex. Although the complex was stable in 500 mM NaCl and 1% NP-40, the BALF5 protein became dissociated in the presence of 0.1% sodium dodecyl sulfate. Experiments using lysates from insect cells superinfected with combinations of recombinant baculoviruses capable of expressing each of viral replication proteins showed that not the BMRF1 Pol accessory subunit but rather the BALF5 Pol catalytic subunit directly interacts with the BBLF4-BSLF1-BBLF2/3 complex. Furthermore, double infection with pairs of recombinant viruses revealed that each component of the BBLF4-BSLF1-BBLF2/3 complex makes contact with the BALF5 Pol catalytic subunit. The interactions of the EBV DNA polymerase with the EBV putative helicase-primase complex warrant particular attention because they are thought to coordinate leading- and lagging-strand DNA synthesis at the replication fork.

Antigen-driven expansion and contraction of CD8+-activated T cells in primary EBV infection

The origin of the increased numbers of CD8+ atypical lymphocytes, expressing activated markers such as HLA-DR or CD45RO, in the peripheral blood of patients with infectious mononucleosis (IM) has been debated. Using a recently developed assay to detect intracellular accumulation of IFN-gamma in EBV-reactive T cells by FACS, we have demonstrated that 34-54% of HLA-DR+/CD8+ and 34-60% of CD45RO+/CD8+ T cells in the PBMCs of febrile patients suffering from IM are EBV-specific. The EBV-specific CD8+ T cell counts in the PBMCs of four febrile patients suffering from IM ranged between 2,260 and 8,200/microl, decreasing to 5.1% and 7.9% of the counts in the first samples over 10 days in two donors. The decline of CD8+ T cell subpopulations, namely HLA-DR+, CD45RO+, and EBV-specific T cells, was in parallel with the drop in the EBV genome load. These data indicate that the Ag-driven expansion of CD8+ T cells and subsequent contraction with the Ag decline in vivo in humans is effective for clearing virus-infected cells with minimal disturbance of the homeostasis of the immune system.

Rapid determination of Epstein-Barr virus-specific CD8(+) T-cell frequencies by flow cytometry

We have developed an efficient and rapid method for detection of Epstein-Barr virus (EBV)-specific CD8(+) T-cell frequencies both in freshly isolated peripheral blood mononuclear cells (PBMCs) and in vitro established cytotoxic T lymphocyte (CTL) lines. Responder cells are thereby stimulated with an autologous lymphoblastoid cell line for 5 hours and intracellular accumulation of interferon gamma (IFNgamma) is detected by multiparameter flow cytometric analysis. EBV-specific CD8(+) T-cell frequencies ranged between 0.63% and 1. 29% in PBMCs of 5 healthy long-term EBV carriers. Using EBV-specific T-cell lines, it was shown that flow cytometric analysis is more sensitive than limiting dilution analysis for CTL precursors and enzyme-linked immunospot assay detecting IFNgamma-producing T cells. The class I restriction of IFNgamma production was confirmed using an anti-class I monoclonal antibody (MoAb). Information on other cytokine production of EBV-specific CTLs could be obtained using combinations of anti-cytokine MoAbs. The sensitive and rapid nature of the flow cytometric assay for EBV-specific CD8(+) T-cell frequency has significant advantages for evaluation of EBV-specific CD8(+) T-cell responses in PBMCs of patients with EBV-related diseases.

Cell cycle regulation of human CDC6 protein. Intracellular localization, interaction with the human mcm complex, and CDC2 kinase-mediated hyperphosphorylation

The binding of mammalian MCM complexes to chromatin is cell cycle-regulated and under CDC2 kinase negative control. Here, we investigated the properties of mammalian CDC6 protein, a candidate regulator of MCM. The levels of CDC6 were relatively constant during the HeLa cell cycle. In asynchronous cells, CDC6 was mainly detected in the nuclei with immunostaining, but some CDC6 was not extractable with nonionic detergent. In contrast to the chromatin-bound MCM, this fraction of CDC6 was resistant to DNase I treatment, suggesting that it binds to the detergent- and nuclease-resistant nuclear structure. In S phase cells, CDC6 became detectable in the cytoplasm with immunostaining; however, the level of the bound CDC6 was unchanged. In G(2)/M phase cells, the level of the bound CDC6 was still maintained, which was hyperphosphorylated by CDC2 kinase. These data suggest that some CDC6 protein is associated with the specific nuclear structure throughout the cell cycle and that major binding sites on chromatin differ between MCM and CDC6. However, co-immunoprecipitation assays with chemical cross-linking indicated that a small part of the chromatin-bound MCM is present close to the bound CDC6.

Increased frequency of antigen-specific CD8(+) cytotoxic T lymphocytes infiltrating an Epstein-Barr virus-associated gastric carcinoma

Gastric adenocarcinomas carrying Epstein-Barr virus (EBV) are known to be accompanied by massive lymphocyte infiltration. To characterize the tumor-infiltrating lymphocytes (TILs), we isolated and cultured such cells from a surgically resected EBV-associated gastric carcinoma. They were found to be positive for CD3, CD8, T-cell receptor beta chain, and cytotoxic molecules. The isolated TILs consisted of human leukocyte antigen (HLA) class I-restricted CD8(+) cytotoxic T lymphocytes (CTLs), which killed autologous EBV-transformed cells (but not phytohemagglutinin blast cells) and recognized HLA-A24 as restriction molecules. However, the TILs did not recognize known EBV antigenic peptides presented by HLA-A24 molecules, nor HLA-A24(+) fibroblasts infected with vaccinia recombinant virus expressing each of the EBV latent proteins. EBV(+) gastric carcinomas do not express conventional target proteins of EBV-specific CTLs, and the data suggest that some cellular proteins may be involved in the strong T-cell response to EBV-associated gastric carcinoma. In addition, our data suggest that class I-restricted, antigen-specific CD8(+) CTLs are specifically expanded within EBV(+) gastric carcinoma tissue.

Characterization of Epstein-Barr virus (EBV)-infected natural killer (NK) cell proliferation in patients with severe mosquito allergy; establishment of an IL-2-dependent NK-like cell line

The clinical evidence of a relationship between severe hypersensitivity to mosquito bite (HMB) and clonal expansion of EBV-infected NK cells has been accumulated. In order to clarify the mechanism of EBV-induced NK cell proliferation and its relationship with high incidence of leukaemias or lymphomas in HMB patients, we studied clonally expanded NK cells from three HMB patients and succeeded in establishing an EBV-infected NK-like cell line designated KAI3. Immunoblotting and reverse transcriptase-polymerase chain reaction (RT-PCR) analyses revealed that KAI3 cells as well as infected NK cells exhibited an EBV latent infection type II, where EBV gene expression was limited to EBNA 1 and LMP1. As KAI3 was established by culture with IL-2, IL-2 responsiveness of peripheral blood NK cells from patients was examined. The results represented markedly augmented IL-2-induced IL-2R alpha expression in NK cells. This characteristic property may contribute to the persistent expansion of infected NK cells. However, KAI3 cells as well as the NK cells from patients were not protected from apoptosis induced by either an anti-Fas antibody or NK-sensitive K562 cells. Preserved sensitivity to apoptosis might explain the relatively regulated NK cell numbers in the peripheral blood of the patients. To our knowledge, KAI3 is the first reported NK-like cell line established from patients of severe chronic active EBV infection (SCAEBV) before the onset of leukaemias or lymphomas. KAI3 cells will contribute to the study of EBV persistency in the NK cell environment and its relationship with high incidence of leukaemias or lymphomas in HMB patients.

Quantitative analysis of Epstein-Barr virus load by using a real-time PCR assay

To measure the virus load in patients with symptomatic Epstein-Barr virus (EBV) infections, we used a real-time PCR assay to quantify the amount of EBV DNA in blood. The real-time PCR assay could detect from 2 to over 10(7) copies of EBV DNA with a wide linear range. We estimated the virus load in peripheral blood mononuclear cells (PBMNC) from patients with symptomatic EBV infections. The mean EBV-DNA copy number in the PBMNC was 10(3.7) copies/microg of DNA in patients with EBV-related lymphoproliferative disorders, 10(4.1) copies/microg of DNA in patients with chronic active EBV infections, and 10(2.2) copies/microg of DNA in patients with infectious mononucleosis. These numbers were significantly larger than those in either posttransplant patients or immunocompetent control patients without EBV-related diseases. In a patient with infectious mononucleosis, the virus load decreased as the symptoms resolved. The copy number of EBV DNA in PBMNC from symptomatic EBV infections was correlated with the EBV-positive cell number determined by the in situ hybridization assay (r = 0.842; P < 0.0001). These results indicate that the real-time PCR assay is useful for diagnosing symptomatic EBV infection and for monitoring the virus load.

Polymerase chain reaction-proved herpes simplex encephalitis in children

OBJECTIVE

To investigate the clinical features in PCR-proved herpes simplex encephalitis (HSE) in children, excluding neonates.

METHODS

We studied the clinical manifestations and laboratory findings of 24 children in whom the diagnosis of herpes infection was confirmed by the PCR assay and compared them with those of 38 children with central nervous system infections other than HSE.

RESULTS

There were no significant differences between groups in the percentage with fever or convulsions, the initial neurologic symptoms or the level of consciousness. Analysis of cerebrospinal fluid showed no significant differences in the cell count or concentration of protein and glucose. Computerized tomography of the brain identified localized abnormalities in 18 (75%) of the 24 HSE patients and in 10 (31%) of the 32 non-HSE patients (P = 0.001). Periodic lateralized epileptiform discharges, abnormal findings on electroencephalography, were detected in 8 (36%) of 22 HSE patients and in none of the non-HSE patients (P = 0.0001). The rates of moderate to severe morbidity and death were significantly higher in the HSE patients than in the non-HSE patients. Of the 9 HSE patients with a Glasgow Coma Scale score > or = 11, all patients recovered completely. HSE patients younger than 3 years of age were more likely to develop severe sequelae or to die of the disorder than older patients (P = 0.02).

CONCLUSIONS

There were no specific clinical characteristics of HSE patients. The results of electroencephalography and computerized tomography were helpful, but not confirmatory, in diagnosing HSE. The Glasgow Coma Scale score and age significantly influenced the mortality and morbidity in the HSE patients.

[Adoptive immune therapy using EBV-specific CTL]

The Epstein-Barr virus (EBV) has been implicated in the etiology of many lymphoid and other malignancies. Understanding of the immune control of the virus appears to be very important to establish strategy to overcome those disease. Recent advance of T cell biology and the culture technic have made it possible to apply adoptive immune transfer of EBV-specific cytotoxic T lymphocytes (CTL) in clinical settings. This review summarizes immunotherapy using EBV-specific CTL for the treatment of EBV-associated lymphoproliferative disorders in patients receiving bone marrow transplantation and for a patient with severe chronic active EBV infection. Its future application is discussed.

Establishment of anti-Epstein-Barr virus (EBV) cellular immunity by adoptive transfer of virus-specific cytotoxic T lymphocytes from an HLA-matched sibling to a patient with severe chronic active EBV infection

We describe an experience of a specific immune transfer treatment in a patient with chronic active EBV infection. The patient had low anti-EBV T cell-mediated cytotoxic activity in his peripheral blood mononuclear cells (PBMC), which may have been the primary cause of the disease. An EBV-specific cytotoxic T lymphocyte (CTL) line was established from PBMC obtained from the patient's sister whose human leucocyte antigens (HLA) are identical to patient's. The patient received three courses of intravenously administered CTL at 3-week intervals. The number of the cells was increased with each course of treatment. After infusion of the T cell line, anti-EBV CTL activity was detected in the patient's PBMC. CTL activity increased markedly after the second course of immune transfer therapy. The amount of EBV DNA in the patient's plasma showed transient but repeated decreases. Serum levels of tumour necrosis factor-alpha (TNF-alpha), which had elevated before treatment, began to decrease after initiation of treatment. No adverse effects were directly associated with CTL infusions. Despite having previously received a pneumococcal vaccine and prophylactic antibiotics, the patient died of infection caused by Streptococcus pneumoniae bacteraemia 27 days after the third infusion. Although the long-term efficacy and safety of this therapy remains to be established, our findings suggest that adoptive transfer of CTL specific for EBV obtained from an HLA-matched donor might be a promising treatment for patients with chronic active EBV infection.

Intact antigen presentation for Epstein-Barr virus (EBV)-specific CTL by a lymphoblastoid cell line established from a patient with severe chronic active EBV infection

Severe chronic active Epstein-Barr virus (EBV) infection is a lymphoproliferative disease characterized by extremely high antibody titers to EBV, fever, lymphadenopathy, hepatosplenomegaly, and pancytopenia, without any prior immunological abnormality. A spontaneous lymphoblastoid cell line was established from a 4-year-old boy with severe chronic active EBV infection. Immunofluorescence and Western blotting analyses showed that the cell line was of B cell origin and expressed Epstein-Barr nuclear antigens 1, 2 3a, 3b and 3c, and latent membrane protein 1, which are reported to be targets for EBV-specific cytotoxic T lymphocytes (CTL). The cytotoxicity of peripheral blood mononuclear cells derived from the patient and his HLA-identical sister was assayed against the cell line. The cell line was recognized and killed by anti-EBV CTL derived from the HLA-identical sister, but the patient's peripheral blood mononuclear cells had no cytotoxicity. We conclude that antigen presentation in the EBV-infected cells from the patient is intact and sufficient for generation of an EBV-specific CTL response. These observations suggest that severe chronic active EBV infection may not be caused by impaired EBV-antigen presentation of the infected cells but by impaired cellular immune responses to the virus. Our results also suggest the therapeutic possibility that this disease may be treated by adoptive transfer of EBV-specific CTL or bone marrow transplantation from an HLA-matched donor whose immune response to EBV is intact.

The role of self peptides in the allogeneic cross-reactivity of CTLs

This study presents data relevant to understanding the molecular and structural basis for the cross-reactivity of many CTLs on multiple MHC targets. Five anti-H-2Kb alloreactive CTL clones derived from B6.C-H-2bm1 (bm1), B6.C-H-2bm8 (bm8), and B6.C-H-2bm11 (bm11) mice and a Sendai virus-specific H-2Kb-restricted CTL clone were studied. Self peptides extracted from Kb molecules were fractionated by HPLC and tested for their ability to be recognized on RMA/s (H-2b) cells by those clones. For each alloreactive clone, a single dominant peptide peak was found to sensitize target cells. In addition to recognizing peptides presented by the Kb molecule, the five alloreactive clones and the one Sendai virus-specific clone all showed cross-reactivities on a panel of Kbm mutant cells in a peptide-dependent manner. Two CTL clones, one alloreactive and one virus specific, cross-recognized Kbm targets by each responding to a unique self peptide in the context of the mutant MHC molecules. Our data underscore the prevalent idea that TCR-alpha beta have an inherent structural capability to react with several peptide/MHC structural patterns other than the original peptide/MHC pattern that might have been used to select that TCR. The high incidence of cross-reactivity seems to reflect a feature of the mechanism of positive selection in the thymus and the need for T cells in the repertoire to have an expanded capability for responding to a wide variety of foreign Ags.

The role of self peptides in the allogeneic cross-reactivity of CTLs

This study presents data relevant to understanding the molecular and structural basis for the cross-reactivity of many CTLs on multiple MHC targets. Five anti-H-2Kb alloreactive CTL clones derived from B6.C-H-2bm1 (bm1), B6.C-H-2bm8 (bm8), and B6.C-H-2bm11 (bm11) mice and a Sendai virus-specific H-2Kb-restricted CTL clone were studied. Self peptides extracted from Kb molecules were fractionated by HPLC and tested for their ability to be recognized on RMA/s (H-2b) cells by those clones. For each alloreactive clone, a single dominant peptide peak was found to sensitize target cells. In addition to recognizing peptides presented by the Kb molecule, the five alloreactive clones and the one Sendai virus-specific clone all showed cross-reactivities on a panel of Kbm mutant cells in a peptide-dependent manner. Two CTL clones, one alloreactive and one virus specific, cross-recognized Kbm targets by each responding to a unique self peptide in the context of the mutant MHC molecules. Our data underscore the prevalent idea that TCR-alpha beta have an inherent structural capability to react with several peptide/MHC structural patterns other than the original peptide/MHC pattern that might have been used to select that TCR. The high incidence of cross-reactivity seems to reflect a feature of the mechanism of positive selection in the thymus and the need for T cells in the repertoire to have an expanded capability for responding to a wide variety of foreign Ags.

Detection and quantification of virus DNA in plasma of patients with Epstein-Barr virus-associated diseases

Epstein-Barr virus (EBV) causes various diseases, such as infectious mononucleosis (IM), fatal IM, EBV-associated hemophagocytic syndrome (EBVAHS), and chronic active EBV infection (CAEBV). In the present study, cell-free EBV DNA was detected in the plasma of patients with EBV-associated diseases by PCR assay. The patients included 20 patients with IM, 2 patients with fatal IM, 4 patients with EBVAHS, 4 patients with CAEBV, and 38 healthy children (20 EBV seropositive and 18 EBV seronegative). In patients with IM, plasma samples were positive for EBV DNA in all patients (100%) in the acute phase and in 44% of the patients in the convalescent phase, but plasma samples from the 38 healthy control children were negative (0%) for EBV DNA. Quantitative PCR assay revealed that plasma from patients with IM contained the highest amount of virus DNA within 7 days following the onset of disease (mean, 6 x 10(4) copies per ml). The EBV DNA concentration decreased thereafter as the patients recovered. Plasma from patients with fatal IM contained more than 100 times more copies of EBV DNA (3 x 10(7) copies per ml) than plasma from patients with IM. Plasma from patients with the acute phase of EBVAHS contained 10 times more copies of EBV DNA (5 x 10(5) copies per ml) than plasma from IM, and then patients with the number of copies decreased similarly in both groups of patients in the convalescent phase (2 x 10(4) copies per ml). The amount of virus DNA in patients with CAEBV (6 x 10(4) copies per ml) was similar to that noted in patients with IM; however, it became higher (1 x 10(6) copies per ml) when the patients' clinical status deteriorated. These data suggest that the presence of cell-free EBV DNA in plasma is a common phenomenon in patients with EBV-associated diseases. The concentration of EBV DNA in plasma seems to be higher in patients with the more severe clinical categories of EBV diseases.

Characterization of an incompletely assembled major histocompatibility class I molecule (H-2Kb) associated with unusually long peptides: implications for antigen processing and presentation

We have identified two forms of a major histocompatibility complex (MHC) class I molecule, H-2Kb, distinguishable by specific antibodies through a study of a genetically engineered mouse cell line that overexpresses these molecules. One form, a complex associated with beta 2-microglobulin (native, beta 2m+ class I), is detectable by conformation-dependent antibodies. The other form, which remains after preclearing cell lysates of native class I, is only poorly, if at all, associated with beta 2-microglobulin (beta 2m- class I) and is detectable by an antiserum against the cytoplasmic tail region of H-2K molecules. Both forms are also present in normal cell lines. The affinity-purified native class I molecules bind short peptides (8 or 9 residues) and assemble tightly with beta 2-microglobulin. In striking contrast, the beta 2m- class I molecules bind peptides that are longer (> 15 residues) than those bound to native class I molecules. This finding is consistent with the recent evidence that peptides longer than 8-10 amino acid residues are transported into the endoplasmic reticulum and suggests the possibility of a control step for peptide presentation by MHC in which the incompletely processed peptides bind to the heavy chain and a selected fraction undergoes final processing and presentation on the cell surface.

Ingestion of caustic alkali farm products

Since the Poison Prevention Packaging Act took effect, the number of ingestions of caustic alkali from household products has been significantly reduced. Commercial caustic alkalis used on farms, however, were not included in this legislation. Fourteen children over a 5 year period were seen after ingestion of commercial caustic alkalis used on farms. Seven of the children had ingested liquid pipeline cleaners and seven had ingested solid agents used for a variety of reasons. Six of seven children ingesting liquid agents did so from nonoriginal containers into which the caustic had been transferred for convenience. All seven children ingesting solid agents did so from the original container. Eight of the 14 children were found to have second-degree or worse esophageal involvement. Both solid and liquid caustic agents used commercially on farms can cause significant morbidity. Development of a child-resistant container for daily transfer of liquid pipeline agents could be helpful in preventing injuries from liquid pipeline cleaners. Pediatric gastroenterologists as well as primary care physicians in rural areas should be familiar with this type of injury and should take an active role in instructing parents of children living on farms to prevent such injuries. Extension of the Poison Prevention Packaging Act to caustic alkalis used on farms needs to be considered.

Quantitation of cytomegalovirus DNA in lung tissue of bone marrow transplant recipients

Five bone marrow transplant recipients who died of respiratory failure were retrospectively analyzed with polymerase chain reaction (PCR) assay for pulmonary cytomegalovirus (CMV) infection. Two patients had CMV interstitial pneumonitis according to the virus isolation and the histologic and immunofluorescent examinations of the lungs, while the other three patients had non-CMV diseases (ie, idiopathic interstitial pneumonitis, pulmonary aspergillosis, or Streptococcus mitis septicemia). Cytomegalovirus DNA was amplified from the postmortem lung tissue with PCR. The PCR assay showed apparent PCR signals specific to CMV DNA in the two patients with CMV pneumonitis. In contrast, CMV DNA was hardly detectable or undetectable in the three patients without CMV disease. With quantitative PCR assay the initial CMV copy number in the lung tissue of the two patients with CMV pneumonitis was more than 10(4) copies/micrograms DNA and was over 1,000-fold more than that of the three patients without CMV pneumonitis. These results show that quantitative PCR assay could be useful as a diagnostic measure for pulmonary CMV infection.

Relapse of herpes simplex encephalitis in children

The polymerase chain reaction method was used to diagnose herpes simplex encephalitis in children. Initial samples of cerebrospinal fluid from 15 patients with herpes simplex encephalitis were all positive for the herpes simplex virus DNA by polymerase chain reaction assay. In terms of early diagnosis, polymerase chain reaction assay became positive significantly earlier than the detection of intrathecally produced anti-herpes simplex virus antibody using the enzyme-linked immunosorbent assay (4.4 vs 8.9 days after onset; P less than .01). Serial examinations showed that the presence of virus DNA in cerebrospinal fluid continued for 3 to 18 days after the neurologic onset (mean 10.1 days). Four of the 15 patients had a relapse of encephalitis after completing acyclovir therapy. The mean duration of initial acyclovir therapy in the recurrent group was significantly shorter than that in the nonrecurrent group. In recurring cases, herpes simplex virus DNA reappeared temporarily in the cerebrospinal fluid of two patients. These results show that polymerase chain reaction assay is a useful diagnostic tool for the early and noninvasive diagnosis of herpes simplex encephalitis in children. Results also suggest that a comparatively short duration of acyclovir therapy may be related to a relapse of herpes simplex encephalitis in some children.

Prophylactic oral acyclovir in outbreaks of primary herpes simplex virus type 1 infection in a closed community

Oral acyclovir was given prophylactically to 37 children in the early stages of three outbreaks of herpes simplex virus type 1 (HSV-1) infection and the results were compared with those in untreated control subjects in two other outbreaks. The rates of seroconversion to HSV were significantly reduced in children treated with acyclovir compared with control subjects (91% vs 27%, P less than .001). The incidence of symptomatic disease was also significantly reduced (82% vs 0%, P less than .001). In some children receiving prophylactic acyclovir, anti-HSV antibody titers did not rise despite the presence of replicative HSV on throat swabs just before the start of treatment. Restriction endonuclease analysis of isolated HSV-DNA confirmed that one strain was responsible for the five outbreaks. No resistance to acyclovir was detected during the study, and no adverse effects of treatment were noted. In conclusion, short-term prophylactic acyclovir may limit the spread and reduce clinical manifestations of HSV infections in closed communities, although this use should be restricted to communities where severe symptoms are observed.

Detection of viral DNA in neonatal herpes simplex virus infections: frequent and prolonged presence in serum and cerebrospinal fluid

Polymerase chain reaction (PCR) assay was used to detect herpes simplex virus (HSV) DNA in mouth, skin, sera, or cerebrospinal fluid (CSF) from seven neonates with HSV infection. In a culture-negative patient, the diagnosis was confirmed by detection of HSV DNA. Serial examinations revealed that HSV DNA remained in the serum and/or CSF from several patients for 1-2 weeks after the beginning of treatment. Next, the results of PCR assay in neonatal HSV infections were compared with those in older children with herpes simplex encephalitis (HSE). HSV DNA was detected in CSF from four neonates with central nervous system involvement and in CSF from all nine children with HSE. Sera were positive for HSV DNA in five of seven neonates, including two cases of localized infections, but in none of the children with HSE. These results suggest that HSV may be spread principally via viremia in neonates. PCR assay could be useful for the confirmative diagnosis of neonatal HSV infections, especially in culture-negative cases.

Clinical manifestations of primary herpes simplex virus type 1 infection in a closed community

The clinical features and the molecular epidemiology of primary herpes simplex virus type 1 (HSV-1) infection among children younger than 3 years of age were investigated in day-care nursery. Serial sera were assayed for anti-HSV-1 glycoprotein B antibody by enzyme-linked immunosorbent assay. Serologic examinations revealed 55 cases of primary HSV infection during the observation period. Fifty-one of them (93%) had typical herpetic gingivostomatitis, showing a high rate of clinically overt infection. Four outbreaks of herpetic gingivostomatitis were observed during the observation period. Forty-one children were infected with HSV-1 in the outbreaks. The rates of infection in the susceptible children were 81%, 73%, 78%, and 100%, respectively, in the four outbreaks. Restriction endonuclease analysis of DNA of isolated HSV revealed that only one strain of HSV-1 had been transmitted among children for a long period.

Human cytomegalovirus infection during childhood: detection of viral DNA in peripheral blood by means of polymerase chain reaction

Polymerase chain reaction (PCR) technique was applied to detect cytomegalovirus (CMV) DNA. Two pairs of synthetic oligonucleotide primers were used to amplify DNA from the immediate early 1 and the late antigen genes of CMV, respectively. Either primer sets could detect as few as 0.01 plaque-forming unit of CMV strain AD 169 by Southern blot hybridization. Sixteen CMV clinical isolates were examined and all were found to be positive by the both primer sets. The PCR was used to detect CMV DNA in peripheral blood from six children with elevated anti-CMV antibody titers, who showed abnormal liver-function tests. In three immunocompromised patients, all blood samples were positive for CMV DNA. In three immunocompetent young infants with primary CMV infection, CMV DNA was detected from peripheral blood of one patient during acute phase. Presence of CMV DNA in peripheral blood seemed to be related with the extent of CMV infection, and possibly diagnostic for CMV hepatitis.