Antibodies Against Chikungunya in Northern Mozambique During Dengue Outbreak, 2014

An outbreak of dengue and high densities of Aedes aegypti were reported in 2014 in northern Mozambique, suggesting an increased risk for other arboviruses such as chikungunya virus (CHIKV) in this region. The aim of this study was to investigate the occurrence of CHIKV during an outbreak of dengue virus (DENV) in Pemba city in northern Mozambique in 2014. Febrile patients (n = 146) seeking medical attention at the Pemba Provincial Hospital between March and April 2014 were enrolled in this study. Blood samples from each participant were tested for chikungunya and DENV RNA, IgM and IgG antibodies using PCR and ELISA, respectively. The median age of the patients was 26 years (interquartile range: 20-34 years), and 52.7% (77/146) were female. We found that 7.0% (8/114) of the patients were positive for CHIKV IgM and 31.5% (46/146) presented with CHIKV IgG antibodies. DENV IgM and IgG antibodies were detected in 38.3% (46/120) and 28.2% (33/117) of the patients, respectively. This study is the first investigation regarding the occurrence of CHIKV in the north of Mozambique over the last 60 years and our data suggest that Mozambicans had been silently exposed to the virus in this part of the country, indicating that not only DENV but also CHIKV is an arbovirus to consider in febrile patients seeking medical attention in northern Mozambique.

Dengue Virus Serotype 2 Established in Northern Mozambique (2015-2016)

After the report of an outbreak of dengue virus serotype 2 in 2014 in Nampula and Pemba cities, northern Mozambique, a surveillance system was established by the National Institute of Health. A study was performed during 2015-2016 to monitor the trend of the outbreak and confirm the circulating serotype of dengue virus (DENV). After the inclusion of consenting patients who met the case definition, samples from 192 patients were tested for the presence of nonstructural protein 1 antigen, and 60/192 (31%) samples were positive. Further analysis included DENV IgM antibodies, with 39 (20%) IgM positive cases. Reverse transcriptase (RT) PCR was performed for identification of the prevailing DENV serotype; 21/23 tested samples were DENV-2 positive, with DENV-2 present in both affected cities. When sequencing DENV, phenotype Cosmopolitan was identified. The surveillance indicates ongoing spread of DENV-2 in northern Mozambique 2 years after the first report of the outbreak.

Acute Uncomplicated Febrile Illness in Children Aged 2-59 months in Zanzibar - Aetiologies, Antibiotic Treatment and Outcome

Background

Despite the fact that a large proportion of children with fever in Africa present at primary health care facilities, few studies have been designed to specifically study the causes of uncomplicated childhood febrile illness at this level of care, especially in areas like Zanzibar that has recently undergone a dramatic change from high to low malaria transmission.

Methods

We prospectively studied the aetiology of febrile illness in 677 children aged 2–59 months with acute uncomplicated fever managed by IMCI (Integrated Management of Childhood Illness) guidelines in Zanzibar, using point-of-care tests, urine culture, blood-PCR, chest X-ray (CXR) of IMCI-pneumonia classified patients, and multiple quantitative (q)PCR investigations of nasopharyngeal (NPH) (all patients) and rectal (GE) swabs (diarrhoea patients). For comparison, we also performed NPH and GE qPCR analyses in 167 healthy community controls. Final fever diagnoses were retrospectively established based on all clinical and laboratory data. Clinical outcome was assessed during a 14-day follow-up. The utility of IMCI for identifying infections presumed to require antibiotics was evaluated.

Findings

NPH-qPCR and GE-qPCR detected ≥1 pathogen in 657/672 (98%) and 153/164 (93%) of patients and 158/166 (95%) and 144/165 (87%) of controls, respectively. Overall, 57% (387/677) had IMCI-pneumonia, but only 12% (42/342) had CXR-confirmed pneumonia. Two patients were positive for Plasmodium falciparum. Respiratory syncytial virus (24.5%), influenza A/B (22.3%), rhinovirus (10.5%) and group-A streptococci (6.4%), CXR-confirmed pneumonia (6.2%), Shigella (4.3%) were the most common viral and bacterial fever diagnoses, respectively. Blood-PCR conducted in a sub-group of patients (n = 83) without defined fever diagnosis was negative for rickettsiae, chikungunya, dengue, Rift Valley fever and West Nile viruses. Antibiotics were prescribed to 500 (74%) patients, but only 152 (22%) had an infection retrospectively considered to require antibiotics. Clinical outcome was generally good. However, two children died. Only 68 (11%) patients remained febrile on day 3 and three of them had verified fever on day 14. An additional 29 (4.5%) children had fever relapse on day 14. Regression analysis determined C-reactive Protein (CRP) as the only independent variable significantly associated with CXR-confirmed pneumonia.

Conclusions

This is the first study on uncomplicated febrile illness in African children that both applied a comprehensive laboratory panel and a healthy control group. A majority of patients had viral respiratory tract infection. Pathogens were frequently detected by qPCR also in asymptomatic children, demonstrating the importance of incorporating controls in fever aetiology studies. The precision of IMCI for identifying infections requiring antibiotics was low.

Universal single-probe RT-PCR assay for diagnosis of dengue virus infections

BACKGROUND

Dengue is a mosquito-borne viral disease that has become more prevalent in the last few decades. Most patients are viremic when they present with symptoms, and early diagnosis of dengue is important in preventing severe clinical complications associated with this disease and also represents a key factor in differential diagnosis. Here, we designed and validated a hydrolysis-probe-based one-step real-time RT-PCR assay that targets the genomes of dengue virus serotypes 1-4.

METHODOLOGY/PRINCIPAL FINDINGS

The primers and probe used in our RT-PCR assay were designed to target the 3' untranslated region of all complete genome sequences of dengue virus available in GenBank (n = 3,305). Performance of the assay was evaluated using in vitro transcribed RNA, laboratory-adapted virus strains, external control panels, and clinical specimens. The linear dynamic range was found to be 104-1011 GCE/mL, and the detection limit was between 6.0×102 and 1.1×103 GCE/mL depending on target sequence. The assay did not cross-react with human RNA, nor did it produce false-positive results for other human pathogenic flaviviruses or clinically important etiological agents of febrile illnesses. We used clinical serum samples obtained from returning travelers with dengue-compatible symptomatology (n = 163) to evaluate the diagnostic relevance of our assay, and laboratory diagnosis performed by the RT-PCR assay had 100% positive agreement with diagnosis performed by NS1 antigen detection. In a retrospective evaluation including 60 archived serum samples collected from confirmed dengue cases 1-9 days after disease onset, the RT-PCR assay detected viral RNA up to 9 days after appearance of symptoms.

CONCLUSIONS/SIGNIFICANCE

The validation of the RT-PCR assay presented here indicates that this technique can be a reliable diagnostic tool, and hence we suggest that it be introduced as the method of choice during the first 5 days of dengue symptoms.

Detection of antibodies against H5 and H7 strains in birds: evaluation of influenza pseudovirus particle neutralization tests

Introduction

Avian influenza viruses circulate in bird populations, and it is important to maintain and uphold our knowledge of the viral strains that are currently of interest in this context. Here, we describe the use of hemagglutinin-pseudotype retroviruses based on highly pathogenic influenza viruses for the screening of avian sera for influenza A antibodies. Our aim was also to determine whether the pseudovirus neutralization tests that we assessed were sensitive and simple to use compared to the traditional methods, including hemagglutination inhibition assays and microneutralization tests.

Material and methods

H5 and H7 pseudovirus neutralization tests were evaluated by using serum from infected rabbits. Subsequently, the assays were further investigated using a panel of serum samples from avian species. The panel contained samples that were seropositive for five different hemagglutinin subtypes as well as influenza A seronegative samples.

Results and discussion

The results suggest that the pseudovirus neutralization test is an alternative to hemagglutination inhibition assays, as we observed comparable titers to those of both standard microneutralizations assays as well as hemagglutinin inhibition assays. When evaluated by a panel of avian sera, the method also showed its capability to recognize antibodies directed toward low-pathogenic H5 and H7. Hence, we conclude that it is possible to use pseudoviruses based on highly pathogenic avian influenza viruses to screen avian sera for antibodies directed against influenza A subtypes H5 and H7.

Stability of a formalin-inactivated Rift Valley fever vaccine: evaluation of a vaccination campaign for cattle in Mozambique

In Africa and the Arabian Peninsula, outbreaks of Rift Valley fever (RVF) are characterized by abortions in gestating animals and high mortality rates among domestic ruminants. An immunization program using a formalin-inactivated vaccine was initiated in Mozambique in 2002 to control RVF in cattle. In this intervention, the vaccine must be transported for more than a week within the country before it can be administered to the animals, and it is practically impossible to maintain low storage temperatures during that time. Here, we evaluated the influence of transportation conditions on the efficacy of the vaccine. Sixty-three previously unvaccinated and RVF virus seronegative cattle were divided into four groups, which were given vaccine that had been stored for 1 week at 4°C (n=9, group A), at 25°C (n=8, group B), or alternating between 4 and 25°C (n=8, group C), or under the temperature conditions ordinarily occurring during transportation within Mozambique (n=38, group D). The antibody responses induced were monitored for 6-9 months and in some animals up to 21 months. Two immunizations (3 weeks apart) with the formalin-inactivated vaccine induced a long-lasting neutralizing antibody response that was still detectable up to 21 months later. The antibody titers in the animals did not differ significantly between the temperature-assigned vaccine groups A, B, and C, whereas they were significantly higher in group D. These results show that the formalin-inactivated RVF virus vaccine is stable, and, importantly, it is not adversely affected by the variation in temperature that ordinarily occurs during transport within Mozambique.

Effect of acute Plasmodium falciparum malaria on reactivation and shedding of the eight human herpes viruses

Human herpes viruses (HHVs) are widely distributed pathogens. In immuno-competent individuals their clinical outcomes are generally benign but in immuno-compromised hosts, primary infection or extensive viral reactivation can lead to critical diseases. Plasmodium falciparum malaria profoundly affects the host immune system. In this retrospective study, we evaluated the direct effect of acute P. falciparum infection on reactivation and shedding of all known human herpes viruses (HSV-1, HSV-2, VZV, EBV, CMV, HHV-6, HHV-7, HHV-8). We monitored their presence by real time PCR in plasma and saliva of Ugandan children with malaria at the day of admission to the hospital (day-0) and 14 days later (after treatment), or in children with mild infections unrelated to malaria. For each child screened in this study, at least one type of HHV was detected in the saliva. HHV-7 and HHV-6 were detected in more than 70% of the samples and CMV in approximately half. HSV-1, HSV-2, VZV and HHV-8 were detected at lower frequency. During salivary shedding the highest mean viral load was observed for HSV-1 followed by EBV, HHV-7, HHV-6, CMV and HHV-8. After anti-malarial treatment the salivary HSV-1 levels were profoundly diminished or totally cleared. Similarly, four children with malaria had high levels of circulating EBV at day-0, levels that were cleared after anti-malarial treatment confirming the association between P. falciparum infection and EBV reactivation. This study shows that acute P. falciparum infection can contribute to EBV reactivation in the blood and HSV-1 reactivation in the oral cavity. Taken together our results call for further studies investigating the potential clinical implications of HHVs reactivation in children suffering from malaria.

Anti-Epstein-Barr virus antibodies as serological markers of multiple sclerosis: a prospective study among United States military personnel

BACKGROUND

Elevated Epstein-Barr virus (EBV) antibody titers are risk factors for multiple sclerosis (MS), but the strength and consistency of this association are not well characterized.

OBJECTIVES

The objectives of this study were to determine whether this association is confounded by vitamin D or modified by gender or race, and the usefulness of EBV nuclear antigen (EBNA) antibodies as a marker for MS.

METHODS

We conducted a prospective study among US military personnel. Antibody titers against EBV antigens were measured in serum samples from 222 individuals who developed MS and 444 age, sex, and race/ethnicity matched controls. Conditional logistic regression was used to estimate relative risks.

RESULTS

MS risk increased with increasing titers of anti-EBNA complex (p < 10(-9)) and anti-EBNA-1 (p = 5.8 × 10(-9)) titers. MS risk was 36-fold higher among individuals with anti-EBNA complex IgG titers ≥320 than among those with titers <20 (95% confidence interval [CI] 9.6-136), and 8-fold higher among those with anti-EBNA-1 ≥320 than among those with anti-EBNA-1 <20 (95% CI 2.6-23). These associations were consistent across gender and race/ethnicity groups and independent from 25-hydroxyvitamin D levels. Areas under the receiver operating characteristic (ROC) curves were 0.67 for EBNA complex and 0.65 for EBNA-1.

CONCLUSIONS

Serum titers of pre-onset anti-EBNA antibodies are strong, robust markers of MS risk and could be useful in an MS risk score.

Anchored pan dengue RT-PCR and fast sanger sequencing for detection of dengue RNA in human serum

A large number of human infections are caused by different dengue virus strains, mainly in the tropical and subtropical parts of the world, but also outside the endemic regions. RT-PCR methods are used widely for detection of dengue virus RNA in acute-phase serum samples; however, new sequence variation can inhibit these methods. An assay was developed integrating an anchored Pan Dengue RT-PCR with a new Fast Sanger sequencing protocol. For broad detection and identification of dengue virus RNA, including new strains of all serotypes, the conserved 3' genome end was targeted for highly specific cDNA synthesis. A combination of degenerated primers was used for second strand synthesis, followed by tag primed amplification. The mixture of generated amplicons was identified directly by the Fast Sanger sequencing from the anchored 3' genome end. Evaluating the assay on human serum RNA spiked with viral RNA representing the four dengue serotypes demonstrated a detection limit of 44-124 copies viral RNA per reaction for a two-step format of the anchored Pan Dengue RT-PCR and 100-500 copies for a one-step protocol, respectively. The different serotypes were clearly identified from the generated sequences. Further, the 5-hr procedure was evaluated and compared to standard real-time RT-PCR protocols on acute-phase serum samples from patients with confirmed dengue infections. This assay demonstrates a strategy for virus detection, which combines nucleic acid amplification adapted for dengue virus RNA with direct and rapid sequencing. It provides a tolerance for new sequence variation and the strategy should be applicable for other RNA viruses.

Primary infection with the Epstein-Barr virus and risk of multiple sclerosis

To determine whether multiple sclerosis (MS) risk increases following primary infection with the Epstein-Barr virus (EBV), we conducted a nested case-control study including 305 individuals who developed MS and 610 matched controls selected among the >8 million active-duty military personnel whose serum has been stored in the Department of Defense Serum Repository. Time of EBV infection was determined by measuring antibody titers in serial serum samples collected before MS onset among cases, and on matched dates among controls. Ten (3.3%) cases and 32 (5.2%) controls were initially EBV negative. All of the 10 EBV-negative cases became EBV positive before MS onset; in contrast, only 35.7% (n = 10) of the 28 controls with follow-up samples seroconverted (exact p value = 0.0008). We conclude that MS risk is extremely low among individuals not infected with EBV, but it increases sharply in the same individuals following EBV infection.

Monitoring of herpes simplex virus DNA types 1 and 2 viral load in cerebrospinal fluid by real-time PCR in patients with herpes simplex encephalitis

A quantitative polymerase chain reaction (PCR) assay was evaluated retrospectively on 92 cerebrospinal fluid (CSF) samples from 29 patients with herpes simplex virus (HSV) encephalitis with the aim to study if the concentration of HSV genomes can be used as a prognostic marker and for monitoring of antiviral therapy. The results were compared to those obtained previously by nested PCR, and the numbers of HSV genomes/ml were evaluated in correlation to patient outcome and treatment. The aims were to compare the sensitivity of a conventional nested PCR to a quantitative PCR, to investigate the range of HSV genome concentration in initial samples and to evaluate possible relationships between the HSV DNA concentrations in CSF, neopterin levels, and outcome of disease. The 29 initial samples contained between 2 x 10(2) and 42 x 10(6) HSV genomes/ml. There was no apparent correlation between the amount of HSV DNA in the initial samples and income status, initial neopterin levels, or prognosis. The number of HSV genomes/ml declined after treatment in all patients, but HSV DNA was still detectable after day 20 in 3 out of 16 patients. A long duration of genome detectability was found to correlate with poor outcome. There was no difference in sensitivity between the nested PCR and the quantitative PCR. While the quantitative PCR is more rational than a nested PCR, the quantitation of HSV genomes does not seem very useful as a prognostic marker in HSV encephalitis.

Fatal subarachnoidal haemorrhage in a Norwegian traveller with dengue virus infection

We present a Norwegian female in her thirties who acquired dengue fever caused by dengue virus serotype 2 while travelling to Mexico. When hospitalised 3 days after symptom onset, the patient had severe headache, fever, rash and a positive tourniquet test, but did not fulfil the criteria of dengue haemorrhagic fever (DHF). Five days later she developed a fatal subarachnoidal haemorrhage. A post-mortem examination failed to reveal any intracranial arterial aneurysm. Our case was consistent with so called 'dengue fever with haemorrhages', a recently described entity that mainly affects adults and may cause severe bleedings also in the absence of DHF.

Gene segment reassortment between American and Asian lineages of avian influenza virus from waterfowl in the Beringia area

Since prehistoric times, the Bering Strait area (Beringia) has served as an avenue of dispersal between the Old and the New Worlds. On a field expedition to this area, we collected fecal samples from dabbling ducks, geese, shorebirds, and gulls on the Chukchi Peninsula, Siberia, and Pt. Barrow, Alaska, and characterized the subtypes of avian influenza virus present in them. Four of 202 samples (2%) from Alaska were positive for influenza A virus RNA in two independent polymerase chain reaction (PCR)-based screening assays, while all shorebird samples from the Chukchi Peninsula were negative. Subtypes H3N8 and H6N1 were recorded once, while subtype H8N4 was found in two samples. Full-length sequences were obtained from the three unique isolates, and phylogenetic analysis with representative sequences for the Eurasian and North American lineages of influenza A virus showed that one HA gene clustered with the Eurasian rather than the North American lineage. However, the closest relative to this sequence was a North American isolate from Delaware described in 2002, indicating that a H6 spillover from Asia has established itself in North America.

Population differences in immune marker profiles associated with human T-lymphotropic virus type I infection in Japan and Jamaica

The natural history of human T-lymphotropic virus type I (HTLV-I) has been shown to differ markedly by geographic area. The differences include contrasting patterns of risk of adult T-cell lymphoma (ATL) and HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), which may be due in part to differences in host immune response to infection. To characterize variations in host immunity across populations, we compared serologic immune marker patterns in HTLV-I-endemic populations in Japan and Jamaica. We matched 204 participants with archived blood from the Miyazaki Cohort Study (Japan) and the Food Handlers Study (Jamaica)-i.e., 51 HTLV-I-positive ("carriers") and 51 HTLV-I-negative individuals ("noncarriers") from each population-by age, sex and blood collection year. We compared plasma concentrations of markers of T-cell-mediated (antigen-specific) and nonspecific immunity using regression models and correlation coefficients. Compared to Jamaican HTLV-I noncarriers, Japanese noncarriers had higher covariate-adjusted mean levels of T-cell activation markers, including antibody to Epstein-Barr virus nuclear antigen-1 (reciprocal titer 27 vs. 71, respectively, p=0.005), soluble interleukin-2 receptor-alpha (477 vs. 623 pg/mL, p=0.0008) and soluble CD30 (34 vs. 46 U/mL, p=0.0001) and lower levels of C-reactive protein (1.1 vs. 0.43 microg/mL, p=0.0004). HTLV-I infection was associated with activated T-cell immunity in Jamaicans but with diminished T-cell immunity in Japanese persons. The observed population differences in background and HTLV-I-related host immunity correspond closely to the divergent natural histories of infection observed among HTLV-I carriers in Japan and Jamaica and corroborate a role for host immune status in the contrasting patterns of ATL and HAM/TSP risk.

Puumala hantavirus excretion kinetics in bank voles (Myodes glareolus)

One-sentence summary for table of contents: Virus may be transmitted by saliva, urine, and feces, and saliva may play a role in transmission to humans.

Puumala hantavirus is present in bank voles (Myodes glareolus) and is believed to be spread mainly by contaminated excretions. In this study, we subcutaneously inoculated 10 bank voles with Puumala virus and sampled excretions until day 133 postinfection. Levels of shed viral RNA peaked within 11–28, 14–21, and 11–28 days postinfection for saliva, urine, and feces, respectively. The latest detection of viral RNA was 84, 44, and 44 days postinfection in saliva, urine, and feces, respectively. In contrast, blood of 5 of 6 animals contained viral RNA at day 133 postinfection, suggesting that bank voles secrete virus only during a limited time of the infection. Intranasal inoculations with bank vole saliva, urine, or feces were all infectious for virus-negative bank voles, indicating that these 3 transmission routes may occur in nature and that rodent saliva might play a role in transmission to humans.

Migrating birds and tickborne encephalitis virus

During spring and autumn 2001, we screened 13,260 migrating birds at Ottenby Bird Observatory, Sweden, and found 3.4% were infested with ticks. Four birds, each a different passerine species, carried tickborne encephalitis virus (TBEV)–infected ticks (Ixodes ricinus). Migrating birds may play a role in the geographic dispersal of TBEV-infected ticks.

A molecular link between malaria and Epstein-Barr virus reactivation

Although malaria and Epstein–Barr (EBV) infection are recognized cofactors in the genesis of endemic Burkitt lymphoma (BL), their relative contribution is not understood. BL, the most common paediatric cancer in equatorial Africa, is a high-grade B cell lymphoma characterized by c-myc translocation. EBV is a ubiquitous B lymphotropic virus that persists in a latent state after primary infection, and in Africa, most children have sero-converted by 3 y of age. Malaria infection profoundly affects the B cell compartment, inducing polyclonal activation and hyper-gammaglobulinemia. We recently identified the cystein-rich inter-domain region 1α (CIDR1α) of the Plasmodium falciparum membrane protein 1 as a polyclonal B cell activator that preferentially activates the memory compartment, where EBV is known to persist. Here, we have addressed the mechanisms of interaction between CIDR1α and EBV in the context of B cells. We show that CIDR1α binds to the EBV-positive B cell line Akata and increases the number of cells switching to the viral lytic cycle as measured by green fluorescent protein (GFP) expression driven by a lytic promoter. The virus production in CIDR1α-exposed cultures was directly proportional to the number of GFP-positive Akata cells (lytic EBV) and to the increased expression of the EBV lytic promoter BZLF1. Furthermore, CIDR1α stimulated the production of EBV in peripheral blood mononuclear cells derived from healthy donors and children with BL. Our results suggest that P. falciparum antigens such as CIDR1α can directly induce EBV reactivation during malaria infection that may increase the risk of BL development for children living in malaria-endemic areas. To our knowledge, this is the first report to show that a microbial protein can drive a latently infected B cell into EBV replication.

Malaria and Epstein–Barr virus (EBV) infections are recognized cofactors in the genesis of endemic Burkitt lymphoma, the most common paediatric cancer in equatorial Africa. EBV is a ubiquitous virus residing in B lymphocytes that establishes a lifelong persistence in the host after primary infection. EBV has two lifestyles: latent infection (non-productive), and lytic replication (productive). Children living in malaria-endemic areas exhibit an elevated viral load, and acute malaria infection increases the levels of circulating EBV. The mechanisms leading to viral reactivation during Plasmodium falciparum malaria infection are not well understood. Cystein-rich inter-domain region 1α (CIDR1α) is a domain of a large protein expressed at the surface of P. falciparum–infected red blood cells. Based on previous findings showing that CIDR1α activates and expands the B cells compartment where EBV persists, we assessed the impact of CIDR1α on viral reactivation. Here, we identify CIDR1α as the first microbial protein able to drive a latently EBV-infected B cell (no virus production) into lytic replication (virus production). Our results suggest that P. falciparum–derived proteins can lead to a direct reactivation of EBV during acute malaria infection, increasing the risk of Burkitt lymphoma development for children living in malaria-endemic areas.

Plasma Titers of Antibodies against Epstein-Barr Virus BZLF1 and Risk of Multiple Sclerosis

BACKGROUND/AIMS

Results of recently conducted prospective studies have demonstrated that the presence of high titers of anti-EBNA-1 or anti-EBNA complex IgG antibodies in healthy individuals is a strong risk factor for multiple sclerosis (MS). Antibodies to BZLF1, the product of the homonymous early lytic gene, have been found to be related to risk of nasopharyngeal carcinoma, but have not been previously measured in MS studies.

METHODS

We examined whether high levels of anti-BZLF1 IgG antibodies also predict MS risk in a nested case-control study among women in the Nurses Health Study and Nurses Health Study II cohorts.

RESULTS

Results of this prospective study suggest that antibody titers to EBNAs are the strongest predictor of MS risk.

CONCLUSION

Little further contribution may be provided by measuring anti-BZLF1 antibodies in regard to MS risk.

Post-transplant lymphoproliferative disease and other Epstein-Barr virus diseases in allogeneic haematopoietic stem cell transplantation after introduction of monitoring of viral load by polymerase chain reaction

The clinical value of monitoring of Epstein-Barr virus (EBV) viraemia by quantitative polymerase chain reaction during 1 y was evaluated. 39 recipients of allogeneic hematopoietic stem cell transplantation (SCT) were followed. More than 100 EBV genome equivalents (gEq)/ml in blood or plasma were found in 16/39 patients (41%) at 34 d (range 1-139) post-transplant. Seven of these 16 patients developed EBV disease; 3 post-transplant lymphoproliferative disease (PTLD), 1 myelitis, 1 encephalitis and 2 reactivations with fever. EBV diseases were only found in the high-risk group among recipients of mismatched related or unrelated donor grafts or in patients who underwent reduced-intensity conditioning. In this group, 3/20 (15%) developed PTLD. Conditioning with antithymocyte globulin was significantly associated with EBV disease (p<0.01). EBV load in plasma was more strongly associated with EBV disease than viral load in blood. A cut-off level of 1000 gEq/ml plasma distinguished EBV disease from asymptomatic viraemia, but not PTLD from other EBV diseases. Weekly monitoring of EBV load in plasma in high-risk patients in the first 3 months following SCT seems to be of value for prediction of EBV disease. Therapy for PTLD including rituximab was evaluated during 2 y and showed response in 4/6 cases.

Nitric oxide and peroxynitrite have different antiviral effects against hantavirus replication and free mature virions

Reactive nitrogen intermediates (RNI), like nitric oxide (NO) and peroxynitrite, have antiviral effects against certain viruses. Hantaviruses, like other members of the Bunyaviridae family, have previously not been shown to be sensitive to RNI. In this study, we compared the effects of NO and peroxynitrite on hantavirus replication and free mature virions in vitro, and of inducible nitric oxide synthase (iNOS) in hantavirus‐infected suckling mice. The NO‐generating compound S‐nitroso‐N‐acetylpenicillamine (SNAP), as well as cytokine‐induced NO, strongly inhibited hantavirus replication in Vero E6 cells, while pretreatment of free virions with SNAP only had a limited effect on their viability. In contrast, 3‐morpholinosydnonimine hydrochloride (SIN‐1), a peroxynitrite donor, inhibited virus replication only to a very low extent in vitro, but pretreatment of virus with SIN‐1 led to a considerably lowered viability of the virions. Infections of various human cell types per se did not induce NO production. The viral titers in iNOS^–/– mice were higher compared to the controls, suggesting that NO inhibits hantavirus replication in vivo. In conclusion, we show that NO has strong antiviral effects on hantavirus replication, and peryoxynitrite on mature free virions, suggesting that different RNI can have different effects on various parts of the replication cycle for the same virus.

Variation in DNA repair genes ERCC2, XRCC1, and XRCC3 and risk of follicular lymphoma

The reasons for the positive association between skin cancer and non-Hodgkin's lymphoma are not known but may be due to common susceptibility involving suboptimal DNA repair. Therefore, we investigated selected polymorphisms and haplotypes in three DNA repair genes, previously associated with skin cancer and DNA repair capacity, in risk of follicular lymphoma, including possible gene interaction with cigarette smoking and sun exposure. We genotyped 19 single nucleotide polymorphisms (SNP) in the ERCC2, XRCC1, and XRCC3 genes in 430 follicular lymphoma patients and 605 controls within a population-based case-control study in Denmark and Sweden. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using unconditional logistic regression and haplotype associations were assessed with a global score test. We observed no associations between variation in the ERCC2 and XRCC1 genes and follicular lymphoma risk. In XRCC3, increased risk of follicular lymphoma was suggested for rare homozygotes of three SNPs [Rs3212024: OR, 1.8 (95% CI, 1.1-2.8); Rs3212038: OR, 1.5 (95% CI, 1.0-2.4); Rs3212090: OR, 1.5 (95% CI, 1.0-2.5)]. These results were strengthened in current cigarette smokers. However, evidence of differences in XRCC3 haplotype distributions between follicular lymphoma cases and controls was weak, both overall and in current smokers. We conclude that polymorphic variation in the XRCC3 gene, but not in ERCC2 or XRCC1, may be of importance for susceptibility to follicular lymphoma, perhaps primarily in current smokers. The link between skin cancer and follicular lymphoma is unlikely to be mediated through common variation in the studied DNA repair gene polymorphisms.

Exogenous nitric oxide inhibits Crimean Congo hemorrhagic fever virus

Crimean Congo hemorrhagic fever virus (CCHFV) is a geographically widespread pathogen that causes severe hemorrhagic fever with high mortality. Even though one of the main objectives focuses on the progress of antiviral agents, the research on CCHFV is strongly hampered due to its BSL-4 classification. Nitric oxide (NO), a mediator with broad biological effects, has been shown to possess inhibitory properties against various pathogens. The molecule constitutes a component of the innate immunity and serves to assist in the early immunological events where it contributes to clearance of microorganisms. In this study, we investigated the inhibitory properties of exogenous NO on CCHFV. We found that NO had a significant antiviral activity against CCHFV replication. By using the NO-donor S-nitroso-N-acetylpenicillamine (SNAP) we were able to show up to 99% reduction in virion progeny yield. In contrast, 3-morpholinosydnonimine hydrochloride (SIN-1), a peroxynitrite donor, had no significant antiviral activity against CCHFV. Furthermore the expression of viral proteins; the nucleocapsid protein and the glycoprotein, were clearly reduced with increasing concentrations of SNAP. We have also shown that the amount of total vRNA in SNAP-treated cells was reduced by about 50% compared to the controls.

Clearance of Circulating Epstein‐Barr Virus DNA in Children with Acute Malaria after Antimalaria Treatment

Children living in malaria-endemic regions have a high incidence of Burkitt lymphoma (BL), the etiology of which involves Plasmodium falciparum malaria and Epstein-Barr virus (EBV) infections. In the present study, we compared EBV DNA loads in plasma and saliva samples from Ugandan children with acute malaria (M+) at the time of diagnosis and 14 days after antimalaria treatment, children without malaria (M-), and children with BL. EBV DNA was detected, by real-time polymerase chain reaction, in 31% of the plasma and in 79% of the saliva samples from children in the M+ group. Antimalaria treatment led to clearance of plasma viral load in 85% of the cases but did not affect the levels in saliva. There was a significant difference in plasma EBV loads across the groups. The lowest levels were detected in samples from the M- group, increased levels were detected in samples from the M+ group, and levels reached the highest values in samples from children with BL. The same trend was evident in the frequency and levels of anti-BZLF1 antibodies, which is indicative of viral reactivation. In the M+ group, the positive plasma samples clustered around 7-9 years of age, the peak incidence of BL. The clearance of circulating EBV after antimalaria treatment suggests a direct relationship between active malaria infection and viral reactivation.

DNA microarray technique for detection and identification of seven flaviviruses pathogenic for man

A flavivirus microarray was developed for detection and identification of yellow fever (YF), West Nile, Japanese encephalitis (JE), and the dengue 1-4 viruses, which are causing severe human disease all over the world. The microarray was based on 500-nucleotide probe fragments from five different parts of the seven viral genomes. A low-stringent amplification method targeting the corresponding regions of the viral genomic RNA was developed and combined with hybridization to the microarray for detection and identification. For distinction of the generated virus-specific fluorescence-patterns a fitting analysis procedure was adapted. The method was verified as functional for all seven flaviviruses and the strategy for the amplification, combined with the long probes, provided a high tolerance for smaller genetic variability, most suitable for these rapidly changing RNA viruses. A potentially high detection and identification capacity was proven on diverged strains of West Nile and dengue viruses. The lower limit for detection was equivalent, or better, when compared to routinely used RT-PCR methods. The performance of the method was verified on human patient samples containing dengue viruses, or normal human serum spiked with YF or JE viruses. The results demonstrated the ability of the flavivirus microarray to screen simultaneously a sample for several viruses in parallel, in combination with a good lower limit of detection.

Ganciclovir is associated with low or undetectable Epstein-Barr virus DNA load in cerebrospinal fluid of patients with HIV-related primary central nervous system lymphoma

BACKGROUND

Epstein-Barr virus (EBV) is pathogenically linked to human immunodeficiency virus (HIV)-related primary central nervous system lymphoma (PCNSL) and is found in virtually all HIV-related PCNSL cases. The objective of this study was to assess the effect of ganciclovir on EBV DNA replication in patients with HIV-related PCNSL.

PATIENTS AND METHODS

EBV DNA was measured by real-time polymerase chain reaction in cerebrospinal fluid and plasma samples from 25 patients with HIV-related PCNSL. Eight of these patients were receiving ganciclovir for concurrent cytomegalovirus infections.

RESULTS

EBV DNA was detected in cerebrospinal fluid samples obtained from 15 (88%) of 17 ganciclovir-untreated patients and 4 (50%) of 8 ganciclovir-treated patients (P = .028). EBV DNA load was significantly lower for treated patients, compared with untreated patients (median value, 2.15 vs. 4.16 log copies/mL; P = .001). Analysis of sequential cerebrospinal fluid samples from 7 patients showed that EBV DNA decreased in samples obtained from 2 patients following the start of ganciclovir administration but did not decrease in samples obtained from the 5 untreated patients. In addition, patients who received ganciclovir survived longer than the untreated patients (median duration of survival, 181 vs. 72 days; P = .006).

CONCLUSION

The effect of ganciclovir on EBV DNA load in cerebrospinal fluid supports the hypothesis that EBV is replicating in patients with PCNSL. This observation, together with the effect of ganciclovir therapy on patient survival, suggests that this drug might be useful for the management of PCNSL.

Loss of IL-7Ralpha is associated with CD4 T-cell depletion, high interleukin-7 levels and CD28 down-regulation in HIV infected patients

OBJECTIVE

Elevated levels of interleukin (IL)-7 are present in the blood of HIV-positive patients and it is known that IL-7 receptor (IL-7R)alpha expression decreases on T cells during HIV infection. The subset(s) of T cells with low IL-7Ralpha and the consequence of low IL-7Ralpha expression for T-cell survival are poorly characterized.

DESIGN

The frequency of IL-7Ralpha-negative T cells in HIV-positive patients was studied in relation to CD4 T-cell counts, IL-7 concentration and survival in culture. We analysed IL-7Ralpha expression in different T-cell populations and in relation to Bcl-2 expression.

METHODS

Specimens from 38 HIV-1 patients and 17 controls were examined. IL-7Ralpha and Bcl-2 expression in different T-cell populations was studied by flow cytometry. The influence of IL-7Ralpha expression on T-cell survival was studied by culturing T cells in the presence of IL-7.

RESULTS

Down-regulation of IL-7Ralpha on T cells correlated with depletion of CD4 T cells (P < 0.001) and also with increased concentration of serum IL-7 (P < 0.05). The decreased IL-7Ralpha expression was associated with low Bcl-2 expression and with the reduced survival capacity of T cells in the presence of IL-7 in vitro. Particularly, T cells with memory phenotype showed a decreased IL-7Ralpha expression in association with CD28 down-regulation.

CONCLUSIONS

The positive effects of IL-7 on survival and homeostatic proliferation of T cells might be severely impaired in HIV-infected individuals due to IL-7Ralpha down-regulation. Differentiation towards a CD28-negative memory phenotype in response to chronic activation may lead to an overall decrease of IL-7 mediated survival within the peripheral T-cell pool.

Optimized diagnosis of acute dengue fever in Swedish travelers by a combination of reverse transcription-PCR and immunoglobulin M detection

The dengue viruses (genus Flavivirus, family Flaviviridae) are mosquito borne and cause 100 million cases of dengue fever each year in most tropical and subtropical areas of the world. Increased global travel has been accompanied by an increased import not only of dengue but also of severe fevers of unknown origin to Sweden. Fifty-seven Swedish travelers to dengue epidemic areas, with clinical and serologically diagnosed dengue fever, were included in this study. To find fast and reliable methods to diagnose dengue in the early phase of the disease, patient acute-phase sera were investigated for the presence of dengue-specific immunoglobulin M (IgM) antibodies by enzyme-linked immunosorbent assay (ELISA) and also for dengue serotype (DEN-1 to DEN-4)-specific RNA by different PCR assays. The results showed that 15/20 (75%) of the samples collected 5 days or later post onset of disease, but only 5/37 (14%) of the samples collected on days 0 to 4, contained dengue-specific IgM. Of the samples collected on days 0 to 4 post onset, dengue RNAs of subtypes 1, 2, and 3 were detected by multiplex and/or by TaqMan PCR in 29/37 (78%); of these PCR-positive samples, 93% (27/29) were found IgM negative. By a combination of IgM ELISA and PCR assays, 84% (48/57) of the acute-phase samples were found to be positive. Our results demonstrated that detection of dengue viral RNA by reverse transcription-PCR and Taq-Man PCR is an excellent tool for the early diagnoses of dengue fever and that the IgM assay is a reliable complement for samples collected from day 5 post onset.

OKT3 and ganciclovir treatments are possibly related to the presence of Epstein-Barr virus in serum after liver transplantation

The development of Epstein-Barr virus (EBV) associated lymphoproliferative disorder (PTLD) is related to EBV genome numbers in serum or plasma and B-cells, and the level of immunosuppression. EBV DNA viremia, defined as presence of EBV genomes in serum or plasma, is common in immunodeficiency. This survey of EBV viremia was performed by real-time polymerase chain reaction (PCR) on consecutive serum samples of 21 patients with acute (n = 3) or chronic liver disease (n = 18) during the first year after liver transplantation (LTX). Cytomegalovirus (CMV) DNA was analyzed with PCR in serum or leukocytes. The levels of EBV and CMV viremia were related to PTLD and the effect of different anti-rejection regimens. All patients were EBV-seropositive pre-LTX. In total, 24 of 152 (16%) samples from 10 of 21 (48%) individuals were EBV positive [five of 11 cyclosporin A (CsA); five of 10 tacrolimus treated cases]. EBV viremia was demonstrated in five of seven patients with OKT3 therapy. The number of EBV DNA positive samples was highest (26%) at 14 days after LTX. In the OKT3 treated groups, the medians of EBV DNA copy numbers were 1600/ml (range 230-7200) and 380/ml (range 120-860) in the CsA and tacrolimus patients, respectively (P < 0.02). One patient developed EBV lymphoma and another one EBV hepatitis 13 months and 24 days post-LTX, respectively. Both patients had received OKT3. Their EBV genome load was not significantly different from what was found in other patients. After ganciclovir therapy, EBV DNA was eradicated from serum in four of five patients for several months. EBV DNA load was not affected by CMV infection or disease. We conclude that presence of EBV in serum is a possible marker of an active infection and an early ganciclovir therapy may be beneficial. Quantification of EBV load offers the potential to implement pre-emptive interventions.

Circulating epstein-barr virus in children living in malaria-endemic areas

Children living in malaria-endemic regions have high incidence of Burkitt's lymphoma (BL), the aetiology of which involves Plasmodium falciparum malaria and Epstein-Barr virus (EBV) infections. Acute malarial infection impairs the EBV-specific immune responses with the consequent increase in the number of EBV-carrying B cells in the circulation. To further understand the potential influence of malarial infection on the EBV persistence in children living in malaria-endemic areas, we studied the occurrence and quantified cell-free EBV-DNA in plasma from 73 Ghanaian children with and without acute malarial infection. Viral DNA was detected in 40% of the samples (47% in the malaria-infected and 34% in the nonmalaria group) but was absent in plasma from Ghanaian adults and healthy Italian children. These findings provide evidence that viral reactivation is common among children living in malaria-endemic areas, and may contribute to the increased risk for endemic BL. The data also suggest that the epidemiology of EBV infection and persistence varies in different areas of the world.

Delayed viremia and antibody responses in Puumala hantavirus challenged passively immunized cynomolgus macaques

No specific therapy is currently available against hemorrhagic fever with renal syndrome (HFRS) or hantavirus pulmonary syndrome. In order to study if passive immunization could inhibit hantavirus infection and/or symptoms, we inoculated two cynomolgus macaques with neutralizing monoclonal antibodies and subsequently challenged them with wild-type Puumala virus (PUUV), recently shown to induce typical signs of milder HFRS in cynomolgus macaques. Although viral load and antibody titers did not differ substantially as compared to the two control monkeys, a delayed onset of viremia and seroconversion was observed in the immunized monkeys. Interestingly, one of the immunized monkeys showed no symptoms, nor elevated of levels of IL-6, IL-10, and TNF-alpha, while the other developed severe symptoms and elevated levels of those cytokines, believed to be involved in PUUV-pathogenesis.

An international external quality assessment of nucleic acid amplification of herpes simplex virus

BACKGROUND

There is an increasing awareness of the need for external quality control of diagnostic virology.

OBJECTIVES

To assess the quality of nucleic acid amplification tests (NAT) of herpes simplex within Europe.

STUDY DESIGN

Herpes simplex virus (HSV) proficiency panels were produced at the Swedish Institute for Infectious Disease Control on behalf of the European Union Concerted Action for Quality Control of Nucleic Acid Amplification in 1999 and 2000. Nine reference laboratories evaluated the production process. Each panel consisted of 12 coded samples with various concentrations of inactivated, freeze-dried HSV type 1 (HSV-1), and HSV type 2 (HSV-2), or negative controls. Positive samples included HSV-1 and HSV-2 in a range of concentrations (2 x 10(2) to 2 x 10(7) genome copies per ml) similar to those found in cerebrospinal fluids from patients with HSV encephalitis.

RESULTS

Sixty-six participants reported a total of 76 data sets for panel 1, and 71 reported 78 data sets for panel 2. The majority of the participants employed qualitative 'in-house' polymerase chain reaction (PCR) methods, either in a single, nested or semi-nested format. For panel 2, 9 laboratories reported use of 'real-time' PCR in contrast to 3 for panel 1. Three laboratories submitted quantitative results on both panels. Thirty percent of the data sets had correct results for the entire panel 1. In 6 data sets (8%) a total of 11 false positive results were reported. For panel 2, 28% of the data sets had correct result. Nineteen false positive results were reported in 14 data sets (18%), but most of the incorrect results reflected a lack of test sensitivity.

CONCLUSIONS

The relatively high frequency of false positive results and the large number of false-negative results, albeit at low copy number, stress the need for improvement in the quality of HSV NAT and for external quality control programmes.

A multiplex real-time PCR for quantification of HIV-1 DNA and the human albumin gene in CD4+ cells

We have established a simple system for measuring HIV-1 DNA load in CD4+ cells. In a multiplex configuration, a conserved region in the HIV-1 pol gene and a section of the human albumin gene were simultaneously amplified to estimate the number of HIV-1 DNA copies per cellular genome. An established Epstein-Barr virus (EBV) standard system was used to calibrate the HIV-1 quantification. Our multiplex PCR system was tested on different in vitro developed HIV-1 strains and on longitudinal samples from eight patients. The system was able to amplify both in vitro and in vivo samples of various genetic compositions. In all eight patients, HIV-1 DNA was detected and ranged between 0.17 and 51x10-3 copies per CD4+ cell and could be monitored longitudinally, including long-term PI-ART and STI. The measured HIV-1 DNA load may be used to select the best time for the institution or re-institution of therapy.

HIV type 1 DNA development during long-term supervised therapy interruption

We studied the pattern of HIV-1 DNA development and the association to other HIV-related factors during long-term supervised therapy interruption (LT-STI). Fifteen patients were treated with long-time protease inhibitor-based antiretroviral therapy (PI-ART). They had HIV-1 RNA at <50 copies/ml over 33.4 (SD 9.5) months and CD4(+) cell counts of 875 (SD 415) x 10(6)/liter. A real-time polymerase chain reaction, amplifying fragments of the HIV-1 pol gene and the human albumin gene simultaneously, was used to quantify HIV-1 DNA molecules in CD4(+) cells. The quantity of HIV-1 DNA in CD4(+) cells increased during LT-STI in all 15 patients, with an average doubling time of 2 months. Tentatively, three patterns were observed: rapid initial increase with subsequent stabilizing levels, rapid continuous increase, and slow increase. The HIV-1 DNA slope was positively related to the HIV-1 RNA maximum and steady state level and the baseline HIV-1 DNA value. It was inversely related to the decrease in CD4(+) cells both before the start of PI-ART and during the LT-STI. To conclude, HIV-1 DNA persists in infected CD4(+) cells despite long-term effective PI-ART and will increase after therapy interruption. The most important clinical predictor of long-term STI failure was the rapid CD4(+) cell decline before PI-ART. In patients with a steep pre-PI-ART slope it may be prudent to continue treatment and not initiate therapy interruption.

Epstein-Barr virus DNA load in cerebrospinal fluid and plasma of patients with AIDS-related lymphoma

Detection of Epstein-Barr virus (EBV) DNA in the cerebrospinal fluid (CSF) is associated with acquired immunodeficiency syndrome (AIDS)-related brain lymphoma. Real-time polymerase chain reaction (PCR) was performed to quantify EBV DNA in CSF and plasma from 42 patients with AIDS-related non-Hodgkin's lymphoma (NHL). Twenty patients had primary central nervous system lymphoma (PCNSL) and 22 systemic NHL, including 12 with central nervous system involvement (CNS-NHL). As controls, 16 HIV-infected patients with other CNS disorders were examined. EBV DNA was detected in the CSF from 16/20 (80%) patients with PCNSL, 7/22 (32%) with systemic NHL, 8/12 (67%) with CNS-NHL, and 2/16 (13%) of the controls. The viral EBV DNA levels were significantly higher in the CSF from patients with PCNSL or CNS-NHL compared to patients with systemic NHL or controls. EBV DNA was detected in plasma from 5/16 (31%) patients with PCNSL, 9/16 (56%) with systemic NHL, 4/9 (44%) with CNS-NHL, and 4/15 (27%) controls. No difference in plasma viral load was found between patient groups. From the patients with CNS-NHL, plasma samples drawn prior to CNS involvement contained significantly higher EBV DNA levels than those from systemic NHL patients without subsequent CNS involvement. EBV DNA levels in the CSF, but not in plasma, from patients treated with antiherpes drugs were significantly lower than in untreated patients. High CSF EBV DNA levels were found in HIV-associated brain lymphomas and the viral load can be clinically useful. High plasma EBV DNA levels might predict CNS involvement in systemic NHL.

Detection of Epstein-Barr Virus, but not Human Herpesvirus 8, DNA in Cervical Secretions From Swedish Women by Real-Time Polymerase Chain Reaction

BACKGROUND

Epstein-Barr virus (EBV) and human herpesvirus 8 (HHV-8) are two related herpesviruses that may be sexually transmitted.

GOAL

To examine the presence of HHV-8 and EBV DNA in the female genital tract.

STUDY DESIGN

Real-time polymerase chain reaction systems for quantification of DNA from HHV-8, EBV, and herpes simplex virus type 2 were developed and used for examination of cervical secretions from 112 Swedish women. HHV-8, EBV, and herpes simplex virus type 2 serology was also performed on samples from all subjects.

RESULTS

EBV DNA was found in 10 cervical secretion samples, sometimes in high amounts. No cervical secretion or leukocyte sample contained detectable HHV-8 DNA. Antibodies to HHV-8-latent and -lytic antigens were found in 2.7 % and 24% of serum samples, respectively.

CONCLUSION

This study supports a possible sexual route of transmission for EBV but not for HHV-8. The new real-time polymerase chain reaction systems could be valuable in future studies of relations between virus load and disease.

A repetitive sequence of Epstein-Barr virus nuclear antigen 6 comprises overlapping T cell epitopes which induce HLA-DR-restricted CD4(+) T lymphocytes

Most human adults carry the Epstein-Barr virus (EBV) and develop immunological memory against the structural and the virus-encoded cellular proteins. The EBV nuclear antigen 6 (EBNA6) elicits cytotoxic T cell responses and it also maintains a persistent antibody response. The majority of sera from EBV-seropositive individuals reacts with a synthetic peptide, p63, comprising 21 amino acids of a repetitive region of EBNA6. CD4(+) T lymphocytes, with specificity for p63, could be recalled from the T cell repertoire of EBV carriers that expressed certain HLA-DR allotypes which were identified as good binders of p63 by an in vitro flow cytometric assay. Analysis of the HLA-DR/p63 interaction by molecular mechanics calculations indicated the presence of multiple overlapping epitopes which were predicted to bind in a HLA-DRB1 allo- and subtype-specific manner. Specific activation of p63-selected long-term CD4(+) T cell cultures resulted in a proliferative response, in the production of IL-2 and in the secretion of high levels of tumor necrosis factor as measured by bioassays. Proliferation and cytokine production of p63-specific T cells could be induced by p63-loaded HLA-DR-matched antigen-presenting cells and by B cells co-expressing relevant HLA-DR molecules and EBNA6. Our results show that peptides of an EBNA6 repeat region induce CD4(+) T cells which can react with EBNA6-carrying cells in many individuals. We suggest that these T(h) cells may be important in conditioning dendritic cells for initiation potent virus-specific immune responses, provide help for EBV-specific B cells, drive IgG isotype switch and support the sustained effector function of memory cytotoxic T lymphocytes.

Demethylation of the Epstein-barr virus origin of lytic replication and of the immediate early gene BZLF1 is DNA replication independent. Brief report

Epstein-Barr virus (EBV) episomal DNA is extensively methylated in Burkitt lymphoma derived cell lines. In this study we examined whether lytic viral cycle reactivation is dependent on demethylation of critical viral genes. Viral replication was induced in the Burkitt's lymphoma cell line Daudi by the combination of 12-O-tetradecanoylphorbol-13-acetate (TPA) and sodium-butyrate. Two regions necessary for EBV replication, the BZLF1 immediate early region and the origin of lytic cycle replication (ori Lyt) were demethylated during the early phase of the lytic virus cycle. Demethylation was observed while production of new (unmethylated) viral DNA was blocked by phosphonoformic acid (PFA). This suggests that demethylation, which may be instrumental for the onset of the lytic cycle, is an active process independent of viral DNA replication

Horizontal transfer of DNA by the uptake of apoptotic bodies

In this study we have raised the question of whether DNA can be transferred from one cell to another by phagocytosis of apoptotic bodies. We have used integrated copies of the Epstein-Barr virus (EBV) as a marker to follow the fate and expression pattern of apoptotic DNA in the phagocytotic host. Apoptosis was induced in EBV-carrying cell lines by irradiation before cultivation with either human fibroblasts, macrophages, or bovine aortic endothelial cells. Analysis of the expression pattern of EBV-encoded genes was performed by immunofluorescent staining as well as in situ hybridization. Cocultivation of apoptotic bodies from lymphoid cell lines containing integrated but not episomal copies of EBV resulted in expression of the EBV-encoded genes EBER and EBNA1 in the recipient cells at a high frequency. Fluorescence in situ hybridization analysis showed uptake of human chromatin as well as integrated EBV-DNA into the nuclei of bovine aortic endothelial cells. These data show that DNA may be rescued and reused from apoptotic bodies by somatic cells. In addition, our findings suggest that apoptotic bodies derived from EBV-carrying B lymphocytes may serve as the source of viral transfer to cells that lack receptors for the EBV virus in vivo.

Visualization of alternative Epstein-Barr virus expression programs by fluorescent in situ hybridization at the cell level

Epstein-Barr virus (EBV) transforms human B lymphocytes into immortalized lymphoblastoid cell lines (LCLs). They regularly express six virally encoded nuclear proteins (EBNA1 to EBNA6) and three membrane proteins (LMP1, LMP2A, and LMP2B). In contrast, EBV-carrying Burkitt lymphoma (BL) cells in vivo and derived type I cell lines that maintain the BL phenotype express only EBNA1. During prolonged in vitro culturing, most EBV-carrying BL lines drift toward a more immunoblastic (type II or III) phenotype. Their viral antigen expression is upregulated in parallel. We have used fluorescent in situ hybridization to visualize viral transcripts in type I and III BL lines and LCLs. In type I cells, EBNA1 is encoded by a monocistronic message that originates from the Qp promoter. In type III cells, the EBNA1 transcript is spliced from a giant polycistronic message that originates from one of several alternative Wp or Cp promoters and encodes all six EBNAs. We have obtained a "track" signal with a BamHI W DNA probe that could hybridize with the polycistronic but not with the monocistronic message in two type III BL lines (Namalwa-Cl8 and MUTU III) and three LCLs (LCL IB4-D, LCL-970402, and IARC-171). A BamHI K probe that can hybridize to both the monocistronic and the polycistronic message visualized the same pattern in the type III BLs and the LCLs as the BamHI W probe. A positive signal was obtained with the BamHI K but not the BamHI W probe in the type I BL lines MUTU I and Rael. The RNA track method can thus distinguish between cells that use a type III and those that use a type I program. The former cells hybridize with both the W and the K probes, but the latter cells hybridize with only the K probe. Our findings may open the way for studies of the important but still unanswered question of whether cells with type I latency arise from immunoblasts with a full type III program or are generated by a separate pathway during primary infection.

Specific methylation patterns in two control regions of Epstein-Barr virus latency: the LMP-1-coding upstream regulatory region and an origin of DNA replication (oriP)

The Epstein-Barr virus (EBV) can establish at least four different forms of latent infection. Previously, we have shown that the level of methylation of the EBV genome varies, depending on the form of latency. The methylation status of CpGs was analyzed by the bisulfite genomic sequencing technique in four different cell types representing different forms of latency. The dyad symmetry element of the origin of replication (oriP) region and the latent membrane protein 1 (LMP-1) regulatory sequence (LRS) were studied. The dyad symmetry element has four binding sites for EBNA-1. In a cell with type I latency, a region upstream of the dyad symmetry element was highly methylated, whereas the dyad symmetry element was unmethylated in the EBNA-1-binding region. The LRS was extensively methylated in the LMP-1-negative cell line Rael, in contrast to a LMP-1-expressing nasopharyngeal carcinoma tumor (NPC C15), which was almost completely unmethylated. The methylation pattern of LRS in type I and type III Burkitt lymphoma cells of similar parental origins confirmed that demethylation of some regions takes place upon phenotypic drift.

Direct identification by PCR of EBV types and variants in clinical samples

Both Epstein-Barr virus (EBV) type A and type B, and variants of type A, were identified simultaneously by polymerase chain reaction (PCR) amplification of a DNA region coding for a 13 amino acid repeat in the Epstein-Barr virus nuclear antigen (EBNA) 6. Whereas this region varies extensively in type A isolates, no variation was seen in type B isolates. When a repetitive region in the LMP1-coding region was amplified by PCR, it was possible to distinguish individual variants of type B isolates from each other. Forty-two saliva samples from HIV-1-carrying individuals were examined for the presence of type A and type B virus. Both types and multiple variants of each type were found with a much higher frequency than in the saliva samples from healthy individuals. Type A EBV alone was detected in mouthwash samples from 6 infectious mononucleosis (IM) patients. Both type A and B were detected in the peripheral blood B-lymphocytes (PBL) from 1 healthy individual. The same type A variant was demonstrated both in PBL and in the mouthwash sample from another healthy individual. In this study it was shown that a combination of the EBNA 6- and LMP 1-specific PCRs followed by Southern hybridisation can be used to identify both type A and type B virus, as well as to distinguish between multiple variants of the same strain, in saliva and B-cells from both healthy and immunosuppressed individuals.

Rapid occurrence of lymphoproliferative disease after pancreas-kidney transplantation performed during acute primary Epstein-Barr virus infection

Generalized lymphoproliferative disease occurred in a 30-year-old woman 15 days after she underwent simultaneous pancreas-kidney transplantation. Because of the rapid progression of this disorder, it was necessary to remove the grafts and discontinue immunosuppression 19 days after transplantation. Serological analysis demonstrated that the patient, who was Epstein-Barr virus (EBV)-seronegative 3 months before, was seroconverting at the time of the transplantation. EBV therefore was acquired just before the transplantation, either by a blood transfusion 4 months earlier or from the patient's EBV-positive boyfriend. The latter source appeared most likely, as concluded from the investigation of the EBV strains from the patient's boyfriend and from the blood and organ donors. Donor origin of lymphoblastoid cells was excluded by sex chromosomal analysis. Initiation of immunosuppression during a primary EBV infection carries the risk of very rapid development of B-cell lymphoproliferative disease. This emphasizes the need for active monitoring of EBV infections in transplant recipients and for the development of preventive strategies.

Transmission of donor Epstein-Barr virus (EBV) in transplanted organs causes lymphoproliferative disease in EBV-seronegative recipients

Epstein-Barr virus (EBV) is associated with post-transplant lymphoproliferative disease (PTLD). To determine whether the donor EBV isolate is transmitted to the recipient via the allograft and causes PTLD, EBV isolates from four cases of PTLD in cadaveric heart and/or lung transplant recipients were compared with the donor isolates by PCR and DNA sequence analysis. Two recipients who were EBV seronegative at transplantation acquired an EBV isolate indistinguishable from that of the donor and developed PTLD. In contrast, in two patients who were seropositive before transplantation, the donor isolate differed from that present in PTLD of the recipient. The results suggest that the acquisition of donor EBV is a risk factor for PTLD development in a previously seronegative transplant recipient.