Detection of EBV RNA (EBER-1 and EBER-2) in malaria lymph nodes by in situ hybridization

Acute Plasmodium falciparum malaria in African children allows expansion of latent Epstein-Barr virus infection, leading to colonization of lymph nodes by virus-infected lymphoblasts in 60% of cases as demonstrated by in situ hybridization for the detection of EBER-1 and EBER-2 RNA. This probably arises against a background of malaria-induced immunosuppression to EBV and concurrent lymphoid activation. The relevance of the results to the pathogenesis of African endemic Burkitt's lymphoma is discussed.

DNA viruses in the pathogenesis of sporadic chronic idiopathic intestinal pseudo-obstruction

BACKGROUND

Hereditary forms of chronic idiopathic intestinal pseudo-obstruction (CIIP) are well described but the aetiology of most cases of sporadic CIIP is unknown.

AIM

To determines whether herpes viruses can persist in the gastrointestinal tract, thereby implicating them in the pathogenesis of CIIP.

METHODS

Twenty one specimens of small and large intestine from 13 patients with CIIP (eight visceral myopathy, three visceral neuropathy, two undifferentiated), and 12 patients operated on for colorectal cancer (controls) were examined for evidence of Herpesvirus DNA (cytomegalovirus, Epstein-Barr virus (EBV), herpes simplex virus type 1, and varicella zoster virus) by nested polymerase chain reaction (PCR) and in situ DNA hybridisation (ISH) to localise signal to the muscularis propria or myenteric plexus.

RESULTS

Screening with nested PCR produced three patients with positive results. One patient with an inflammatory visceral neuropathy had EBV detected in the small intestine by PCR, and ISH demonstrated localisation to neurones in the myenteric plexus. A patient with a visceral myopathy had EBV DNA in both the small and large intestine; and one patient with a visceral neuropathy had small intestine positive for CMV DNA (both negative by ISH). No control tissue was positive for any virus.

CONCLUSIONS

In individual patients there appears to be evidence linking a viral aetiology to sporadic CIIP. The role of neurotropic viruses in acute and chronic motility disturbances needs further study.

Epstein-Barr virus-associated Hodgkin's disease: epidemiologic characteristics in international data

Hodgkin's disease (HD) has long been suspected to have an infectious precursor, and indirect evidence has implicated Epstein-Barr virus (EBV), a ubiquitous herpesvirus, as a causal agent. Recent molecular studies using EBER in situ hybridization or latency membrane protein-I (LMP-I) immunohistochemistry have identified EBV latent infection in up to 50% of HD tumors. However, the epidemiologic features of these cases have not been examined in detail. To explore the epidemiology of EBV-positive HD so as to understand the role of EBV in HD etiology more clearly, this project accumulated patient data from 14 studies that had applied these EBV assays to HD tumors. With information on age at diagnosis, sex, ethnicity, histologic subtype, country of residence, clinical stage and EBV tumor status from 1,546 HD patients, we examined risk for EBV-positive disease using logistic regression. Forty percent of subjects had EBV-positive tumors, and EBV prevalence varied significantly across groups defined by the study variables. Odds ratios (OR) for EBV-associated HD were significantly elevated for Hispanics vs. whites (OR = 4.1), mixed cellularity vs. nodular sclerosis histologic subtypes (OR = 7.3, 13.4, 4.9 for ages 0-14, 15-49, 50+ years), children from economically less-developed vs. more-developed regions and young adult males vs. females (OR = 2.5). These findings suggest that age, sex, ethnicity and the physiologic effects of poverty may represent biologic modifiers of the EBV association and confirm that this association is strongly but variably linked to histologic subtype. The data augment biologic evidence that EBV is actively involved in HD pathogenesis in some cases but describe epidemiologic complexity in this process.

Is EBV persistence in vivo a model for B cell homeostasis?

We have measured the absolute numbers of EBV-infected B cells in the peripheral blood of healthy persistently infected individuals. Single measurements on a panel of 15 healthy individuals demonstrate that the frequency varies over a wide range from 1-50 per 10(6) B cells. Repeat measurements over 1-3.5 years on several individuals whose frequencies varied over a 10-fold range showed that the variation does not represent the fluctuation in the frequency that can occur within an individual; rather, the frequencies are specific to the individual. The frequency within an individual measured over time is stable and contributes less than 10% to the variance seen in the whole population. These measurements suggest that the level of EBV-infected B cells is tightly regulated and we propose that the same homeostatic mechanisms that regulate the levels of normal B cells also regulate B cells latently infected with EBV.

The Kaposi sarcoma-associated herpesvirus (KSHV) is present as an intact latent genome in KS tissue but replicates in the peripheral blood mononuclear cells of KS patients

Short DNA sequences have been identified, originally in association with Kaposi's sarcoma (KS) biopsies, that are highly homologous to oncogenic, lymphotropic herpesviruses. Recently a virus, Kaposi sarcoma associated herpesvirus (KSHV) or human herpesvirus-8 (HHV-8), bearing these sequences has been identified in a cell line derived from a body cavity-based lymphoma. In this report, we show that the same sequences are present in KS biopsies as DNA molecules of a form and size characteristic of latent herpesviruses-large, covalently closed, circular episomes. The genomes migrate with an apparent size larger than the herpesvirus Epstein-Barr virus (172 kb). This form of the viral genome was found in four of four biopsies and three of five peripheral blood samples from KS patients. Linear forms of the viral genome, characteristic of viral replication, were not detected in the biopsies, but were present in the peripheral blood of three out of five patients. The sequences for KSHV/HHV-8 were also detected in the blood of four of five allograft patients and three of five healthy donors without KS suggesting that the virus is widespread throughout the human population.

Epstein-Barr virus and the B cell: that's all it takes

Recent experiments demonstrate that a much broader range of B cells harbor Epstein-Barr virus (EBV) in vivo than was previously expected from in vitro studies. In this review it is argued that EBV persists in vivo by integrating its biology with that of the normal B cells within which it resides, and that the B cell provides all the environments necessary for EBV to maintain its life cycle.

Rhabdomyolysis: an unusual complication of cytotoxic chemotherapy

Acute rhabdomyolysis has rarely been reported after cytotoxic chemotherapy, including cytarabine and 5-azacytidine. We observed a case of acute rhabdomyolysis and renal failure after treatment with mitoxantrone and cyclophosphamide. No other cause of muscle injury could be identified, although biochemical analysis of a muscle biopsy specimen revealed a deficiency of muscle phosphorylase activity. Retreatment with doxorubicin and paclitaxel was not associated with recurrent rhabdomyolysis.

Down-regulation of Epstein-Barr virus nuclear antigen 1 in Reed-Sternberg cells of Hodgkin's disease

AIMS

To demonstrate Epstein-Barr virus (EBV) encoded nuclear antigen 1 (EBNA-1) gene expression in EBV associated disorders using a new monoclonal antibody (1H4-1) on routinely processed tissues.

METHODS

The pressure cooker antigen retrieval method was used for the immunohistochemical demonstration of EBNA-1 gene expression in formalin fixed, EBV positive tissues from Hodgkin's disease, infectious mononucleosis, HIV associated non-Hodgkin's lymphomas, post-transplant lymphomas, and undifferentiated nasopharyngeal carcinoma (NPC). EBV encoded EBNA-2, latent membrane protein 1 (LMP-1) and BZLF-1 gene expression was also examined using commercially available monoclonal antibodies.

RESULTS

Of the 34 EBER in situ hybridisation positive cases of Hodgkin's disease examined, none expressed EBNA-1 in the Reed-Sternberg cells. These cells were nevertheless strongly LMP-1 positive in all cases. Strong EBNA-1 staining was seen in all cases of EBER positive HIV associated non-Hodgkin's lymphoma (five of five), nasopharyngeal carcinoma (five of five), infectious mononucleosis (three of three), and post-transplant lymphoma (one of one). These cases also expressed LMP-1, EBNA-2 and BZLF-1, but at differing levels.

CONCLUSION

The pressure cooker antigen retrieval procedure is a sensitive and reliable adjunct to immunohistochemistry, especially with antibodies which are otherwise ineffective on routinely processed tissues. The EBNA-1 gene is not expressed at detectable levels in the malignant cells of Hodgkin's disease, but is consistently expressed in other EBV associated disorders. This finding has important implications for the role of EBNA-1 in the biology of EBV.

Amplification of bacterial DNA using highly conserved sequences: automated analysis and potential for molecular triage of sepsis

OBJECTIVE

The clinical diagnosis of sepsis remains difficult, particularly in the young child, and would be improved by a rapid and reliable method for identification of bacteria in blood and other body fluids. Polymerase chain reaction (PCR) amplification of highly conserved DNA sequences found in all bacteria would permit fast and sensitive determination of the presence of bacteria in clinical specimens.

METHODOLOGY

A primer pair for highly conserved regions of bacterial DNA encoding 16S ribosomal RNA (rDNA) was utilized for PCR amplification. PCR products were analyzed by gel electrophoresis, and, after modification of the primers, by an automated 96-well plate reader.

RESULTS

rDNA was amplified from 12 different species of bacteria, including Gram-negative and -positive organisms. No signal was observed when total human DNA was used as template. Colorimetric analysis of amplified sequences using a 96-well format was also successful.

CONCLUSIONS

We conclude that a single primer pair designed to anneal to a highly conserved region of bacterial DNA can amplify DNA specimens from a variety of different bacteria, while not amplifying human DNA. Such a molecular genetics approach can be fully automated with existing robotic technology. Because of speed, sensitivity, and cost, molecular triage of patients with signs and symptoms of possible bacterial infection will decrease morbidity and mortality among those with unrecognized bacteremia who are managed as outpatients, and will dramatically reduce hospital expenses from individuals who are admitted and are not bacteremic.

Epstein-Barr virus infection and bcl-2 proto-oncogene expression. Separate events in the pathogenesis of Hodgkin's disease?

The present study was undertaken to investigate whether Epstein-Barr virus-(EBV) encoded latent membrane protein (LMP) induces the expression of BCL-2 in Hodgkin and Reed-Sternberg (HRS) cells of Hodgkin's disease (HD) and thereby provide a possible mechanism for the role of EBV in the pathogenesis of this disease. Fifty-three cases of HD were studied for the presence of EBV using EBV-encoded RNA in situ hybridization and LMP immunohistochemistry. Immunostaining for BCL-2 on paraffin material was performed using microwave treatment of tissue sections before the application of the primary monoclonal antibody. EBV was located in HRS cells in 16 cases (30%). All cases that were EBV-encoded RNA in situ hybridization positive, also expressed LMP. BCL-2 expression in HRS cells was detected in 16 cases (30%), but only two of these were also EBV-positive. In both of these cases, only occasional HRS cells expressed BCL-2, in contrast to LMP, which was detected in nearly all such cells. BCL-2 staining was predominantly cytoplasmic with some membrane pattern. These results demonstrate that BCL-2 expression can be detected in HRS cells in routinely processed HD tissue and that whereas EBV does not induce the expression of BCL-2 in HD, BCL-2 may have a role in the pathogenesis of EBV-negative cases of HD.

Epstein-Barr virus in Hodgkin disease. Relation to age and subtype

BACKGROUND

Epstein-Barr virus (EBV) has been associated with Hodgkin disease (HD), but its relationship to the age of the patients and the histologic subtype is not well defined. The possibility that other lymphotropic herpesviruses, such as cytomegalovirus (CMV) and human herpesvirus type 6 (HHV-6) could be involved in the pathogenesis of HD is also unclear.

METHODS

Paraffin-embedded material from 77 cases of HD was studied. This consisted of 24 specimens from children (mean age, 11.4 years), 36 from young adults (mean age, 28.8 years), and 17 from older adults (mean age, 53.8 years). EBV was detected in Hodgkin and Reed-Sternberg cells (HR-S) by a sensitive in situ hybridization technique based on the detection of Epstein-Barr-encoded RNA. Viral activity was subsequently demonstrated in HR-S cells by using monoclonal antibodies to EBV latent membrane protein.

RESULTS

EBV was found in a total of 25 of 77 cases (32%). There was no significant difference in EBV positivity between the different age groups. However, the prevalence of EBV varied between different subtypes: 68% of mixed cellularity cases were found to be positive by contrast with 24% nodular sclerosis, 0% lymphocyte predominant, and 14% lymphocyte depleted. Analysis of the histologic reports of a further 783 cases of HD to determine the age distribution of the different subtypes revealed an absence of an older adult second peak in the age distribution curve. In situ hybridization for CMV and HHV-6 was negative in all cases.

CONCLUSIONS

It was concluded that EBV is predominantly associated with mixed cellularity HD, and there is no correlation with the age of the patient.

Epstein-Barr virus in angioimmunoblastic T-cell lymphomas

Epstein-Barr virus (EBV) has been proposed as a possible infective agent involved in the pathogenesis of angioimmunoblastic lymphadenopathy (AIL), a progressive and often fatal lymphoproliferative disorder. We have studied 19 cases of AIL-like lymphomas for the presence of EBV using a sensitive in situ hybridization technique based on the detection of Epstein-Barr encoded RNAs with digoxigenin-labelled oligonucleotide probes. EBV was found in 11 cases; in seven of these EBV was detected in occasional cells. Immunocytochemical studies to investigate viral gene expression, revealed the presence of EBV-encoded latent membrane protein only in those cases which had appreciable numbers of positive cells by in situ hybridization. The intensity of staining varied from case to case and the overall proportion of cells staining for latent membrane protein in a given case was considerably less than that by in situ hybridization. In situ hybridization for cytomegalovirus and human herpes virus type-6 was negative in all cases. We discuss these findings in the light of the proposed role of EBV in the pathogenesis of AIL and conclude that the presence of EBV is a consequence of the disease rather than the cause.

Epstein-Barr virus in Reed-Sternberg-like cells in non-Hodgkin's lymphomas

In the course of our study on Hodgkin's disease (HD), ten cases of non-Hodgkin's lymphomas (NHL) containing Hodgkin and Reed-Sternberg-like (HRS) cells were encountered. Many of these cases had initially been diagnosed as HD, but on careful review of the histology, with the aid of immunophenotyping studies, they were reclassified as NHL. The presence of Epstein-Barr virus (EBV) in these HRS-like cells was investigated using a combination of EBER in situ hybridization (ISH) and immunostaining for the detection of EBV-encoded latent membrane protein (LMP). HRS-like cells in four cases (two lymphoplasmacytoid lymphomas, one Richter's transformation of lymphoplasmacytoid lymphoma, and one immunoblastic lymphoma of T-cell type) were found to be EBV-positive. In two of these cases, a second biopsy taken up to 10 years later also contained EBV in the HRS-like cells. In three of the four cases, HRS-like cells expressed the activation antigen CD30, but the expression of B- or T-cell antigens was variable. All cases of T-cell-rich B-cell lymphomas were negative for EBV. In conclusion, EBV may play a role in the development of HRS-like cells in some cases of NHL. The relationship of HRS-like cells to HRS cells of HD is discussed.

Epstein Barr virus (EBV) encoded small RNAs: targets for detection by in situ hybridisation with oligonucleotide probes

AIMS

To develop a rapid, sensitive, and specific non-isotopic in situ hybridisation (NISH) procedure for the detection of Epstein-Barr virus in formalin fixed, paraffin wax embedded tissues.

METHODS

Two low molecular weight RNAs, designated EBER-1 and EBER-2 (Epstein-Barr encoded RNA), were used: cells latently infected with EBV secrete large amounts of EBERs. The method uses digoxigenin labelled anti-sense oligonucleotides, corresponding to sequences in EBER-1 and EBER-2.

RESULTS

The use of these probes, in conjunction with high temperature microwave denaturation, ensured that the technique was considerably more sensitive than other in situ hybridisation techniques for detecting EBV. Furthermore, the hybridisation signal was morphologically distinct in that only the nucleus and not the nucleolus give a positive signal. No cross-hybridisation was observed with cells infected with other lymphotropic herpes viruses.

CONCLUSION

The sensitivity, simplicity, and rapidity of this technique make it ideal for diagnostic use, and for studies investigating the role of this virus in neoplastic disease.

Presence of Epstein-Barr virus in Hodgkin's disease is not exclusive to Reed-Sternberg cells

Thirty-three cases of Hodgkin's disease (HD) have been studied for the presence of Epstein-Barr virus (EBV) using a novel nonisotopic in situ hybridization procedure, based on the detection of Epstein-Barr encoded RNAs with oligonucleotide probes. An intense and morphologically distinct nuclear staining, sparing the nucleolus was seen in a total of 12 cases (36%). In six of these cases, the signal was located to the Hodgkin and Reed-Sternberg cells (HR-S); in the other six positive cases, the signal was observed only in the non-neoplastic small lymphocytes. These lymphocytes were few in number and immunocytochemistry results were consistent with a B-cell phenotype. The presence of EBV in those cases characterized by nuclear staining of small lymphocytes was confirmed by the polymerase chain reaction (PCR) analysis. The authors report the detection of EBV in small lymphocytes in HD by in situ hybridization and discuss the implications of these findings in relation to the proposed etiologic association between EBV and HD.

X-ray analyses of aspartic proteinases. IV. Structure and refinement at 2.2 A resolution of bovine chymosin

The structure of calf chymosin (EC 3.4.23.3), the aspartic proteinase from the gastric mucosa, was solved using the technique of molecular replacement. We describe the use of different search models based on distantly related fungal aspartic proteinases and investigate the effect of using only structurally conserved regions. The structure has been refined to a crystallographic R-factor of 17% at 2.2 A resolution with an estimated co-ordinate error of 0.21 A. In all, 136 water molecules have been located of which eight are internal. The structure of chymosin resembles that of pepsin and other aspartic proteinases. However, there is a considerable rearrangement of the active-site "flap" and, in particular, Tyr75 (pepsin numbering), which forms part of the specificity pockets S1 and S1'. This is probably a consequence of crystal packing. Electrostatic interactions on the edge of the substrate binding cleft appear to account for the restricted proteolysis of the natural substrate kappa-casein by chymosin. The local environment of invariant residues is examined, showing that structural constraints and side-chain hydrogen bonding can play an important role in the conservation of particular amino acids.

Inhibitory effects of urine on the polymerase chain reaction for cytomegalovirus DNA

The inhibitory effects of urine samples taken from neonates and older children, some of which were known to be infected with cytomegalovirus, on the polymerase chain reaction (PCR) were investigated. Urea was the major inhibitory component of urine and inhibited the PCR at a concentration of more than 50 mM. Urine samples from older children were more inhibitory than those from neonates. This correlated with the higher concentration of urea generally found in urine samples from older children compared with neonatal urines. Two of 13 neonatal urine samples, however, were inhibitory despite low urea concentrations--presumably due to metabolites derived from parenteral nutrition. The inhibitory effects of urine were effectively removed by simple dialysis or ultrafiltration. The sensitivity and specificity of PCR for detecting cytomegalovirus DNA in urine were further improved by using "nested" primers and a modified PCR protocol entailing the use of reduced reactants in the first 20 cycles of a two-stage 50 cycle PCR.

Simplified procedures for applying the polymerase chain reaction to routinely fixed paraffin wax sections

The polymerase chain reaction was applied to the analysis of DNA contained in archival paraffin wax embedded material. DNA suitable for the reaction was obtained from these tissues by simple extraction methods, without previous dewaxing of tissue sections. When compared with unfixed material, the reaction efficiency was compromised, so that an increased number of amplification cycles were required to produce equivalent amounts of amplified product. This in turn led to an increase in amplification artefacts, which can be minimised by a simple modification of the standard reaction. Amplification of relatively large DNA fragments was not always successful, and it seems prudent to bear this in mind when designing oligonucleotide primers which are to be used for the amplification of archival material. The efficiency of the procedure can be improved by dividing the amplification cycles into two parts: this reduces the amount of reagent needed, is relatively simple and inexpensive, and can be performed in one working day.

X-ray analyses of aspartic proteinases. II. Three-dimensional structure of the hexagonal crystal form of porcine pepsin at 2.3 A resolution

The molecular structure of the hexagonal crystal form of porcine pepsin (EC 3.4.23.1), an aspartic proteinase from the gastric mucosa, has been determined by molecular replacement using the fungal enzyme, penicillopepsin (EC 3.4.23.6), as the search model. This defined the space group as P6522 and refinement led to an R-factor of 0.190 at 2.3 A resolution. The positions of 2425 non-hydrogen protein atoms in 326 residues have been determined and the model contains 371 water molecules. The structure is bilobal, consisting of two predominantly beta-sheet lobes which, as in other aspartic proteinases, are related by a pseudo 2-fold axis. The strands of the mixed beta-sheets (1N and 1C) of each lobe are related by an intra-lobe topological 2-fold symmetry. Two further beta-sheets, 2N and 2C, are each composed of two topologically related beta-hairpins folded below the 1N and 1C sheets. A further six-stranded sheet (3) spans the two lobes and forms a structure resembling an arch upon which the four other sheets reside. The interface between sheets 1N and 1C forms the catalytic centre consisting of absolutely conserved aspartate residues 32 and 215, which are shielded from solvent by a beta-hairpin loop (75 to 78). The crystal structure of a mammalian aspartic proteinase indicates that interactions with substrate may be more extensive on the prime side of the active site cleft than in the fungal enzymes and involve Tyr189 and the loop 290 to 295, perhaps contributing to the transpeptidase activity of pepsin and the specificity of the renins. Comparison with the high-resolution structure of pepsinogen gives a root-mean-square deviation of 0.9 A and reveals that, in addition to local rearrangement at the active site, there appears to be a rigid group movement of part of the C-terminal lobe of pepsin towards the cleft on activation. A large proportion of the absolutely conserved residues in aspartic proteinases are polar and buried. An examination of the pepsin structure reveals that these side-chains are involved in hydrogen-bond interactions with either the main chain of the protein or other conserved side-chains of the enzyme or propart.

New HLA-D alleles associated with DR1 and DR2

The present study describes two new HLA-D specificities : LD 13, associated with DR1, and LD14 associated with DR2. LD13 is defined by an HTC who is the bc offspring of an a: A25, B18, DR7, Dw7/b: A33, B14, DR1, Dx father, and of a c: A24, B14, Dr1, Dx/d: A26, B41, DR5, Dw5 mother. This HTC was included both as a responder and as a stimulator in our cross-reference studies of 8W HTCs. While failing to cluster with any other 8W HTC, it typed 2 of 64 panel members carrying a "blank" HLA-D, linked to DR1. To exclude the possibility that HTC-LD13 might be a split of Dwl, the entire family was tested with the Family Set of 8W HTCs. No typing responses to any 8W Dw1 HTCs were observed. Furthermore, checkerboard experiments between HTC-LD13 and 8WDw1 HTCs showed strong reciprocal stimulation. The LD13 specificity was only found in Ashkenazi Jews and may be in linkage disequilibrium with HLA-B14. LD14 is defined by three, SD different, HTCs deriving from the same family of Sicilian descent. The family was included in the 8th Workshop and each HTC was shown to have inherited DR2, MT1 from both parents. When tested as stimulators, on our HLA-D reference panel, these cells were clustered in a distinct group, LD14, associated with DR2. None of the 8W HTCs appeared to belong to this cluster. The antigen frequency of LD14 is 0.03.

Hemangiomas of the striated muscle

Presented are three cases of hemangiomas of skeletal muscle in which the presenting symptom was pain. Examination revealed almost spot tenderness at the site of the tumor, but no masses were palpable. Treatment was exicision. Results of surgery usually are good, although local recurrence can follow incomplete resection, as it did in one of our cases.