RESUMO
Male ICR mice were orally administered samarium nitrate [Sm(NO3)3] to investigate its effects on sperm concentration and sperm quality. After acute exposure to ≥2880.00 mg/kg Sm(NO3)3 via intragastric gavage, sperm motility and acrosome integrity were decreased, and the sperm malformation percentage was increased (P < 0.05). After subchronic exposure to ≥500.00 mg/L Sm(NO3)3 administered via drinking water for 90 days, relative gonad weight, sperm concentration, and sperm quality significantly decreased (P < 0.05). Sperm malformation also increased after subchronic exposure to Sm, which was found to be the most sensitive index. Sperm head malformation accounted for the largest proportion of all types of sperm malformations evaluated. Of the six different subtypes of head malformation, irregular shape accounted for the largest proportion.
Assuntos
Acrossomo/efeitos dos fármacos , Samário/toxicidade , Motilidade dos Espermatozoides/efeitos dos fármacos , Acrossomo/patologia , Animais , Masculino , Camundongos , Camundongos Endogâmicos ICR , Samário/administração & dosagem , Contagem de EspermatozoidesRESUMO
Correlations between genetic polymorphisms of three matrix metalloproteinase (MMP) genes and susceptibility to chronic obstructive pulmonary disease (COPD) were investigated. Relevant case-control studies were selected using rigorous inclusion and exclusion criteria. The comprehensive Meta-analysis 2.0 software was used to conduct the statistical analysis. An odds ratio with 95% confidence intervals was applied to assess the correlation between genetic polymorphisms of MMPs and susceptibility to COPD. Twelve high-quality studies were selected for inclusion in this meta-analysis. These studies included a combined total of 1533 COPD patients and 1530 healthy controls. The result of the meta-analysis showed that MMP-9 rs3918242 C > T was significantly correlated with increased susceptibility to COPD. However, MMP-1 rs1799750 1G > 2G and MMP-3 rs3025058 5A > 6A were not associated with COPD risk (all P > 0.05). Based on our meta-analysis, MMP-9 rs3918242 C > T is correlated with susceptibility to COPD, but MMP-1 rs1799750 1G > 2G and MMP-3 rs3025058 5A > 6A are not. These results should be further confirmed using a larger sample size.
Assuntos
Metaloproteinase 1 da Matriz/genética , Metaloproteinase 3 da Matriz/genética , Metaloproteinase 9 da Matriz/genética , Doença Pulmonar Obstrutiva Crônica/genética , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Masculino , Polimorfismo de Nucleotídeo Único , Doença Pulmonar Obstrutiva Crônica/patologiaRESUMO
The aim of the current study was to explore the correlation between serum homocysteine (HCY) levels and the methylene tetrahydrofolate reductase (MTHFR) gene 677C/T polymorphism and coronary heart disease (CHD). We consecutively enrolled 208 patients with CHD confirmed by CTA or coronary angiography from our hospital. An additional 200 healthy volunteers were enrolled as the control group. Serum HCY levels, MTHFR C677T genotype, and other related indicators were evaluated for the two groups. Compared to those in the control group, the serum HCY levels in the CHD patients were significantly higher (P < 0.05). The proportion of individuals with the heterozygous MTHFR CT genotype and homozygous mutant TT genotype among CHD patients was significantly higher than that in the control group (P < 0.05). In the acute coronary syndrome (ACS) subgroup, the proportion of those with the CT and TT genotypes was significantly higher than that of the stable CHD subgroup (P < 0.05). In summary, serum HCY levels were elevated in CHD patients, and the frequency of the CT and TT genotypes were also significantly increased, especially among the ACS subgroup. Taken together, this suggests that serum HCY levels and MTHFR C677T genotypes are correlated with CHD.
Assuntos
Doença da Artéria Coronariana/sangue , Doença da Artéria Coronariana/genética , Homocisteína/sangue , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Polimorfismo Genético/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Frequência do Gene/genética , Predisposição Genética para Doença/genética , Genótipo , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Intercellular adhesion molecule-1 (ICAM-1) is an important factor in the progression of inflammatory responses in vivo. To develop a new anti-inflammatory drug to block the biological activity of ICAM-1, we produced a monoclonal antibody (Ka=4.19×10−8 M) against human ICAM-1. The anti-ICAM-1 single-chain variable antibody fragment (scFv) was expressed at a high level as inclusion bodies in Escherichia coli. We refolded the scFv (Ka=2.35×10−7 M) by ion-exchange chromatography, dialysis, and dilution. The results showed that column chromatography refolding by high-performance Q Sepharose had remarkable advantages over conventional dilution and dialysis methods. Furthermore, the anti-ICAM-1 scFv yield of about 60 mg/L was higher with this method. The purity of the final product was greater than 90%, as shown by denaturing gel electrophoresis. Enzyme-linked immunosorbent assay, cell culture, and animal experiments were used to assess the immunological properties and biological activities of the renatured scFv.
Assuntos
Animais , Feminino , Humanos , Masculino , Camundongos , Expressão Gênica/fisiologia , Fragmentos de Imunoglobulinas/biossíntese , Molécula 1 de Adesão Intercelular/imunologia , Redobramento de Proteína , Renaturação Proteica , Anticorpos de Cadeia Única/biossíntese , Complexo Antígeno-Anticorpo , Anti-Inflamatórios/farmacologia , Anticorpos Monoclonais/biossíntese , Adesão Celular , Cromatografia , Diálise , Ensaio de Imunoadsorção Enzimática , Pavilhão Auricular/efeitos dos fármacos , Escherichia coli/genética , Vetores Genéticos , Fragmentos de Imunoglobulinas/farmacologia , Corpos de Inclusão/metabolismo , Molécula 1 de Adesão Intercelular/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Plasmídeos , Engenharia de Proteínas/métodos , Anticorpos de Cadeia Única/farmacologia , Xilenos/farmacologiaRESUMO
Intercellular adhesion molecule-1 (ICAM-1) is an important factor in the progression of inflammatory responses in vivo. To develop a new anti-inflammatory drug to block the biological activity of ICAM-1, we produced a monoclonal antibody (Ka=4.19 × 10(-8) M) against human ICAM-1. The anti-ICAM-1 single-chain variable antibody fragment (scFv) was expressed at a high level as inclusion bodies in Escherichia coli. We refolded the scFv (Ka=2.35 × 10(-7) M) by ion-exchange chromatography, dialysis, and dilution. The results showed that column chromatography refolding by high-performance Q Sepharose had remarkable advantages over conventional dilution and dialysis methods. Furthermore, the anti-ICAM-1 scFv yield of about 60 mg/L was higher with this method. The purity of the final product was greater than 90%, as shown by denaturing gel electrophoresis. Enzyme-linked immunosorbent assay, cell culture, and animal experiments were used to assess the immunological properties and biological activities of the renatured scFv.
Assuntos
Expressão Gênica/fisiologia , Fragmentos de Imunoglobulinas/biossíntese , Molécula 1 de Adesão Intercelular/imunologia , Redobramento de Proteína , Renaturação Proteica , Anticorpos de Cadeia Única/biossíntese , Animais , Anti-Inflamatórios/farmacologia , Anticorpos Monoclonais/biossíntese , Complexo Antígeno-Anticorpo , Adesão Celular , Cromatografia , Diálise , Pavilhão Auricular/efeitos dos fármacos , Ensaio de Imunoadsorção Enzimática , Escherichia coli/genética , Feminino , Vetores Genéticos , Humanos , Fragmentos de Imunoglobulinas/farmacologia , Corpos de Inclusão/metabolismo , Molécula 1 de Adesão Intercelular/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Masculino , Camundongos , Plasmídeos , Engenharia de Proteínas/métodos , Anticorpos de Cadeia Única/farmacologia , Xilenos/farmacologiaRESUMO
Blumea balsamifera is a commercially important medicinal herb in China and other parts of Asia. It is used to produce borneol. This plant grows in the wild, but resources have diminished greatly in recent years. We examined the genetic diversity of this species to help develop conservation strategies; 35 plants from five provinces were analyzed using AFLPs. Eight AFLP primer combinations generated 1367 fragments, giving a mean of 172 fragments per primer combination. Polymorphism in the germplasm analysis was found for 1360 (99.48%) of the fragments, of which 264 (19.27%) fragments were unique (accession specific) and 423 (25.33%) of the fragments were rare (present in less than 10% of the accessions). The polymorphic fragments were used to group the accessions in a UPGMA phenogram. Most grouping was geographical. In general, accessions coming from Guizhou and Guangxi showed higher diversities as these accessions were scattered in different groups. The genetic distance estimated by Jaccard similarity coefficient index showed low variability among genotypes (coefficient value ranged from 0.60 to 0.95). More attention should be given to the study and conservation of the biodiversity of this economically important genus.
Assuntos
Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Asteraceae/genética , Variação Genética , Marcadores Genéticos , Humanos , Medicina Tradicional ChinesaRESUMO
Embryo abortion in mango severely damages mango production worldwide. The mechanisms by which the mango embryos abort have long been an intriguing question. We used subtractive suppression hybridization to investigate the differentially expressed genes involved in this process. We generated 2 cDNA libraries from normal seed and aborted seed embryos of mango cultivar 'Jinhuang'. One thousand five hundred and seventy-two high-quality expressed sequence tags (ESTs) were obtained, with 1092 from the normal seed tester library and 480 from the aborted seed tester library. These ESTs were assembled into 783 unigenes, including 147 contigs and 636 singletons in contigs; 297 singletons in gene ontology (GO) indicated coverage of a broad range of GO categories. Seven candidate genes from different categories were selected for semi-quantitative PCR analysis, and their possible functions in embryo abortion are discussed. These data provide new insight into the genetic regulation of embryo abortion in mango and may aid in further identification of novel genes and their functions.
Assuntos
Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Mangifera/embriologia , Mangifera/genética , Hibridização de Ácido Nucleico/métodos , Sementes/genética , Sequência de Bases , Etiquetas de Sequências Expressas , Anotação de Sequência Molecular , Infertilidade das Plantas/genética , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
We examined the types of Epstein-Barr virus-associated nuclear antigen-1 (EBNA-1) gene carboxy (C)-terminal mutations occurring in Hodgkin's disease (HD) and reactive tissues from two different geographic regions. Previously reported EBNA-1 C-terminal region amino acid sequence variants, based on the amino acid at codon 487, include Prototype (P)-ala, which is found in the B95.8-derived prototype virus, P-thr, Variant (V)-leu, V-val, and V-pro. Using polymerase chain reaction (PCR) to amplify portions of the EBNA-1 gene, followed by DNA sequencing, we found a single EBNA-1 gene sequence variant in each tissue, whether reactive or neoplastic and whether from Brazil or the United States. Variant EBNA-1 gene sequences were more common in both neoplastic and non-neoplastic tissues from different geographic areas than the so-called prototype sequence. In the 17 Brazilian HD cases, 4 cases had P-thr variants and 13 had V-leu variants. In the six reactive tissues from Brazil, one had a P-ala variant, two had P-thr variants, and three had V-leu variants. In the 12 American HD cases, 2 had P-ala variants, 6 had P-thr variants, and 4 had V-leu variants. The 11 American reactive tissues included 2 P-ala variants, 5 P-thr variants, and 4 V-leu variants. In both countries, there were similar variant EBNA-1 sequences present in normal tissues and HD cases. Compared with the P-ala and P-thr cases, the V-leu cases were more likely to have the 30-bp latent membrane protein 1 (LMP1) gene deletion (P = 0.0075). In addition, cases of HD with the V-leu were statistically associated with a substitution of asparagine for glutamine at codon 322 of the C-terminal portion of the LMP1 gene. Our results suggest that any variation in EBNA-1 gene sequence is caused by a polymorphism present in pre-existing viral strains in the underlying population, and not a mutation occurring during oncogenesis.
Assuntos
Antígenos Nucleares do Vírus Epstein-Barr/genética , Genes Virais , Doença de Hodgkin/genética , Brasil , Deleção de Genes , Doença de Hodgkin/virologia , Humanos , Polimorfismo Genético , Análise de Sequência de DNA , Estados UnidosRESUMO
A 30-bp deletion in the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) gene has been reported in nasopharyngeal carcinoma and EBV-associated malignant lymphomas. Information on this deletion in EBV-associated gastric carcinoma (EBVaGC) is limited. The association of gastric carcinoma (GC) with EBV was examined by EBV-encoded RNA (EBER) in situ hybridization in 510 patients from Japan and 80 patients from Brazil. We studied the prevalence of 30-bp LMP1 gene deletion in EBVaGC in Japan (29 cases) and Brazil (four cases) in comparison with the corresponding EBER1-positive metastatic lesions in lymph nodes (10 cases) and EBV-infected reactive lymphocytes from dissected nonmetastatic lymph nodes (22 cases), microdissected non-neoplastic gastric mucosa of EBVaGC (five cases), and EBV-nonassociated GC (25 cases). We studied the status of the LMP1 gene by Southern blot hybridization of polymerase chain reaction products obtained after amplification with primers flanking the site of the deletion. We also performed EBV typing and LMP1 protein immunohistochemistry. EBV DNA was amplified by polymerase chain reaction in 30 of 33 EBVaGC cases, 8 of 10 metastatic carcinomas, 14 non-neoplastic tissues from 27 EBVaGC cases, and 12 of 25 non-EBV-associated GC cases with EBER1-positive lymphocytes. The 30-bp LMP1 gene deletion was observed in 23 of 26 (88.5%) cases of EBVaGC from Japan and two of four (50%) cases of Brazilian EBVaGC as compared with EBER1-positive reactive lymphocytes from 11 of 14 (78.6%) EBVaGC cases and 9 of 12 (75%) cases of non-EBV-associated GC. The variant type (the 30-bp deletion variant or nondeleted wild type) of LMP1 gene was the same among reactive lymphocytes, primary and secondary lesions of EBVaGC in all cases for which all three tissue types were studied (six of six). There was no correlation between the presence of the 30-bp deletion with depth of cancer invasion or presence of metastasis. Type A was detected in all available EBV-positive cases. The similar high incidence of 30-bp deletion in LMP1 gene in both carcinoma cells and reactive lymphocytes in EBVaGC cases suggests that this deletion may not be relevant to the pathogenesis of EBVaGC.
Assuntos
Carcinoma/virologia , Deleção de Genes , Herpesvirus Humano 4/genética , Metástase Linfática/genética , Linfócitos/virologia , Neoplasias Gástricas/virologia , Proteínas da Matriz Viral/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Brasil/etnologia , Carcinoma/etnologia , Carcinoma/genética , Feminino , Humanos , Hibridização In Situ , Japão/etnologia , Linfócitos/fisiologia , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Neoplasias Gástricas/etnologia , Neoplasias Gástricas/genéticaRESUMO
A 30-basepair (bp) deletion in the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) gene has been reported in nasopharyngeal carcinoma and EBV-associated malignant lymphomas. Prior studies have found the deletion in about 10% to 28% of cases of Hodgkin's disease (HD), particularly in cases with aggressive histology. We studied the prevalence of 30-bp LMP1 gene deletion in EBV-positive HD in the United States (US) (12 cases) and Brazil (26 cases) with comparison to reactive lymphoid tissues (21 cases) and HD without EBV-positive Reed-Sternberg cells (15 cases). We studied the status of the LMP1 gene by Southern blot hybridization of polymerase chain reaction (PCR) products obtained after amplification with primers spanning the site of the deletion. We also performed EBV typing, EBER1 in situ hybridization, and LMP1 protein immunohistochemistry. EBV was detected in 12/26 (46%) cases of HD from the US and 26/27 (96%) cases of Brazilian HD. The 30-bp LMP1 gene deletion was observed in 4/12 (33%) cases of EBV-positive HD from US, and 12/26 (46%) cases of Brazilian EBV-positive HD, including 3 cases of type B EBV, as compared with 12/21 (57%) reactive lymphoid tissues and 9/15 (60%) cases of EBV-negative HD. US and Brazilian HD showed a higher prevalence of the 30-bp LMP1 gene deletion, compared with studies of others. The unexpected finding of high incidence of 30-bp deletion in LMP1 gene in reactive lymphoid tissue and HD without EBV-positive Reed-Sternberg cells suggests that this deletion may not be relevant to HD pathogenesis in most cases.
Assuntos
Frequência do Gene , Herpesvirus Humano 4/genética , Doença de Hodgkin/genética , Doença de Hodgkin/patologia , Tecido Linfoide/patologia , Deleção de Sequência , Proteínas da Matriz Viral/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Composição de Bases , Brasil/epidemiologia , Capsídeo/genética , Feminino , Doença de Hodgkin/epidemiologia , Doença de Hodgkin/virologia , Humanos , Tecido Linfoide/virologia , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Estados Unidos/epidemiologia , Latência Viral/genéticaRESUMO
Both Epstein-Barr virus (EBV) types A and B are found in endemic Burkitt's lymphoma (BL) occurring in equatorial Africa. We studied 17 cases of Brazilian BL previously demonstrated to be EBV-positive to determine the EBV type as well as the presence of a characteristic 30 bp deletion within the 3' end of the latent membrane protein-1 (LMP-1) gene that may be important to the pathogenesis of several EBV-associated neoplasms. All cases in which the age was known were children. We found type A EBV in 13 of 14 (93%) evaluable cases, and type B in one case. The LMP-1 deletion was found in 12 of 15 (80%) evaluable cases, including the one case of type B EBV, and a similar high prevalence (59%) of the deletion was detected in EBV-positive normal and reactive lymphoid tissues from individuals from the same geographic region. The high proportion of cases associated with type A EBV suggests that immunodeficiency is not an important factor in the pathogenesis of Brazilian BL, in contrast to endemic African BL. The presence of the LMP-1 deletion in a high prevalence in the normal population in this region is unexplained.
Assuntos
Linfoma de Burkitt/virologia , Herpesvirus Humano 4/classificação , Adolescente , Sequência de Bases , Brasil/epidemiologia , Linfoma de Burkitt/epidemiologia , Criança , Feminino , Deleção de Genes , Genes Virais/genética , Genótipo , Herpesvirus Humano 4/genética , Humanos , Tecido Linfoide/virologia , Masculino , Dados de Sequência Molecular , Reação em Cadeia da PolimeraseRESUMO
The incidence of Burkitt's lymphoma (BL) in Brazil is intermediate between the endemic form of equatorial Africa and the sporadic form in the United States. To characterize these lymphomas, we evaluated the clinical, morphologic, and immunohistochemical features of 24 Brazilian cases of BL. We also analyzed the cases for the presence of Epstein-Barr virus (EBV)-RNA using a highly sensitive and specific method of in situ hybridization. Most cases presented with involvement of intraabdominal organs, similar to the sporadic form of BL. EBV-RNA was detected in 17 of 24 cases (71%) in all or virtually all the tumor cells. This prevalence of EBV-positivity in our cases is intermediate between the endemic form of BL in equatorial Africa (100%) and the sporadic form in the United States (30%). These findings suggest that EBV plays an important role in the pathogenesis of BL in Brazil. This intermediate incidence of EBV infection may explain in part the differences of incidence of BL in different geographic regions.
Assuntos
Linfoma de Burkitt/epidemiologia , Linfoma de Burkitt/virologia , Herpesvirus Humano 4/isolamento & purificação , Adolescente , Adulto , Brasil/epidemiologia , Linfoma de Burkitt/patologia , Criança , Pré-Escolar , Feminino , Herpesvirus Humano 4/genética , Humanos , Imuno-Histoquímica , Hibridização In Situ , Masculino , RNA Viral/genéticaRESUMO
The incidence of non-Hodgkin's lymphoma of the nasal region is much higher in Peru than in the United States and is similar to the incidence of sinonasal lymphomas in Asian countries. To characterize these lymphomas, we evaluated the clinical, morphologic, and immunohistochemical features of 14 cases and also analyzed the cases for Epstein-Barr virus (EBV) RNA using a sensitive and specific in situ hybridization method. Morphologically, the cases consisted of nine large cell immunoblastic lymphomas, one diffuse mixed cell lymphoma, one diffuse small cleaved lymphoma, one small noncleaved lymphoma, and two cases unclassifiable in the Working Formulation. Eleven cases demonstrated evidence of T lineage, two were of B lineage and one of indeterminate immunophenotype. In 13 of the lymphoma cases including all of the T-cell lymphomas, EBV RNA was detected in a high percentage of cells. Double-labeling immunohistochemical and in situ hybridization studies identified CD43 positivity in the cells labeling for EBV RNA. Much smaller amounts of EBV RNA were detectable in six of eight control benign nasopharyngeal biopsy specimens, and two were completely negative. These findings are similar to the prevalence of EBV-positive T-cell lymphomas in Asian countries and differ from the findings of the more common EBV-negative B-cell nasal lymphomas in the United States. These findings suggest that EBV plays a role in the development of nasal T-cell lymphomas and that the incidence of EBV infection may explain the reported "East-West" difference in the incidence of nasal T-cell lymphomas.
Assuntos
Herpesvirus Humano 4 , Linfoma/microbiologia , Linfoma/patologia , Neoplasias Nasais/microbiologia , Neoplasias Nasais/patologia , Linfócitos T/fisiologia , Infecções Tumorais por Vírus/complicações , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Imuno-Histoquímica , Imunofenotipagem , Hibridização In Situ , Incidência , Linfoma/genética , Masculino , Pessoa de Meia-Idade , Neoplasias Nasais/genética , Infecções Tumorais por Vírus/epidemiologiaRESUMO
The Epstein-Barr virus (EBV) has been implicated in the pathogenesis of Hodgkin's disease (HD). This study was undertaken to determine whether the association of EBV with HD showed geographical variation, as in Burkitt's lymphoma. We studied 32 formalin-fixed, paraffin-embedded cases of HD occurring in Peru. EBV DNA-RNA in situ hybridization was performed using a 30-base biotinylated antisense oligonucleotide complementary to the EBER1 gene of EBV. EBV immunohistochemistry was also performed, using a monoclonal antibody (MoAb) to the latent membrane protein (LMP1) of EBV. Identification of the precise cellular subset staining with EBV was accomplished via double-labeling with MoAbs directed against Reed-Sternberg cells (LeuM1/CD15) and B cells (L26/CD20). EBV RNA was identified in all or virtually all of the Reed-Sternberg cells and variants in 30 of the 32 (94%) cases of HD by in situ hybridization. LMP1 expression was identified in 83% of the EBER1-positive cases. Double-labeling studies confirmed the localization of EBV RNA to CD15-expressing Hodgkin's cells. This study found an extremely high prevalence of EBV in Peruvian HD, in contrast to the much lower percentage of EBV-associated cases of HD occurring in "Western" patients.
Assuntos
DNA Viral/análise , Herpesvirus Humano 4/isolamento & purificação , Doença de Hodgkin/microbiologia , RNA Viral/análise , Células de Reed-Sternberg/microbiologia , Proteínas Ribossômicas , Proteínas da Matriz Viral , Adolescente , Adulto , Anticorpos Monoclonais , Antígenos Virais/análise , Criança , Pré-Escolar , DNA Viral/genética , Feminino , Herpesvirus Humano 4/genética , Doença de Hodgkin/classificação , Doença de Hodgkin/patologia , Humanos , Hibridização In Situ , Masculino , Proteínas de Membrana/análise , RNA Viral/genética , Proteínas de Ligação a RNA/análise , Células de Reed-Sternberg/patologia , Proteínas do Envelope Viral/análiseRESUMO
BACKGROUND: Epstein-Barr virus (EBV)-associated post-transplantation lymphoproliferative disease (PTLD) develops in 1 to 10 percent of transplant recipients, in whom it can be treated by a reduction in the level of immunosuppression. We postulated that the tissue expression of the small RNA transcribed by the EBER-1 gene during latent EBV infection would identify patients at risk for PTLD. METHODS: We studied EBER-1 gene expression in liver specimens obtained from 24 patients 2 days to 22 months before the development of PTLD, using in situ hybridization with an oligonucleotide probe. Control specimens were obtained from 20 recipients of allografts with signs of injury due to organ retrieval, acute graft rejection, or viral hepatitis in whom PTLD had not developed 9 to 71 months after the biopsy. RESULTS: Of the 24 patients with PTLD, 17 (71 percent) had specimens in which 1 to 40 percent of mononuclear cells were positive for the EBER-1 gene. In addition, 10 of these 17 patients (59 percent) had specimens with histopathological changes suggestive of EBV hepatitis. In every case, EBER-1-positive cells were found within the lymphoproliferative lesions identified at autopsy. Only 2 of the 20 controls (10 percent) had specimens with EBER-1-positive cells (P < 0.001), and such cells were rare. CONCLUSIONS: EBER-1 gene expression in liver tissue precedes the occurrence of clinical and histologic PTLD. The possibility of identifying patients at risk by the method we describe here and preventing the occurrence of PTLD by a timely reduction of immunosuppression needs to be addressed by future prospective studies.