Prevalence of TT virus infection in blood donors with elevated ALT in the absence of known hepatitis markers

OBJECTIVE

Recently a novel DNA virus (TT virus) has been identified in Japan and shown to be associated with elevated aminotransferase levels after blood transfusion. The exact role of TTV in the pathogenesis of liver disease is yet to be established. Our aim was to determine the prevalence and role of TTV in the pathogenesis of elevated transaminases in healthy blood donors in the absence of markers for viral hepatitis A-C.

METHODS

Stored sera were collected from 99 healthy blood donors with elevated alanine amino transferase (ALT) values that were discovered at the time of blood donation. A total of 146 samples were obtained from healthy donors with normal ALT values who were used as controls. None of the patients or controls had a history of blood transfusion or had clinical signs of acute or chronic hepatitis. Serological markers for hepatitis A, hepatitis B, and hepatitis C viruses were negative. TTV DNA was amplified and detected using polymerase chain reaction followed by gel electrophoresis.

RESULTS

Five of 99 (5%) samples obtained from donors with elevated ALT had TTV DNA detected by PCR, as compared to one of 146 (0.7%) of those with normal ALT (p = 0.006). Among those with elevated ALT, mean ALT values in patients with TTV (296 +/- 305 U/L) were higher than in patients without TTV (95 +/- 37 U/L), but the difference was not statistically significant (p = 0.08). The two samples with highest ALT values (both >450 U/L) were among the five samples with detectable TTV DNA in serum.

CONCLUSIONS

Although TTV is not likely to explain the majority of elevated ALT cases in otherwise healthy blood donors, TTV infection may potentially be associated with some cases. Based on these findings, we propose that the role of TTV in the pathogenesis of acute and chronic liver diseases merits further investigation.

Analysis of candidate-host immunogenetic determinants in herpes simplex virus-associated Mollaret's meningitis

Infection due to herpes simplex virus (HSV) is associated with recurrent aseptic meningitis (Mollaret's meningitis); however, the neuropathogenesis of this disease remains unknown. We collected 20 cerebrospinal fluid (CSF) specimens that were positive for HSV DNA by using polymerase chain reaction (PCR) assay from patients with a clinical diagnosis of Mollaret's meningitis. Patients were predominantly female (female:male, 22:1), with an average age of 32.8 years (range, 18-46 years). Using direct sequence analysis of HSV PCR products obtained from the CSF, we determined that all of the patients were infected with HSV type 2. In addition, we evaluated polymorphisms in 2 human genomic loci, which are associated with either severe or recurrent microbial infections (interferon-gamma receptor [IFN-gammaR] and mannose binding lectin [MBL]); these host genes were also amplified directly from the CSF specimens. No mutations were found in exons 2 or 3 of the IFN-gammaR gene (n=20). In contrast, there were 4 (20%), 4 (20%), and 0 mutations found in codons 52, 54, and 57, respectively, in exon 1 of MBL (n=20). A significantly higher frequency of codon 52 mutations (P=.04) was observed, compared with racially matched control patients.

The GT-rich sequence in the U5 region of Rous sarcoma virus long terminal repeat is required for transcription termination and 3' processing

The sequences in the LTR of Rous sarcoma virus that are required for transcription termination and polyadenylation have been determined. A vector containing LTR-neo-LTR has been constructed and deletions in the U5 region of the downstream LTR have been made. The DNAs from wild-type and deletion mutant recombinant plasmids were introduced into QT6 cells and G418-resistant transformants were selected. Those transformants with neo sequences in the arrangement, LTR-neo-LTR, were analyzed for transcription termination and polyadenylation by Northern blot analysis and by S1 protection experiments. The results indicate that the polyadenylation signal, AATAAA, located in the U3 region alone, is not sufficient for 3' end processing and that the sequence between +20 and +44 in the U5 region is absolutely required for transcription termination or endonucleolytic cleavage and polyadenylation.

Cloning of Rous sarcoma virus enhancer factor genes. II. RSV-EF-II, abundantly expressed in fibroblasts and muscle tissue, binds to an octamer sequence, 5'-GTACCACC-3', in the noncoding strand of RSV enhancer

Rous sarcoma virus (RSV) mainly replicates in avian fibroblasts, and the U3 enhancer region of the long terminal repeats of RSV contains the determinants for its tissue-tropic expression. We describe the cloning and characterization of an avian gene that encodes a protein capable of binding to the enhancer region of Rous sarcoma virus. A PCR-derived probe corresponding to the U3 region of RSV was used to isolate a cDNA clone by screening a chicken cDNA expression library. The cDNA is predicted to encode a polypeptide of 298 amino acids that is homologous to the Y-box (inverted CCAAT) family of DNA-binding transcription factors. This factor, which we refer to as Rous sarcoma virus enhancer factor-II (RSV-EF-II), shows 99% aa identity over a 105-amino-acid stretch that is highly conserved in all Y-box proteins, and is commonly referred to as the cold shock domain. RSV-EF-II selectively binds to single-stranded DNA, and the binding site, as determined by electrophoretic mobility shift assays, consists of the sequence 5' GTACCACC 3' located between nucleotides -112 to -119 in the noncoding strand of the RSV enhancer. Although RSV-EF-II shares considerable homology with the Y-box family of proteins, it does not bind to the inverted CCAAT boxes at positions -65 to -69 and -129 to -133 in the RSV LTR. Northern analysis indicates that RSV-EF-II-specific transcripts are expressed predominantly in avian fibroblasts and muscle tissue. The results of these binding and mRNA expression expriments suggest that RSV-EF-II may play an important role in tissue- and host-specific expression of RSV LTR-driven gene expression. Further, we show that RSV-EF-II acts as a repressor of transcription.

Transcription in nematodes: early Ascaris embryos are transcriptionally active

In this report we analyze early zygotic gene expression in the parasitic nematode Ascaris lumbricoides var. suum. Using synchronous populations of early embryonic stages, nuclei were isolated, and in vitro run-off transcription assays were performed. We find transcriptional activity as early as the 4- to 8-cell stage. The percentage of RNA polymerase II activity, as measured in these assays, is greater than 80% of the total transcription at the 60-cell stage. Furthermore, we show that a specific transcript (actin) can be identified in all early stages tested.