High and persistent excretion of hepatitis A virus in immunocompetent patients.

The duration and level of virus excretion in blood and faeces of patients with hepatitis A virus (HAV) infection were studied in relation to levels of alanine aminotransferase (ALT), disease severity and HAV genotype. Clinical data, blood and faeces were collected from 27 patients with acute hepatitis A (median age: 33 years) for a maximum of 26 weeks. Single blood donations from 55 other patients with acute HAV (median age: 32 years) were also used. Virus loads were quantified by competitive nested RT-PCR. HAV was excreted in faeces for a median period of 81 days after disease onset, with 50% of patients still excreting high levels at Day 36 (2 x 10(6) - 2 x 10(8) copies/ml faeces suspension). Viraemia was detected, but not quantifiable, for a median period of 42 days. In the first 10 days of illness, higher ALT levels were correlated with higher viraemia levels. Comparison of patients infected with genotype 1a with those infected with type 1b did not differ significantly in terms of the duration of HAV excretion or jaundice. In conclusion, faecal excretion of HAV is at a high titre in the first month, perhaps making patients infectious for a longer period than assumed currently. Blood banks should be aware that viraemia may be present for more than 1 month, and genotype did not affect the duration of virus excretion or jaundice

Different transmission patterns of hepatitis A virus for two main risk groups as evidenced by molecular cluster analysis

Men who have sex with men and traveling children are the most important risk groups for transmission of hepatitis A virus (HAV) in Amsterdam, The Netherlands. Between these two risk groups, different HAV genotypes are found. In this study the patterns of introduction and transmission of HAV were investigated in the two groups. HAV sequences from Amsterdam patients were divided according to risk: (I) travelers and their contacts, (II) homosexual men and their contacts. The sequences in each risk group were then grouped into clusters based on the genetic distances between the sequences. Among travelers many sporadic cases were found, the clusters were small, and introduced frequently into the population, mostly in the second half of each calendar year, indicating a seasonal pattern of introduction and transmission after the summer holidays. Among men who have sex with men the clusters were bigger and remained present for a longer time; sporadic cases were few, and introduction of new strains occurred only occasionally but throughout the year. Our findings indicate that new HAV strains are frequently imported into Amsterdam by travelers, but they are limited in the extent and season of their spread. In contrast, HAV is only occasionally imported into the male homosexual and bisexual population, but remains endemic and spreads to a large number of individuals without a seasonal patter

Imprinted silencing of Slc22a2 and Slc22a3 does not need transcriptional overlap between Igf2r and Air

Silencing of the paternal allele of three imprinted genes (Igf2r, Slc22a2 and Slc22a3) requires cis expression of the Air RNA that overlaps the promoter of one of them (Igf2r). Air is a non-coding RNA whose mode of action is unknown. We tested the role of the Igf2r promoter and the role of transcriptional overlap between Igf2r and Air in silencing in this cluster. We analyzed imprinted expression in mice in which the Igf2r promoter is replaced by a thymidine kinase promoter that preserves a transcription overlap with Air, and in mice with a deleted Igf2r promoter that lack any transcriptional overlap with Air. Imprinted silencing of Air, Slc22a2 and Slc22a3 is maintained by the replacement promoter and also in the absence of transcriptional overlap with Air. These results exclude a role for the Igf2r promoter and for transcriptional overlap between Igf2r and Air in silencing Air, Slc22a2 and Slc22a3. Although these results do not completely exclude a role for a double-stranded RNA silencing mechanism, they do allow the possibility that the Air RNA has intrinsic cis silencing properties

Two Years’ Prospective Collection of Molecular and Epidemiological Data Shows Limited Spread of Hepatitis A Virus outside Risk Groups in Amsterdam, 2000–2002

We performed a viral sequencing study on samples representing all reported primary cases of acute hepatitis A virus (HAV) infection reported for 2 years in Amsterdam. Two regions of HAV RNA were amplified, sequenced, and used for phylogenetic analysis. Of 156 cases, strains of 104 isolates (66.6%) clustered into 3 genotypes: 1A, 1B, and 3. Two separate transmission circles occurred, without mutual interrelation. In genotype 1A, 4 clusters occurred in men having sex with men (MSM), and the fifth cluster was related to a virus from Morocco. In genotype 1B, 6 small clusters were directly related to the Moroccan virus. In genotype 3, strains were related to a virus from Pakistan. Our analysis indicates that, to stop transmission of HAV in Amsterdam, the entire MSM population and travelers to countries where HAV is endemic, especially children, should be vaccinated. Prevention strategies need not include the vaccination of all children living in Amsterda

The CHEK2 1100delC Mutation Identifies Families with a Hereditary Breast and Colorectal Cancer Phenotype

Because of genetic heterogeneity, the identification of breast cancer–susceptibility genes has proven to be exceedingly difficult. Here, we define a new subset of families with breast cancer characterized by the presence of colorectal cancer cases. The 1100delC variant of the cell cycle checkpoint kinase CHEK2 gene was present in 18% of 55 families with hereditary breast and colorectal cancer (HBCC) as compared with 4% of 380 families with non-HBCC (P<.001), thus providing genetic evidence for the HBCC phenotype. The CHEK2 1100delC mutation was, however, not the major predisposing factor for the HBCC phenotype but appeared to act in synergy with another, as-yet-unknown susceptibility gene(s). The unequivocal definition of the HBCC phenotype opens new avenues to search for this putative HBCC-susceptibility gene

Evaluation of cytokine responses against novel Mtb antigens as diagnostic markers for TB disease

Objective: We investigated the accuracy of host markers detected in Mtb antigen-stimulated whole blood culture supernatant in the diagnosis of TB. Methods: Prospectively, blood from 322 individuals with presumed TB disease from six African sites was stimulated with four different Mtb antigens (Rv0081, Rv1284, ESAT-6/CFP-10, and Rv2034) in a 24 h whole blood stimulation assay (WBA). The concentrations of 42 host markers in the supernatants were measured using the Luminex multiplex platform. Diagnostic biosignatures were investigated through the use of multivariate analysis techniques. Results: 17% of the participants were HIV infected, 106 had active TB disease and in 216 TB was excluded. Unstimulated concentrations of CRP, SAA, ferritin and IP-10 had better discriminating ability than markers from stimulated samples. Accuracy of marker combinations by general discriminant analysis (GDA) identified a six analyte model with 77% accuracy for TB cases and 84% for non TB cases, with a better performance in HIV uninfected patients. Conclusions: A biosignature of 6 cytokines obtained after stimulation with four Mtb antigens has moderate potential as a diagnostic tool for pulmonary TB disease individuals and stimulated marker expression had no added value to unstimulated marker performance