Human pegivirus isolates characterized by deep sequencing from hepatitis C virus-RNA and human immunodeficiency virus-RNA-positive blood donations, France.

Human pegivirus (HPgV, formerly GBV-C) is a member of the genus Pegivirus, family Flaviviridae. Despite its identification more than 20 years ago, both natural history and distribution of this viral group in human hosts remain under exploration. Analysis of HPgV genomes characterized up to now points out the scarcity of French pegivirus sequences in databases. To bring new data regarding HPgV genomic diversity, we investigated 16 French isolates obtained from hepatitis C virus-RNA and human immunodeficiency virus-RNA-positive blood donations following deep sequencing and coupled molecular protocols. Initial phylogenetic analysis of 5'-untranslated region (5'-UTR)/E2 partial sequences permitted to assign HPgV isolates to genotypes 2 (n = 15) and 1 (n = 1), with up to 16% genetic diversity observed for both regions considered. Seven nearly full-length representative genomes were characterized subsequently, with complete polyprotein coding sequences exhibiting up to 13% genetic diversity; closest nucleotide (nt) divergence with available HPgV sequences was in the range 7% to 11%. A 36 nts deletion located on the NS4B coding region (N-terminal part, 12 amino acids) of the genotype 1 HPgV genome characterized was identified, along with single nucleotide deletions in two genotype 2, 5'-UTR sequences.

Molecular epidemiology of KI and WU polyomaviruses in healthy blood donors, south-eastern France.

The epidemiology of human polyomaviruses KI (KIPyV) and WU (WUPyV) in healthy populations is described poorly in the literature. The frequency of KIPyV and WUPyV viraemia was evaluated in a cohort of blood donors from south-eastern France. Plasma samples (n=640) were investigated for the presence of KIPyV/WUPyV DNA using a conserved real-time PCR detection system (VP2 gene). Three plasma samples (3/640; ∼0.5%) exhibited a positive fluorescence signal, with a low viral load (<500 copies/ml plasma); no additional amplicons were identifiable by agarose gel analysis. Sequencing highlighted the KIPyV origin of the three amplified sequences and the occurrence of point mutations. The sustained detection of KIPyV DNA in two serial samples (9 months) was in favor of a possible persistence of the virus in blood of healthy individuals. Further studies will be needed in order to explore both the prevalence and potential clinical impact of KIPyV/WUPyV on infected hosts.

High levels of molecular polymorphism at the KIR2DL4 locus in French and Congolese populations: impact for anthropology and clinical studies.

To characterize KIR2DL4 molecular polymorphism, a cloning-sequencing protocol was performed in 49 French and 52 Teke Congolese individuals. These two populations exhibited high levels of genetic diversity for KIR2DL4, possibly under the influence of natural selection. The most frequent alleles in French individuals (i.e., *00801 and *00802 with a cumulated frequency of approximately 43%) were not the same in Congolese individuals (i.e., *00103 at 47%). In the latter population, four new allelic variants were detected, three of them harboring nonsynonymous substitutions leading to amino acid changes in the extracellular and cytoplasmic domains of the protein. Expression patterns of KIR2DL4 were tightly linked with 9 and 10 poly-adenine polymorphism in exon 7 (i.e., 9A and 10A type alleles). French individuals exhibited a majority of 9A alleles (62%), whereas Congolese individuals had a dominant subset of 10A alleles (72%), suggesting that KIR2DL4 polymorphism could be under the influence of various environmental and pathogenic backgrounds. We conclude that KIR2DL4 might be a good candidate to study for anthropology. In addition, the discovery of its intrinsic variability is shedding light on potential differences among human populations in relation to immunologic functions.

Positive association of DRB1 04 and DRB1 15 alleles with Fya immunization in a Southern European population.

BACKGROUND: Anti-Fy(a) has been implicated in hemolytic transfusion reactions. However, not all Fy(a-) patients develop anti-Fy(a) after transfusion with 1 unit of blood [Fy(a+)]. This study was designed to identify HLA-DRB1 alleles associated with a predisposition to Fy(a) immunization after blood transfusion. STUDY DESIGN AND METHODS: To identify HLA-DRB1 alleles prone to immunization after blood transfusion or pregnancy, HLA-DRB1 genotyping using polymerase chain reaction with sequence-specific oligonucleotide nonradioactive probe/sequence-specific priming methods was performed on blood samples from 67 immunized patients and 200 unrelated controls from the same southern European population in a case-control retrospective study. RESULTS: Ninety-six percent of patients with anti-Fy(a) had at least one HLA-DRB1 04 or HLA-DRB1 15 allele compared to 34% of controls (p(c) < 0.001). Furthermore HLA-DRB1 04 and HLA-DRB1 1501 frequencies were significantly increased in Fy(a)-immunized patients (35% vs. 12%, p(c) < 0.001; and 30% vs. 19%, p(c) < 0.001, respectively). Among HLA-DRB1 04 allelic subtypes, DRB1 0401 and DRB1 0403 alleles were more strongly correlated with Fy(a) immunization (51% vs. 24% and 19% vs. 9%; p(c) < 0.001, respectively). CONCLUSIONS: This study indicated that HLA-DRB1 04 and DRB1 1501 are overrepresented in Fy(a)-immunized patients. The correlation between these alleles and Fy(a) immunization could be due to a particular presentation of the Fy(a) peptide in HLA-DRB1 molecules.