Studies of determinants of development of inhibitory Abs to factor VIII in people with hemophilia A indicate a complex process involving multiple factors. The Hemophilia Inhibitor Genetics Study ...(HIGS) Combined Cohort was formed to extend our understanding of the genetic background of risk. The study group contains 833 subjects from 3 independent cohorts: brother pairs and singletons with and without a history of inhibitors, as well as 104 brother pairs discordant for inhibitor status. Using an Illumina iSelect platform, 13 331 single-nucleotide polymorphisms from 1081 genes, primarily immune response and immune modifier genes, were typed. Each cohort was analyzed separately with results combined using a meta-analytic technique. After adjustment for potential confounders, 53 single-nucleotide polymorphisms were found to be significant predictors of inhibitor status using the criteria of odds ratios in the same direction in all cohorts or allowing for a 20% interval around an odds ratio = 1 in 1 of the 3 and significant in at least 2. Of the 53 markers, 13 had meta P < .001. Eight of the 53 were significant predictors among the discordant pairs. Results support the complexity of the immune response and encourage further research with the goal of understanding the pathways involved.
•The data demonstrate the complexity of the genetic contribution to inhibitor development in people with hemophilia A.•Potentially decisive markers have been identified, indicating the importance of further evaluation of intracellular signaling pathways.
Next-generation sequencing has critical applications in virus discovery, diagnostics, and environmental surveillance. We used metagenomic sequence libraries for retrospective screening of plasma ...samples for the recently discovered human hepegivirus 1 (HHpgV-1). From a cohort of 150 hepatitis C virus (HCV)-positive case-patients, we identified 2 persons with HHpgV-1 viremia and a high frequency of human pegivirus (HPgV) viremia (14%). Detection of HHpgV-1 and HPgV was concordant with parallel PCR-based screening using conserved primers matching groups 1 (HPgV) and 2 (HHPgV-1) nonstructural 3 region sequences. PCR identified 1 HHPgV-1-positive person with viremia from a group of 195 persons with hemophilia who had been exposed to nonvirally inactivated factor VII/IX; 18 (9%) were HPgV-positive. Relative to HCV and HPgV, active infections with HHpgV-1 were infrequently detected in blood, even in groups that had substantial parenteral exposure. Our findings are consistent with lower transmissibility or higher rates of virus clearance for HHpgV-1 than for other bloodborne human flaviviruses.
BACKGROUND: Human parvovirus 4 (PARV4) is a newly discovered parvovirus prevalent in injecting drug users and other groups with histories of parenteral exposure including persons with hemophilia ...exposed to non–virally inactivated clotting factor concentrates. To investigate its potential ongoing transmission to persons with hemophilia treated with plasma‐derived, virally inactivated clotting factors, we screened a large cohort of persons with hemophilia for antibody seroconversion to PARV4 over a 5‐year observation period.
STUDY DESIGN AND METHODS: Samples from 195 persons with hemophilia enrolled in the Hemophilia Growth and Development Study cohort were screened for PARV4 antibodies at the start and end of a 5‐year period of treatment with exclusively virally inactivated clotting factor concentrates. Samples collected at intermediate time points from subjects seroconverting over the study period were screened to narrow down the seroconversion time and investigate immunoglobulin (Ig)M responses, duration of acute viremia, and clinical presentations.
RESULTS: PARV4 seroprevalence at the outset of the study was 44%. Over the observation period, nine subjects (seven human immunodeficiency virus positive) seroconverted for anti‐PARV4 (incidence, 1.7%/year). Infected subjects showed relatively prolonged durations of viremia (mean, 7 months) and weak, transient IgM responses during acute infections. Clotting factors inactivated by solvent/detergent or by wet or dry heat were infectious. The most common clinical presentations were rashes and exacerbation of hepatitis.
CONCLUSION: This study identifies PARV4 as a transfusion‐transmissible agent that is resistant to viral inactivation. Of concern, infections may still regularly occur in those exposed to plasma‐derived blood products. Urgent evaluation of the incidence of PARV4 in treated individuals and disease associations of PARV4 infections is required.
BackgroundPARV4 is a human parvovirus that was first detected in and cloned from an individual with a human immunodeficiency virus (HIV) seroconversion–like illness and that subsequently persisted in ...the lymphoid tissue and bone marrow. In contrast to human parvovirus B19 infections, PARV4 infections are most frequently detected in injection drug users (IDUs), particularly those who are coinfected with HIV type 1 (HIV-1). To investigate the routes of transmission of PARV4 and to ascertain whether infections are acquired through plasma-derived blood products, we developed a novel anti-PARV4 enzyme-linked immunosorbent assay (ELISA) to determine its seroprevalence in subjects with parenteral exposure MethodsPARV4 viral protein 2 (VP2) was expressed and used as antigen in an indirect ELISA, to detect anti-PARV4 immunoglobulin G ResultsAll 50 adult control subjects who were nonparenterally exposed to PARV4 were anti-PARV4 negative, in contrast to HIV-infected and HIV–uninfected IDUs, who had antibody frequencies of 67% and 33%, respectively. Predominantly parenteral transmission was confirmed by the finding of similar frequencies of infection among HIV-coinfected and HIV–uninfected hemophiliacs (11 of 20 individuals and 4 of 15 individuals, respectively) who were treated with nonvirally inactivated factor VIII/factor IX, whereas all but 1 of the 35 nonhemophiliac siblings of these siblings were found to be seronegative (despite having close household contact) ConclusionsThe present study provides convincing evidence that PARV4 is primarily transmitted parenterally. Evidence for widespread infection of hemophiliacs treated with nonvirally inactivated clotting factor creates fresh safety concerns for plasma-derived blood products, particularly because parvoviruses are relatively resistant to virus inactivation
The human mitochondrial genome includes only 13 coding genes while nuclear-encoded genes account for 99% of proteins responsible for mitochondrial morphology, redox regulation, and energetics. ...Mitochondrial pathogenesis occurs in HIV patients and genetically, mitochondrial DNA haplogroups with presumed functional differences have been associated with differential AIDS progression.
Here we explore whether single nucleotide polymorphisms (SNPs) within 904 of the estimated 1,500 genes that specify nuclear-encoded mitochondrial proteins (NEMPs) influence AIDS progression among HIV-1 infected patients. We examined NEMPs for association with the rate of AIDS progression using genotypes generated by an Affymetrix 6.0 genotyping array of 1,455 European American patients from five US AIDS cohorts. Successfully genotyped SNPs gave 50% or better haplotype coverage for 679 of known NEMP genes. With a Bonferroni adjustment for the number of genes and tests examined, multiple SNPs within two NEMP genes showed significant association with AIDS progression: acyl-CoA synthetase medium-chain family member 4 (ACSM4) on chromosome 12 and peroxisomal D3,D2-enoyl-CoA isomerase (PECI) on chromosome 6.
Our previous studies on mitochondrial DNA showed that European haplogroups with presumed functional differences were associated with AIDS progression and HAART mediated adverse events. The modest influences of nuclear-encoded mitochondrial genes found in the current study add support to the idea that mitochondrial function plays a role in AIDS pathogenesis.
Background. High-throughput genome-wide techniques have facilitated the identification of previously unknown host proteins involved in cellular human immunodeficiency virus (HIV) infection. Recently, ...3 independent studies have used small interfering RNA technology to silence each gene in the human genome to determine the importance of each in HIV infection. Genes conferring a significant effect were termed HIV-dependency factors (HDFs). Methods. We assembled high-density panels of 6380 single-nucleotide polymorphisms (SNPs) in 278 HDF genes and tested for genotype associations with HIV infection and AIDS progression in 1633 individuals from clinical AIDS cohorts. Results. After statistical correction for multiple tests, significant associations with HIV acquisition were found for SNPs in 2 genes, NCOR2 and IDH1. Weaker associations with AIDS progression were revealed for SNPs within the TM9SF2 and EGFR genes. Conclusions. This study independently verifies the influence of NCOR2 and IDH1 on HIV transmission, and its findings suggest that variation in these genes affects susceptibility to HIV infection in exposed individuals.
Background. Human immunodeficiency virus type 1 (HIV-1) coreceptor tropism, the ability of the virus to enter cells via CCR5 or CXCR4, is a viral characteristic mediated by the envelope gene. The ...impact of coreceptor tropism on the natural history of HIV-1 infection has not been fully explored. Methods. Coreceptor tropism was measured using a recombinant virus single-cycle assay on plasma specimens obtained at baseline from 126 children and adolescents in the Hemophilia Growth and Development Study cohort who were enrolled from 1989 through 1990 and underwent follow-up through 1997. Results. Detectable CXCR4-using virus at baseline was associated with a lower baseline CD4+ T cell count and a higher plasma HIV-1 RNA level. In addition, it independently predicted a greater decrease in CD4+ T cell count over time (P < .001) and was associated with a 3.8-fold increased risk of progression to clinical AIDS. Conclusions. This study demonstrates that coreceptor tropism, as assessed by this single-cycle assay, independently influences the natural history of HIV-1 disease.
Haemophilia A is a congenital bleeding disorder characterised by recurrent haemorrhages into the major joints. Haemophilic arthropathy is a well-established outcome of recurrent joint bleeding; ...however, it is clear that multiple factors determine the extent and severity of its occurrence. We sought to identify genetic factors related to abnormalities in range of motion (ROM) in the knees, ankles and elbows in a cohort of children and adolescents with haemophilia A not treated primarily with regular prophylaxis. Using data from the Haemophilia Growth and Development Study, we examined associations between 13,342 genetic markers and ROM scores measured at six-month intervals for up to seven years. As a first step, ordered logistic regression models were fit for each joint separately. A subset of SNP markers showing significant effects (p<0.01) on the right and left sides for at least two joints were included in a full model fit using a multivariate generalised linear mixed model assuming an ordinal response. The models contained all ROM scores obtained at all visits. Twenty-five markers analysed in the full model showed either increased or decreased risk of ROM abnormalities at the p<0.001 level. Several genes identified at either the first or second stage of the analysis have been associated with arthritis in a variety of large studies. Our results support the likelihood that risk for haemophilic arthropathy is associated with genetic factors, the identification of which holds promise for further advancing the individualisation of treatment.
Background. Host genetic variation influences human immunodeficiency virus (HIV) infection and progression to AIDS. Here we used clinically well-characterized subjects from 5 pretreatment HIV/AIDS ...cohorts for a genome-wide association study to identify gene associations with rate of AIDS progression. Methods. European American HIV seroconverters (n = 755) were interrogated for single-nucleotide polymorphisms (SNPs) (n = 700,022) associated with progression to AIDS 1987 (Cox proportional hazards regression analysis, co-dominant model). Results. Association with slower progression was observed for SNPs in the gene PARD3B. One of these, rs11884476, reached genome-wide significance (relative hazard = 0.3; P = 3.370 × 10⁻⁹) after statistical correction for 700,022 SNPs and contributes 4.52% of the overall variance in AIDS progression in this study. Nine of the top-ranked SNPs define a PARD3B haplotype that also displays significant association with progression to AIDS (hazard ratio, 0.3; P = 3.220 × 10⁻ɸ). One of these SNPs, rs10185378, is a predicted exonic splicing enhancer; significant alteration in the expression profile of PARD3B splicing transcripts was observed in B cell lines with alternate rs10185378 genotypes. This SNP was typed in European cohorts of rapid progressors and was found to be protective for AIDS 1993 definition (odds ratio, 0.43, P = .025). Conclusions. These observations suggest a potential unsuspected pathway of host genetic influence on the dynamics of AIDS progression.
The presence of antibodies (Abs) in hemophilia A patients can potentially influence the therapeutic qualities of factor VIII (fVIII) administration. Much work has been focused on the presence of ...inhibitory antibodies, whereas the quantitation of noninhibitory anti-fVIII antibodies has been largely undetermined. Our objective was to develop a sensitive and specific fluorescence-based immunoassay (FLI) for the quantitation of anti-fVIIIAbs in human plasma. Affinity-purified human anti-fVIIIAb, isolated from a hemophilia A subject, was used as a calibrator with a detectability limit of 40 (±1.5) pM. The calibrator and the human plasma anti-fVIIIAb were captured on recombinant fVIII (rfVIII)– coupled microspheres and probed with mouse anti–human Ig–R-phycoerythrin. Plasma samples from 150 healthy donors and 39 inhibitor-negative hemophilia A subjects were compared with 4 inhibitor-positive hemophilia A plasma samples with inhibitor titers of 1 BU/mL (94.6 ± 0.8 nM), 11 BU/mL (214.3 ± 7.1 nM), 106 BU/mL (2209.4 ± 84.9 nM), 140 BU/mL (2417.7 ± 3.8 nM) as measured by the Nijmegen method. We also describe the validation of a mouse anti–human fVIIIAb as a surrogate calibrator. Four healthy individuals (3%) showed detectable anti-fVIIIAb in the range of 0.6 to 6.2 nM, whereas 13 (33%) of the 39 inhibitor-free hemophilia A subjects were positive for anti-fVIIIAb in the range of 0.5 to 20 nM. The method may be useful for therapeutic management of hemophilia A patients.
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