Executive summary of the NHLBI State of the Science (SOS) Workshop: Overview and next steps in generating a national blueprint for future research on factor VIII inhibitors

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150611/1/hae13713_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150611/2/hae13713.pd

Effect of a Single Amino Acid Change in MHC Class I Molecules on the Rate of Progression to AIDS

Background From studies of genetic polymorphisms and the rate of progression from human immunodeficiency virus type 1 (HIV-1) infection to the acquired immunodeficiency syndrome (AIDS), it appears that the strongest susceptibility is conferred by the major-histocompatibility-complex (MHC) class I type HLA-B*35,Cw*04 allele. However, cytotoxic T-lymphocyte responses have been observed against HIV-1 epitopes presented by HLA-B*3501, the most common HLA-B*35 subtype. We examined subtypes of HLA-B*35 in five cohorts and analyzed the relation of structural differences between HLA-B*35 subtypes to the risk of progression to AIDS. Methods Genotyping of HLA class I loci was performed for 850 patients who seroconverted and had known dates of HIV-1 infection. Survival analyses with respect to the rate of progression to AIDS were performed to identify the effects of closely related HLAB* 35 subtypes with different peptide-binding specificities. Results HLA-B*35 subtypes were divided into two groups according to peptide-binding specificity: the HLA-B*35-PY group, which consists primarily of HLAB* 3501 and binds epitopes with proline in position 2 and tyrosine in position 9; and the more broadly reactive HLA-B*35-Px group, which also binds epitopes with proline in position 2 but can bind several different amino acids (not including tyrosine) in position 9. The influence of HLA-B*35 in accelerating progression to AIDS was completely attributable to HLAB* 35-Px alleles, some of which differ from HLA-B*35- PY alleles by only one amino acid residue. Conclusions This analysis shows that, in patients with HIV-1 infection, a single amino acid change in HLA molecules has a substantial effect on the rate of progression to AIDS. The different consequences of HLA-B*35-PY and HLA-B*35-Px in terms of disease progression highlight the importance of the epitope specificities of closely related class I molecules in the immune defense against HIV-1

Association of DC-SIGN Promoter Polymorphism with Increased Risk for Parenteral, but Not Mucosal, Acquisition of Human Immunodeficiency Virus Type 1 Infection

There is considerable debate about the fundamental mechanisms that underlie and restrict acquisition of human immunodeficiency virus type 1 (HIV-1) infection. In light of recent studies demonstrating the ability of C type lectins to facilitate infection with HIV-1, we explored the potential relationship between polymorphisms in the DC-SIGN promoter and risk for acquisition of HIV-1 according to route of infection. Using samples obtained from 1,611 European-American participants at risk for parenteral (n = 713) or mucosal (n = 898) infection, we identified single-nucleotide polymorphisms in the DC-SIGN promoter using single-strand conformation polymorphism. Individuals at risk for parenterally acquired infection who had −336C were more susceptible to infection than were persons with −336T (odds ratio = 1.87, P = 0.001). This association was not observed in those at risk for mucosally acquired infection. A potential role for DC-SIGN specific to systemic acquisition and dissemination of infection is suggested

CCR5AS lncRNA variation differentially regulates CCR5, influencing HIV disease outcome.

Multiple genome-wide studies have identified associations between outcome of human immunodeficiency virus (HIV) infection and polymorphisms in and around the gene encoding the HIV co-receptor CCR5, but the functional basis for the strongest of these associations, rs1015164A/G, is unknown. We found that rs1015164 marks variation in an activating transcription factor 1 binding site that controls expression of the antisense long noncoding RNA (lncRNA) CCR5AS. Knockdown or enhancement of CCR5AS expression resulted in a corresponding change in CCR5 expression on CD4+ T cells. CCR5AS interfered with interactions between the RNA-binding protein Raly and the CCR5 3' untranslated region, protecting CCR5 messenger RNA from Raly-mediated degradation. Reduction in CCR5 expression through inhibition of CCR5AS diminished infection of CD4+ T cells with CCR5-tropic HIV in vitro. These data represent a rare determination of the functional importance of a genome-wide disease association where expression of a lncRNA affects HIV infection and disease progression

Clinical issues in inhibitors

Anamestic inhibitors represent the major complication of haemophilia therapy now that clotting factor concentrates are virtually free of pathogen-transmission risk. Conventional clotting factor replacement is usually insufficient to prevent or treat bleeding in a haemophilia patient with a high responding inhibitor so that alternative treatment with bypassing agents is required. Despite their relative efficacy, their use does not achieve the same invariable haemostasis that patients without inhibitors do following treatment with factor concentrate replacement. This has led to the attempt to eradicate such inhibitors with immune tolerance induction. Success is not invariable, however, and many patients with long-term persistent high-titre inhibitors continue to experience great morbidity. Recently, this has given rise on a limited basis to attempts to use bypassing agents in prophylaxis regimens in an effort to alleviate this extreme morbidity. Each of these strategies is discussed in the context of their relative benefits and risks

Knowledge, Attitudes, and Behaviors of Youths in the US Hemophilia Population: Results of a National Survey

Objectives. The National Hemophilia Foundation and the Centers for Disease Control and Prevention conducted a national survey focusing on knowledge about, attitudes toward, and behaviors associated with key prevention activities among youths with hemophilia and used the data gathered to design a health promotion campaign. Methods. A national, random sample of 459 patients was drawn from 20 hemophilia treatment centers and 8 hemophilia associations; 110 (24%) of the respondents were young people. A telephone questionnaire was used to measure knowledge, behaviors, and barriers to prevention. Results. Thirty-six percent of the youth respondents believed that joint disease cannot be prevented; 60% managed hemophilia by avoiding physical activity. Only 31% of the respondents treated bleeding episodes within 1 hour. Although hepatitis was a clear threat to this hemophilic cohort, 78% did now know transmission routes for hepatitis C, and 67% did not know transmission routes for hepatitis B. Conclusions. Young people with chronic disorders need help understanding that they can prevent complications. We identified key messages for a hemophilia prevention campaign, including exercising to ensure healthy joints and treating bleeding episodes early and adequately

Delays in maturation among adolescents with hemophilia and a history of inhibitors

Inhibitory antibodies to factors VIII or IX have the potential to affect a broad range of outcomes among people with hemophilia; however, their possible effect on growth and maturation has not been explored. We evaluated skeletal maturation (bone age), pubertal progression, serum testosterone levels, height velocity, and stature in the multicenter Hemophilia Growth and Development Study. A total of 333 children and adolescents (mean age, 12.4 years) were enrolled from 1989 to 1990 and followed for 7 years. Of these, 18% (n = 60) had a history of inhibitors. Bone age among HIV− adolescents with a history of inhibitors lagged 9 or more months behind those without inhibitors at every age from 12 to 15 years. Those with a history of inhibitors were older at every Tanner stage transition, attained a lower maximum growth velocity, and their serum testosterone levels were significantly lower compared with those without inhibitors. Delays were greater among HIV+ patients with a history of inhibitors compared with those without inhibitors; however, the differences were generally small and not statistically significant. The results of this investigation underscore the importance of monitoring the growth and maturation of children and adolescents with hemophilia, particularly those with inhibitors

The importance of genetic factors for the development of arthropathy: a longitudinal study of children and adolescents with haemophilia A

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