HLA-DQ strikes again: genome-wide association study further confirms HLA-DQ in the diagnosis of asthma among adults.

BACKGROUND: Asthma is a common chronic respiratory disease in children and adults. An important genetic component to asthma susceptibility has long been recognized, most recently through the identification of several genes (e.g., ORMDL3, PDE4D, HLA-DQ, and TLE4) via genome-wide association studies. OBJECTIVE: To identify genetic variants associated with asthma affection status using genome-wide association data. METHODS: We describe results from a genome-wide association study on asthma performed in 3855 subjects using a panel of 455 089 single nucleotide polymorphisms (SNPs). RESULT: The genome-wide association study resulted in the prioritization of 33 variants for immediate follow-up in a multi-staged replication effort. Of these, a common polymorphism (rs9272346) localizing to within 1 Kb of HLA-DQA1 (chromosome 6p21.3) was associated with asthma in adults (P-value = 2.2E-08) with consistent evidence in the more heterogeneous group of adults and children (P-value = 1.0E-04). Moreover, some genes identified in prior asthma GWAS were nominally associated with asthma in our populations. CONCLUSION: Overall, our findings further replicate the HLA-DQ region in the pathogenesis of asthma. HLA-DQA1 is the fourth member of the HLA family found to be associated with asthma, in addition to the previously identified HLA-DRA, HLA-DQB1 and HLA-DQA2.

Seroepidemiologic studies of cytomegalovirus and Epstein-Barr virus infections in relation to human immunodeficiency virus type 1 infection in selected recipient populations. Transfusion Safety Study Group.

Antibodies to human cytomegalovirus (CMV) and Epstein-Barr virus (EBV) were evaluated among 1,171 persons with and without antibodies to human immunodeficiency virus type 1 (anti-HIV-1). These included 97 blood donors, 577 persons given blood components or products, and 497 controls. A significantly higher proportion of anti-HIV-1 positive than -negative donors were anti-CMV-positive, a finding associated with homosexual contact among some of the former. Among subjects with treated clotting disorders, there was no difference in prevalence of anti-CMV or anti-EBV between anti-HIV-1-positive and -negative persons. The prevalence of antibodies to EBV early antigens showed no relationship to anti-HIV-1 status. Anti-CMV positivity in anti-HIV-1-negative donors was associated with an increase in mean CD8 counts and lower mean CD4/CD8 ratio. Anti-CMV and anti-EBV positivity in anti-HIV-1-positive subjects with treated clotting disorders was not associated with a lower CD4 or higher CD8 count than HIV-1 infection alone. Subjects who developed AIDS after enrollment had no significant difference in median time from entry to diagnosis when analyzed by serologic evidence of CMV and EBV antibody status at entry, and a few subjects had AIDS at entry without serologic evidence of prior CMV or EBV infection. The overall results are consistent with acquisition and progression of HIV-1 independently of coincident CMV or EBV infection.

A Bayesian approach to multipoint mapping in nuclear families.

We describe the application of a Markov Chain Monte Carlo approach for multipoint mapping of a quantitative trait locus to the Nuclear Families simulated data. The method involves repeated sampling of genotype vectors for each nuclear family from their conditional distributions, given phenotypes, markers, and model parameters, using peeling and gene dropping, followed by random sampling of each model parameter given genotypes and the other parameters. Reversible jump methods are used to sample the number of trait loci.