Increasing Levels of Serum Heat Shock Protein 70 Precede the Development of AIDS-Defining Non-Hodgkin Lymphoma Among Carriers of HLA-B8-DR3.

BACKGROUND: We hypothesized that carriage of presumably high Hsp70-producing gene variants on a specific human major histocompatibility complex haplotype, the 8.1 ancestral haplotype (8.1AH), may predispose HIV-infected individuals to AIDS-non-Hodgkin lymphoma (NHL). SETTING: We compared serum Hsp70 levels in the years preceding the diagnosis of AIDS-NHL in a matched case-control study (n = 151 pairs) nested in the Multicenter AIDS Cohort Study. METHODS: We tested the impact of 8.1AH-specific single-nucleotide polymorphism (SNP) and joint SNP-human leukocyte antigen extended haplotypes previously associated with AIDS-NHL in the Multicenter AIDS Cohort Study on the circulating Hsp70 levels in mixed linear models. RESULTS: We report elevated serum levels of Hsp70 in the 4 years preceding the diagnosis of AIDS-NHL in cases that carry 8.1AH, but not in noncarrier cases and not in carrier- or non-carrier-matched controls. The strongest predictor of higher serum Hsp70 was the haplotype A-G-A-C formed by SNPs rs537160(A) and rs1270942(G) in the complement factor CFB gene cluster, and rs2072633(A) and rs6467(C) in nearby RDBP and CYP21A2 located 70 Kb apart from the Hsp70 gene cluster. The association with A-G-A-C haplotype (beta = 0.718; standard error = 0.182; P = 0.0002) and with other 8.1AH-specific haplotypes including the high-producing tumor necrosis factor-alpha haplotype rs909253(G)-rs1800629(A) (beta = 0.308; standard error = 0.140; P = 0.032) were observed only with NHL identified as an AIDS-defining condition, but not as a post-AIDS condition, nor in combined AIDS and post-AIDS cases. CONCLUSION: Our combined genetic and functional approach suggests that the altered level of Hsp70 is a correlate of 8.1AH-mediated AIDS-NHL. Further investigation of the Hsp70 gene cluster and nearby loci that are tagged by A-G-A-C could better elucidate the genetic determinants of the malignancy.

Access, Education and Policy Awareness: Predictors of Influenza Vaccine Acceptance Among VHA Healthcare Workers.

OBJECTIVE To identify predictors of influenza vaccine acceptance among VHA healthcare workers (HCWs), with emphasis on modifiable factors related to promotion campaigns. DESIGN Survey. SETTING National single-payer healthcare system with 140 hospitals and 321,000 HCWs. PARTICIPANTS National voluntary sample of HCWs in the Veterans Health Administration (VHA) system. METHODS We invited a random sample of 5% of all VHA HCWs to participate. An 18-item intranet-based survey inquired about occupation, vaccination status, employer policy, and local campaign efforts. RESULTS The response rate was 17.4%. Of 2,502 initial respondents, 2,406 (96.2%) provided usable data. This sample includes respondents from all 140 VA hospitals. Self-reported influenza vaccination rates were highest among physicians (95.6%) and licensed independent providers (88.3%). Nonclinical staff (80.7%) reported vaccine uptake similar to other certified but nonlicensed providers (81.2%). The strongest predictor of vaccine acceptance among VHA HCWs was individual awareness of organizational policy. Vaccine acceptance was also higher among HCWs who reported more options for access to vaccination and among those in facilities with more education activities. CONCLUSIONS Influenza vaccine acceptance varied significantly by employee awareness of employer policy and on-site access to vaccine. Employer-sponsored activities to increase access continue to show positive returns across occupations. Local influenza campaign efforts to educate HCWs may have reached saturation in this target group. These results suggest that focused communications to increase HCW awareness and understanding of employer policy can drive further increase in influenza vaccination acceptance. Infect Control Hosp Epidemiol 2017;38:970-975.

CD4:CD8 lymphocyte ratio as a quantitative measure of immunologic health in HIV-1 infection: findings from an African cohort with prospective data.

In individuals with human immunodeficiency virus type 1 (HIV-1) infection, CD4:CD8 lymphocyte ratio is often recognized as a quantitative outcome that reflects the critical role of both CD4(+) and CD8(+) T-cells in HIV-1 pathogenesis or disease progression. Our work aimed to first establish the dynamics and clinical relevance of CD4:CD8 ratio in a cohort of native Africans and then to examine its association with viral and host factors, including: (i) length of infection, (ii) demographics, (iii) HIV-1 viral load (VL), (iv) change in CD4(+) T-lymphocyte count (CD4 slope), (v) HIV-1 subtype, and (vi) host genetics, especially human leukocyte antigen (HLA) variants. Data from 499 HIV-1 seroconverters with frequent (monthly to quarterly) follow-up revealed that CD4:CD8 ratio was stable in the first 3 years of infection, with a modest correlation with VL and CD4 slope. A relatively normal CD4:CD8 ratio (>1.0) in early infection was associated with a substantial delay in disease progression to severe immunodeficiency (<350 CD4 cells/µl), regardless of other correlates of HIV-1 pathogenesis (adjusted hazards ratio (HR) = 0.43, 95% confidence interval (CI) = 0.29-0.63, P < 0.0001). Low VL (<10,000 copies/ml) and HLA-A*74:01 were the main predictors of CD4:CD8 ratio >1.0, but HLA variants (e.g., HLA-B*57 and HLA-B*81) previously associated with VL and/or CD4 trajectories in eastern and southern Africans had no obvious impact on CD4:CD8 ratio. Collectively, these findings suggest that CD4:CD8 ratio is a robust measure of immunologic health with both clinical and epidemiological implications.

Body Mass Index Is Associated With Mucosal Disease in Crohn's: Results of a Case-Control Study.

BACKGROUND: Recent studies have suggested that increased body mass index (BMI) may have an adverse effect on treatment outcomes and natural history in Crohn's disease (CD). We aimed to test the hypothesis that CD patients with higher BMI would be more likely than those with lower BMI to have persistent active mucosal disease. METHODS: We designed a case-control study. Sample population comprised CD patients with active disease at the beginning of observation. At the end of observation, cases had persistent active mucosal disease and controls had entered remission. With multivariable logistic regression models, we evaluated the effect of baseline BMI as a continuous variable and a categorical variable on persistent active mucosal disease. RESULTS: We analyzed data from 104 patients (36 cases and 68 controls). In a model containing BMI as a continuous variable, higher BMI was significantly associated with persistent active mucosal disease (odds ratio (OR) = 1.09 per unit increase; 95% confidence interval (CI), 1.02 - 1.17; P = 0.012). In a model containing BMI as a categorical variable, obese patients were 2.7 times more likely to have persistent active mucosal disease compared to non-obese patients (OR = 2.72; 95% CI, 1.00 - 7.35; P = 0.049). CONCLUSION: Excessive weight measured both quantitatively as BMI and categorically as obesity in CD patients is associated with persistent active mucosal disease.

Host genetics and viral load in primary HIV-1 infection: clear evidence for gene by sex interactions.

Research in the past two decades has generated unequivocal evidence that host genetic variations substantially account for the heterogeneous outcomes following human immunodeficiency virus type 1 (HIV-1) infection. In particular, genes encoding human leukocyte antigens (HLA) have various alleles, haplotypes, or specific motifs that can dictate the set-point (a relatively steady state) of plasma viral load (VL), although rapid viral evolution driven by innate and acquired immune responses can obscure the long-term relationships between HLA genotypes and HIV-1-related outcomes. In our analyses of VL data from 521 recent HIV-1 seroconverters enrolled from eastern and southern Africa, HLA-A*03:01 was strongly and persistently associated with low VL in women (frequency = 11.3 %, P < 0.0001) but not in men (frequency = 7.7 %, P = 0.66). This novel sex by HLA interaction (P = 0.003, q = 0.090) did not extend to other frequent HLA class I alleles (n = 34), although HLA-C*18:01 also showed a weak association with low VL in women only (frequency = 9.3 %, P = 0.042, q > 0.50). In a reduced multivariable model, age, sex, geography (clinical sites), previously identified HLA factors (HLA-B*18, B*45, B*53, and B*57), and the interaction term for female sex and HLA-A*03:01 collectively explained 17.0 % of the overall variance in geometric mean VL over a 3-year follow-up period (P < 0.0001). Multiple sensitivity analyses of longitudinal and cross-sectional VL data yielded consistent results. These findings can serve as a proof of principle that the gap of "missing heritability" in quantitative genetics can be partially bridged by a systematic evaluation of sex-specific associations.

Mitochondrial DNA variation and virologic and immunological HIV outcomes in African Americans.

OBJECTIVE: To evaluate the impact of mitochondrial DNA (mtDNA) haplogroups on virologic and immunological outcomes of HIV infection. DESIGN: HAART-naive African American adolescent participants to the Reaching for Excellence in Adolescent Care and Health study. METHODS: The mtDNA haplogroups were inferred from sequenced mtDNA hypervariable regions HV1 and HV2 and their predictive value on HIV outcomes were evaluated in linear mixed models, controlled for human leukocyte antigen (HLA)-B27, HLA-B57 and HLA-B35-Px alleles and other covariates. RESULTS: We report data showing that the mtDNA L2 lineage, a group composed of L2a, L2b and L2e mtDNA haplogroups in the studied population, is significantly associated (beta  = -0.08; Bonferroni-adjusted P = 0.004) with decline of CD4 T cells (median loss of 8 ± 1 cells per month) in HAART-naive HIV-infected individuals of African American descent (n = 133). No significant association (P < 0.05) with set-point viral load was observed with any of the tested mtDNA haplogroups. The present data concur with previous findings in the AIDS Clinical Trials Group study 384, implicating the L2 lineage with slower CD4 T-cell recovery after antiretroviral therapy in African Americans. CONCLUSIONS: Whereas the L2 lineage showed an association with unfavorable immunological outcomes of HIV infection, its phylogenetic divergence from J and U5a, two lineages associated with accelerated HIV progression in European Americans, raises the possibility that interactions with common nucleus-encoded variants drive HIV progression. Disentangling the effects of mitochondrial and nuclear gene variants on the outcomes of HIV infection is an important step to be taken toward a better understanding of HIV/AIDS pathogenesis and pharmacogenomics.

KIR2DS4 promotes HIV-1 pathogenesis: new evidence from analyses of immunogenetic data and natural killer cell function.

BACKGROUND: KIR2DS4 gene variants encode full-length and truncated protein products, with only the former serving as membrane-bound receptors to activate natural killer (NK) cells. We have previously shown that full-length KIR2DS4 was associated with relatively high viral load and accelerated heterosexual HIV-1 transmission. Our objective here was to provide confirmatory data and to offer new insights about the potential mechanisms. METHODOLOGY/PRINCIPAL FINDINGS: Mixed models for repeated (longitudinal) outcome measurements on 207 HIV-1 seropositive American youth revealed an association of full-length KIR2DS4 with relatively high viral load and low CD4+ T-cell count (p<0.01 for both). Depending on KIR2DS4 expression (presence or absence) on cell surface, NK cells from 43 individuals with untreated, chronic HIV-1 infection often differed in functional properties, including degranulation and secretion of IFN-γ and MIP-1ß. In particular, polyfunctional NK cells were enriched in the KIR2DS4-positive subset. CONCLUSIONS/SIGNIFICANCE: Full-length KIR2DS4 promotes HIV-1 pathogenesis during chronic infection, probably through the maintenance of an excessively pro-inflammatory state.

Dynamics of viremia in primary HIV-1 infection in Africans: insights from analyses of host and viral correlates.

In HIV-1 infection, plasma viral load (VL) has dual implications for pathogenesis and public health. Based on well-known patterns of HIV-1 evolution and immune escape, we hypothesized that VL is an evolving quantitative trait that depends heavily on duration of infection (DOI), demographic features, human leukocyte antigen (HLA) genotypes and viral characteristics. Prospective data from 421 African seroconverters with at least four eligible visits did show relatively steady VL beyond 3 months of untreated infection, but host and viral factors independently associated with cross-sectional and longitudinal VL often varied by analytical approaches and sliding time windows. Specifically, the effects of age, HLA-B(⁎)53 and infecting HIV-1 subtypes (A1, C and others) on VL were either sporadic or highly sensitive to time windows. These observations were strengthened by the addition of 111 seroconverters with 2-3 eligible VL results, suggesting that DOI should be a critical parameter in epidemiological and clinical studies.

A candidate gene approach for virally induced cancer with application to HIV-related Kaposi's sarcoma.

Like other members of the γ-herpesvirus family, human herpes virus 8, the etiologic agent of classic and HIV-related Kaposi's sarcoma (HIV-KS) acquired and evolved several human genes with key immune modulatory and cellular growth control functions. The encoded viral homologs substitute for their human counterparts but escape cellular regulation, leading to uncontrolled cell proliferation. We postulated that DNA variants in the human homologs of viral genes that potentially alter the expression or the binding of the encoded factors controlling the antiviral response may facilitate viral interference. To test whether cellular homologs are candidate susceptibility genes, we evaluated the association of DNA variants in 92 immune-related genes including seven cellular homologs with the risk for HIV-KS in a matched case and control study nested in the Multicenter AIDS Cohort Study. Low- and high-risk gene-by-gene interactions were estimated by multifactor dimensionality reduction and used as predictors in conditional logistic models. Among the most significant gene interactions at risk (OR=2.84-3.92; Bonferroni- adjusted p=9.9 × 10(-3) - 2.6 × 10(-4) ), three comprised human homologs of two latently expressed viral genes, cyclin D1 (CCND1) and interleukin-6 (IL-6), in conjunction with angiogenic genes (VEGF, EDN-1 and EDNRB). At lower significance thresholds (adjusted p < 0.05), human homologs related to apoptosis (CFLAR) and chemotaxis (CCL2) emerged as candidates. This "proof of concept" study identified human homologs involved in the regulation of type I interferon-induced signaling, cell cycle and apoptosis potentially as important determinants of HIV-KS.

Allelic-dependent expression of an activating Fc receptor on B cells enhances humoral immune responses.

B cells are pivotal regulators of acquired immune responses, and recent work in both experimental murine models and humans has demonstrated that subtle changes in the regulation of B cell function can substantially alter immunological responses. The balance of negative and positive signals in maintaining an appropriate B cell activation threshold is critical in B lymphocyte immune tolerance and autoreactivity. FcγRIIb (CD32B), the only recognized Fcγ receptor on B cells, provides immunoglobulin G (IgG)-mediated negative modulation through a tyrosine-based inhibition motif, which down-regulates B cell receptor-initiated signaling. These properties make FcγRIIb a promising target for antibody-based therapy. We report the discovery of allele-dependent expression of the activating FcγRIIc on B cells. Identical to FcγRIIb in the extracellular domain, FcγRIIc has a tyrosine-based activation motif in its cytoplasmic domain. In both human B cells and B cells from mice transgenic for human FcγRIIc, FcγRIIc expression counterbalances the negative feedback of FcγRIIb and enhances humoral responses to immunization in mice and to BioThrax vaccination in a human anthrax vaccine trial. Moreover, the FCGR2C-ORF allele is associated with the risk of development of autoimmunity in humans. FcγRIIc expression on B cells challenges the prevailing paradigm of unidirectional negative feedback by IgG immune complexes via the inhibitory FcγRIIb, is a previously unrecognized determinant in human antibody/autoantibody responses, and opens the opportunity for more precise personalized use of B cell-targeted antibody-based therapy.

Genomic copy number variants: evidence for association with antibody response to anthrax vaccine adsorbed.

BACKGROUND: Anthrax and its etiologic agent remain a biological threat. Anthrax vaccine is highly effective, but vaccine-induced IgG antibody responses vary widely following required doses of vaccinations. Such variation can be related to genetic factors, especially genomic copy number variants (CNVs) that are known to be enriched among genes with immunologic function. We have tested this hypothesis in two study populations from a clinical trial of anthrax vaccination. METHODS: We performed CNV-based genome-wide association analyses separately on 794 European Americans and 200 African-Americans. Antibodies to protective antigen were measured at week 8 (early response) and week 30 (peak response) using an enzyme-linked immunosorbent assay. We used DNA microarray data (Affymetrix 6.0) and two CNV detection algorithms, hidden markov model (PennCNV) and circular binary segmentation (GeneSpring) to determine CNVs in all individuals. Multivariable regression analyses were used to identify CNV-specific associations after adjusting for relevant non-genetic covariates. RESULTS: Within the 22 autosomal chromosomes, 2,943 non-overlapping CNV regions were detected by both algorithms. Genomic insertions containing HLA-DRB5, DRB1 and DQA1/DRA genes in the major histocompatibility complex (MHC) region (chromosome 6p21.3) were moderately associated with elevated early antibody response (ß = 0.14, p = 1.78×10(-3)) among European Americans, and the strongest association was observed between peak antibody response and a segmental insertion on chromosome 1, containing NBPF4, NBPF5, STXMP3, CLCC1, and GPSM2 genes (ß = 1.66, p = 6.06×10(-5)). For African-Americans, segmental deletions spanning PRR20, PCDH17 and PCH68 genes on chromosome 13 were associated with elevated early antibody production (ß = 0.18, p = 4.47×10(-5)). Population-specific findings aside, one genomic insertion on chromosome 17 (containing NSF, ARL17 and LRRC37A genes) was associated with elevated peak antibody response in both populations. CONCLUSION: Multiple CNV regions, including the one consisting of MHC genes that is consistent with earlier research, can be important to humoral immune responses to anthrax vaccine adsorbed.

Human leukocyte antigens and cellular immune responses to anthrax vaccine adsorbed.

Interindividual variations in vaccine-induced immune responses are in part due to host genetic polymorphisms in the human leukocyte antigen (HLA) and other gene families. This study examined associations between HLA genotypes, haplotypes, and homozygosity and protective antigen (PA)-specific cellular immune responses in healthy subjects following immunization with Anthrax Vaccine Adsorbed (AVA). While limited associations were observed between individual HLA alleles or haplotypes and variable lymphocyte proliferative (LP) responses to AVA, analyses of homozygosity supported the hypothesis of a "heterozygote advantage." Individuals who were homozygous for any HLA locus demonstrated significantly lower PA-specific LP than subjects who were heterozygous at all eight loci (median stimulation indices [SI], 1.84 versus 2.95, P = 0.009). Similarly, we found that class I (HLA-A) and class II (HLA-DQA1 and HLA-DQB1) homozygosity was significantly associated with an overall decrease in LP compared with heterozygosity at those three loci. Specifically, individuals who were homozygous at these loci had significantly lower PA-specific LP than subjects heterozygous for HLA-A (median SI, 1.48 versus 2.13, P = 0.005), HLA-DQA1 (median SI, 1.75 versus 2.11, P = 0.007), and HLA-DQB1 (median SI, 1.48 versus 2.13, P = 0.002) loci, respectively. Finally, homozygosity at an increasing number (≥ 4) of HLA loci was significantly correlated with a reduction in LP response (P < 0.001) in a dose-dependent manner. Additional studies are needed to reproduce these findings and determine whether HLA-heterozygous individuals generate stronger cellular immune response to other virulence factors (Bacillus anthracis LF and EF) than HLA-homozygous subjects.

Structure of tumor necrosis factor-alpha haploblocks in European populations.

DNA variants in the tumor necrosis factor-α (TNF) and linked lymphotoxin-α genes, and specific alleles of the highly polymorphic human leukocyte antigen B (HLA-B) gene have been implicated in a plethora of immune and infectious diseases. However, the tight linkage disequilibrium characterizing the central region of the human major histocompatibility complex (MHC) containing these gene loci has made difficult the unequivocal interpretation of genetic association data. To alleviate these difficulties and facilitate the design of more focused follow-up studies, we investigated the structure and distribution of HLA-B-specific MHC haplotypes reconstructed in a European population from unphased genotypes at a set of 25 single nucleotide polymorphism sites spanning a 66-kilobase long region across TNF. Consistent with the published data, we found limited genetic diversity across the so-called TNF block, with the emergence of seven common MHC haplotypes, termed TNF block super-haplotypes. We also found that the ancestral haplotype 8.1 shares a TNF block haplotype with HLA-B*4402. HLA-B*5701, a known protective allele in HIV-1 pathogenesis, occurred in a unique TNF block haplotype.

Disparities in lung transplantation before and after introduction of the lung allocation score.

BACKGROUND: In May 2005, the Lung Allocation Score (LAS) became the primary method for determining allocation of lungs for organ transplantation for those at least 12 years of age in the United States. During the pre-LAS period, black patients were more likely than white patients to become too sick or die while awaiting transplant. The association between gender and lung transplant outcomes has not been widely studied. METHODS: Black and white patients aged ≥ 18 years registered on the United Network for Organ Sharing (UNOS) lung transplantation waiting list from January 1, 2000, to May 3, 2005 (pre-LAS, n = 8,765), and from May 4, 2005, to September 4, 2010 (LAS, n = 8,806), were included. Logistic regression analyses were based on smaller cohorts derived from patients listed in the first 2 years of each era (2,350 pre-LAS, and 2,446 LAS) to allow for follow-up time. Lung transplantation was the primary outcome measure. Multivariable analyses were performed within each interval to determine the odds that a patient would die or receive a lung transplant within 3 years of listing. RESULTS: In the pre-LAS era, black patients were more likely than white patients to become too sick for transplantation or die within 3 years of waiting list registration (43.8% vs 30.8%; odds ratio [OR], 1.84; p < 0.001). Race was not associated with death or becoming too sick while listed for transplantation in the LAS era (14.0% vs 13.3%; OR, 0.93; p = 0.74). Black patients were less likely to undergo transplantation in the pre-LAS era (56.3% vs 69.2%; OR, 0.54; p < 0.001) but not in the LAS era (86.0% vs 86.7%; OR, 1.07; p = 0.74). Women were more likely than men to die or become too sick for transplantation within 3 years of listing in the LAS era (16.1% vs 11.3%; OR, 1.58; p < 0.001) compared with the pre-LAS era (33.4% vs 30.7%; OR, 1.19; p = 0.08). CONCLUSION: Racial disparities in lung transplantation have decreased with the implementation of LAS as the method of organ allocation; however, gender disparities may have actually increased in the LAS era.

HLA-B*57 versus HLA-B*81 in HIV-1 infection: slow and steady wins the race?

Two human leukocyte antigen (HLA) variants, HLA-B*57 and -B*81, are consistently known as favorable host factors in human immunodeficiency virus type 1 (HIV-1)-infected Africans and African-Americans. In our analyses of prospective data from 538 recent HIV-1 seroconverters and cross-sectional data from 292 subjects with unknown duration of infection, HLA-B*57 (mostly B*57:03) and -B*81 (exclusively B*81:01) had mostly discordant associations with virologic and immunologic manifestations before antiretroviral therapy. Specifically, relatively low viral load (VL) in HLA-B*57-positive subjects (P ≤ 0.03 in various models) did not translate to early advantage in CD4(+) T-cell (CD4) counts (P ≥ 0.37). In contrast, individuals with HLA-B*81 showed little deviation from the normal set point VL (P > 0.18) while maintaining high CD4 count during early and chronic infection (P = 0.01). These observations suggest that discordance between VL and CD4 count can occur in the presence of certain HLA alleles and that effective control of HIV-1 viremia is not always a prerequisite for favorable prognosis (delayed immunodeficiency). Of note, steady CD4 count associated with HLA-B*81 in HIV-1-infected Africans may depend on the country of origin, as observations differed slightly between subgroups enrolled in southern Africa (Zambia) and eastern Africa (Kenya, Rwanda, and Uganda).

Cumulative impact of host and viral factors on HIV-1 viral-load control during early infection.

In HIV-1 infection, the early set-point viral load strongly predicts both viral transmission and disease progression. The factors responsible for the wide spectrum of set-point viral loads are complex and likely reflect an interplay between the transmitted virus and genetically defined factors in both the transmitting source partner and the seroconverter. Indeed, analysis of 195 transmission pairs from Lusaka, Zambia, revealed that the viral loads in transmitting source partners contributed only ∼2% of the variance in early set-point viral loads of seroconverters (P = 0.046 by univariable analysis). In multivariable models, early set-point viral loads in seroconverting partners were a complex function of (i) the viral load in the source partner, (ii) the gender of the seroconverter, (iii) specific HLA class I alleles in the newly infected partner, and (iv) sharing of HLA-I alleles between partners in a transmission pair. Each of these factors significantly and independently contributed to the set-point viral load in the newly infected partner, accounting for up to 37% of the variance observed and suggesting that many factors operate in concert to define the early virological phenotype in HIV-1 infection.

Role of transmitted Gag CTL polymorphisms in defining replicative capacity and early HIV-1 pathogenesis.

Initial studies of 88 transmission pairs in the Zambia Emory HIV Research Project cohort demonstrated that the number of transmitted HLA-B associated polymorphisms in Gag, but not Nef, was negatively correlated to set point viral load (VL) in the newly infected partners. These results suggested that accumulation of CTL escape mutations in Gag might attenuate viral replication and provide a clinical benefit during early stages of infection. Using a novel approach, we have cloned gag sequences isolated from the earliest seroconversion plasma sample from the acutely infected recipient of 149 epidemiologically linked Zambian transmission pairs into a primary isolate, subtype C proviral vector, MJ4. We determined the replicative capacity (RC) of these Gag-MJ4 chimeras by infecting the GXR25 cell line and quantifying virion production in supernatants via a radiolabeled reverse transcriptase assay. We observed a statistically significant positive correlation between RC conferred by the transmitted Gag sequence and set point VL in newly infected individuals (p = 0.02). Furthermore, the RC of Gag-MJ4 chimeras also correlated with the VL of chronically infected donors near the estimated date of infection (p = 0.01), demonstrating that virus replication contributes to VL in both acute and chronic infection. These studies also allowed for the elucidation of novel sites in Gag associated with changes in RC, where rare mutations had the greatest effect on fitness. Although we observed both advantageous and deleterious rare mutations, the latter could point to vulnerable targets in the HIV-1 genome. Importantly, RC correlated significantly (p = 0.029) with the rate of CD4+ T cell decline over the first 3 years of infection in a manner that is partially independent of VL, suggesting that the replication capacity of HIV-1 during the earliest stages of infection is a determinant of pathogenesis beyond what might be expected based on set point VL alone.

A genome-wide association study of host genetic determinants of the antibody response to Anthrax Vaccine Adsorbed.

Several lines of evidence have supported a host genetic contribution to vaccine response, but genome-wide assessments for specific determinants have been sparse. Here we describe a genome-wide association study (GWAS) of protective antigen-specific antibody (AbPA) responses among 726 European-Americans who received Anthrax Vaccine Adsorbed (AVA) as part of a clinical trial. After quality control, 736,996 SNPs were tested for association with the AbPA response to 3 or 4 AVA vaccinations given over a 6-month period. No SNP achieved the threshold of genome-wide significance (p=5 × 10(-8)), but suggestive associations (p<1 × 10(-5)) were observed for SNPs in or near the class II region of the major histocompatibility complex (MHC), in the promoter region of SPSB1, and adjacent to MEX3C. Multivariable regression modeling suggested that much of the association signal within the MHC corresponded to previously identified HLA DR-DQ haplotypes involving component HLA-DRB1 alleles of *15:01, *01:01, or *01:02. We estimated the proportion of additive genetic variance explained by common SNP variation for the AbPA response after the 6 month vaccination. This analysis indicated a significant, albeit imprecisely estimated, contribution of variation tagged by common polymorphisms (p=0.032). Future studies will be required to replicate these findings in European Americans and to further elucidate the host genetic factors underlying variable immune response to AVA.

Role of activating FcγR gene polymorphisms in Kawasaki disease susceptibility and intravenous immunoglobulin response.

BACKGROUND: A functional polymorphism in the inhibitory IgG-Fc receptor gene FcγRIIB influences intravenous immunoglobulin (IVIG) response in Kawasaki disease (KD), a vasculitis preferentially affecting the coronary arteries in children. We tested the hypothesis that the polymorphisms in the activating receptors (FcγRIIA, FcγRIIIA, and FcγRIIIB) also influence susceptibility, IVIG treatment response, and coronary artery disease in patients with KD. METHODS AND RESULTS: We genotyped polymorphisms in the activating FcγRIIA, FcγRIIIA, and FcγRIIIB using pyrosequencing in 443 patients with KD, including 266 trios and 150 single parent-child pairs, in northwest United States and genetically determined race with 155 ancestry informative markers. We used family-based association to test for transmission disequilibrium and further generated pseudosibling controls for comparisons with the cases. The FcγRIIA-131H variant showed an association with KD (P=0.001) with an additive odds ratio (OR) of 1.51 (95% CI, 1.16-1.96; P=0.002) for the primary combined population, which persisted in both white (P=0.04) and Asian (P=0.01) subgroups and is consistent with the recent genome-wide association study. We also identified overtransmission of the FcγRIIIB neutrophil antigen 1 (NA1) variant among IVIG nonresponders (P=0.0002) and specifically to white IVIG nonresponders (P=0.007). ORs for overall and white nonresponders were 3.67 (95% CI, 1.75-7.66; P=0.0006) and 3.60 (95% CI, 1.34-9.70; P=0.01), respectively. Excess NA1 transmission also occurred in patients with KD with coronary artery disease (OR(additive), 2.13; 95% CI, 1.11-4.0; P=0.02). CONCLUSIONS: A common variation in FcγRIIA is associated with increased KD susceptibility. The FcγRIIIB-NA1 variant, which confers higher affinity for IgG than the NA2 variant, is a determining factor for treatment response. These activating FcγRs play an important role in KD pathogenesis and the IVIG antiinflammatory mechanism.

HLA-B signal peptide polymorphism influences the rate of HIV-1 acquisition but not viral load.

Human leukocyte antigen alleles influence the immune response to HIV-1. Signal peptides cleaved from those alleles bind to HLA-E and mediate natural killer cell function. Signal peptides of HLA-A and HLA-C proteins carry methionine (Met) at anchor position 2 (P2); those of HLA-B carry Met or threonine (Thr). Different P2 residues alter HLA-E binding to its cognate receptors and may impact HIV-1 acquisition. Among Zambian couples (N = 566) serodiscordant for HIV-1, P2-Met accelerated acquisition in the HIV-1-negative partner (relative hazard [RH], 1.79). Among seroconverting Zambian (n = 240) and Rwandan (n = 64) partners, P2-Met also accelerated acquisition (RH, 1.47 and RH, 1.83 respectively). HLA-B alleles displaying the reportedly protective Bw4 epitope carry P2-Thr. Bw4/P2-Thr and Bw6/P2-Thr showed similar protective effects compared with Bw6/P2-Met. Neither motif was associated with viral load. The influence of HLA-B alleles on HIV/AIDS may derive from multiple motifs in and beyond the mature proteins.