INSIGHTS INTO THE INTERPLAY BETWEEN KIR GENE FREQUENCIES AND CHRONIC HBV INFECTION IN BURKINA FASO

Background/Objective: The receptors of natural killer cells "Killer Cell Immunoglobulin-Like Receptor" (KIR) regulate the activity of Natural killer cells in the innate response against viral infections. To date there is no accurate method to identify high risk groups for cirrhosis and HCC in Sub-Saharan Africa. Therefore, this investigation was undertaken to assess the association between KIR genes frequencies and chronic infection HBV infection in Burkina Faso’s population. Methods: Chronic HBV carriers and healthy patients were selected for this study. The viral load for HBV were performed to confirm the serological status for HBV of the studied cohort. In addition, SSP-PCR was used to characterize the frequencies of KIR genes. Results: The study suggested that inhibitory genes KIR2DL2, KIR2DL3 and activator gene KIR2DS2 (p˂0.001 for all and OR = 2.82; 2.48 and 3.84 respectively) might be associated with chronic stages of HBV infection.  While inhibitory genes KIR3DL1 (p = 0.0018 OR = 0.49), KIR3DL2 (p = 0.005 OR = 0.40), the activator gene KIR2DS1 (p = 0.014 OR = 0.47) and the pseudo gene KIR2DP1 (p = 0.011 OR = 0.49) could be associated with immunity against HBV infection. Patients who carried the KIR3DL2 gene had a high HBV viral load compared to the rest of the study population. Conclusion: Our data showed an evidence of correlation between the propensity of developing chronic HBV infection and certain KIR gene frequencies and that KIR3DL1, KIR3DL2, KIR2DS1 and KIR2DP1 might confer a protective status against chronic HBV infection in Burkina Faso’s patients

A genome-wide association study of resistance to HIV infection in highly exposed uninfected individuals with hemophilia A

Human genetic variation contributes to differences in susceptibility to HIV-1 infection. To search for novel host resistance factors, we performed a genome-wide association study (GWAS) in hemophilia patients highly exposed to potentially contaminated factor VIII infusions. Individuals with hemophilia A and a documented history of factor VIII infusions before the introduction of viral inactivation procedures (1979-1984) were recruited from 36 hemophilia treatment centers (HTCs), and their genome-wide genetic variants were compared with those from matched HIV-infected individuals. Homozygous carriers of known CCR5 resistance mutations were excluded. Single nucleotide polymorphisms (SNPs) and inferred copy number variants (CNVs) were tested using logistic regression. In addition, we performed a pathway enrichment analysis, a heritability analysis, and a search for epistatic interactions with CCR5 Δ32 heterozygosity. A total of 560 HIV-uninfected cases were recruited: 36 (6.4%) were homozygous for CCR5 Δ32 or m303. After quality control and SNP imputation, we tested 1 081 435 SNPs and 3686 CNVs for association with HIV-1 serostatus in 431 cases and 765 HIV-infected controls. No SNP or CNV reached genome-wide significance. The additional analyses did not reveal any strong genetic effect. Highly exposed, yet uninfected hemophiliacs form an ideal study group to investigate host resistance factors. Using a genome-wide approach, we did not detect any significant associations between SNPs and HIV-1 susceptibility, indicating that common genetic variants of major effect are unlikely to explain the observed resistance phenotype in this populatio

Phylogenetic ctDNA analysis depicts early-stage lung cancer evolution.

The early detection of relapse following primary surgery for non-small-cell lung cancer and the characterization of emerging subclones, which seed metastatic sites, might offer new therapeutic approaches for limiting tumour recurrence. The ability to track the evolutionary dynamics of early-stage lung cancer non-invasively in circulating tumour DNA (ctDNA) has not yet been demonstrated. Here we use a tumour-specific phylogenetic approach to profile the ctDNA of the first 100 TRACERx (Tracking Non-Small-Cell Lung Cancer Evolution Through Therapy (Rx)) study participants, including one patient who was also recruited to the PEACE (Posthumous Evaluation of Advanced Cancer Environment) post-mortem study. We identify independent predictors of ctDNA release and analyse the tumour-volume detection limit. Through blinded profiling of postoperative plasma, we observe evidence of adjuvant chemotherapy resistance and identify patients who are very likely to experience recurrence of their lung cancer. Finally, we show that phylogenetic ctDNA profiling tracks the subclonal nature of lung cancer relapse and metastasis, providing a new approach for ctDNA-driven therapeutic studies

Fc Effector Function Contributes to the Activity of Human Anti-CTLA-4 Antibodies.

With the use of a mouse model expressing human Fc-gamma receptors (FcγRs), we demonstrated that antibodies with isotypes equivalent to ipilimumab and tremelimumab mediate intra-tumoral regulatory T (Treg) cell depletion in vivo, increasing the CD8+ to Treg cell ratio and promoting tumor rejection. Antibodies with improved FcγR binding profiles drove superior anti-tumor responses and survival. In patients with advanced melanoma, response to ipilimumab was associated with the CD16a-V158F high affinity polymorphism. Such activity only appeared relevant in the context of inflamed tumors, explaining the modest response rates observed in the clinical setting. Our data suggest that the activity of anti-CTLA-4 in inflamed tumors may be improved through enhancement of FcγR binding, whereas poorly infiltrated tumors will likely require combination approaches

Fc-Optimized Anti-CD25 Depletes Tumor-Infiltrating Regulatory T Cells and Synergizes with PD-1 Blockade to Eradicate Established Tumors

CD25 is expressed at high levels on regulatory T (Treg) cells and was initially proposed as a target for cancer immunotherapy. However, anti-CD25 antibodies have displayed limited activity against established tumors. We demonstrated that CD25 expression is largely restricted to tumor-infiltrating Treg cells in mice and humans. While existing anti-CD25 antibodies were observed to deplete Treg cells in the periphery, upregulation of the inhibitory Fc gamma receptor (FcγR) IIb at the tumor site prevented intra-tumoral Treg cell depletion, which may underlie the lack of anti-tumor activity previously observed in pre-clinical models. Use of an anti-CD25 antibody with enhanced binding to activating FcγRs led to effective depletion of tumor-infiltrating Treg cells, increased effector to Treg cell ratios, and improved control of established tumors. Combination with anti-programmed cell death protein-1 antibodies promoted complete tumor rejection, demonstrating the relevance of CD25 as a therapeutic target and promising substrate for future combination approaches in immune-oncology

LILRB2 Interaction with HLA Class I Correlates with Control of HIV-1 Infection.

Natural progression of HIV-1 infection depends on genetic variation in the human major histocompatibility complex (MHC) class I locus, and the CD8+ T cell response is thought to be a primary mechanism of this effect. However, polymorphism within the MHC may also alter innate immune activity against human immunodeficiency virus type 1 (HIV-1) by changing interactions of human leukocyte antigen (HLA) class I molecules with leukocyte immunoglobulin-like receptors (LILR), a group of immunoregulatory receptors mainly expressed on myelomonocytic cells including dendritic cells (DCs). We used previously characterized HLA allotype-specific binding capacities of LILRB1 and LILRB2 as well as data from a large cohort of HIV-1-infected individuals (N = 5126) to test whether LILR-HLA class I interactions influence viral load in HIV-1 infection. Our analyses in persons of European descent, the largest ethnic group examined, show that the effect of HLA-B alleles on HIV-1 control correlates with the binding strength between corresponding HLA-B allotypes and LILRB2 (p = 10-2). Moreover, overall binding strength of LILRB2 to classical HLA class I allotypes, defined by the HLA-A/B/C genotypes in each patient, positively associates with viral replication in the absence of therapy in patients of both European (p = 10-11-10-9) and African (p = 10-5-10-3) descent. This effect appears to be driven by variations in LILRB2 binding affinities to HLA-B and is independent of individual class I allelic effects that are not related to the LILRB2 function. Correspondingly, in vitro experiments suggest that strong LILRB2-HLA binding negatively affects antigen-presenting properties of DCs. Thus, we propose an impact of LILRB2 on HIV-1 disease outcomes through altered regulation of DCs by LILRB2-HLA engagement

A Novel Functional Variant in the Stem Cell Growth Factor Promoter Protects against Severe Malarial Anemia▿

Plasmodium falciparum malaria is a leading global cause of infectious disease burden. In areas in which P. falciparum transmission is holoendemic, such as western Kenya, severe malarial anemia (SMA) results in high rates of pediatric morbidity and mortality. Although the pathophysiological basis of SMA is multifactorial, we recently discovered that suppression of unexplored hematopoietic growth factors that promote erythroid and myeloid colony development, such as stem cell growth factor (SCGF) (C-type lectin domain family member 11A [CLEC11A]), was associated with enhanced development of SMA and reduced erythropoietic responses. To extend these investigations, the relationships between a novel SCGF promoter variant (−539C/T, rs7246355), SMA (hemoglobin [Hb] < 6.0 g/dl), and reduced erythropoietic responses (reticulocyte production index [RPI], <2.0) were investigated with Kenyan children (n = 486) with falciparum malaria from western Kenya. Circulating SCGF was positively correlated with hemoglobin levels (r = 0.251; P = 0.022) and the reticulocyte production index (RPI) (r = 0.268; P = 0.025). Children with SMA also had lower SCGF levels than those in the non-SMA group (P = 0.005). Multivariate logistic regression analyses controlling for covariates demonstrated that individuals with the homologous T allele were protected against SMA (odds ratio, 0.57; 95% confidence interval [95% CI] 0.34 to 0.94; P = 0.027) relative to CC (wild-type) carriers. Carriers of the TT genotype also had higher SCGF levels in circulation (P = 0.018) and in peripheral blood mononuclear cell culture supernatants (P = 0.041), as well as an elevated RPI (P = 0.005) relative to individuals with the CC genotype. The results presented here demonstrate that homozygous T at −539 in the SCGF promoter is associated with elevated SCGF production, enhanced erythropoiesis, and protection against the development of SMA in children with falciparum malaria

GlycA, a novel inflammatory marker, is associated with subclinical coronary disease.

ObjectiveGlycA, a novel NMR biomarker of inflammation, has been associated with incident cardiovascular disease (CVD) in the general population, but its association with CVD among HIV-infected individuals is unknown. We examined the associations between GlycA and subclinical coronary plaque among HIV-infected and HIV-uninfected men participating in Multicenter AIDS Cohort Study (MACS).DesignCross-sectional analysis of 935 men with plasma measurement of GlycA and noncontrast cardiac computed tomography (CT) and/or coronary CT angiography.MethodsWe used multivariable Poisson and linear regression to assess associations of GlycA with prevalent coronary atherosclerosis and plaque extent, respectively.ResultsMean ± SD age was 54 ± 7 years; 31% were black; 63% HIV-infected. GlycA levels were higher in HIV-infected compared with HIV-uninfected men (397 ± 68 vs. 380 ± 60 μmol/l, P = 0.0001) and higher for men with detectable viral load vs. undetectable (413 ± 79 vs. 393 ± 65 μmol/l, P = 0.004). After adjusting for HIV serostatus, demographic and CVD risk factors, every 1SD increment in GlycA level was associated with a higher prevalence of coronary artery calcium (CAC &gt;0) [prevalence ratio 1.09 (95% CI 1.03-1.15)] and coronary stenosis at least 50% [1.20 (1.02-1.41)]. These associations were not significantly altered after adjusting for traditional inflammatory biomarkers or differ by HIV serostatus. Among men with plaque, GlycA was positively associated with the extent of CAC and total plaque.ConclusionHIV infection was associated with higher GlycA levels. In both HIV-infected and HIV-uninfected individuals, GlycA was significantly associated with several measures of subclinical coronary atherosclerosis, independent of other CVD risk factors and inflammatory biomarkers. These findings suggest the potential role of GlycA in CVD risk stratification among HIV patients

GlycA, a novel inflammatory marker, is associated with subclinical coronary disease.

ObjectiveGlycA, a novel NMR biomarker of inflammation, has been associated with incident cardiovascular disease (CVD) in the general population, but its association with CVD among HIV-infected individuals is unknown. We examined the associations between GlycA and subclinical coronary plaque among HIV-infected and HIV-uninfected men participating in Multicenter AIDS Cohort Study (MACS).DesignCross-sectional analysis of 935 men with plasma measurement of GlycA and noncontrast cardiac computed tomography (CT) and/or coronary CT angiography.MethodsWe used multivariable Poisson and linear regression to assess associations of GlycA with prevalent coronary atherosclerosis and plaque extent, respectively.ResultsMean ± SD age was 54 ± 7 years; 31% were black; 63% HIV-infected. GlycA levels were higher in HIV-infected compared with HIV-uninfected men (397 ± 68 vs. 380 ± 60 μmol/l, P = 0.0001) and higher for men with detectable viral load vs. undetectable (413 ± 79 vs. 393 ± 65 μmol/l, P = 0.004). After adjusting for HIV serostatus, demographic and CVD risk factors, every 1SD increment in GlycA level was associated with a higher prevalence of coronary artery calcium (CAC &gt;0) [prevalence ratio 1.09 (95% CI 1.03-1.15)] and coronary stenosis at least 50% [1.20 (1.02-1.41)]. These associations were not significantly altered after adjusting for traditional inflammatory biomarkers or differ by HIV serostatus. Among men with plaque, GlycA was positively associated with the extent of CAC and total plaque.ConclusionHIV infection was associated with higher GlycA levels. In both HIV-infected and HIV-uninfected individuals, GlycA was significantly associated with several measures of subclinical coronary atherosclerosis, independent of other CVD risk factors and inflammatory biomarkers. These findings suggest the potential role of GlycA in CVD risk stratification among HIV patients

Multistage Genomewide Association Study Identifies a Locus at 1q41 Associated with Rate of HIV-1 Disease Progression to Clinical AIDS

Background. A mean of 9–10 years of human immunodeficiency virus type 1 (HIV-1) infection elapse before clinical AIDS develops in untreated persons, but this rate of disease progression varies substantially among individuals. To investigate host genetic determinants of the rate of progression to clinical AIDS, we performed a multistage genomewide association study. Methods. The discovery stage comprised 156 individuals from the Multicenter AIDS Cohort Study, enriched with rapid and long-term nonprogressors to increase statistical power. This was followed by replication tests of putatively associated genotypes in an independent population of 590 HIV-1–infected seroconverters. Results. Significant associations with delayed AIDS progression were observed in a haplotype located at 1q41, 36 kb upstream of PROX1 on chromosome 1 (relative hazard ratio, 0.69; Fisher’s combined P = 6.23 x 10-7). This association was replicated further in an analysis stratified by transmission mode, with the effect consistent in sexual or mucosal and parenteral transmission (relative hazard ratios, 0.72 and 0.63, respectively; combined P = 1.63 x 10-6). Conclusions. This study identified and replicated a locus upstream of PROX1 that is associated with delayed progression to clinical AIDS. PROX1 is a negative regulator of interferon-γ expression in T cells and also mitigates the advancement of vascular neoplasms, such as Kaposi sarcoma, a common AIDS-defining malignancy. This study adds to the cumulative polygenic host component that effectively regulates the progression to clinical AIDS among HIV-1–infected individuals, raising prospects for potential new avenues for therapy and improvements in AIDS prognosis