Polymorphism in RANTES chemokine promoter affects HIV-1 disease progression

RANTES gene G-403A polymorphism and coronary artery disease: a meta analysis of observational studies

Objective

The G-403A polymorphism in RANTES gene may be involved in the development of coronary artery disease (CAD) through increasing RANTES-mediated leukocyte trafficking and activation. However, studies investigating the relationship between G-403A polymorphism and CAD yielded contradictory and inconclusive results. In order to shed some light on these inconsistent findings, a meta analysis was performed to clarify the role of G-403A polymorphism of RANTES gene in the susceptibility of CAD.

Methods

A systemic literature search of PubMed and EMBASE was conducted from their inception to March 23, 2012, to retrieve related studies. In addition, Conference Proceedings Citation Index-Science was searched, authors of relevant studies were contacted, and reference lists of the included studies and their related citations in PubMed were reviewed for additional pertinent studies.

Results

A total of 8 eligible studies were identified, with a total of 4252 CAD cases and 2150 controls. There was no evidence of significant association between G-403A polymorphism and CAD risk in any genetic model or pairwise comparisons (additive model: OR = 1.046, 95% CI = 0.883–1.239, I² = 65.9%; recessive model: OR = 1.140, 95% CI = 0.774–1.678, I² = 53.1%; dominant model: OR = 1.000, 95% CI = 0.820–1.21), I² = 62.6%; AA vs GG: OR = 1.141, 95% CI = 0.734–1.773, I² = 61.2%; GA vs GG: OR = 0.993, 95% CI = 0.800–1.232, I² = 64.6%). Subgroup analysis and meta regression indicated that ethnicity and genotyping method accounted for the significant heterogeneity among studies. In the stratified analysis by ethnic group, G-403A polymorphism was found to be associated with increased CAD risk in Caucasian population whereas its protective role was observed in Asian population in some but not all comparisons.

Conclusion

Data from the current meta-analysis do not support the existence of a relationship between G-403A polymorphism and the development of CAD, and large sample size study employing unified genotyping method is needed to further evaluate the influence of G-403A polymorphism on susceptibility of CAD.

Host genetics of HIV acquisition and viral control

Since the discovery of HIV as the cause of AIDS, numerous insights have been gained from studies of its natural history and epidemiology. It has become clear that there are substantial interindividual differences in the risk of HIV acquisition and course of disease. Meanwhile, the field of human genetics has undergone a series of rapid transitions that have fundamentally altered the approach to studying HIV host genetics. We aim to describe the field as it has transitioned from the era of candidate-gene studies and the era of genome-wide association studies (GWAS) to its current state in the infancy of comprehensive sequencing. In some ways the field has come full circle, having evolved from being driven almost exclusively by our knowledge of immunology, to a bias-free GWAS approach, to a point where our ability to catalogue human variation far outstrips our ability to biologically interpret it.

RANTES gene polymorphisms and risk of pediatric asthma: A meta-analysis

Numerous studies have evaluated the association between regulated upon activation, normal T cells expressed and secreted (RANTES) gene polymorphisms (-403G/A and -28C/G) and risk of pediatric asthma. However, the results have been inconsistent. A meta-analysis of the association between RANTES gene polymorphisms and pediatric asthma risk was performed in the current study. A search for published literature was conducted in the Google Scholar, PubMed and the CNKI databases (January 2000 to April 2012) and seven studies were retrieved. The associations between RANTES gene polymorphisms and pediatric asthma risk were estimated by pooled odds ratio (OR) and 95% confidence interval (CI) using a fixed- or random-effects model. Meta-analysis results revealed no significant association between the -403G/A polymorphism and risk of pediatric asthma. In the subgroup analysis by ethnicity, no association was identified between the -403G/A polymorphism and pediatric asthma risk in Caucasian and Asian populations. In the -28C/G group, the meta-analysis indicated a significant association between the -28C/G polymorphism and pediatric asthma susceptibility among the total population (recessive model: OR, 1.34; 95% CI, 1.04-1.72). However, when the subgroup analysis was performed by ethnicity, no significant associations were identified in Asians and Europeans. This result suggests that the -28C/G polymorphism may not be associated with pediatric asthma risk, while the observed increase in the risk of pediatric asthma may be due to racial differences. Additional large-scale studies are required to provide conclusive evidence on the effects of RANTES gene polymorphisms on the risk of pediatric asthma.

Study of the association between -403G/A and -28C/G RANTES gene polymorphisms and asthma in Lebanon

CONTEXT:

Asthma is a complex inflammatory condition often associated with bronchial hyper reactivity and atopy. Genetic and environmental factors are implicated in the etiopathogenesis of asthma. Regulated upon Activation Normal T- cell Expressed and Secreted (RANTES) is a CC chemokine responsible for the recruitment of inflammatory cells, suggesting a possible role for this chemokine in asthma. Both -403A and -28G alleles of the RANTES promoter region were found to be associated with asthma/atopy in some but not all studies.

AIM:

The purpose of this study was to investigate the genetic influence of -403A and -28G alleles of the RANTES promoter region on the development of asthma in Lebanon.

SETTINGS AND DESIGN:

This case control study was conducted at Makassed Hospital, Beirut on 40 asthmatic patients and 38 healthy controls.

METHODS:

RANTES gene polymorphisms -403G/A and -28C/G alleles were genotyped using PCR-RFLP.

RESULTS:

No significant differences in allele or genotype frequencies for the RANTES gene polymorphisms between asthmatic patients and controls were found. The difference of the -403 GA genotype frequency between patients and controls was not statisti-cally significant; (OR=0.8, 95% CI=0.2-2.3, P=0.8). Similarly, the difference of the A-allele frequencies between patients and con-trols was not significant (OR=0.824, CI=0.3–2.2, P=0.7).

CONCLUSIONS:

Our data show that RANTES gene promoter polymorphisms are not associated with asthma susceptibility in the Lebanese population.

RANTES, MCP-1 chemokines and factors describing rheumatoid arthritis

The MCP-1/CCL2 as well as RANTES/CCL5 chemokines are potent chemoattractants involved in immunoregulatory and inflammatory processes of rheumatoid arthritis. Recent studies demonstrated elevated levels of MCP-1 and RANTES in plasma, synovial fluid, and the synovial tissue of patients with RA. To examine the relationship among MCP-1 and RANTES single nucleotide polymorphisms and circulating levels and rheumatoid arthritis (RA), a total of 156 RA patients and 125 controls were recruited into the study. An association of -855 C/G MCP-1 polymorphism to IgM RF within the RA patients was observed. The lowest circulating levels of RANTES were observed in the AA variant of RANTES -403 G/A polymorphism. Furthermore, an association of -403 AA variant to circulating levels of IL-15 and IL-10 was found. No associations of factors describing rheumatoid arthritis (RFs, ANA, anti-CCP-positive/negative, DAS 28 score and number of swollen joints) with MCP-1 levels, genotype distribution, allelic frequencies and/or frequencies of haplotypes composed of all three studied polymorphisms in promoter region of MCP-1, and RANTES polymorphism were observed. We conclude that the RANTES promoter polymorphism is associated to circulating levels of RANTES, IL15 and IL10. However, our findings suggest that polymorphisms in the MCP-1 and RANTES gene promoters do not contribute significantly to the interindividual RA susceptibility and/or severity in Caucasians.

Genetic correlates influencing immunopathogenesis of HIV infection

Variability to HIV infection, its progression as well as responsiveness to antiretroviral therapy (ART) is observed among individuals including viraemia controllers or exposed uninfected, rapid versus slow progressors and ART responders compared to non responders. This differential responsiveness/vulnerability to HIV-1 is governed by multiple host genetic factors that include HLA, cytokines, chemokines, their receptors and others. This review highlights the influence of these genetic factors on HIV/AIDS outcome; however, in India, the information in this area is very limited and most of these genetic studies have been conducted in Caucasian and South African populations. Considering, the population specific differences in the frequencies of protective or susceptibility favouring alleles and their influence on the disease outcome, it is of utmost importance to strengthen ongoing efforts towards defining largely unknown genetic propensity in Indian population, particularly by recruitment of large cohorts of well categorized exposed uninfected individuals, rapid, long term non progressors and elite viraemic controllers. Multi-parametric analysis of these potentially interactive immunogenetic variables in these cohorts may help to define potential targets for diagnostics and therapy in a population specific manner.

Identification of the platelet-derived chemokine CXCL4/PF-4 as a broad-spectrum HIV-1 inhibitor

The natural history of HIV-1 infection is highly variable in different individuals, spanning from a rapidly progressive course to a long-term asymptomatic infection. A major determinant of the pace of disease progression is the in vivo level of HIV-1 replication, which is regulated by a complex network of cytokines and chemokines expressed by immune and inflammatory cells. The chemokine system is critically involved in the control of HIV-1 replication by virtue of the role played by specific chemokine receptors, most notably CCR5 and CXCR4, as cell-surface coreceptors for HIV-1 entry; hence, the chemokines that naturally bind such coreceptors act as endogenous inhibitors of HIV-1. Here, we show that the CXC chemokine CXCL4 (PF-4), the most abundant protein contained within the α-granules of platelets, is a broad-spectrum inhibitor of HIV-1 infection. Unlike other known HIV-suppressive chemokines, CXCL4 inhibits infection by the majority of primary HIV-1 isolates regardless of their coreceptor-usage phenotype or genetic subtype. Consistent with the lack of viral phenotype specificity, blockade of HIV-1 infection occurs at the level of virus attachment and entry via a unique mechanism that involves direct interaction of CXCL4 with the major viral envelope glycoprotein, gp120. The binding site for CXCL4 was mapped to a region of the gp120 outer domain proximal to the CD4-binding site. The identification of a platelet-derived chemokine as an endogenous antiviral factor may have relevance for the pathogenesis and treatment of HIV-1 infection.

RANTES gene polymorphisms (-403G>A and -28C>G) associated with hepatitis B virus infection in a Saudi population

Besides the host immune response, genetic and environmental factors play crucial roles in the manifestation of hepatitis B virus (HBV) infection. "Regulated on activation normal T-cell expressed and secreted" factor (RANTES) plays a vital role in CD4(+), CD8(+) T-lymphocyte and dendritic cell activation and proliferation in inflammation. Single nucleotide polymorphisms (SNPs) in the RANTES gene are associated with several viral and non-viral diseases. Association studies have invariably indicated a lack of association between RANTES gene SNPs and HBV infection in ethnic populations, even though RANTES gene SNPs exhibit distinct ethnic distributions. Despite the high prevalence of HBV infections in Saudi Arabia, no studies have been made concerning a possible relationship between RANTES gene polymorphisms and susceptibility to and progression of HBV infection. We examined -403G>A and -28C>G RANTES gene variants in 473 healthy controls and 484 HBV patients in ethnic Saudi populations. Significant differences were found in the genotype and allele distributions of the SNPs between the controls and the HBV patients. Both SNPs were significantly linked to viral clearance in these subjects. Our data demonstrate for the first time in a Saudi population, a relationship between the RANTES gene polymorphisms and the clinical course of HBV infection and underscore the importance of evaluating the genetic background of the affected individual to determine how it may affect disease progression.

Genetic polymorphisms of CCL2, CCL5, CCR2 and CCR5 genes in Sahariya tribe of North Central India: an association study with pulmonary tuberculosis

The association of genetic variants of chemokines, CCL2 [MCP-1 (monocyte chemoattractant protein-1)], CCL5 [RANTES (regulated on activation, normal T-cell expressed and secreted)] and their receptors CCR2 and CCR5, respectively, earlier reported to be associated with susceptibility to pulmonary tuberculosis (PTB) in certain ethnic populations, were explored in Sahariya tribe, a primitive tribe of North Central India having a high prevalence of TB. We genotyped 215 cases and 215 controls of Sahariya tribe for polymorphisms in CCL2 (-2518A/G, -362G/C) by PCR-RFLP method and in CCR2 (V64I), CCL5 (-403G/A, -28C/G) and CCR5 (-59029G/A) by ARMS-PCR method. The frequencies of 'AA' genotype and 'A' allele of -403G/A were found significantly higher in cases than in controls (OR, 2.616 [95%CI, 1.302-5.320] and OR, 1.348 [95%CI, 0.980-1.853], respectively). Conversely, the frequencies of 'AA' genotype and 'A' allele of V64I were significantly (p=0.05 and 0.04, respectively) higher in controls than in cases. Also, the "AA" genotype of V64I was found to provide significant (p=0.05) protection against high bacillary load (3+). Likewise, the comparison of frequencies of different combinations of these polymorphisms further strengthens the association of -403G/A with susceptibility and V64I with resistance to TB in Sahariya tribe. However, no significant association of other polymorphisms with either resistance or susceptibility to TB was found. Thus, our findings support the association of -403G/A and V64I polymorphisms with genetic susceptibility and resistance to TB, respectively , alone or in combination with other polymorphisms in Sahariya tribe.

HIV-1 disease progression is associated with bile-salt stimulated lipase (BSSL) gene polymorphism

Background

DC-SIGN expressed by dendritic cells captures HIV-1 resulting in trans-infection of CD4⁺ T-lymphocytes. However, BSSL (bile-salt stimulated lipase) binding to DC-SIGN interferes with HIV-1 capture. DC-SIGN binding properties of BSSL associate with the polymorphic repeated motif of BSSL exon 11. Furthermore, BSSL binds to HIV-1 co-receptor CXCR4. We hypothesized that BSSL modulates HIV-1 disease progression and emergence of CXCR4 using HIV-1 (X4) variants.

Results

The relation between BSSL genotype and HIV-1 disease progression and emergence of X4 variants was studied using Kaplan Meier and multivariate Cox proportional hazard analysis in a cohort of HIV-1 infected men having sex with men (n = 334, with n = 130 seroconverters). We analyzed the association of BSSL genotype with set-point viral load and CD4 cell count, both pre-infection and post-infection at viral set-point. The number of repeats in BSSL exon 11 were highly variable ranging from 10 to 18 in seropositive individuals and from 5–17 in HRSN with 16 repeats being dominant (>80% carry at least one allele with 16 repeats). We defined 16 to 18 repeats as high (H) and less than 16 repeats as low (L) repeat numbers. Homozygosity for the high (H) repeat number BSSL genotype (HH) correlated with high CD4 cell numbers prior to infection (p = 0.007). In HIV-1 patients, delayed disease progression was linked to the HH BSSL genotype (RH = 0.462 CI = 0.282–0.757, p = 0.002) as was delayed emergence of X4 variants (RH = 0.525, 95% CI = 0.290–0.953, p = 0.034). The LH BSSL genotype, previously found to be associated with enhanced DC-SIGN binding of human milk, was identified to correlate with accelerated disease progression in our cohort of HIV-1 infected MSM (RH = 0.517, 95% CI = 0.328–0.818, p = 0.005).

Conclusion

We identify BSSL as a marker for HIV-1 disease progression and emergence of X4 variants. Additionally, we identified a relation between BSSL genotype and CD4 cell counts prior to infection.

CCL5-28, CCL5-403, and CCR5 genetic polymorphisms and their synergic effect with alcohol and tobacco consumptions increase susceptibility to hepatocellular carcinoma

The aim of this study was to estimate the relationship between gene polymorphisms of CCL5-28, CCL5-403, and CCR5 to the susceptibility of hepatocellular carcinoma (HCC). A total of 449 subjects, including 347 healthy controls and 102 patients with HCC, were recruited in this study and subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to investigate the impact of these two polymorphic variants on HCC. A significant association between HCC susceptibility and genetic polymorphism, CG heterozygotes of CCL5-28 (AOR=2.35; 95% CI=1.27-4.33, p=0.006), AA homozygotes of CCL5-403 (AOR=5.18; 95% CI=2.25-11.91, p=0.0001), and AA homozygotes of CCR5 (AOR=2.47; 95% CI=1.24-4.90, p=0.009), was found compared with wild genotype after adjusting for other confounders. It was detected that synergistic effect between gene-to-gene polymorphisms increased the risk to have HCC among individuals with CG or GG of CCL5-28, and GA or AA of CCL-403, and GA or AA of CCR5 (AOR=3.42; 95% CI=1.39-8.38, p=0.007) compared to individuals with wild genotypes of CCL5-28, CCL-403, and CCR5. Also, alcohol or tobacco consumption increased the risk to have HCC among subjects with CG heterozygotes of CCL5-28 (alcohol: p=0.001; tobacco: p=0.006), AA homozygotes (alcohol: p=0.0004; tobacco: p≤0.0001) or GA heterozygotes (tobacco: p=0.03) of CCL5-403, and AA homozygotes of CCR5 (alcohol: p=0.02; tobacco: p=0.02), respectively. Gene polymorphisms of CCL5-28, CCL5-403, and CCR5 play an important factor for the susceptibility of HCC, respectively. The synergic effects of these two gene polymorphisms to tobacco or alcohol consumption significantly increase the risk to develop HCC.

CCL5-independent helper T lymphocyte responses to immuno-dominant pneumococcal surface protein A epitopes

Understanding the requirements for protection against pneumococcal carriage and pneumonia will greatly benefit efforts in controlling these diseases. Several antigens, in addition to the polysaccharide capsule, have been implicated in both the virulence and protective immunity against Streptococcus pneumoniae; one of the best-studied S. pneumoniae antigens is pneumococcal surface protein A (PspA). Recently, it was shown that genetic polymorphisms could diminish CCL5 expression, which results in increased susceptibility to and progression of infectious diseases. We previously showed CCL5 blockade reduced PspA-specific humoral and cellular pneumococcal immunity, during S. pneumoniae strain EF3030-induced carriage, by diminishing IFN-γ and enhancing IL-10 secretion by effector T cells. We also identified immuno-dominant helper T lymphocyte (HTL) epitopes in PspA peptide 19-23 (PspA(199-246)), which caused comparatively more cytokine secretion and proliferation responses by splenic and cervical lymph node (CLN) CD4(+) T cells from mice previously challenged with S. pneumoniae strain EF3030. In this study, we sought to determine if PspA(199-246)-specific CD4(+) T cells responses were resistant to the effect of CCL5 deficiency. In short, T cell responses against these HTL epitopes were resistant to CCL5 inhibition, than compared to cells from control or naïve mice, and unaffected by reduced co-stimulatory molecule expression caused by CCL5 blockade. CCL5 deficiency also corresponded with a higher number of IL-10(+) CD11b(+) CD11c(Lo) and CD11b(+) CD11c(Hi) cells and lower IFN-γ expression by similar cells, than compared to controls. These data confirm CCL5 is an essential factor for optimal pneumococcal adaptive immunity and show CD4(+) T cell responses to PspA(199-246) are largely resistant to CCL5 deficiency.

Role of exonic variation in chemokine receptor genes on AIDS: CCRL2 F167Y association with pneumocystis pneumonia

Chromosome 3p21-22 harbors two clusters of chemokine receptor genes, several of which serve as major or minor coreceptors of HIV-1. Although the genetic association of CCR5 and CCR2 variants with HIV-1 pathogenesis is well known, the role of variation in other nearby chemokine receptor genes remain unresolved. We genotyped exonic single nucleotide polymorphisms (SNPs) in chemokine receptor genes: CCR3, CCRL2, and CXCR6 (at 3p21) and CCR8 and CX3CR1 (at 3p22), the majority of which were non-synonymous. The individual SNPs were tested for their effects on disease progression and outcomes in five treatment-naïve HIV-1/AIDS natural history cohorts. In addition to the known CCR5 and CCR2 associations, significant associations were identified for CCR3, CCR8, and CCRL2 on progression to AIDS. A multivariate survival analysis pointed to a previously undetected association of a non-conservative amino acid change F167Y in CCRL2 with AIDS progression: 167F is associated with accelerated progression to AIDS (RH = 1.90, P = 0.002, corrected). Further analysis indicated that CCRL2-167F was specifically associated with more rapid development of pneumocystis pneumonia (PCP) (RH = 2.84, 95% CI 1.28-6.31) among four major AIDS-defining conditions. Considering the newly defined role of CCRL2 in lung dendritic cell trafficking, this atypical chemokine receptor may affect PCP through immune regulation and inducing inflammation.

[Genetic susceptibility to infections]

Infectious diseases are among the leading causes of morbidity and mortality worldwide. The spectrum of clinical manifestations of infections is highly variable, ranging from asymptomatic infection or mild illness to rapid progression of disease and death. Twin studies first showed an inheritable component of many infections and epidemiological and genetic studies revealed definite gene loci and polymorphisms for most of the clinically relevant infectious diseases. Reliable genetic markers which represent susceptibility or resistance to infections, prognosis of disease and response to treatment are necessary to define risk populations and to plan therapy regimens. Genetic research can also help in identifying target structures for novel therapy strategies and anitimicrobial agents. In this article the genetic background of important infections is reviewed and examples of successful exploitation of genetic findings and translation into practical medicine are given.

Genetic and Immunological Factors Involved in Natural Resistance to HIV-1 Infection

Infection with Human immunodeficiency virus type-1 (HIV-1) induces severe alterations of the immune system leading to an increased susceptibility to opportunistic infections and malignancies. However, exposure to the virus does not always results in infection. Indeed, there exist individuals who have been repeatedly exposed to HIV-1 but do not exhibit clinical or serological evidence of infection, known as exposed seronegative individuals. Many studies have focused on the different mechanisms involved in natural resistance to HIV-1 infection, and have reported several factors associated with this phenomenon, including the presence of genetic polymorphisms in the viral coreceptors, innate and adaptive immune cells with particular phenotypic and functional features, and molecules such as antibodies and soluble factors that play an important role in defense against infection by HIV-1. The study of these factors could be the key for controlling this viral infection. This review summarizes the main mechanisms involved in resistance to HIV-1 infection.

Polymorphisms in the RANTES gene increase susceptibility to active tuberculosis in Tunisia

RANTES plays a pivotal role in attracting and activating various leukocyte populations that control Mycobacterium tuberculosis infection. The present study investigated the relationship between the RANTES polymorphisms (-28C/G; rs2280788, and -403G/A; rs2107538) and susceptibility to active tuberculosis (TB) in Tunisian populations. A total of 168 patients with pulmonary TB (pTB), 55 with extrapulmonary TB (epTB), and 150 control subjects were studied. Genotype analyses were carried out using polymerase chain reaction-restriction fragment length polymorphism method. We found that the -28 GG genotype was significantly associated with susceptibility to pTB (odds ratio [OR]=11.19; 95% confidence intervals [CI], 5.14-25; P corrected for the number of genotypes [Pc]=10(-8)) and epTB (OR=11.67; 95% CI, 4.74-29.33; Pc=10(-8)). However, the -28 CC genotype was found to be significantly associated with resistance to pTB (OR=0.08; 95% CI, 0.04-0.16; Pc=10(-8)) and epTB development (OR=0.11; 95% CI, 0.05-0.27; Pc=10(-8)). -403A allele was associated with increased risk development of epTB (OR=2.21; 95% CI, 1.18-4.14; p=0.007). G-G and A-C haplotypes and the AG/GC diplotype were associated with increase susceptibility to pTB (OR=7.88, 95% CI, 5.38-11.55; Pc=3.10(-8); OR=2.32, 95% CI, 1.32-4.11; Pc=3.10(-3); OR=13.26, 95% CI, 6.06-29.89; Pc=3.10(-8); respectively) and epTB (OR=6.64, 95% CI, 4-11.05; Pc=3.10(-8); OR=2.6, 95% CI, 1.26-5.35; Pc=12.10(-3); OR=11.26, 95% CI, 4.44-29.28; Pc=3.10(-8); respectively). Collectively, our findings suggested an association of the RANTES -28C/G and -403G/A functional polymorphisms with susceptibility to Mycobacterium tuberculosis infection in Tunisian populations.

CCL5/RANTES gene polymorphisms in Slavonic patients with myocardial infarction

Coronary artery inflammation is a critical process in the pathogenesis of myocardial infarction (MI). The chemokine CCL5/RANTES (regulated upon activation, normal T cells expressed and secreted) is expressed in advanced atherosclerotic lesions. Functional polymorphisms of the RANTES gene can, therefore, be involved in the pathogenesis of coronary artery disease. We examined the association of polymorphisms in the RANTES gene with myocardial infarction in Slavonic populations of Czech and Russian origin. A total of 467 post-MI patients and 337 control subjects were genotyped for RANTES promoter G-403A (rs2107538) and intron 1.1 T/C (rs2280789) variants by PCR-SSP. Both RANTES genotypes and allele frequencies did not differ between case and control groups. Haplotype-based analysis also failed to reveal an association between MI and investigated markers. Strong linkage disequilibrium was detected between particular RANTES alleles. The data do not support an association between RANTES G-403A polymorphism and MI, as reported previously.

MCP-1 -2518 A/G functional polymorphism is associated with increased susceptibility to active pulmonary tuberculosis in Tunisian patients

Monocyte chemoattractant protein-1 (MCP-1) plays crucial role in protective immunity against Mycobacterium tuberculosis (MT). In this study, we examined whether single nucleotide polymorphism (SNP) -2518 A/G (rs 1024611) of MCP-1 affect the susceptibility to active tuberculosis (TB) in Tunisian populations. Genomic DNA from patients with active TB (168 cases of pulmonary TB and 55 cases of extrapulmonary TB) and ethnically controls (150 cases) was genotyped for the MCP-1 -2518 A/G SNP by polymerase chain reaction fragment length polymorphism (PCR-RFLP). We observed that -2518 G allele and GG genotype (high MCP-1 producer) frequencies were significantly more elevated in active pulmonary TB group in comparison to control group [34 vs. 22%; P = 0.0007; 15 vs. 5%, P corrected for the number of genotypes (Pc) = 0.015; respectively]. Additionally, they were associated with increased risk development of this clinical form of TB [odds ratio (OR) = 1.83, 95% confidence intervals (CI) = 1.26-2.66; OR = 3.1, 95% CI = 1.28-7.76; respectively]. However, wild type allele -2518 A and AA genotype were over-represented in control group (78 and 62%) and seem to be protective factors against TB. Moreover, -2518 AA genotype was more frequent in control group and was associated with resistance against development of active pulmonary TB (OR = 0.56, 95% CI = 0.35-0.89, Pc = 0.03). Our findings confirm the key role of -2518 A/G SNP of MCP-1 and support its association with resistance/susceptibility to the development of active pulmonary TB in the Tunisian population.

The RANTES gene promoter polymorphisms are associated with the risk of atherothrombotic cerebral infarction in Northern Han Chinese

BACKGROUND

Regulated upon activation, normal T-cell expressed and secreted (RANTES) plays an important role in the inflammatory process. This study is aimed at evaluating the potential association of the -403G/A (rs2107538) and -28C/G (rs2280788) polymorphisms of the RANTES gene promoter with the risk of atherothrombotic cerebral infarction (ACI) in Northern Han Chinese.

METHOD

A total of 314 patients with ACI and 389 unrelated aged-matched healthy controls were recruited. Their genotypes of the RANTES gene promoter -403G/A (rs2107538) and -28C/G (rs2280788) were analyzed by multiplex polymerase chain reaction (multiplex PCR) and multiplex SNaPshot analysis. The potential association of genotyping and allele frequencies with ACI in this population was assessed statistically.

RESULTS

The frequencies of -403AA genotype and A allele in ACI male patients were significantly higher than that in healthy controls (P=0.007, P=0.009, respectively). Female patients were not different. Multiple logistic regression analysis revealed that the -403AA genotype in males was significantly associated with an increased risk of ACI, even after adjusting for confounding factors (OR=4.344; 95% CI=1.969-9.582; P<0.001). Although there was no significant association of the -28C/G polymorphism with ACI, the A-(403)C-(28) haplotype was significantly associated with an increased risk of ACI in Han Chinese [OR=1.56, 95% CI=1.23-1.98, P<0.001].

CONCLUSIONS

Our data suggest that the -403AA genotype and A allele of the RANTES promoter were associated with increased risk for the development of ACI in male Northern Han Chinese.

Mendelian randomization: potential use of genetics to enable causal inferences regarding HIV-associated biomarkers and outcomes

PURPOSE OF REVIEW

It is unknown whether biomarkers simply correlate with or are causal for HIV-associated outcomes. Mendelian randomization is a genetic epidemiologic approach used to disentangle causation from association. Here, we discuss the potential use of Mendelian randomization for differentiating whether biomarkers are correlating with or causal for HIV-associated outcomes.

RECENT FINDINGS

Mendelian randomization refers to the random allocation of alleles at the time of gamete formation. In observational epidemiology, this refers to the use of genetic variants to estimate a causal effect between a modifiable risk factor and an outcome of interest. A formal Mendelian randomization study using a genetic marker as a proxy for the biomarker has not been conducted in the HIV field. However, in the postgenomic era, this approach is being used increasingly. Examples are evidence for the causal role of BMI in blood pressure and noncausal role of C-reactive protein in coronary heart disease. We discuss the conceptual framework, uses, and limitations of Mendelian randomization in the context of HIV infection as well as specific biomarkers (IL-6, C-reactive protein) and genetic determinants (e.g., in CCR5, chemokine, and DARC genes) that associate with HIV-related outcomes.

SUMMARY

Making the distinction between correlation and causality has particular relevance when a biomarker (e.g., IL-6) is potentially modifiable, in which case a biomarker-guided targeted treatment strategy may be feasible. Although the tenets of Mendelian randomization rest on strong assumptions, and conducting a Mendelian randomization study in HIV infection presents many challenges, it may offer the potential to identify causal biomarkers for HIV-associated outcomes.

Human immunodeficiency virus type 1 long-term non-progressors: the viral, genetic and immunological basis for disease non-progression

A small subset of human immunodeficiency virus type 1 (HIV-1)-infected, therapy-naive individuals--referred to as long-term non-progressors (LTNPs)--maintain a favourable course of infection, often being asymptomatic for many years with high CD4(+) and CD8(+) T-cell counts (>500 cells  μl(-1)) and low plasma HIV-RNA levels (<10 ,000 copies ml(-1)). Research in the field has undergone considerable development in recent years and LTNPs offer a piece of the puzzle in understanding the ways that persons can naturally control HIV-1 infection. Their method of control is based on viral, genetic and immunological components. With respect to virological features, genomic sequencing has shown that some LTNPs are infected with attenuated strains of HIV-1 and harbour mutant nef, vpr, vif or rev genes that contain single nuclear polymorphisms, or less frequently, large deletions, in conserved domains. Studies have also shown that some LTNPs have unique genetic advantages, including heterozygosity for the CCR5-Δ32 polymorphism, and have been found with excitatory mutations that upregulate the production of the chemokines that competitively inhibit HIV-1 binding to CCR5 or CXCR4. Lastly, immunological factors are crucial for providing LTNPs with a natural form of control, the most important being robust HIV-specific CD4(+) and CD8(+) T-cell responses that correlate with lower viral loads. Many LTNPs carry the HLA class I B57 allele that enhances presentation of antigenic peptides on the surface of infected CD4(+) cells to cytotoxic CD8(+) T cells. For these reasons, LTNPs serve as an ideal model for HIV-1 vaccine development due to their natural control of HIV-1 infection.

Gene expression variability within and between human populations and implications toward disease susceptibility

Variations in gene expression level might lead to phenotypic diversity across individuals or populations. Although many human genes are found to have differential mRNA levels between populations, the extent of gene expression that could vary within and between populations largely remains elusive. To investigate the dynamic range of gene expression, we analyzed the expression variability of ∼18, 000 human genes across individuals within HapMap populations. Although ∼20% of human genes show differentiated mRNA levels between populations, our results show that expression variability of most human genes in one population is not significantly deviant from another population, except for a small fraction that do show substantially higher expression variability in a particular population. By associating expression variability with sequence polymorphism, intriguingly, we found SNPs in the untranslated regions (5′ and 3′UTRs) of these variable genes show consistently elevated population heterozygosity. We performed differential expression analysis on a genome-wide scale, and found substantially reduced expression variability for a large number of genes, prohibiting them from being differentially expressed between populations. Functional analysis revealed that genes with the greatest within-population expression variability are significantly enriched for chemokine signaling in HIV-1 infection, and for HIV-interacting proteins that control viral entry, replication, and propagation. This observation combined with the finding that known human HIV host factors show substantially elevated expression variability, collectively suggest that gene expression variability might explain differential HIV susceptibility across individuals.

Many human genes have population-specific expression levels, which are linked to population-specific polymorphisms and copy-number variations. However, it is unclear whether human genes show similar dynamic range of expression between populations. In this work we analyzed HapMap gene expression compendium, and quantified the between-population and within-population expression variability for ∼18,000 human transcripts. We first concluded that the majority of the human genes have similar levels of within-population variability. However, a small fraction (∼4%) does show much higher expression variability in one population, and the deviation is consistently associated with increased SNP heterozygosity in their UTR regulatory regions. We further showed that genes with the greatest within-population expression variability are significantly enriched for chemokine signaling associated with HIV-1 infection. Combined with the finding that human HIV-1 host factors tend to have increased expression variability within populations, our analysis may explain, at least in part, different susceptibility to HIV infection within the human population. This work provides a fresh angle for analyzing gene expression variations in populations.

Effect of host genetics on the development of cytomegalovirus retinitis in patients with AIDS

BACKGROUND

Cytomegalovirus (CMV) retinitis is a common opportunistic infection among patients with AIDS and still causes visual morbidity despite the wide spread usage of highly active antiretroviral therapy (HAART). The ubiquitous CMV pathogen contains a human interleukin-10 (IL-10) homolog in its genome and utilizes it to evade host immune reactions through an IL-10 receptor mediated immune-suppression pathway.

METHODS

Effects of IL-10R1, IL-10 and previously described AIDS restriction gene variants are investigated on the development of CMV retinitis in the Longitudinal Study of the Ocular Complications of AIDS (LSOCA) cohort (N = 1284).

RESULTS

In European Americans (n = 750), a haplotype carrying an amino acid changing variation in the cytoplasmic domain (S420L) of IL-10R1 can be protective (OR, 0.14; 95% CI, 0.02-0.94; P = .04) against, whereas another haplotype carrying an amino acid changing variation in the extracellular domain (I224V) of IL-10R1 can be more susceptible (OR, 6.21; 95% CI, 1.22- 31.54; P = .03) to CMV retinitis. In African Americans (n = 534), potential effects of IL-10 variants are observed.

CONCLUSION

Host genetics may have a role in the occurrence of CMV retinitis in patients infected with HIV.

Effect of host genetics on incidence of HIV neuroretinal disorder in patients with AIDS

Approximately 10%-15% of patients with AIDS but without ocular opportunistic infections will have a presumed neuroretinal disorder (HIV-NRD), manifested by reduced contrast sensitivity and abnormal visual fields. The loss of contrast sensitivity often is sufficient to impair reading speed. To evaluate the effect of host genetics on HIV-NRD, we explored validated AIDS restriction gene variants CCR5Delta32, CCR2-64I, CCR5 P1, SDF-3'A, IL-10-5'A, RANTES -403A, RANTES -28G, RANTES-In1.1C, CX3CR1-249I, CX3CR1-280M, IFNG-179T, MDR1-3435T, and MCP-1364G, each of which has been implicated previously to influence HIV-1 infection, AIDS progression, therapy response, and antiviral drug metabolism, and an IL-10 receptor gene, IL-10R1, in the Longitudinal Study of the Ocular Complications of AIDS cohort. In European Americans (cases = 55, controls = 290), IL-10-5'A variant and its promoter haplotype (hazard ratio = 2.09, confidence interval. 1.19 to 3.67, P = 0.01), in African Americans (cases = 54, controls = 180), RANTES-In1.1C and the associated haplotype (hazard ratio = 2.72, confidence interval.: 1.48 to 5.00, P = 0.001), showed increased HIV-NRD susceptibility. Although sample sizes are small and P values do not pass a strict Bonferroni correction, our results suggest that, in European Americans, an IL-10-related pathway, and, in African Americans, chemokine receptor ligand polymorphisms in RANTES are risk factors for HIV-NRD development. Clearly, further studies are warrented.

Functional characterization of single-nucleotide polymorphisms in the human undifferentiated embryonic-cell transcription factor 1 gene

Single-nucleotide polymorphisms (SNPs) are single-nucleotide sequence variations between individuals. Two missense SNPs are present in the human undifferentiated embryonic-cell transcription factor 1 (UTF1) gene and their consequences for UTF1 function are investigated in this study. Expression of the UTF1 gene is restricted to pluripotent cells and UTF1 is a chromatin-associated protein with core histone-like properties. UTF1 further acts as a transcriptional repressor and is required for proper differentiation of pluripotent cells. Two missense mutations in UTF1 are reported: rs11599284, which results in a glycine to an arginine change at amino acid 73, and rs4480453, resulting in a leucine to methionine change at amino acid 275. To study the effects of these two SNPs, P19CL6 mouse embryonic carcinoma cells stably expressing eGFP-hUTF1 constructs containing either one or both SNPs were generated. The single and double SNPs did not alter the localization or transcriptional repressor activity of the protein. Further, the single SNPs did not alter the chromatin association and mobility of hUTF1. However, the double mutant, G73R/L275M, demonstrated a decreased chromatin association, indicating a degree of protein malfunction.

Congenital toxoplasmosis: candidate host immune genes relevant for vertical transmission and pathogenesis

Toxoplasma gondii infects a variety of vertebrate hosts, including humans. Transplacental passage of the parasite leads to congenital toxoplasmosis. A primary infection during the first weeks of gestation causes vertical transmission at low rate, although it causes major damage to the embryo. Transmission frequency increases to near 80% by the end of pregnancy, but the proportion of ill newborns is low. For transmission and pathogenesis, the parasite genetics is certainly important. Several host innate and adaptative immune response genes are induced during infection in adults, which control the rapidly replicating tachyzoite. The T helper 1 (Th1) response is protective, although it has to be modulated to avoid inflammatory damage. Paradoxical observations on this response pattern in congenital toxoplasmosis have been reported, as it may be protective or deleterious, inducing sterile abortion or favoring parasite transplacental passage. Regarding pregnancy, an early Th1 microenvironment is important for control of infectious diseases and successful implantation, although it has to be regulated to support trophoblast survival. Polymorphism of genes involved in these parallel phenomena, such as Toll-like receptors (TLRs), adhesins, cytokines, chemokines or their receptors, immunoglobulins or Fc receptors (FcRs), might be important in susceptibility for T. gondii vertical transmission, abortion or fetal pathology. In this study some examples are presented and discussed.

Role of chemokine and cytokine polymorphisms in the progression of HIV-1 disease

Allelic variants of the genes for chemokine receptors and their natural ligands, the chemokines, and cytokines can affect HIV-1 disease progression. This study investigates the level of expression of the CCR5-Delta32, CCR2b-641, RANTES In1.1C, SDF-1 3'A, IL-10-5'-592A and IL-4-589T alleles in two unique HIV-1 infected patient cohorts that represent the two distinct stages of disease progression, namely rapid progressors (RPs) and long term non-progressors (LTNPs) (n=12/group) were recruited. Quantitation of the gene expression of CCR5-Delta32, CCR2b-641, RANTES In1.1C, SDF-1 3'A, IL-10-5'-592A and IL-4-589T in peripheral blood mononuclear leukocytes (PBML) isolated from patients was performed by real time, quantitative (Q)-PCR using DNA was isolated from PBML. We observed that expression of these HIV-protective alleles was generally greater in the LTNP cohort than the RP cohort. LTNPs expressed more of the protective chemokine, SDF-1alpha than RPs, and no statistically significant difference was observed in RANTES production between the LTNPs and RPs. The LTNPs expressed significantly less amounts of cytokines IL-10 and IL-4 as compared to the RPs. Our results demonstrate that gene polymorphisms for CCR5-Delta32, CCR2b-641, RANTES In1.1C, SDF-1 3'A, IL-10-5'-592A and IL-4-589T may be used as clinical markers to predict progression of HIV-1 infections.

Host genes associated with HIV/AIDS: advances in gene discovery

Twenty-five years after the discovery of HIV as the cause of AIDS there is still no effective vaccine and no cure for this disease. HIV susceptibility shows a substantial degree of individual heterogeneity, much of which can be conferred by host genetic variation. In an effort to discover host factors required for HIV replication, identify crucial pathogenic pathways, and reveal the full armament of host defenses, there has been a shift from candidate-gene studies to unbiased genome-wide genetic and functional studies. However, the number of securely identified host factors involved in HIV disease remains small, explaining only approximately 15-20% of the observed heterogeneity - most of which is attributable to human lymphocyte antigen (HLA) variants. Multidisciplinary approaches integrating genetic epidemiology to systems biology will be required to fully understand virus-host interactions to effectively combat HIV/AIDS.

Association between regulated upon activation, normal T cells expressed and secreted (RANTES) -28C/G polymorphism and asthma risk--a meta-analysis

Regulated upon activation, normal T-cell expressed and secreted (RANTES) is one of the most extensively studied C-C chemokines in allergic inflammation. A growing body of evidence suggests that many cell types present in asthmatic airways have the capacity to generate RANTES, which directly supported the potential role of RANTES in asthma. A number of studies have evaluated the functional polymorphism -28C/G in the RANTES promoter region, which had been found to affect the transcription of the RANTES gene, in relation to asthma susceptibility. However, the results remain conflicting rather than conclusive. This meta-analysis on 1894 asthma cases and 1766 controls for -28C/G from 9 published case-control studies showed that the variant allele -28G was associated with significantly increased risk of asthma (GG+CG vs CC: OR=1.24, 95%CI=1.08-1.41) without any between-study heterogeneity.In the stratified analysis by asthma type, age and ethnicity, we found that the increased asthma risk associated with -28G/C polymorphism was more evident in children (OR=1.24, 95%CI=1.06-1.45), Asian group (OR=1.27, 95%CI=1.04-1.56) and African group (OR=1.72, 95%CI=1.07-2.78). These results suggest that RANTES -28G/C polymorphism may contribute to asthma development, especially in children and in Asian population. Additional well-designed large studies were required for the validation of this association.

Host genetics influences on HIV type-1 disease

HIV host genetic studies seek to describe as comprehensively as possible the effect of human genetic variation on the individual response to HIV type-1 (HIV-1) infection. Many associations between specific gene variants and HIV-1 disease outcomes have been reported over the past 15 years. Although most of them have yet to be confirmed or have been proven false-positives, the identification of several definitive genotype-phenotype associations has shed new light on HIV-1 pathogenesis. This review discusses these results in the context of the new genome-wide approaches that now make it possible to globally assess the influence of the host genome on HIV-1-related outcomes.

CCL3 genotype and current depression increase risk of HIV-associated dementia

BACKGROUND: The prevalence of Human immunodeficiency virus (HIV)-associated dementia (HAD) has continued to rise even as incidence has fallen. Several host genetic variants have been identified that modify risk for HAD. However, the findings have not been replicated consistently and most studies did not consider the multitude of factors that might themselves confer risk for HAD. In the current study, we sought to replicate the findings of previous studies in a neurologically and behaviorally well-characterized cohort. METHODS: The sample consisted of 143 HIV+ individuals enrolled in the National NeuroAIDS Tissue Consortium (NNTC). Based on consensus diagnosis, 117 were considered neurologically normal upon study entry, and 26 had HAD. Seven single-nucleotide polymorphisms (SNPs) were genotyped within seven genes (CCL2, CCL3, CCL5, interleukin-1α [IL-1α], IL-10, stromal cell-derived factor 1, and tumor necrosis factor-α). Logistic regression analysis was used to predict group membership (normal vs HAD), with predictor variables including length of infection, age, current drug dependence, current depression, and genotype. RESULTS: The two groups were statistically similar with regards to demographic characteristics, current drug use, and disease factors. The HAD group had significantly greater number of individuals with current depression. Only one SNP, rs1130371 within the gene for CCL3, was entered into the analysis as the others showed symmetric distribution between groups. Logistic regression indicated that current depression and CCL3 genotype were significant predictors of HAD. Depression conferred a fivefold greater risk of HAD, while the TT genotype for CCL3 SNP (rs1130371) was associated with twofold risk for HAD. CONCLUSION: Depression and CCL3 genotype predicted HAD. The fact that SNPs previously found to be associated with HAD were not in our analysis, and that rs1130371 is in high linkage disequilibrium with neighboring genes indicates that more dense genotyping in significantly larger cohorts is required to further characterize the relationship between genotype and risk for HAD.

The Role of RANTES Promoter Polymorphism in Functional Dyspepsia

Altered inflammatory immune responses have been shown to be associated with functional gastro intestinal disorder. We aimed to clarify the effect of functional promoter polymorphism of RANTES, which is a potent chemoattractant peptide for memory T lymphocytes and eosinophils, on the risk of functional dyspepsia in a Japanese population. RANTES promoter C-28G polymorphism was genotyped in 246 subjects including 134 FD patients according to Roma III criteria and 112 non-symptomatic healthy controls. Although frequency of RANTES promoter polymorphisms in overall dyspeptic patients and non-symptomatic healthy controls did not show any significant differences, a significant association was found between G carrier and reduced risk of PDS according to Roma III criteria (age, sex, H. pylori infection adjusted OR  = 0.23, 95% CI = 0.06–0.80). We also found that the same genotype held a lower risk of PDS in H. pylori positive PDS subjects (age, sex adjusted OR = 0.11, 95% CI = 0.01–0.94). Our data suggest that RANTES promoter -28G carriers is associate with a reduced risk of PDS especially in H. pylori positive subjects.

Preinfection human immunodeficiency virus (HIV)-specific cytotoxic T lymphocytes failed to prevent HIV type 1 infection from strains genetically unrelated to viruses in long-term exposed partners

Understanding the mechanisms underlying potential altered susceptibility to human immunodeficiency virus type 1 (HIV-1) infection in highly exposed seronegative (ES) individuals and the later clinical consequences of breakthrough infection can provide insight into strategies to control HIV-1 with an effective vaccine. From our Seattle ES cohort, we identified one individual (LSC63) who seroconverted after over 2 years of repeated unprotected sexual contact with his HIV-1-infected partner (P63) and other sexual partners of unknown HIV-1 serostatus. The HIV-1 variants infecting LSC63 were genetically unrelated to those sequenced from P63. This may not be surprising, since viral load measurements in P63 were repeatedly below 50 copies/ml, making him an unlikely transmitter. However, broad HIV-1-specific cytotoxic T-lymphocyte (CTL) responses were detected in LSC63 before seroconversion. Compared to those detected after seroconversion, these responses were of lower magnitude and half of them targeted different regions of the viral proteome. Strong HLA-B27-restricted CTLs, which have been associated with disease control, were detected in LSC63 after but not before seroconversion. Furthermore, for the majority of the protein-coding regions of the HIV-1 variants in LSC63 (except gp41, nef, and the 3' half of pol), the genetic distances between the infecting viruses and the viruses to which he was exposed through P63 (termed the exposed virus) were comparable to the distances between random subtype B HIV-1 sequences and the exposed viruses. These results suggest that broad preinfection immune responses were not able to prevent the acquisition of HIV-1 infection in LSC63, even though the infecting viruses were not particularly distant from the viruses that may have elicited these responses.

Romero J, Carretero R, Tallada Buñuel M, Ruiz Cabello F, Manuel Cózar Olmo J. [Polymorphisms in inflammatory response genes in metastatic renal cancer]

Inflammation has been implicated as an etiological factor in different human cancers. Allelic variations in the genes implicated in inflammation are candidates as genetic determinants or markers of renal carcinoma risk. The present stud investigates whether polymorphisms of the genes that give rise to increases in the levels of proinflammatory cytokines and chemokines are associated with an increased risk of renal carcinoma. To this effect, a number of case-control studies were designed to assess the correlation between renal carcinoma and polymorphisms IL10-1082 A/G (rs 1800896), IL10-592 A/C (rs 1800872), IL10-819 C/T (rs 1800871), IL10-1082 A/G, IL4-590 C/T (rs 2243250), TNF-A-308 A/G (rs 1800629), RANTES-403 G/A (rs 2107538), IL1-A-889 C/T (rs 1800587), MCP-1 2518 G/A (rs 1024611), CTLA-4/+49 A/G (rs 231775) and CTLA-4 CT60 A/G (rs 3087243) in 127 renal carcinoma patients and in 176 healthy subjects. The results obtained in relation to cytokine polymorphism IL-10-1082 A/G indicate that AG heterozygosity status is the principal risk factor in relation to locally advanced or metastatic tumor stage and renal carcinoma. In the case of the molecule CTLA4, the results obtained in renal cancer reveal an association between the polymorphisms of the CTLA-4 gene and an increased risk of developing renal cell carcinoma. A high genotypic frequency of polymorphisms CTLA4/CT60-AA and CTLA4/A49G-AA is observed in patients with renal cell carcinoma versus the controls. An association has been established between polymorphism CTLA4/CT60 and tumor grade in patients with renal cell carcinoma. Logistic regression analysis has confirmed these data, demonstrating a high frequency of the AA genotype in patients with high-grade tumors. The results obtained support the hypothesis that different genetic factors implicated in the regulation of adaptive immune responses, stromal cell composition and local cytokine production levels may be crucial elements in the modification of the clinicopathological parameters of renal carcinoma.

Effect of variation in RANTES promoter on serum RANTES levels and risk of recurrent wheezing after RSV bronchiolitis in children from Han, Southern China

To investigate the association among RANTES (regulated on activation normal T cell expressed and secreted) gene promoter polymorphism, serum RANTES levels, and recurrent wheezing after RSV (respiratory syncytial virus) bronchiolitis in children (1-12 months of age) from Han, Southern china. Three hundred twenty children with RSV bronchiolitis and 272 controls were enrolled in the 3-year follow-up study. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RELP), enzyme-linked immunosorbent assay (ELISA) kit and luciferase analysis were the mainly used methods, which were used to genotype the RANTES (-403 G/A), assess the serum RANTES levels and the RANTES promoter activity. As the results showed, the RANTES (-403 G/A) in the promoter region was associated with recurrent wheezing after RSV bronchiolitis (p < 0.05) and serum RANTES levels (RANTES genotype G/G: 26.03 +/- 7.46 ng/ml G/A: 28.22 +/- 6.44 ng/ml A/A: 30.12 +/- 5.88 ng/ml). Functional analyses of RANTES promoter activity indicated that the RANTES (-403 G to A) mutation increases the transcriptional activity of the RANTES promoter. In conclusion, the RANTES (-403 G/A) polymorphism increases RANTES transcriptional activity resulted in a high serum RANTES levels, thus increased the risk of recurrent wheezing after RSV bronchiolitis.

Effect of RANTES promoter genotype on the severity of intestinal metaplasia in Helicobacter pylori-infected Japanese subjects

BACKGROUND

A complex interaction of host genetic and environmental factors may be relevant in the development of Helicobacter pylori (H. pylori)-related gastro-duodenal diseases. RANTES is a potent chemoattractant peptide for memory T lymphocytes and eosinophils, and has been shown to be enhanced in H. pylori-infected gastric mucosa. We aimed to clarify the effect of RANTES functional promoter polymorphism on the risk of gastro-duodenal diseases in a Japanese population.

METHODS

Four hundred and eighty-three subjects, comprising 106 gastric ulcer, 52 duodenal ulcer, and 325 non-ulcer subjects, were included in this study. Restriction fragment length polymorphism (RFLP) analysis was performed for polymorphisms at -28 C/G in the RANTES gene promoter region. Gastritis scores of antral gastric mucosa were assessed according to the updated Sydney system.

RESULTS

There were no significant differences in the RANTES promoter genotype distributions among non-ulcer subjects, ulcer patients, and gastric and duodenal ulcers. However, the degree of intestinal metaplasia was significantly lower among G carriers in H. pylori-infected subjects aged 60 years or older (C/C vs. G carriers; 1.28 +/- 1.02 vs. 0.83 +/- 0.89, P = 0.0357). In addition, we also found that the same genotype held a lower risk of more severe intestinal metaplasia in H. pylori-infected female subjects (C/C vs. G carriers; 0.91 +/- 1.03 vs. 0.41 +/- 0.73, P = 0.0443).

CONCLUSION

The polymorphism of RANTES promoter is not associated with the susceptibility to peptic ulcer diseases, but the -28 G carrier is associated with a reduced risk of developing more severe intestinal metaplasia in H. pylori-positive subjects aged 60 years and older and in female subjects.

Cytokines associated with bronchopulmonary dysplasia or death in extremely low birth weight infants

OBJECTIVE

The goal was to develop multivariate logistic regression models for the outcome of bronchopulmonary dysplasia and/or death at postmenstrual age of 36 weeks by using clinical and cytokine data from the first 28 days.

METHODS

For 1067 extremely low birth weight infants in the Neonatal Research Network of the National Institute of Child Health and Human Development, levels of 25 cytokines were measured in blood collected within 4 hours after birth and on days 3, 7, 14, and 21. Stepwise regression analyses using peak levels of the 25 cytokines and 15 clinical variables identified variables associated with bronchopulmonary dysplasia/death. Multivariate logistic regression analysis was performed for bronchopulmonary dysplasia/death by using variables selected through stepwise regression. Similar analyses were performed by using average cytokine values from days 0 to 21, days 0 to 3, and days 14 to 21.

RESULTS

Of 1062 infants with available data, 606 infants developed bronchopulmonary dysplasia or died. On the basis of results from all models combined, bronchopulmonary dysplasia/death was associated with higher concentrations of interleukin 1beta, 6, 8, and 10 and interferon gamma and lower concentrations of interleukin 17, regulated on activation, normal T cell expressed and secreted, and tumor necrosis factor beta. Compared with models with only clinical variables, the addition of cytokine data improved predictive ability by a statistically significant but clinically modest magnitude.

CONCLUSIONS

The overall cytokine pattern suggests that bronchopulmonary dysplasia/death may be associated with impairment in the transition from the innate immune response mediated by neutrophils to the adaptive immune response mediated by T lymphocytes.

Genetic determinants of HIV-1 infection and progression to AIDS: susceptibility to HIV infection

Interindividual variability in susceptibility to HIV-1 infection, its transmission, disease progression, and response to antiviral therapy has been attributed to host determinants and variability in multiple genes. Although most people exposed to the virus go on to develop full-blown disease at variable intervals, a proportion of them, labeled as long-term nonprogressors or exposed uninfected, possess 'natural resistance' to infection. A better understanding of genetic and immunologic basis of such a natural resistance to infection would bear important implications in designing therapeutic vaccine designs. The genetic variants that could influence susceptibility to HIV-1 and limit AIDS vary in different populations and among individuals. Meta-analyses of large cohort studies have identified numerous 'AIDS restriction genes' that regulate HIV cell entry (particularly chemokine coreceptors and their ligands), acquired and innate immunity (major histocompatibility complex, killer cell immunoglobulin-like receptor, and cytokines), and others [tripartite interaction motif 5 alpha (TRIM5alpha) and apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G] that influence outcome of HIV infection. Studies carried out in the Indian population with regard to genetic polymorphisms in chemokine receptors have shown that (i) the protective CCR5 Delta32 variant is rare, (ii) CCR5HHE carrying *59402A is associated with increased likelihood of infection and development of AIDS, and (iii) the Indian population generally has low CCL3L1 copy numbers (approximately 2.3). These data have implications in developing screening tests that could identify people at higher or lower risk of infection and rate of disease progression, predict vaccine responsiveness in clinical trials and understand the pathogenic mechanisms.

Genetic diversity of RANTES gene promoter and susceptibility to coronary artery disease and restenosis after percutaneous coronary intervention

Regulated on activation, normal T cell expressed and secreted (RANTES) gene promoter is a regulatory region and a site of notable genetic diversity. In order to explore a possible interaction between RANTES promoter genetic diversity and susceptibility to coronary artery disease (CAD) and in stent restenosis (ISR), we initially sequenced a locus extending from -516 to 40 covering the entire region of the RANTES promoter in 100 subjects randomly selected from our cohort. Four single nucleotide polymorphisms (SNPs) were identified: -403G/A, -256G/A, -109C/T and -28C/G. The frequency of the -109C/T and -256G/A variations was <0.01, and was considered to be of limited significance. The frequency of the -403G/A and -28C/G polymorphisms was evaluated in the entire sample, which consisted of 118 patients subjected to percutaneous coronary intervention (PCI) without ISR on angiographic re-evaluation (no IRS group), 74 CAD patients with ISR on angiographic re-evaluation (IRS group) and 146 controls without angiographic evidence of CAD (no CAD group). No association was established between the RANTES promoter genotype and ISR. A genotype-phenotype interaction was observed between the -403G/A polymorphism and CAD. The -403A homozygotes were significantly more common in the CAD group than in the controls. The severity of CAD among case subjects, expressed as the mean number of diseased vessels, was significantly higher among -403A homozygotes as compared to wild-type homozygotes and heterozygotes. In conclusion, the RANTES -403A allele was associated with the presence and severity of CAD independently of conventional cardiovascular risk factors. The RANTES promoter genotype did not influence susceptibility to ISR in patients subjected to PCI.

The role of host genetics in the susceptibility for HIV-associated neurocognitive disorders

Despite progress in the treatment of the Human Immunodeficiency virus (HIV), there continues to be a high prevalence of infected individuals who develop neurocognitive deficits and disorders. Our understanding of the potential cause of HIV-associated neurocognitive disorders (HAND) continues to develop on many fronts. Among them is the study of host genetics. Here, we review the most current information regarding the association between host genetics and risk for HIV infection, AIDS, and HAND. We focus on the role of dopamine dysfunction in the etiology of HAND, and propose a number of genetic polymorphisms within genes related to dopaminergic functioning and other neurobiological factors that may confer vulnerability or protection against HAND.