Polymorphism in RANTES chemokine promoter affects HIV-1 disease progression

Distribution and effects of polymorphic RANTES gene alleles in HIV/HCV coinfection -- a prospective cross-sectional study

AIM

Chemokines and their receptors are crucial for immune responses in HCV and HIV infection. RANTES gene polymorphisms lead to altered gene expression and influence the natural course of HIV infection. Therefore, these mutations may also affect the course of HIV/HCV coinfection.

METHODS

We determined allele frequencies of RANTES-403 (G --> A), RANTES-28 (C --> G) and RANTES-IN1.1 (T --> C) polymorphisms using real-time PCR and hybridization probes in patients with HIV (n = 85), HCV (n = 112), HIV/HCV coinfection (n = 121), and 109 healthy controls. Furthermore, HIV and HCV loads as well as CD4(+) and CD8(+) cell counts were compared between different RANTES genotypes.

RESULTS

Frequencies of RANTES-403 A, RANTES-28 G and RANTES-IN1.1 C alleles were higher in HIV infected patients than in healthy controls (-403: 28.2% vs 15.1%, P = 0.002; -28: 5.4% vs 2.8%, not significant; IN1.1: 19.0% vs 11.0%, P = 0.038). In HIV/HCV coinfected patients, these RANTES alleles were less frequent than in patients with HIV infection alone (15.4% P = 0.002; 1.7%; P = 0.048; 12.0%; not significant). Frequencies of these alleles were not significantly different between HIV/HCV positive patients, HCV positive patients and healthy controls.

CONCLUSION

All three RANTES polymorphisms showed increased frequencies of the variant allele exclusively in patients with HIV monoinfection. The finding that the frequencies of these alleles remained unaltered in HIV/HCV coinfected patients suggests that HCV coinfection interferes with selection processes associated with these alleles in HIV infection.

Polymorphism of RANTES chemokine gene promoter is not associated with long-term nonprogressive HIV-1 infection of more than 16 years

To examine whether polymorphisms of the RANTES chemokine gene promoter are associated with long-term nonprogressive HIV-1 infection in white Spanish subjects, we performed a cross-sectional genetic association case-control study. Two-hundred sixty-seven white Spaniards were studied: 58 were HIV-1-infected long-term nonprogressors (LTNPs) of more than 16 years, 109 were HIV-1-infected usual progressors (UPs), and 100 were control subjects. Three RANTES single nucleotide polymorphisms (SNPs) at positions -28C>G, -109T>C, and -403G>A were assessed. The prevalence of the CCR5Delta 32 allele was also examined. Genotyping was performed using polymerase chain reaction and automatic sequencing analysis methods. Genotype and allele frequencies between the 3 groups were compared by the chi2 test and the Fisher exact test. The distribution of allelic variants of RANTES in controls, UPs, and LTNPs, respectively, was 3%, 2%, and 5% for -28G; 4%, 2%, and 2% for -109C; and 18%, 18%, and 18% for -403A (P = not significant). The differences were still nonsignificant when we exclusively analyzed individuals not carrying the CCR5Delta32 allele. We conclude that LTNP of more than 16 years is not associated with SNPs in the RANTES gene promoter in white Spanish HIV-1-infected subjects.

HIV and the chemokine system: 10 years later

The unexpected encounter, 10 years ago, between human immunodeficiency virus (HIV) and the chemokine system has dramatically advanced our understanding of the pathogenesis of AIDS, opening new perspectives for the development of effective prophylactic and therapeutic measures. To initiate infection, the HIV-1 external envelope glycoprotein, gp120, sequentially interacts with two cellular receptors, CD4 and a chemokine receptor (or coreceptor) like CCR5 or CXCR4. This peculiar two-stage receptor-interaction strategy allows gp120 to maintain the highly conserved coreceptor-binding site in a cryptic conformation, protected from neutralizing antibodies. The differential use of CCR5 and CXCR4 defines three HIV-1 biological variants (R5, R5X4, X4), which vary in their prevalence during the disease course. The evolutionary choice of HIV-1 to exploit chemokine receptors as cellular entry gateways has turned their chemokine ligands into endogenous antiviral factors that variably modulate viral transmission, disease progression and vaccine responses. Likewise, the natural history of HIV-1 infection is influenced by specific polymorphisms of chemokine and chemokine-receptor genes. The imminent clinical availability of coreceptor-targeted viral entry inhibitors raises new hope for bridging the gap towards a definitive cure of HIV infection.

CCL5 Modulates Pneumococcal Immunity and Carriage

Understanding the requirements for protection against pneumococcal carriage and pneumonia will greatly benefit efforts in controlling these diseases. Recently, it has been shown that genetic polymorphisms can result in diminished expression of CCL5, which results in increased susceptibility to and progression of infectious diseases. We show that CCL5, together with Th cytokine mRNA expression, is temporally up-regulated during pneumococcal carriage. To determine the contribution of CCL5 to pneumococcal surface antigen A-specific humoral and cellular pneumococcal immunity, mice were treated with anti-CCL5 or control Abs before and during Streptococcus pneumoniae strain EF3030-challenge for the initiation of carriage. CCL5 blockade resulted in a decrease of CD4(+) and CD8(+) T cells as well as CD11b(+) cells in the spleen, cervical lymph node, lung, and nasopharyngeal associated lymphoid tissue during the recognition phase of the pneumococcal adaptive immune response. CCL5 blockade significantly reduced the Ag-specific IgG2a and IgG1 Abs in serum and IgA Ab levels in nasal washes. These decreases also corresponded to reductions in Ag-specific T cell (mucosal and systemic) responses. CCL5 inhibition resulted in decreasing the quantity of IL-4- and IFN-gamma-secreting CD4(+) T cells and increasing the number of Ag-specific IL-10-producing CD4(+) T cells; these changes combined also corresponded with the transition from pneumococcal carriage to lethal pneumonia. These data suggest that CCL5 is an essential factor for the induction and maintenance of protective pneumococcal immunity.

Protective effects of IL4-589T and RANTES-28G on HIV-1 disease progression in infected Thai females

OBJECTIVE

To evaluate the effect of polymorphisms in interleukin-4 (IL4) and RANTES promoters on disease progression in HIV-1 infected Thais.

DESIGN

Antiretroviral (ARV) drug-free HIV-1 infected females from the prospective cohort.

METHODS

A total of 246 DNA samples were genotyped for IL4 and RANTES promoter polymorphisms by PCR-RFLP. Associations of genotype with HIV-1 disease progression were assessed with respect to baseline clinical data including plasma HIV-1 load, CD4 cell counts, and proportion of symptomatic/AIDS, and survival status during 3 years of follow-up.

RESULTS

Patients with homozygous IL4-589T allele showed a significantly lower HIV-1 viral load (P = 0.005) and a higher CD4 cell count (P = 0.003) than the other patients with heterozygous IL4-589C/T or homozygous IL4-589C allele. Kaplan-Meier analysis demonstrated an apparent but insignificant trend towards better survival in homozygous IL4-589T patients. On the other hand, patients with RANTES-28G allele showed a significantly better survival while those with RANTES In1.1C allele without RANTES-28G showed a significantly poorer survival compared with those who did not possess either RANTES In1.1C or RANTES-28G (P = 0.02), although those polymorphisms only weakly associated with baseline viral load and CD4 cell counts.

CONCLUSIONS

Our results implicate the significant protective effect of IL4-589T and RANTES-28G on HIV disease progression in Thais. In contrast, RANTES In1.1C without RANTES-28G had an accelerating effect on HIV disease progression.

Genetics of allergic disease

Currently, more than 20.3 million Americans report having asthma and an even greater number suffer from allergies. The cost for treatment of these dis-eases in the United States is greater than $8 billion with more than 40% of this total representing drug expenditure [59]. An intense effort has been made to understand the genetic components of asthma and allergies and how the identified genetic differences influence disease progression and response to drugs. In the future, it will be possible in the clinical setting to analyze a patient's genetic repertoire. From this information, the physician will gain in-sight into the genes involved in producing that subject's allergic and asthmatic phenotype; understand the natural history of that patient's disease;and predict responses (positive and negative) to pharmacologic agents. The end result will be the ability to tailor a specific treatment regime for each patient and reduce the overall cost of health care related to allergies and asthma.

Host genetics of HIV-1 susceptibility

Susceptibility to HIV-1 and the rate of disease progression reflect the influence of the genetic diversity of the virus as well as the variation in host factors. The virus will co-evolve with the host, escaping and adapting to host-determined influences. Dominant host factors currently identified include diversity in the major histocompatibility complex class I, and alleles of chemokine, chemokine receptor and cytokine genes. Recent work proposes new variants in life cycle genes and in antiviral innate defense, which modify HIV-1 susceptibility. Comparative genomics generates information on host cell barriers that may explain the current distribution of these viruses among human and nonhuman primates. A greater understanding of the genetic basis of human susceptibility to HIV-1 contributes to an understanding of the pathogenesis of the disease, helps identify new targets for prophylaxis and vaccine development and will lead to predictive tools to identify those at risk of rapid disease progression.

Use of a combined ex vivo/in vivo population approach for screening of human genes involved in the human immunodeficiency virus type 1 life cycle for variants influencing disease progression

Humans differ substantially with respect to susceptibility to human immunodeficiency virus type 1 (HIV-1). We evaluated variants of nine host genes participating in the viral life cycle for their role in modulating HIV-1 infection. Alleles were assessed ex vivo for their impact on viral replication in purified CD4 T cells from healthy blood donors (n = 128). Thereafter, candidate alleles were assessed in vivo in a cohort of HIV-1-infected individuals (n = 851) not receiving potent antiretroviral therapy. As a benchmark test, we tested 12 previously reported host genetic variants influencing HIV-1 infection as well as single nucleotide polymorphisms in the nine candidate genes. This led to the proposition of three alleles of PML, TSG101, and PPIA as potentially associated with differences in progression of HIV-1 disease. In a model considering the combined effects of new and previously reported gene variants, we estimated that their effect might be responsible for lengthening or shortening by up to 2.8 years the period from 500 CD4 T cells/mul to <200 CD4 T cells/mul.

Global human genetics of HIV-1 infection and China

Genetic polymorphisms in human genes can influence the risk for HIV-1 infection and disease progression, although the reported effects of these alleles have been inconsistent. This review highlights the recent discoveries on global and Chinese genetic polymorphisms and their association with HIV-1 transmission and disease progression.

Molecular and cellular mechanisms of neuronal cell death in HIV dementia

The deaths of neurons, astrocytes and endothelial cells have been described in patients with HIV (human immunodeficiency virus) dementia. HIV-1 does not infect neurons; instead, neurotoxic substances shed by infected glia and macrophages can induce a form of programmed cell death called apoptosis in neurons. These neurotoxins include the HIV-1 proteins Tat and gp120, as well as pro-inflammatory cytokines, chemokines, excitotoxins and proteases. In this article we review the evidence for apoptosis of various cell types within the brain of HIV-infected patients, and describe in vitro and in vivo experimental studies that have elucidated the mechanisms by which HIV causes apoptosis of brain cells.

Polymorphisms in the promoter region of RANTES in Han Chinese and their relationship with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex multisystem autoimmune disease afflicting more than 600,000 individuals in China. RANTES (regulated on activation, normal T cell expressed and secreted, 17q11.2-q12) is a member of the proinflammatory cytokine family known as "chemokines". It plays an important role in the attraction and recruitment of lymphocytes, monocytes and eosinophils to sites of inflammation. A total of 146 SLE patients and 159 random healthy volunteer individuals in Han Chinese patients were enrolled in this study. Genotypes of RANTES -403 locus and -28 locus were observed to be different in all racial groups. The frequency of individuals who possessed G allele at -28 locus among SLE patients was not significantly different from that among normal controls. A total of seven compound genotypes at -403 locus and -28 locus were observed in this study. The frequency of this compound genotype (-403 G/G, -28 C/C) was different between the two groups. The distribution of genotypes and alleles at RANTES-403 locus was observed to be significantly different between renal damaged group and no renal damaged group (P<0.05), while there was no significant difference in distribution of genotypes and alleles at RANTES-28 locus between the two groups. These results suggest that (a) two genetic polymorphisms in the RANTES promoter do not correlate with SLE as individual polymorphisms. (b) interaction of the polymorphisms at two loci probably exerts a risk effect against SLE and (c) polymorphism at RANTES-403 locus is probably related with renal damage.

Association of IL-13, RANTES, and leukotriene C4 synthase gene promoter polymorphisms with asthma and/or atopy in African Americans

PURPOSE

IL-13, RANTES (Regulated on Activation, Normal T cells Expressed and Secreted), and cysteinyl leukotrienes are asthma and atopy mediators. Two RANTES -403(G to A) and -28(C to G), an -1055 IL-13(C to T), and a -444(A to C) leukotriene C4 synthase (LTC4S) single nucleotide polymorphisms (SNPs) have been shown in Caucasians and Asians as asthma and atopy risk factors. We studied these SNPs in African Americans with asthma and/or atopy.

METHODS

We studied 61 patients with asthma and/or atopy and 129 to 157 newborn controls for the -403 RANTES, -28 RANTES, and -1055 IL-13 SNPs, as well as 47 patients and 60 newborn controls for the -444 LTC4S SNP.

RESULTS

The two groups did not significantly differ at the genotypes of the -403 and -28 RANTES SNP. On the other hand, the mutant TT genotype for the -1055 IL-13 SNP was detected in 19.7% of patients versus 12.7% in controls (P < 0.04, OR 2.9, 95% CI 1.0-8.0), and the mutant T allele in 58.3% versus 36.6% in controls (P < 0.02, OR 2.4, 95% CI 1.1-5.2). In a similar fashion, for the -444 LTC4S SNP, the mutant AC genotype was detected in 19.1% versus 10.0% in controls (P > 0.28); mutant C allele had an OR of 2.1 (95% CI 0.7-6.3).

CONCLUSION

African American asthmatics/atopics had higher frequency of the TT mutant gene for the -1055 IL-13 SNP and of its mutant T allele. Regarding the -444 LTC4S SNP, there was a definite difference, although not statistically significant, with an OR of 2.1 for the mutant AC genotype in patients. If these findings become reproduced by larger studies, it may suggest that IL-13 and LTC4S SNPs can be used as predictive markers for asthma/atopy in African Americans.

Cytokine and chemokine gene polymorphisms among ethnically diverse North Americans with HIV-1 infection

Twenty-four common single nucleotide polymorphisms (SNPs) in 10 cytokine and chemokine genes were defined in 579 North Americans at high risk of HIV-1 infection due to sexual behavior and injection drug use. Among the 3 major ethnic (African-American, Hispanic/Latino, and other) groups involved, HIV-1-seropositive individuals differed significantly from ethnically matched HIV-1-seronegative individuals (odds ratios = 2.13-4.82; P = 0.003-0.05) for several SNPs and haplotypes defined at the IL4, IL4R, IL6, IL10, CCL5 (RANTES), and CXCL12 (SDF1) loci. In addition, the homozygous IL4-590T/T genotype was associated with higher (+87-131 cells/microL) CD4 T-cell counts in HIV-1-infected and AIDS-free adolescents not receiving antiretroviral therapy (adjusted P = 0.004). No SNPs at IFNG, IL2, IL12B, TNF, or CCL2 (MCP1) showed any association with HIV-related outcomes. Additional typing for IL1A, IL1B, IL1R1, IL1RN, and TGFB1 SNPs also failed to demonstrate any influence on HIV-1 infection or virologic/immunologic control in more selected patient groups. Coupled with previous findings, our data suggest that heritable IL4 and IL10 variations may contribute to the acquisition or progression of HIV infection and that the effects of other targeted loci in the cytokine and chemokine system cannot be established unequivocally in the study populations.

Chemokines and their receptors: roles in specific clinical conditions and measurement in the clinical laboratory

Considerable progress has been achieved in our knowledge of the function of the chemokine system and in understanding its role in the pathophysiology of human diseases. This complex system, presently including approximately 50 cytokines and 20 receptors, coordinates leukocyte recruitment in a variety of human diseases, ranging from infectious and inflammatory diseases to cancer. A large body of literature has been published describing various assays for the measurement of chemokines in biologic fluids and tissues. We review information available on the role of chemokines in selected human diseases and provide examples of clinical situations in which chemokine determination might be of practical value, and we describe the currently available assays for their measurement.

Association study of functional genetic variants of innate immunity related genes in celiac disease

Background

Recent evidence suggest that the innate immune system is implicated in the early events of celiac disease (CD) pathogenesis. In this work for the first time we have assessed the relevance of different proinflammatory mediators typically related to innate immunity in CD predisposition.

Methods

We performed a familial study in which 105 celiac families characterized by the presence of an affected child with CD were genotyped for functional polymorphisms located at regulatory regions of IL-1α, IL-1β, IL-1RN, IL-18, RANTES and MCP-1 genes. Familial data was analysed with a transmission disequilibrium test (TDT) that revealed no statistically significant differences in the transmission pattern of the different genetic markers considered.

Results

The TDT analysis for IL-1α, IL-1β, IL-1RN, IL-18, and MCP-1 genes genetic variants did not reveal biased transmission to the affected offspring. Only a borderline association of RANTES promoter genetic variants with CD predisposition was observed.

Conclusion

Our results suggest that the analysed polymorphisms of IL-1α, IL-1β, IL-1RN, IL-18, RANTES and MCP-1 genes do not seem to play a major role in CD genetic predisposition in our population.

Preferential transmission and association of the -403 G --> A promoter RANTES polymorphism with atopic asthma

Asthma is a complex inherited disease. The study was undertaken to identify the association of RANTES promoter polymorphisms with atopy and asthma using family-based association tests (FBATs) and generation-specific case-control analyses. We identified 154 nuclear families (453 individuals) in whom we established RANTES promoter status using the RFLP-PCR method. Of the two known promoter polymorphisms -403G/A and -28C/G, only the former appeared with a clinically relevant frequency. A total of 61 families were eligible for assessment of transmission of the allele with asthma and atopy by the pedigree disequilibrium test (PDT). Overall, allele frequency for -403A was 38.3% and 84 of 89 (94.3%) alleles were transmitted with physician diagnosed asthma (PDA) (P=0.001). All 89 children with atopy received the mutant allele, which was more than expected following Mendelian Laws of transmission (P=0.0001). In 303 unrelated parents, significant associations of the mutant allele were for atopy with or without asthma (P=0.001). In 150 unrelated children, significant associations were for atopy alone (P=0.001) and asthma (P=0.001). No associations were found for bronchial hyper-responsiveness (BHR). The -403 G --> A is transmitted with atopy and atopic asthma, although its contribution appears to relate more to atopy than asthma and BHR.

RANTES G-401A polymorphism is associated with allergen sensitization and FEV1 in Chinese children

G-401A polymorphism in RANTES promoter was associated with near-fatal asthma and atopic dermatitis in children. We studied whether gain-of-function mutations in RANTES gene were associated with asthma and atopy-related traits in Chinese children. Plasma total and aeroallergen-specific IgE concentrations were measured using micro-particle immunoassay and fluorescent enzyme immunoassay, respectively. Restriction fragment length polymorphism was used to genotype RANTES G-401A and C-28G. One hundred and twenty-nine asthmatic children and 66 controls were recruited. Their mean logarithmic plasma total IgE concentrations were 2.53 and 1.98, respectively (P<0.0001). RANTES G-401A was not associated with physician-diagnosed asthma (P = 0.408). However, RANTES G-401A allele was significantly associated with IgE sensitization to cat (odds ratio 2.35; 95% CI 1.15-4.77; P = 0.010). Those homozygous for -401A had higher plasma cat-specific IgE levels (P = 0.034). Subjects having -401A were also more likely to have mold-specific IgE (odds ratio 3.82; 95% CI 1.24-12.14; P = 0.007). On spirometry, those with -401A/ A had lower forced expiratory volume in 1-s (FEV1; P = 0.044). RANTES C-28G was not associated with any outcome in this study. In conclusion, the gain-of-function mutation at -401 of RANTES promoter is associated with sensitization to cat and mold allergens and FEV1 in Chinese children.

Soluble chemokine CCR5 receptor is present in human plasma

In view of the natural resistance to infection by HIV and occasional delayed clinical manifestation of the disease, as also the fact that the virus is able to enter only cells that express CD4 and a co-receptor, we initiated a search for a soluble co-receptor that might compete with its membrane counterpart. Using a sandwich ELISA system, a soluble human CCR5 receptor (sCCR5) was indeed detected in the circulation. Immunoprecipitation of sCCR5-positive plasma samples from Israelis of Ethiopian and non-Ethiopian origin with mAb 2D7, a conformation-dependent anti-CCR5 antibody, revealed the presence of an approximately 22 kDa protein. A panel of antibodies directed against the membrane receptor was used to characterize the structure of the soluble CCR5: mAb CTC8, recognizing the N-terminal sequence of the protein, 10YDIN13; "multidomain" mAbs FAB181B and FAB183B that are dependent upon the presence of Q93 and D95 in ECL1 and K171 and E172 in ECL2A, and mAb FAB182B, recognizing the stretch 184YSQYQF189, which spans the C-terminal part of the second extracellular loop. The presence of short soluble CCR5 in human plasma has not been previously described. Among HIV-negative non-Ethiopian Israelis, 20.4% were sCCR5-positive, as against only 10.5% in HIV-positives. However, 7.1% of HIV-negative Ethiopian Israelis were sCCR5 positive, as were 5.6% HIV-positives. Plasma concentrations of MIP-1beta, the CCR5 agonist, were twice as high in sCCR5-positives (140.8+/-25.8 pg/ml) as in the sCCR5-negatives (77.6+/-11.0 pg/ml, P=0.0157). A significant positive correlation between plasma levels of sCCR5 and MIP-1beta was found (Fig. 4, r=0.8, P<0.0001).

The effect of RANTES chemokine genetic variants on early HIV-1 plasma RNA among African American injection drug users

HIV-1 plasma RNA is a prognostic indicator of HIV-1, and increased levels of HIV-1 plasma RNA are associated with rapid progression to AIDS. Because chemokines and chemokine receptors are involved in the binding and entry of HIV-1, possible effects of host genetics on viral RNA levels should be visible in early infection. HIV-1 plasma RNA was measured within 2 years of seroconversion in 198 seroincident injection drug users followed in the AIDS Link to Intravenous Experience cohort. Genetic variants were identified in the chemokine receptors (CCR2, CCR5, and CCR5 promoter) and the chemokine RANTES using TaqMan and restriction fragment length polymorphism assays. Linear regression of RANTES haplotypes on early HIV-1 plasma RNA identified individuals homozygous for the RANTES R1 haplotype as having a lower viral load by almost one-half log10 unit compared with those bearing non-RANTES R1 haplotypes (-0.43, 95% confidence interval: -0.74, -0.12). Genetic variants in RANTES may downregulate RANTES gene expression and increase early HIV-1 plasma RNA. Because RANTES is a critical chemokine and competitively inhibits HIV-1 by binding to its receptor CCR5, treatment to enhance RANTES expression may assist in delaying the progression of AIDS by decreasing the initial viral load.

Structure and dynamics of a predicted ferredoxin-like selenoprotein in Japanese encephalitis virus

Homologues of the selenoprotein glutathione peroxidase (GPx) have been previously identified in poxviruses and in RNA viruses including HIV-1 and hepatitis C virus (HCV). Sequence analysis of the NS4 region of Japanese encephalitis virus (JEV) suggests it may encode a structurally related but functionally distinct selenoprotein gene, more closely related to the iron-binding protein ferredoxin than to GPx, with three highly conserved UGA codons that align with essential Cys residues of ferredoxin. Comparison of the probe JEV sequence to an aligned family of ferredoxin sequences gave an overall 30.3% identity and 45.8% similarity, and was statistically significant at 4.9 S.D. (P < 10(-6)) above the average score computed for randomly shuffled sequences. A 3-dimensional model of the hypothetical JEV protein (JEV model) was constructed by homology modeling using SYBYL, based upon a high resolution X-ray structure of ferredoxin (PDB code: 1awd). The JEV model and the model from 1awd were subsequently subjected to molecular dynamics simulations in aqueous medium using AMBER 6. The solution structure of the JEV model indicates that it could fold into a tertiary structure globally similar to ferredoxin 1awd, with RMSD between the averaged structures of 1.8 A for the aligned regions. The modeling and MD simulations data also indicate that this structure for the JEV protein is energetically favorable, and that it could be quite stable at room temperature. This protein might play a role in JEV infection and replication via TNF and other cellular stimuli mediated via redox mechanisms.

Effects of single nucleotide polymorphisms in the RANTES promoter region in healthy and HIV-infected indigenous Chinese

We determined the occurrence of the single nucleotide polymorphisms (SNPs) -403A/G and -28C/G in the promoter region of RANTES in 1082 Chinese blood donors from northern and southern China and 249 HIV patients from southern China. Compared to healthy adults, Chinese AIDS patients had a significantly higher frequency of the -403G allele and haplotype I, -403G/-28C (P < 0.05), and a lower frequency of the -403A/A genotype (P < 0.01). Symptomatic patients had a higher frequency of the -28G allele and a lower frequency of the -28C/C genotype (P < or = 0.01). The plasma RANTES level was significantly lower in blood donors homozygous for haplotype I than in those who were homozygous for haplotypes II and III (P < 0.05). The frequency of the -403G allele was found to be higher in Chinese than in indigenous Africans, but lower than in Caucasians, Hispanics, and African Americans. The frequency of the -28G allele was comparable in Chinese and Japanese; this allele is rare in other ethnic groups. Results suggest that -403G may be associated with increased susceptibility to HIV infection, while -28G may be associated with advanced disease progression. The impact of SNPs on HIV infection appears to be unique in Chinese.

Influence of host genetic variation on susceptibility to HIV type 1 infection

For this review of genetic susceptibility to human immunodeficiency virus type 1 infection, far more information was available on factors involved in acquisition of the virus by an uninfected "recipient" than on propagation by the infected "donor." Genetic variation presumably alters transmission from an infected host primarily by regulating the replication of virus and the concentration of particles circulating in blood and mucosal secretions of the potential donor. Thus, the effects of host genetic variation on transmission are inextricably bound to the well-established and powerful effects on virus load at different stages of infection. Teasing apart the effects in both donors and recipients has been and will continue to be quite difficult.

Insights into the role of host genetic and T-cell factors in resistance to HIV transmission from studies of highly HIV-exposed Thais

Studies of resistance to HIV-1 transmission are likely to be valuable for the design of vaccines and other efforts to prevent HIV. Here, we review the T-cell and genetic factors associated with resistance to HIV-1 transmission in studies of highly exposed but persistently seronegative (HEPS) women from northern Thailand. Women were enrolled in two sex-worker studies and in a discordant couple study. We performed Cr51 cytotoxic T lymphocyte (CTL), interferon-gamma (IFN-gamma) ELISPOT, and proliferation assays as well as genetic studies, including HLA-class I typing. CTL and ELISPOT studies showed a skewing of T-cell responses to conserved HIV-1 proteins in HEPS, but not in HIV-1-seropositive women. T-cell responses were extremely long-lived in some HEPS women. In the two sex-worker studies, HLA-A11 was associated with resistance to HIV-1 transmission. These data provide promise for the ability of CTL to control HIV and emphasize the importance of developing HIV vaccines that stimulate strong, long-lasting Tcell responses.

Dominant Effects of CCR2-CCR5 Haplotypes in HIV-1 Disease Progression

Three haplotypes for the CCR2-CCR5 region previously have been shown to affect AIDS progression; however, it is not known if the protective and accelerating effects of the haplotypes are relatively constant throughout infection or exert their effects early or late in HIV type 1 infection. The authors report the relative contributions to AIDS progression of CCR2 64I, CCR5 Delta32, and the CCR5 promoter haplotype +.P1.+ in the GRIV cohort, which included patients representing the extremes of the distribution for AIDS progression: rapid progressors (RP) who developed CD4 T-cell counts of <300/ mm within 3 years after the last HIV-1-seronegative test and slow progressors (SP) who were HIV-1 infected for > or =8 years with CD4 T-cell counts of >500/mm. Comparing the RP with a seroconverter control group including intermediate progressors to AIDS, we observed the early protective effect of CCR5 Delta32 (odds ratio = 0.25; P = 0.007) was similar in strength to the early susceptible effect of CCR5 +.P1.+ (odds ratio = 2.1, P = 0.01). Comparison of the intermediate control group to the SP showed weaker and less significant odd ratios, suggesting that the effect of these factors tended to be stronger on early progression; the tendency towards a disproportionately early effect was significant for CCR5 Delta32 (P = 0.04) but not for CCR5 +.P1.+ (P = 0.12). Follow-up of SP demonstrated that these polymorphisms have little effect after 8 years, because the subset of SP who had progression after study entry had the same genotype distribution as the global population of SP, suggesting that factors other than CCR5 or CCR2 genetic variants must be responsible for the long-term maintenance of nonprogression.

Chemokine gene polymorphisms associate with gender in patients with uveitis

Uveitis is an inflammatory condition of ocular tissue characterized by leukocyte infiltration, tissue damage, and decreased visual acuity. Chemokines have been implicated in the pathogenesis of uveitis. Polymorphisms in the genes encoding chemokines have been described as affecting chemokine production or function. We analyzed the frequency of single-nucleotide polymorphisms (SNPs) in genes encoding CCL2 (-2518 and -2076) and CCL5 (-403 and -28) in patients with Behçet's disease (BD), a systemic form of uveitis, and patients with retinal vasculitis (RV), an organ-specific form of disease. We report that there was no association between any SNP and disease. However, when segregated on the basis of gender the CCR5 -403 AA genotype was only found in male patients with BD. Similarly, CCL2 genotypes 1/2 were predominant in males, while genotype 4 was significantly associated with disease in female patients with BD. Differences in disease symptoms and severity between males and females have been described in BD and gender-specific genetic differences in chemokine gene function may be involved.

Mycobacterium tuberculosis-induced CXCR4 and chemokine expression leads to preferential X4 HIV-1 replication in human macrophages

Opportunistic infections such as pulmonary tuberculosis (TB) increase local HIV-1 replication and mutation. As AIDS progresses, alteration of the HIV-1 gp120 V3 sequence is associated with a shift in viral coreceptor use from CCR5 (CD195) to CXCR4 (CD184). To better understand the effect of HIV/TB coinfection, we screened transcripts from bronchoalveolar lavage cells with high density cDNA arrays and found that CXCR4 mRNA is increased in patients with TB. Surprisingly, CXCR4 was predominately expressed on alveolar macrophages (AM). Mycobacterium tuberculosis infection of macrophages in vitro increased CXCR4 surface expression, whereas amelioration of disease reduced CXCR4 expression in vivo. Bronchoalveolar lavage fluid from TB patients had elevated levels of CCL4 (macrophage inflammatory protein-1beta), CCL5 (RANTES), and CX3CL1 (fractalkine), but not CXCL12 (stromal-derived factor-1alpha). We found that M. tuberculosis infection of macrophages in vitro increased viral entry and RT of CXCR4-using [corrected] HIV-1, but not of CCR5-using [corrected] HIV-1. Lastly, HIV-1 derived from the lung contains CD14, suggesting that they were produced in AM. Our results demonstrate that TB produces a permissive environment for replication of CXCR4-using virus by increasing CXCR4 expression in AM and for suppression of CCR5-using HIV-1 by increasing CC chemokine expression. These changes explain in part why TB accelerates the course of AIDS. CXCR4 inhibitors are a rational therapeutic approach in HIV/TB coinfection.

Haplotype-tagging RANTES gene variants influence response to antiviral therapy in chronic hepatitis C

The response to antiviral therapy for chronic hepatitis C virus (HCV) is complex and is determined by both environmental and genetic factors. Recently, interacting gene polymorphisms of the chemokine RANTES have been shown to affect HIV disease progression. Our aim was to assess if these RANTES variants are associated with response to anti-HCV therapy. Three linked RANTES single nucleotide polymorphisms (403 G/A, Int1.1 T/C, and 3' 222 T/C) were determined in 297 Caucasian patients who were treated for chronic HCV infection and 152 control subjects. Characteristic nucleotide combinations on single chromosomes (haplotypes) were reconstructed and tested for disease association. Four common RANTES haplotypes (prevalence > 3%) were identified in patients and controls [corrected]. There was a strong association of RANTES haplotype distribution with outcome of antiviral combination therapy (P = .007). Specifically, RANTES haplotypes carrying Int1.1 C and 3' 222 C alleles were more frequent in nonresponders than in patients with a sustained response to antiviral therapy (odds ratio 1.9, P = .01). The influence of these RANTES haplotypes on the outcome of therapy was more pronounced in patients infected with HCV genotypes 1 and 4 (odds ratio 2.3, P = .02). Because RANTES haplotypes carrying Int1.1 C are known to down-regulate RANTES transcriptional activity in vitro, the haplotype analysis fits the hypothesis of a diminished T helper 1 lymphocyte response in patients with a negative response to antiviral therapy. In conclusion, RANTES haplotypes might contribute to the polygenic interaction between HCV and the host immune system and could help to risk stratify patients prior to antiviral therapy.

Persistence of low levels of simian immunodeficiency virus in macaques that were transiently viremic by conventional testing

Transient SIV viremia after experimental SIV challenge has been documented. Whether SIV persists in these transiently viremic macaques remains unclear. In the present study, we applied a sensitive PCR and found persistent low levels of SIVmne infection (LLSI) (range: 0.1-5.3 SIV DNA copies/10(6) PBMC) in seven macaques that were transiently positive by conventional assays, which was 10(2)- to 10(6)-fold less than those of SIVmne infected monkeys with typical disease progression. SIV envelope V1 sequences remained homogeneous in these macaques for the 6-year study period, with a mean evolution rate of 0.005% per site per year, which was not different from zero (P = 0.612) and significantly lower than that (0.56-1.18%) in macaques with progressive infection of SIVmne. LLSI macaques have remained free from SIV-associated illness, and are still alive 10 years after virus inoculation. Understanding the mechanisms underlying this outcome may provide valuable insight into therapy and vaccine development.

The role of chemokines in atherosclerosis: recent evidence from experimental models and population genetics

PURPOSE OF REVIEW

Atherosclerosis is an inflammatory disease process. This review discusses the recent genetic evidence from animal models and human populations that highlight the importance of chemokines in atherosclerosis.

RECENT FINDINGS

CC-chemokine/CC-chemokine receptors (CCR), including CCR2/ MCP-1 (monocyte chemoattractant protein-1) and CCR5/RANTES (regulated on activation, normal T-cell expressed and secreted), have been shown in animal knockout and transgenic studies to have significant effects on atherosclerotic lesion size and macrophage recruitment. More recently fractalkine (CX3C1) and its receptor (CX3CR1) have emerged as another important pathway in atherosclerosis. For example, fractalkine is present in human atherosclerotic lesions and is able to stimulate platelet activation and adhesion. CX3CR1 is expressed on human aortic smooth muscle cells and CX3CR1/apolipoprotein E double knockout mice have significantly reduced atherosclerotic lesion size and macrophage recruitment. Human population genetic studies have tried to assess the importance of chemokines in human atherosclerosis. Currently, there is conflicting evidence regarding an association between polymorphisms in CCR2/MCP-1 and CCR5/RANTES and coronary artery disease. There is evidence, however, for an association between the fractalkine receptor polymorphism (CX3CR1-I249) and coronary artery disease in both human population and function studies.

SUMMARY

Recent transgenic and gene knockout studies in murine models of atherosclerosis have highlighted the importance of chemokines and their receptors in atherosclerosis. Genetic evidence for a role of chemokines and their receptors in human population studies remains under investigation. Identifying chemokine polymorphisms could help to determine pathways that are important in atherosclerosis disease pathology and that may suggest novel therapeutic targets.

Evidence for a cluster of genes on chromosome 17q11–q21 controlling susceptibility to tuberculosis and leprosy in Brazilians

The region of conserved synteny on mouse chromosome 11/human 17q11-q21 is known to carry a susceptibility gene(s) for intramacrophage pathogens. The region is rich in candidates including NOS2A, CCL2/MCP-1, CCL3/MIP-1alpha, CCL4/MIP-1beta, CCL5/RANTES, CCR7, STAT3 and STAT5A/5B. To examine the region in man, we studied 92 multicase tuberculosis (627 individuals) and 72 multicase leprosy (372 individuals) families from Brazil. Multipoint nonparametric analysis (ALLEGRO) using 16 microsatellites shows two peaks of linkage for leprosy at D17S250 (Z(lr) score 2.34; P=0.01) and D17S1795 (Z(lr) 2.67; P=0.004) and a single peak for tuberculosis at D17S250 (Z(lr) 2.04; P=0.02). Combined analysis shows significant linkage (peak Z(lr) 3.38) at D17S250, equivalent to an allele sharing LOD score 2.48 (P=0.0004). To determine whether one or multiple genes contribute, 49 informative single nucleotide polymorphisms were typed in candidate genes. Family-based allelic association testing that was robust to family clustering demonstrated significant associations with tuberculosis susceptibility at four loci separated by intervals (NOS2A-8.4 Mb-CCL18-32.3 kb-CCL4-6.04 Mb-STAT5B) up to several Mb. Stepwise conditional logistic regression analysis using a case/pseudo-control data set showed that the four genes contributed separate main effects, consistent with a cluster of susceptibility genes across 17q11.2.

Human immunodeficiency virus type 1 fitness is a determining factor in viral rebound and set point in chronic infection

Human immunodeficiency virus type 1 (HIV-1) isolates from 20 chronically infected patients who participated in a structured treatment interruption (STI) trial were studied to determine whether viral fitness influences reestablishment of viremia. Viruses derived from individuals who spontaneously controlled viremia had significantly lower in vitro replication capacities than viruses derived from individuals that did not control viremia after interruption of antiretroviral therapy (ART), and replication capacities correlated with pre-ART and post-STI viral set points. Of note, no clinically relevant improvement of viral loads upon STI occurred. Virus isolates from controlling and noncontrolling patients were indistinguishable in terms of coreceptor usage, genetic subtype, and sensitivity to neutralizing antibodies. In contrast, viruses from controlling patients exhibited increased sensitivity to inhibition by chemokines. Sensitivity to inhibition by RANTES correlated strongly with slower replication kinetics of the virus isolates, suggesting a marked dependency of these virus isolates on high coreceptor densities on the target cells. In summary, our data indicate that viral fitness is a driving factor in determining the magnitude of viral rebound and viral set point in chronic HIV-1 infection, and thus fitness should be considered as a parameter influencing the outcome of therapeutic intervention in chronic infection.

Association studies for asthma and atopic diseases: a comprehensive review of the literature

Hundreds of genetic association studies on asthma-related phenotypes have been conducted in different populations. To date, variants in 64 genes have been reported to be associated with asthma or related traits in at least one study. Of these, 33 associations were replicated in a second study, 9 associations were not replicated either in a second study or a second sample in the same study, and 22 associations were reported in just a single published study. These results suggest the potential for a great amount of heterogeneity underlying asthma. However, many of these studies are methodologically limited and their interpretation hampered by small sample sizes.

Association of genetic variants of the chemokine receptor CCR5 and its ligands, RANTES and MCP-2, with outcome of HCV infection

The effect of host genetic variation on the outcome of hepatitis C virus (HCV) infection and its treatment is poorly understood. The chemokine receptors CCR5, CCR2, and CCR3 and their ligands, RANTES, MCP-1, MCP-2, and MIP-1alpha, are involved in the immune responses and the selective recruitment of lymphocytes to the liver in HCV infection. We studied 20 polymorphisms within these genes and investigated their association with persistent carriage of HCV, severity of liver disease, hepatic inflammation, and response to treatment in a large European cohort. Significant associations were found between CCR5-delta32 and reduced portal inflammation (P =.011, odds ratio [OR]: 2.3, 95% confidence interval [CI]: 1.09-4.84) and milder fibrosis (P =.015, OR: 1.97, 95% CI: 1.13-3.42). A promoter polymorphism at position -403 in the RANTES gene was associated with less severe portal inflammation (P =.004). An amino acid change in MCP2, Q46K, was associated with severity of fibrosis (P =.018, OR: 2.29, 95% CI: 1.14-4.58). In conclusion, our study suggests a possible role of the polymorphisms CCR5-delta32, RANTES -403, and MCP-2 Q46K in the outcome of HCV infection.

Rapid detection of the CCR2-V64I, CCR5-A59029G and SDF1-G801A polymorphisms by tetra-primer PCR

OBJECTIVE

To develop tetra-primer PCR assays for detection of the CCR2-V64I, CCR5-A59029G and SDF1-G801A polymorphisms associated with HIV pathogenesis.

DESIGN AND METHODS

For each assay, two primers for the amplification of the gene locus are combined in one tube with two primers for the subsequent allele specific amplification (ASA). In the first set of cycles, pre-amplification of the gene region of interest is ensured by the gene specific primers. In the second set of cycles, lowering the annealing temperature allows ASA on the newly produced template.

RESULTS

Analysis of 90 DNA samples resulted in allele frequencies for CCR2-V64I, CCR5-A59029G and SDF1-G801A which are similar to other Caucasian cohorts. Furthermore, re-analysis of sequenced genomic DNA by tetra-primer PCR analysis (7-11 times) always showed identical results.

CONCLUSION

Our set of single-tube assays allows rapid and reproducible genotyping of the CCR2-V64I, CCR5-A59029G and SDF1-G801A polymorphisms. These inexpensive but accurate assays are valuable for screening these polymorphisms in cohorts of HIV-infected patients.

Polymorphism of human and primate RANTES, CX3CR1, CCR2 and CXCR4 genes with regard to HIV/SIV infection

Among genes that influence human susceptibility to HIV (human immunodeficiency virus) infection or AIDS (acquired immunodeficiency syndrome) progression, chemokine-receptor and chemokine genes were extensively studied because of their role as HIV co-receptors or co-receptor competitors, respectively. We have studied in non-human primates (chimpanzee, gorilla, gibbon, orang-utan, crab-eating and rhesus macaque, baboon and marmoset) the RANTES, CCR2 and CX3CR1 gene sequences in regions surrounding human mutations that were associated with susceptibility to HIV or AIDS progression: RANTES G-403A and C-28G, CCR2 V64I, CX3CR1 V249I and CX3CR1 T280M. Among these five dimorphisms, only RANTES G-403A is observed in one of the eight primate species studied here (gibbon). This suggests that these mutations appeared recently in humans and probably do not account for variable HIV/SIV disease progression in primates. It is noteworthy that chimpanzees, which are naturally resistant to HIV-1- and HIV-2-induced AIDS, do not have the human mutations associated with delayed disease progression. Inter-species and intra-species polymorphic positions are observed in primates and we discuss the potential impact of these mutations on HIV/SIV disease progression. Particularly, we identified polymorphisms in old-world monkey (OWM) genes, and it could be of great importance to analyse the possible association between these polymorphisms and disease progression in OWM species that are currently used in research for HIV vaccine and therapy.

Host genetic factors in the clinical course of HIV-1 infection: chemokines and chemokine receptors

The outcome of HIV-1 infection is highly variable: not all individuals exposed to HIV-1 will become infected, and among individuals who do become infected, the time from seroconversion to AIDS diagnosis is highly variable. Some patients may develop AIDS within 3 years, whereas others may remain asymptomatic for over 15 years. The reasons for these differences are not fully understood, but are thought to reflect the complex interactions between virus and host. In recent years, an important role for host genetic factors in the pathogenesis of HIV-1 infection has increasingly been appreciated. Many novel genetic polymorphisms have been identified and analyzed for their role in HIV-1 transmission and disease progression. In this review, we will give an update of the current knowledge on the role of such polymorphisms in HIV-1 disease. As recent research in this field has focussed on polymorphisms in chemokine and chemokine receptor genes, this will be the main theme of our review.

Persistence of extraordinarily low levels of genetically homogeneous human immunodeficiency virus type 1 in exposed seronegative individuals

Some individuals remain inexplicably seronegative and lack evidence for human immunodeficiency virus type 1 (HIV-1) infection by conventional serologic or virologic testing despite repeated high-risk virus exposures. Here, we examined 10 exposed seronegative (ES) individuals exhibiting HIV-1-specific cytotoxicity for the presence of HIV-1. We discovered HIV-1 DNA in resting CD4(+) T cells (mean, 0.05 +/- 0.01 copies per million cells) at multiple visits spanning 69 to 130 weeks in two ES individuals at levels that were on average 10(4)- to 10(6)-fold lower than those of other HIV-1-infected populations reported. Sequences of HIV-1 envelope and gag genes remained markedly homogeneous, indicating little to undetectable virus replication. These results provide the evidence for HIV-1 infection in ES individuals below the detection limit of standard assays, suggesting that extraordinary control of infection can occur. The two HIV-infected ES individuals remained healthy and were not superinfected with other HIV-1 strains despite continued high-risk sexual exposures to multiple HIV-infected partners. Understanding the mechanisms that confer diminished replicative capacity of HIV-1 in these hosts is paramount to developing strategies for protection against and control of HIV-1 infection.

The RANTES promoter polymorphism: a genetic risk factor for near-fatal asthma in Chinese children

BACKGROUND

RANTES promoter polymorphisms were found associated with asthma/atopy in some studies but not others, possibly reflecting the genetic heterogeneity among different ethnicities and different asthma severity.

OBJECTIVE

The purpose of this investigation was to test the genetic association between the RANTES -28C/G and -403G/A polymorphisms and asthma/atopy in a cohort of Chinese children, with particular emphasis on those patients who had experienced life-threatening asthma attacks.

METHODS

Forty-eight children with near-fatal asthma, 134 children with mild-to-moderate asthma, 69 children with allergic disorders but no asthma, and 107 nonasthmatic nonatopic control children were genotyped through use of a PCR-based assay.

RESULTS

No significant difference was demonstrated for frequency of the RANTES -28C/G polymorphism when the mild-to-moderate asthma, atopic/nonasthmatic, and normal control groups were compared. The RANTES -28G allele was present in a significantly higher proportion of the children with near-fatal asthma compared with the nonasthmatic nonatopic controls (odds ratio, 2.93 [1.41-6.06]; P =.006) and the children with mild-to-moderate asthma (odds ratio, 3.52 [1.73-7.16]; P =.001). The frequency of -28G allele carriage correlated with asthma severity. The RANTES -28G allele was also associated with an increased blood eosinophil count and a higher degree of bronchial hyperresponsiveness. The RANTES -403G/A polymorphism did not influence asthma/atopy susceptibility, blood eosinophil count, or bronchial hyperresponsiveness. Interestingly, a higher frequency of -403A allele carriage was observed in the moderate asthma subgroup compared with the mild asthma analog.

CONCLUSIONS

We conclude that the RANTES -28C/G polymorphism exacerbates asthma severity, representing a genetic risk factor for life-threatening asthma attacks in Chinese children. In addition, the linkage disequilibrium between these 2 polymorphisms is a potential confounder that must be considered in the design and interpretation of RANTES gene association studies.

Fluorescence resonance energy transfer analysis of the RANTES polymorphisms -403G --> A and -28G --> C: evaluation of both variants as susceptibility factors to HIV type 1 infection in the Spanish population

The identification of genetic factors predisposing or protecting against HIV-1 infection has been an important aim in AIDS research. Two of these factors are located in the promoter region of the CCL5 gene, which encodes the RANTES (regulated on activation, normal T cells expressed and secreted) chemokine, an inhibitor agent for M-tropic HIV-1 strains. More specifically, the role of single-nucleotide polymorphisms (SNPs) -403G --> A and -28C --> G has been evaluated in the course of HIV-1 infection in several populations with different genetic, geographic, and ethnic backgrounds. Here we present a fast, simple, reliable, and efficient method for the simultaneous genotyping of these two CCL5 variants. A case-control study has been performed to evaluate the role of -403G --> A and -28C --> G as susceptibility factors for HIV-1 infection in the Spanish population. No differences have been found in the allelic frequencies of either variant or in the haplotype/genotype distribution between patients and controls. These data would be consistent with a lack of association between these SNPs and HIV-1 infection in our population.

Clinical, cellular, and molecular aspects of cancer invasion

Invasion causes cancer malignancy. We review recent data about cellular and molecular mechanisms of invasion, focusing on cross-talk between the invaders and the host. Cancer disturbs these cellular activities that maintain multicellular organisms, namely, growth, differentiation, apoptosis, and tissue integrity. Multiple alterations in the genome of cancer cells underlie tumor development. These genetic alterations occur in varying orders; many of them concomitantly influence invasion as well as the other cancer-related cellular activities. Examples discussed are genes encoding elements of the cadherin/catenin complex, the nonreceptor tyrosine kinase Src, the receptor tyrosine kinases c-Met and FGFR, the small GTPase Ras, and the dual phosphatase PTEN. In microorganisms, invasion genes belong to the class of virulence genes. There are numerous clinical and experimental observations showing that invasion results from the cross-talk between cancer cells and host cells, comprising myofibroblasts, endothelial cells, and leukocytes, all of which are themselves invasive. In bone metastases, host osteoclasts serve as targets for therapy. The molecular analysis of invasion-associated cellular activities, namely, homotypic and heterotypic cell-cell adhesion, cell-matrix interactions and ectopic survival, migration, and proteolysis, reveal branching signal transduction pathways with extensive networks between individual pathways. Cellular responses to invasion-stimulatory molecules such as scatter factor, chemokines, leptin, trefoil factors, and bile acids or inhibitory factors such as platelet activating factor and thrombin depend on activation of trimeric G proteins, phosphoinositide 3-kinase, and the Rac and Rho family of small GTPases. The role of proteolysis in invasion is not limited to breakdown of extracellular matrix but also causes cleavage of proinvasive fragments from cell surface glycoproteins.

RANTES promoter genotype is associated with diabetic nephropathy in type 2 diabetic subjects

OBJECTIVE

To evaluate the effect of RANTES gene promoter polymorphism and RANTES receptor (CCR5 gene) promoter polymorphism on diabetic nephropathy in Japanese type 2 diabetic subjects.

RESEARCH DESIGN AND METHODS

A total 616 Japanese subjects with type 2 diabetes were recruited. Polymorphisms of -28 C/G and -403 G/A in the RANTES gene promoter region, and of 59029 G/A in the CCR5 gene promoter region were detected by PCR-RFLP (restriction fragment length polymorphism). The association of these genotypes with nephropathy was analyzed.

RESULTS

While the RANTES -403 genotype showed no association with nephropathy, the frequency of the -28G allele was significantly higher in the DN2 group (urinary albuminuria-to-creatinine ratio [ACR] >or=300 mg/g creatinine, serum creatinine <2.0 mg/dl) than in the DN0 (ACR <30 mg/g creatinine) and DN1 (ACR >or=30 mg/g creatinine and <300 mg/g creatinine) groups. The frequency of a RANTES -28G-positive genotype (C/G or G/G) was higher in the DN2 group than in the DN0 and DN1 groups (34% vs. 25 and 20%, P = 0.0268, chi(2) = 4.905), and the frequency of a CCR5 59029 A-positive genotype (G/A or A/A) was higher in the DN1 and DN2 groups than in the DN0 group (84 and 85% vs. 76%, P = 0.0123, chi(2) = 6.269). Discriminant analysis showed that the RANTES -28G-positive genotype and CCR5 59029A-positive genotype were independently associated with nephropathy. The percentage of macroalbuminuria was twofold higher in the subjects having -28G or 59029A and threefold higher in the subjects having -28G and 59029A than in the subjects without -28G and 59029A.

CONCLUSIONS

The RANTES promoter -28G genotype and CCR5 promoter 59029A genotype may be independent risk factors for diabetic nephropathy in patients with type 2 diabetes and may have an additive effect on nephropathy.

Host genetic profiles predict virological and immunological control of HIV-1 infection in adolescents

OBJECTIVE

To evaluate the correlation between host genetic profiles and virological and immunological outcomes among HIV-1-seropositive participants from the Reaching for Excellence in Adolescent Care and Health (REACH) cohort.

METHODS

HLA class I and chemokine coreceptor (CCR) alleles and haplotypes were resolved in 227 HIV-1-seropositive adolescents (ages 13-18 years; 75% females; 71% African-Americans) and 183 HIV-seronegative individuals, with quarterly follow-up visits between 1996 and 2000. Each HLA and CCR variant with consistent risk and protective effect on HIV-1 pathogenesis was assigned a score of -1 and +1, respectively. All individual markers and genetic scores were analyzed in relation to plasma viral load (VL) and CD4 T lymphocytes during a 6-12-month interval when no antiretroviral therapy was taken.

RESULTS

HLA-B*57 alone was a strong predictor of VL (P < 0.0001), but composite genetic profiles found in over 50% of patients consistently outperformed the individual component markers in multivariable analyses with or without adjustment for gender, race, age, and membership of clinical patient groups. Adolescents (n = 37) with a favorable combination of VL (< 1000 copies/ml) and CD4 T cell counts (> 450 x 10(6) cells/l) consistently had more positive (+1 to +2) than negative (-1 to -4) HLA and CCR scores compared with those (n = 56) with an unfavorable combination (VL > 16,000 copies/ml and CD4 cells < 450 x 10(6) cells/l) or the remainder (n = 134) of the cohort (overall P < 0.0001).

CONCLUSION

A generalizable genetic scoring algorithm based on seven HLA class I and CCR markers is highly predictive of viremia and immunodeficiency in HIV-1-infected adolescents.

Analysis of gene polymorphisms in the regulatory region of MCP-1, RANTES, and CCR5 in liver transplant recipients

Chemokines and their receptors play a major role in the inflammatory and immune responses that mediate allograft outcome. The production of some chemokines varies among individuals and these variations may be determined by genetic polymorphisms, most commonly within the regulatory region of the gene. We investigated whether the functional polymorphisms of the chemokines RANTES, MCP-1 and chemokine receptor CCR5 are associated with the incidence of acute rejection and long-term liver graft survival. Two hundred nine liver transplant recipients were genotyped using polymerase chain reaction sequence-specific primers for the following polymorphisms: RANTES-28, MCP-1 -2518, and CCR5-59029. There was no association with any of the three genotypes and the incidence of acute rejection episodes. In addition, no association of RANTES-28, MCP-1 -2518, or CCR5 -59029 variants with long-term liver graft survival was found. In conclusion, variants of RANTES-28, MCP-1 -2518, and CCR5-59029 neither influenced the incidence of acute rejection nor affected long-term allograft survival upon liver transplantation in the context of this analysis.

Vpr- and Nef-dependent induction of RANTES/CCL5 in microglial cells

Microglia are pivotal in the pathogenesis of AIDS dementia, as they serve as the major target of HIV infection in the CNS. In addition, activation of microglia correlates best with clinical dementia. Although the beta-chemokine RANTES/CCL5 is important in modulating HIV infection as well as cellular activation, no information is available regarding how its expression is regulated in microglia by HIV-1. Here we report that RANTES/CCL5 expression is induced in microglia by HIV-1, but that this requires infection by HIV-1. This conclusion was supported by (1) the delayed kinetics coinciding with viral replication; (2) the lack of effect of X4 viruses; (3) inhibition by the reverse transcriptase inhibitor AZT, and (4) the lack of effect of cytokine antagonists or antibodies. Interestingly, RANTES/CCL5 production was dependent on the viral accessory protein Vpr, in addition to Nef, demonstrating a novel role for Vpr in chemokine induction in primary macrophage-type cells. Furthermore, the specific p38 MAP kinase inhibitor SB203580 augmented chemokine expression in microglia, indicating a negative role played by p38. These data suggest unique features of RANTES/CCL5 regulation by HIV-1 in human microglial cells.

A functional polymorphism in the RANTES gene promoter is associated with the development of late-onset asthma

The CC chemokine regulated upon activation, normal T-cell expressed and secreted (RANTES) attracts eosinophils, basophils, and T cells during inflammation and immune response, indicating a possible role for this chemokine in asthma. Both the -403A and -28G alleles of the RANTES promoter region exhibit significantly enhanced promoter activity in reporter constructs in vitro. We therefore investigated the genetic influence of these alleles on the development of asthma using case-control analysis in a Japanese population (298 patients with asthma and 311 control subjects). Given the evidence for heterogeneity of asthma according to age at onset, we divided patients with asthma into three subgroups: 117 late-onset patients with asthma (onset at more than 40 years of age), 83 middle-onset patients with asthma (onset at 20 to 40 years of age), and 98 early-onset patients with asthma (onset at less than 20 years of age). The -28G allele was significantly associated with late-onset asthma (odds ratio = 2.033; 95% confidence interval, 1.379-2.998; corrected p < 0.0025) but was not associated with the other two asthma subgroups. The -403A allele was not associated with any of the asthma subgroups. Further evidence of the importance of the -28G allele was a significant increase in the production of RANTES in vitro in individuals who carried this allele. Our findings suggest that, among Japanese, the -28G allele of the RANTES promoter region confers susceptibility to late-onset asthma.