Determination of the CCR2-64I/CCR5-59653T haplotype linkage disequilibrium in a sample of Polish population

It has been reported that different polymorphisms in the regulatory regions of CCR5 and in the CCR2 gene of the chemokine receptors are associated with AIDS. We decided to determine the congruence between CCR5-59653T and CCR2-64I alleles in a group of 281 persons. Frequencies of combined CCR5-59653T and CCR2-64I haplotypes were examined in a group of 281 persons. Among 281 individuals 26 (9.3%) and 24 (8.5%) respectively were carriers of the CCR5-59653T and the CCR2-64I alleles. We also found that 24 persons (8.5%) were carriers of combined CCR2-64I/CCR5-59653T allele. The calculation of the congruence revealed that 92.0% of individuals exhibited the same genotype for both CCR2-64I and CCR5-59653T polymorphisms. Our results confirm that linkage between CCR5-59653T and CCR2-64I alleles is not absolute.     

Decreased density of the CCR5 receptor on the surface of CD4+ lymphocytes and monocytes/macrophages is associated with the CCR5-59653T transition in the promoter region

We compared the density of the CCR5 receptor on the surface of CD4+ lymphocytes and monocytes/macrophages of the homozygote (CCR5-59653C) and the heterozygote (CCR5-59653T), bearing CCR2-64V alleles. Flow cytometric analysis revealed lower density of the CCR5 receptor on the surface of CD4+ lymphocytes and monocytes/macrophages of the heterozygote than in the same cells of the homozygote. Our observation might explain slower replication of HIV and the delay in progression to AIDS in the individuals bearing CCR5-59653T transition.     

中国傣族、景颇族人群中与艾滋病相关的CCR5△32、CCR2b-64I、SDF1-3′A等位基因多态性分布

为了调查HIV-1感染相关的等位基因CCR5△32、CCR2b-64I、SDF1-3′A在我国云南省德宏州傣族景颇族人群中的频率和多态性分布,此课题以101例傣族和113例景颇族人群为研究对象,应用PCR、PCR-RFLP(聚合酶链反应-限制性片段长度多态性)分析方法进行检测,计算突变基因频率;并对其群体分布、性别分布进行统计学分析。结果表明,中国傣族景颇族人群中未发现CCR5△32等位基因突变;傣族CCR2b-64I、SDF1-3′A基因突变频率分别为0.2130和0.2030,景颇族CCR2b-64I和SDF1-3′A基因突变频率分别为0.1637和0.1770;与中国汉族人群相比较,傣族和景颇族中SDF1-3′A突变频率较低（P值分别为0.0322和0.0021）;两个民族的CCR2b-64I和SDF1-3′A等位基因群体分布符合Hardy-Weinberg平衡,在性别之间分布无显著差异。中国傣族景颇族人群的CCR2b-64I等位基因的突变频率与汉族人相似,SDF1-3′A等位基因的突变频率比汉族人低,此两种突变基因在艾滋病发病过程中的影响值得进一步研究。由于未发现CCR5△32基因突变,中国傣族景颇族人群对HIV-1感染可能有较大的遗传易感性。 Abstract:The purpose of the work is to investigate the frequencies and polymorphisms of HIV-1 resistant CCR5delta32,CCR2b-64I,SDF1-3′A alleles in Chinese Dai and Chingpaw populations.Whole blood samples from 101 Dai subjects and 113 Chingpaw were collected randomly and their genomic DNA were extracted with QIAgen Blood Kits.Allelic frequencies were identified by PCR-RFLP analysis.Allelic polymorphisms in Dai population or Chingpaw population and both sexes in the samples were analyzed by χ2 test.The frequencies of CCR5delta32,CCR2b-64I,SDF1-3′A alleles in Dai population were 0.0000,0.2130,0.2030,respectively;The frequencies of CCR5delta32,CCR2b-64I,SDF1-3′A alleles in Chingpaw population were 0.000,0.1637,0.1770,respectively.Distributions of the CCR2b-64I,SDF1-3′A alleles among the both populations were in accordance with Hardy-Weinberg equilibrium.No statistical difference was found in the allelic frequencies of both CCR2b-64I and SDF1-3′A between male and female individuals.The frequencies of CCR5delta32,CCR2b-64I alleles in Chinese Dai and Chingpaw populations are similar to that in Chinese Han population,while the frequency of SDF1-3′A allele in Chinese Dai and Chingpaw populations are lower in contrast to that in Chinese Han population.The genotyping and polymorphism of CCR5delta32,CCR2b-64I,SDF1-3′A alleles in Chinese Dai and Chingpaw populations of Yunnan Province are the first time studied in China.The significance of the three mutant alleles conferring genetic resistance to HIV-1 and AIDS progression remains to be clarified.     

Prevalence of CCR5 and CCR2 HIV-coreceptor gene polymorphisms in Belgium

Polymorphisms of the chemokine receptor genes CCR5 and CCR2 are associated with resistance to HIV-1 infection or delayed progression to AIDS. Few data are available on their combined prevalence in healthy subjects; we therefore examined the occurrence of CCR5-Delta32 and CCR2-64I polymorphisms in a sample of 310 healthy Belgians. Allele frequencies were 0.119 and 0.074 for CCR5-Delta32 and CCR2-64I, respectively. Genotype distributions for both polymorphisms were found to be in accordance with Hardy-Weinberg equilibrium, but a significant (p = 0.002) linkage disequilibrium between CCR5-Delta32 and CCR2-64I was observed. The high prevalence of CCR5-Delta32 and CCR2-64I in Belgians may need to be taken into account in the design of studies of antiretroviral treatments.     

CCR2-64Ⅰ在中国南方14个少数民族群体中的分布

为调查HIV-1感染相关等位基因CCR2-64Ⅰ在我国南方14个少数民族群体的频率和多态性分布, 从上述人群外周血中抽提基因组DNA, 采用PCR和PCR-RFLP等方法进行基因分型。在791例调查对象中, 636例是野生纯合子基因型, 104例为杂合子基因型, 51例为突变纯合子基因型。上述各群体等位基因型的分布符合Hardy-Weinberg平衡。14个民族群体的平均突变基因频率为13.6％, 等位基因频率范围分布在1.6％~30.3％之间, 14个民族群体之间突变基因频率具有显著差异(P<0.05)。广西壮族群体CCR2-64Ⅰ突变基因频率最低, 为1.6％, 云南的六库傈僳族频率最高, 为30.3％。12个群体的突变基因频率均低于中国汉族健康群体, 南方3个少数民族群体基因突变频率显著低于西南11个少数民族群体, 该突变基因在艾滋病发病过程中的影响值得进一步深入研究。     

Combined effect of CCR5-Delta32 heterozygosity and the CCR5 promoter polymorphism -2459 A/G on CCR5 expression and resistance to human immunodeficiency virus type 1 transmission

Exposed seronegative individuals (ES) with persistent high-risk sexual behavior may be less susceptible to human immunodeficiency virus type 1 (HIV-1) infection because they carry the chemokine receptor (CR) gene alleles CCR5 open reading frame (ORF) Delta32, CCR5 promoter -2459G, or CCR2 ORF 64I (CCR2-64I), all of which have been found to diminish HIV-1 infectivity and/or disease progression. To investigate this, we determined the haplotypes for these three genetic loci in 93 ES and 247 low-risk control individuals. To test if protective haplotypes exert their effect by modulating CR expression, we measured the protein expression of CCR5 and CXCR4 on circulating CD4+ T cells and CD14+ monocytes in 71 ES and 92 controls. To avoid investigator bias, the analysis was performed without knowledge of each subject's risk and genotype. The CCR5 -2459G allele was significantly enriched in ES Caucasian men, who constituted the majority (84%) of the ES cohort, compared to the control Caucasian men (P = 0.02). This increase was mostly attributable to a higher frequency of the -2459 A/G versus the -2459 A/A genotype in individuals heterozygous for the delta32 allele (P = 0.012). No protective influence of the CCR2-64I allele was observed. The haplotypes CCR5 ORF delta32/CCR5 -2459A (in complete linkage disequilibrium) and CCR5 ORF wt/CCR5 -2459G had a cumulative negative effect on the expression of CCR5, since we measured significantly reduced CCR5 densities on both T-helper cells and monocytes only when both haplotypes were present. Densities of CCR5 on lymphocytes and monocytes were correlated (r = 0.59; P < 0.0001), indicating concordance of CCR5 expression patterns across different cell types. We conclude that the CCR5 ORF delta32/wt-CCR5 -2459 A/G genotype combination offers an advantage in resisting sexual HIV-1 transmission and that this effect is mediated by a relative paucity of CCR5 on potential target cells of HIV-1.     

Prevalence of alleles associated with HIV resistance in Russia

Genetic polymorphisms of CCR5, CCR2, and SDF1 genes have been associated with resistance during human immunodeficiency virus type 1 (HIV-1) infection and disease progression. In the present report, we studied the frequency and co-occurrence of CCR5Delta32, CCR5-59029A/G, CCR2-64I, and SDF1-3'A allelic variants among HIV-1-seronegative individuals (n = 171) in Moscow. Observed allelic frequencies were 0.0906 [95% confidence interval (CI), 0.06-0.1212] for CCR5Delta32, 0.4072 (95% CI, 0.3542-0.4602) for CCR5-59029G, 0.1061 (95% CI, 0.0728-0.1394) for CCR2-64I, and 0.2218 (95% CI 0.1715-0.2721) for SDF1-3'A. A significant linkage disequilibrium (p = 0.0034) between CCR2-64I and SDF1-3'A alleles was observed.     

Distribution of CCR5-delta32, CCR2-64I, and SDF1-3'A mutations in populations from the Brazilian Amazon region

The frequency distribution of the CCR5-delta32, CCR2-64I, and SDF1-3'A alleles was studied in the urban population of Belém and in Afro-Brazilians, Amerindians, and Japanese immigrants in the state of Pará, Brazil. The results suggest that Amerindians may be genetically more susceptible to HIV-1 infection and disease progression than the other human groups studied.     

CCR5delta32, CCR2-64I, and SDF1-3'A polymorphisms related to resistance to HIV-1 infection and disease in the Ecuadorian population

The aim of this study was to determine the allele frequencies of genetic variants CCR5delta32, CCR2-64I, and SDF1-3'A (SDF1 801 A), which influence susceptibility to HIV-1 infection. We also investigated the effect of these variants on the general Ecuadoran population and on a group of HIV-infected individuals to determine the frequency of these genetics variants.     

Association of polymorphisms in MCP-1, CCR2, and CCR5 genes with the risk and clinicopathological characteristics of prostate cancer

The aim of our study was to determine the effect of monocyte chemotactic protein-1 (MCP-1), CC chemokine receptor 2 (CCR2), and CC chemokine receptor 5 (CCR5) gene polymorphisms on the susceptibility and clinicopathological characteristics of prostate cancer. Genotyping was performed by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method in 156 histopathologically confirmed prostate cancer patients and 152 healthy subjects. Individuals with AA genotype or at least one A allele of CCR2 V64I gene polymorphism had a higher risk for prostate cancer as compared with those with GG genotype (p=0.010 and p=0.028, respectively). CCR5 Δ32/wt genotype and CCR5 Δ32 allele were also found to be involved in the susceptibility to prostate cancer (p=0.028 and p=0.030, respectively). However, there was no significant association between MCP-1-2518 A/G gene polymorphism and prostate cancer risk. Prostate cancer patients carrying AA genotype or at least one A allele of CCR2 V64I had significantly increased risk for high stage disease (p=0.002 and p=0.039, respectively) and metastasis (p=0.004 and p=0.022, respectively). The CCR2 A allele (64I allele) was significantly associated with high T stage (p=0.001) and metastasis (p=0.005) as compared with CCR2 G allele (64V allele). Our data indicate that gene polymorphism of CCR2 V64I may influence the susceptibility and clinicopathological characteristics of prostate cancer and CCR5 Δ32 allele may also be an important risk factor for prostate cancer in Turkish men population.     

A polymorphism in the regulatory region of the CC-chemokine receptor 5 gene influences perinatal transmission of human immunodeficiency virus type 1 to African-American infants

There are natural mutations in the coding and noncoding regions of the human immunodeficiency virus type 1 (HIV-1) CC-chemokine coreceptor 5 (CCR5) and in the related CCR2 protein (the CCR2-64I mutation). Individuals homozygous for the CCR5-Delta32 allele, which prevents CCR5 expression, strongly resist HIV-1 infection. Several genetic polymorphisms have been identified within the CCR5 5' regulatory region, some of which influence the rate of disease progression in adult AIDS study cohorts. We genotyped 1,442 infants (1,235 uninfected and 207 HIV-1 infected) for five CCR5 and CCR2 polymorphisms: CCR5-59353-T/C, CCR5-59356-C/T CCR5-59402-A/G, CCR5-Delta32, and CCR2-64I. The clinical significance of each genotype was assessed by measuring whether it influenced the rate of perinatal HIV-1 transmission among 667 AZT-untreated mother-infant pairs (554 uninfected and 113 HIV-1 infected). We found that the mutant CCR5-59356-T allele is relatively common in African-Americans (20.6% allele frequency among 552 infants) and rare in Caucasians and Hispanics (3.4 and 5.6% of 174 and 458 infants, respectively; P < 0.001). There were 38 infants homozygous for CCR5-59356-T, of whom 35 were African-Americans. Among the African-American infants in the AZT-untreated group, there was a highly significant increase in HIV-1 transmission to infants with two mutant CCR5-59356-T alleles (47.6% of 21), compared to those with no or one mutant allele (13.4 to 14.1% of 187 and 71, respectively; P < 0.001). The increased relative risk was 5.9 (95% confidence interval, 2.3 to 15.3; P < 0.001). The frequency of the CCR5-59356-T mutation varies between population groups in the United States, a low frequency occurring in Caucasians and a higher frequency occurring in African-Americans. Homozygosity for CCR5-59356-T is strongly associated with an increased rate of perinatal HIV-1 transmission.     

CCR2-64I allele is associated with the progression of AIDS in a Han Chinese population

It has been reported that the CCR5-Delta32, CCR2-64I and SDF1-3′A polymorphisms have protective effects against HIV-1 infection and can delay the progression of AIDS in European populations. The aim of this study was to investigate the associations of the three loci with HIV-1 infection and the progression of AIDS in the Han population of northern China. We recruited 78 HIV-1-seropositive individuals and 70 population-matched healthy controls from north China. PCR-RFLP was used to genotype these three polymorphisms in all samples. There were no significant differences in the frequencies of any allele between HIV-1-seropositive individuals and healthy controls. In cases, the associations between the three loci and CD4⁺ T-lymphocyte counts were not significant; however, there was a significant association between the genotype frequency of CCR2-64I and clinical category (P < 0.05). We have identified a potentially important role of CCR2-64I allele in AIDS progression in the northern Chinese population. Further studies are necessary to clarify the contribution of the CCR2-64I allele to the progression of AIDS for the relatively small sample size.     

Genetic diversity and prevalence of CCR2-CCR5 gene polymorphisms in the Omani population

Polymorphisms in the regulatory region of the CCR5 gene affect protein expression and modulate the progress of HIV-1 disease. Because of this prominent role, variations in this gene have been under differential pressure and their frequencies vary among human populations. The CCR2V64I mutation is tightly linked to certain polymorphisms in the CCR5 gene. The current Omani population is genetically diverse, a reflection of their history as traders who ruled extensive regions around the Indian Ocean. In this study, we examined the CCR2-CCR5 haplotypes in Omanis and compared the patterns of genetic diversity with those of other populations. Blood samples were collected from 115 Omani adults and genomic DNA was screened to identify the polymorphic sites in the CCR5 gene and the CCR2V64I mutation. Four minor alleles were common: CCR5-2554T and CCR5-2086G showed frequencies of 49% and 46%, respectively, whereas CCR5-2459A and CCR5-2135C both had a frequency of 36%. These alleles showed moderate levels of heterozygosity, indicating that they were under balancing selection. However, the well-known allele CCR5Δ32 was relatively rare. Eleven haplotypes were identified, four of which were common: HHC (46%), HHE (20%), HHA (14%) and HHF*2 (12%).     

Provincial distribution of three HIV-1 resistant polymorphisms (CCR5-Δ32, CCR2-64I, and SDF1-3′ A) in China

CCR5-Δ32, CCR2-64I, mutants in two chemokine receptors and SDF1-3′A, mutant in a ligand gene, can delay AIDS pathogenesis. The distribution of the three polymorphic loci was studied in 1 046 DNA samples from 26 provinces (cities) in China. No CCR5-Δ 32 was observed. CCR2-64I and SDF1-3′ A had reverse distribution cline from south to north in China, with average frequency of 20.8% and 24.8% respectively. Relative hazard was evaluated. Important information to the epidemiology of AIDS and the origin and spread of these polymorphic loci in Chinese was provided.     

Distribution of the HIV-1 resistance-conferring alleles (CCR5delta32, CCR2-64I, and SDF1 3'A) in Russian, Ukrainian, and Belarusian populations

The frequencies of three alleles, CCR5delta32, CCR2-64I, and SDF1 3'A, known to decrease the risk of AIDS onset and the rate of the disease progression in HIV-infected individuals were determined in three native population samples from Russia, Ukraine, and Belarus. The frequencies of the alleles were 0.15, 0.12, 0.21; 0.12, 0.07, 0.20; and 0.12, 0.08, 0.26 for Russians, Ukrainians, and Belarussians, respectively. The proportion of the individuals without any of three protective alleles among Russians, Ukrainians, and Belarussians constituted 49, 65, and 61%, respectively. The genotype frequencies for the three loci studied were in Hardy-Weinberg equilibrium. Based on the three-locus genotype frequencies, the hazard ratios (relative hazards, RH) of AIDS onset in HIV-infected individuals in each sample were calculated as ranging from 0.79 to 0.88. In the samples of Eastern Slavs analyzed the estimated frequencies of the AIDS-protective alleles tested, as well as the frequencies of the corresponding genotypes and the relative hazards of AIDS onset were within the range of these parameters for the other European populations. The data on the allele frequencies and the relative hazard values in Russians, Ukrainians and Belarussians can be used as the predictors of AIDS onset and progression rate in HIV-1-infected individuals from the populations studied.     

Genetic protection against hepatitis B virus conferred by CCR5Delta32: Evidence that CCR5 contributes to viral persistence

Recovery from acute hepatitis B virus (HBV) infection requires a broad, vigorous T-cell response, which is enhanced in mice when chemokine receptor 5 (CCR5) is missing. To test the hypothesis that production of a nonfunctional CCR5 (CCR5Delta32 [a functionally null allele containing a 32-bp deletion]) increases the likelihood of recovery from hepatitis B in humans, we studied 526 persons from three cohorts in which one person with HBV persistence was matched to two persons who recovered from an HBV infection. Recovery or persistence was determined prior to availability of lamivudine. We determined genotypes for CCR5Delta32 and for polymorphisms in the CCR5 promoter and in coding regions of the neighboring genes, chemokine receptor 2 (CCR2) and chemokine receptor-like 2 (CCRL2). Allele and haplotype frequencies were compared among the 190 persons with viral recovery and the 336 with persistence by use of conditional logistic regression. CCR5Delta32 reduced the risk of developing a persistent HBV infection by nearly half (odds ratio [OR], 0.53; 95% confidence interval [CI], 0.33 to 0.83; P = 0.006). This association was virtually identical in persons with and without a concomitant human immunodeficiency virus infection. Of the nine individuals who were homozygous for the deletion, eight recovered from infection (OR, 0.25; 95% CI, 0.03 to 1.99; P = 0.19). None of the other neighboring polymorphisms examined were associated with HBV outcome. These data demonstrate a protective effect of CCR5Delta32 in recovery from an HBV infection, provide genetic epidemiological evidence for a role of CCR5 in the immune response to HBV, and suggest a potential therapeutic treatment for patients persistently infected with HBV.     

CCR2 and CCR5 genes polymorphisms in women with cervical lesions from Pernambuco,Northeast Region of Brazil: a case-control study

Polymorphisms in chemokine receptors play an important role in the progression of cervical intraepithelial neoplasia (CIN) to cervical cancer (CC). Our study examined the association of CCR2-64I (rs1799864) andCCR5-Δ32 (rs333) polymorphisms with susceptibility to develop cervical lesion (CIN and CC) in a Brazilian population. The genotyping of 139 women with cervical lesions and 151 women without cervical lesions for the CCR2-64I and CCR5-Δ32 polymorphisms were performed using polymerase chain reaction-restriction fragment length polymorphism. The individuals carrying heterozygous or homozygous genotypes (GA+AA) for CCR2-64I polymorphisms seem to be at lower risk for cervical lesion [odds ratio (OR) = 0.37, p = 0.0008)]. The same was observed for the A allele (OR = 0.39, p = 0.0002), while no association was detected (p > 0.05) with CCR5-Δ32 polymorphism. Regarding the human papillomavirus (HPV) type, patients carrying the CCR2-64Ipolymorphism were protected against infection by HPV type 16 (OR = 0.35, p = 0.0184). In summary, our study showed a protective effect ofCCR2-64I rs1799864 polymorphism against the development of cervical lesions (CIN and CC) and in the susceptibility of HPV 16 infection.     

Influence of the CCR2-V64I Polymorphism on Human Immunodeficiency Virus Type 1 Coreceptor Activity and on Chemokine Receptor Function of CCR2b, CCR3, CCR5, and CXCR4

The chemokine receptors CCR5 and CXCR4 are used by human immunodeficiency virus type 1 (HIV-1) in conjunction with CD4 to infect cells. In addition, some virus strains can use alternative chemokine receptors, including CCR2b and CCR3, for infection. A polymorphism in CCR2 (CCR2-V64I) is associated with a 2- to 4-year delay in the progression to AIDS. To investigate the mechanism of this protective effect, we studied the expression of CCR2b and CCR2b-V64I, their chemokine and HIV-1 coreceptor activities, and their effects on the expression and receptor activities of the major HIV-1 coreceptors. CCR2b and CCR2b-V64I were expressed at similar levels, and neither molecule affected the expression or coreceptor activity of CCR3, CCR5, or CXCR4 in cotransfected cell lines. Peripheral blood mononuclear cells (PBMCs) from CCR2-V64I heterozygotes had normal levels of CCR2b and CCR5 but slightly reduced levels of CXCR4. CCR2b and CCR2b-V64I functioned equally well as HIV-1 coreceptors, and CCR2-V64I PBMCs were permissive for HIV-1 infection regardless of viral tropism. The MCP-1-induced calcium mobilization mediated by CCR2b signaling was unaffected by the polymorphism, but MCP-1 signaling mediated by either CCR2b- or CCR2-V64I-encoded receptors resulted in heterologous desensitization (i.e., limiting the signal response of other receptors) of both CCR5 and CXCR4. The heterologous desensitization of CCR5 and CXCR4 signaling by both CCR2 allele receptor types provides a mechanistic link that might help explain the in vivo effects of CCR2 gene variants on progression to AIDS as well as the reported antiviral activity of natural CCR2 ligands.