中国汉族人群DC-SIGN和DC-SIGNR基因遗传多态性

目的了解中国汉族人群DC-SIGN和DC-SIGNR基因颈区重复序列的遗传多态性分布，获得相应位点的汉族人群的遗传学数据。方法应用PCR技术、琼脂糖凝胶电泳结合测序对DC-SIGN和DC-SIGNR基因的颈区重复序列分型，计算DC-SIGNR的多态信息含量。结果DC-SIGN多态性低，颈区绝大多数为等位基因7重复，该等位基因频率为0．9808，但亦检出少量的等位基因4、5、6、8等变异，而美国白人只含有等位基因6、8变异；DC-SIGNR存在高度多态性，多态信息含量为0．5312，存在4、5、6．7、8、9等位基因，检出16种基因型。6／5、7／4、7／5、7／6、7／7、9／5、9．／7、9／9基因型和5、6、7、9等位基因频率在中国汉族人群和美国白人中的分布构成差异有统计学意义（P〈0．01），与美国白人比较，中国汉族人群似乎存在更多的插入突变。结论中国汉人的DC-SIGN和DC-SIGNR基因型分布和基因频率与美国白人相比其差异有统计学意义，并有其独特的群体遗传学特征。     

DC-SIGNR基因多态性与肝功能和HCV病毒载量的相关性

目的研究丙型肝炎患者DC—SIGNR基因颈区重复序列的遗传多态性分布，探讨DC-SIGNR基因多态性与肝功能及丙型肝炎病毒（HCV）载量的关系。方法采用聚合酶链反应（PCR）技术结合DNA测序对238例丙型肝炎患者DC—SIGNR重复序列多态性进行基因分型和测序分析；同时检测患者的HCV—RNA载量和肝功能。结果DC—SIGNR基因型或等位基因与肝功能的相关性不显著。携带7等位基因的患者，其HCV—RNA载量水平低于携带9等位基因的患者（P〈0．05）。此外7/7组基因型的患者其HCV—RNA载量水平低于9/7组基因型的患者，两组比较差异有统计学意义（P〈0．05）。提示HCV更易与携带较长DC—SIGNR等位基因的患者结合。结论DC—SIGNR遗传多态性可能与HCV在个体内的复制有关。但与肝功能不相关。     

The VNTR polymorphism of the CLEC4M gene and susceptibility to HIV-1 infection in Han Chinese population

C-type lectin domain family 4, member M (CLEC4M, also known as DC-SIGNR) is a C-type lectin that functions as a transreceptor for human immunodeficiency virus-1 (HIV-1). The relationship between variable number tandem repeat (VNTR) polymorphism of the DC-SIGNR gene and susceptibility to HIV-1 infection has been under debate. In the present study, a cohort of 287 HIV-1 seropositive patients and 388 ethnically age-matched healthy controls from Han Chinese population were enrolled in order to determine the influence of host genetic factors on HIV-1 infection. A total of 11 genotypes and 5 alleles were found in our population. A cross-sectional comparison between HIV-1 seropostive patients and healthy controls did not reveal significant differences with regards to DC-SIGNR genotype distribution, allele frequencies and homozygotes proportion. In addition, previous studies showed that DC-SIGNR might play different roles in different HIV infection routes. We stratified the patients into two subgroups: sexual contact patients and intravenous drug abuser/blood transfusion patients. Our results showed the frequencies of DC-SIGNR genotypes/alleles in these two subgroups were similar. To our knowledge, this is the first study performed in Northern Chinese. Our findings suggested that DC-SIGNR neck region VNTR polymorphism was not directly associated with hosts’ predisposition for HIV-1 infection and not associated with the HIV-1 routes of infection. By lack of HIV-1 exposed seronegative (HESN) individuals and relative small sample size in present study made our conclusions not strong enough. In addition, the role of the DC-DIGNR neck region in different HIV-1 infection routes remains open for future study.     

DC-SIGN和DC-SIGNR基因多态性分析与HIV-1易感性关系研究

目的通过分析DC-SIGN和DC-SIGNR的基因多态性分布及基因频率在健康人群、HIV-1感染者和HIV-1长期暴露不感染人群（ES）的差别,探讨这两个基因与HIV-1长期暴露不感染的关系。方法纳入三组研究对象,包括健康对照组（160例）,HIV-1感染者组（267例）,ES组（37例）。扩增DC-SIGN和DC-SINGR基因的颈区重复序列进行分析。结果三组人群DC-SIGN基因型以7/7为主,等位基因呈低度多态性。DC-SIGNR基因型以7/7为主,等位基因呈高度多态性,出现了较多的非7/7基因型,其中等位基因6在三组间以及在HIV-1感染者和ES之间分布的差异均有统计学意义（P〈0.05）。结论 DC-SIGN基因多态性变异很低,对人群HIV-1易感性的研究意义不大;DC-SIGNR基因呈高度多态性,其低频率等位基因6可能是人群对HIV-1不易感的保护因素。     

DC-SIGNR基因多态性与人类免疫缺陷病毒-1易感性的关联研究

目的 探索DC-SIGNR基因多态性对中国汉族人群人类免疫缺陷病毒-1(human immunodeficiency virus-1,HIV-1)病毒易感性的影响.方法 用聚合酶链反应、琼脂糖凝胶电泳结合测序对345例HIV-1血清阳性感染者及468例H1V-1血清阴性高危人群的DC-SIGNR基因绞链区重复序列分型,然后用卡方检验检测DC-SIGNR基因各亚型在不同人群组中出现的频率.结果 共发现DC-SIGNR基因14个基因型和5种等位基因,其中等位基因7出现的频率最高(67.1%),明显高于美国白人(67.1% vs.46.0%,P<0.01).HIV-1感染组7/7基因型的出现频率明显低于高危人群组(38.55% vs.48.29%,P=0.0057),而HIV-1感染组的9/5基因型的出现频率明显高于高危人群组(4.35% vs.1.07%,P=0.0029).结论 中国人群DC-SIGNR基因多态性分布有着独特的遗传学特征,中国人群中DC-SIGNR基因型9/5可能增加对HIV-1的易感性.     

The tandem-repeat polymorphism of the DC-SIGNR gene in HCV infection

The C-type lectin DC-SIGNR has been shown to bind hepatitis C virus (HCV). Here, we analysed the tandem-repeat polymorphism of the DC-SIGNR gene with respect to intraindividual HCV replication. In a cross-sectional comparison HCV-infected patients (n = 430) and healthy subjects (n = 100) were genotyped for the DC-SIGNR polymorphism using PCR. The distribution of DC-SIGNR alleles did not differ significantly between the two groups. However, HCV-infected patients with 5-, 6-, and 7-repeat alleles had higher HCV-RNA levels when compared with carriers of 4- and 9-repeat alleles (P < 0.05). Thus, the DC-SIGNR polymorphism might affect HCV loads supporting the concept that DC-SIGNR contributes to HCV replication efficacy.     

The allele 4 of neck region liver-lymph node-specific ICAM-3-grabbing integrin variant is associated with spontaneous clearance of hepatitis C virus and decrease of viral loads

L-SIGN is a C-type lectin expressed on liver sinusoidal endothelial cells involved in the capture of hepatitis C virus and trans-infection of adjacent hepatocyte cells. The neck region of L-SIGN is highly polymorphic, with three to nine tandem repeats of 23 residues. This polymorphism is associated with a number of infectious diseases, but has not been explored in HCV. We therefore investigated the impact of L-SIGN neck region length variation on the outcome of HCV infection. We studied 322 subjects, 150 patients with persistent HCV infection, 63 individuals with spontaneous clearance and 109 healthy controls. In healthy subjects, we found a total of nine genotypes, with the 7/7 genotype being the most frequent (33%) followed by the 7/6 (22.9%) and the 7/5 (18.3%). The frequencies of the alleles were as follows: 7-LSIGN (56.4%), 6-LSIGN (20.2%), 5-L-SIGN (18.3%) and 4-L-SIGN (5%). The frequency of the 7/4 genotype was higher in spontaneous resolvers (14.3%) as compared with the persistent group (4%) (OR = 0.25, 95% CI = 0.07–0.82, p 0.022). In addition, we found that 4-L-SIGN was associated with spontaneous resolution of HCV infection (OR = 0.30, 95%CI, 0.12–0.74, p 0.005). Interestingly, patients with 4-L-SIGN had lower viral loads when compared with carriers of the 5 (p 0.001), 6 (p 0.021) and 7-alleles (p 0.048). The results indicate that neck region polymorphism of L-SIGN can influence the outcome of HCV infection and the four-tandem repeat is associated with clearance of HCV infection.     

Role of Homozygous DC-SIGNR 5/5 Tandem Repeat Polymorphism in HIV-1 Exposed Seronegative North Indian Individuals

Despite multiple sexual exposures to HIV-1 virus, some individuals remain HIV-1 seronegative. Although several genetic factors have been related to HIV-1 resistance, the homozygosity for a mutation in CCR5 gene (the 32-bp deletion, i.e., CCR5-Delta32 allele) is presently considered the most relevant one. The C-type lectins, DC-SIGN (present on dendritic cells and macrophages) and DC-SIGNR (present on endothelial cells in liver and lymph nodes) efficiently bind and transmit HIV-1 to susceptible cell in trans, thereby augmenting the infection. A potential association of the DC-SIGN and DC-SIGNR neck domain repeat polymorphism and risk of HIV-1 infection is currently under debate. To determine the influence of host genetic factors on HIV-1 resistance, we conducted genetic risk association study in HIV-1-exposed seronegative (n = 47) individuals, HIV-1 seronegative (n = 262) healthy control, and HIV-1-infected seropositive patients (n = 168) for polymorphism in neck domain of DC-SIGN and DC-SIGNR genes. The DC-SIGN and DC-SIGNR genotypes were identified by polymerase chain reaction method in DNA extracted from peripheral blood and confirmed by sequencing. Fisher exact or χ ² test was used for static analysis. DC-SIGN genotype and allele distribution was fairly similar in HIV-1-exposed seronegative, HIV-1 seropositive, and HIV-1 seronegative control. There was no statistical significance in the differences in the distribution of DC-SIGN genotypes. A total of 13 genotypes were found in DC-SIGNR neck repeat region polymorphism. Among all the genotypes, only 5/5 homozygous showed significant reduced risk of HIV-1 infection in HIV-1-exposed seronegative individuals (p = 0.009). A unique genotype 8/5 heterozygous was also found in HIV-1 seropositive individual, which is not reported elsewhere.