白细胞介素6基因-572C/G多态性与心肌梗塞易感性的关联研究

目的观察白细胞介素6（interleukin 6，IL6）基因-572C／G多态性在中国人群中的分布频率、与心肌梗塞（myocardial infarction，MI）易感性的关系、对MI患者冠脉病变程度的影响以及初步对该位点基因变异进行功能性分析。方法应用聚合酶链反应．限制性片段长度多态性方法对232例MI患者和260名正常对照者IL6基因-572C／G多态性进行了分析，观察了该基因多态性对冠脉病变程度及外周血单核细胞（peripheral blood mononuclear cells，PBMC）产生IL6能力的影响。结果中国汉族人群存在IL6基因-572C／G多态性；两组人群基因型、等位基因频率差异存在统计学意义，MI组CG＋GG基因型频率、G等位基因频率均显著高于对照组（P〈0．01）；基因型频率的相对风险分析发现，G等位基因携带者息MI的风险是CC基因型的1．68倍（95％CI：1．17—2．41，P〈0．01）；-572C／G多态性在单支、双支、三支冠脉病变组间的分布差异无统计学意义（P〉0．05）；G等位基因携带者氧化低密度脂蛋白刺激24h PBMC产生IL6的能力明显高于CC基因型（P〈0．05）。结论IL6基因-572G等位基因可能是中国汉族人MI的易感因子，这可能与携带该等位基因的人群存在IL6水平的高表达有关。     

基于稀疏表示变量选择方法的影像遗传学数据分析

目的:采用影像遗传学研究方法探索精神分裂症的影像遗传学特征。方法:在传统稀疏回归模型的基础上，改进 了其在不同范数条件下进行变量选择的能力，形成一种基于稀疏表示变量选择算法，并将该算法应用于208 个受试者的 41 236个功能磁共振成像数据和722 177个单核苷酸多态性数据的综合分析。通过对两类数据施加不同的权重因子，并 使用不同的Lp （p=0、0.5、1）范数分别对模型进行求解，筛选出两类数据在不同条件下的显著特征。结果:基因DAOA和 HTR2A在3种范数下均被筛选出。此外，在影像学数据方面，发现中央前回、枕上回、顶下缘角回、角回、内侧和旁扣带脑 回、后扣带回脑区与精神分裂症相关，此发现与先前精神分裂症的临床医学研究结果一致。结论:基于稀疏表示变量选择 方法应用于影像遗传学数据分析是一个有效可行的途径，为今后精神分裂症的影像遗传学研究提供了一种新的研究 思路。     

产前筛查和基因多态性位点在唐氏综合征产前诊断中的应用

目的 在建立可靠的产前筛查方法的同时，采用快速，简便，准确的产前诊断方法，防止唐氏综合征（DS）患儿的出生，方法 采用酶联免疫方法测定妊娠14-20w孕妇血清甲胎蛋白（AFP）和绒毛膜促性腺激素β亚基（β-HCG）浓度，结合孕妇年龄，孕周和体重，用计算机软件进行分析，得到每位孕妇所怀胎儿DS风险系数，对筛查出胎儿唐氏综合征高风险孕妇，再利用21号染色体上的6个多态性位点对其作产前基因诊断。结果 经产前筛查，在395例孕妇中发现10例胎儿唐氏综合征高风险孕妇，其中1例产前基因诊断为胎儿唐氏综合征，与染色体核型分析结果相符。结论 产前筛查结合基因多态性在唐氏综合征产前诊断中具有很好的应用价值。     

Antigens targeted to the Leishmania phagolysosome are processed for CD4+ T cell recognition

Processing of antigen for recognition by class II-restricted CD4⁺ T cells occurs within acidic compartments of the antigen-presenting cell. The exact nature of this compartment has yet to be precisely defined, however, but may vary depending upon the cell type studied and the antigen used. The acidic compartments of macrophages are also responsible for the degradation of ingested micro-organisms and play host to others which are adapted to an intracellular existance. To determine whether the phagolysosome (PL) formed in activated macrophages after ingestion of Leishmania parasites is also a site for entry of antigen into the class II presentation pathway, we have used the approach of genetic transformation. Hence, Leishmania were transfected with the genes for the protein antigens ovalbumin (OVA) and β-galactosidase (β-gal) and after infection were able to deliver these antigens specifically into the PL. Delivery of antigen to this site resulted in the ability of infected macrophages to present these antigens to antigen-specific CD4⁺ T cells. After taking into account the absolute levels of antigen uptake by macrophages, a 4-h processing period for OVA delivered by this or a soluble route led to equivalent levels of T cell activation. Unlike macrophages pulsed with soluble OVA, those with PL-targeted OVA still retained the ability to stimulate T cells after a 24-h processing period. This enhanced lifespan of antigen in macrophages corresponded to the kinetics of degradation of the parasite, suggesting slow release of antigen into the processing pathway. β-gal presentation from the PL was tenfold less efficient under the same conditions. In addition to providing the first information on antigen processing in a protozoan PL, these studies highlight the usefulness of genetically transformed parasites for these types of studies.     

Dizygotic twinning is not associated with methylenetetrahydrofolate reductase haplotypes

BACKGROUND: Folate metabolism is critical to embryonic development, influencing neural tube defects (NTD) and recurrent early pregnancy loss. Polymorphisms in 5,10-methylenetetrahydrofolate reductase (MTHFR) have been associated with dizygotic (DZ) twinning through pregnancy loss. METHODS: The C677T and A1298C polymorphisms in MTHFR were genotyped in 258 Australasian families (1016 individuals) and 118 Dutch families (462 individuals) of mothers of DZ twins and a population sample of 462 adolescent twin families (1861 individuals). Haplotypes were constructed from the alleles, and transmission of the MTHFR haplotypes to mothers of DZ twins and from parents to twins in the adolescent twin families analysed. RESULTS: The C677T and A1298C were common in all three populations (frequencies > 0.29). There was strong linkage disequilibrium (D' = 1) between the variants, showing that specific combinations of alleles (haplotypes) were transmitted together. Three haplotypes accounted for nearly all the variation. There was no evidence of any association between MTHFR genotype and twinning in mothers of twins, or of the loss of specific MTHFR genotypes during twin pregnancies. CONCLUSIONS: It is concluded that variation in twinning frequency is not associated with MTHFR genotype.     

Polymorphisms of toll-like receptor 2 and 4 genes in rheumatoid arthritis and systemic lupus erythematosus

Human toll-like receptors (TLRs) participate in the innate response and signal the activation of adaptive immunity. Therefore, these TLRs may be important in autoimmune diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). We investigated, by using a polymerase chain reaction restriction-fragment length polymorphism method, the possible association between the polymorphisms of TLR2 (Arg677Trp and Arg753Gln) and TLR4 (Asp299Gly and Thr399Ile) genes with the susceptibility or severity of RA and SLE. Our study population consisted of 122 patients with SLE, 224 patients with RA, and a control group of 199 healthy individuals. The TLR2 polymorphisms were very rare in our population; no individual carrying the TLR2-Arg677Trp polymorphism was observed, whereas the TLR2-Arg753Gln polymorphism was present in only 1% of the total population. We found no statistically significant differences in the TLR4-Asp299Gly and the TLR4-Thr399Ile genotype or allele distribution between SLE patients, RA patients, and control individuals. Similarly, no association was found with any of the demographic and clinical parameters tested either in RA or in SLE patients. In conclusion, a case-control study was used to analyze, for the first time, the influence of TLR2 and TLR4 gene polymorphism on the predisposition and clinical characteristics of SLE and RA but provided no evidence for association of TLR2 or TLR4 gene polymorphism with either disease in the population under study.     

beta2-adrenergic receptor gene polymorphisms in myasthenia gravis (MG)

The beta2-adrenergic receptor (beta2-AR) belongs to the group of G-protein coupled receptors and is present mainly on skeletal and cardiac muscle cells and lymphocytes. The gene encoding beta2-AR (ADRB2) displays a moderate degree of heterogeneity in the human population. The distribution of polymorphisms at amino acid positions 16, 27 and 164 is changed in asthma, hypertension and obesity. We have earlier reported a decreased density of the beta2-AR on peripheral blood mononuclear cells and the presence of beta2-AR antibodies in patients with MG. Since certain polymorphisms affect the function of the beta2-AR, it was of interest to analyse these in MG. Using allele-specific polymerase chain reaction amplification, we revealed an over-representation of homozygosity for Arg16 and a lower prevalence of homozygosity for Gly16 in MG patients compared with healthy individuals. The increased frequency of homozygosity for Arg16 was due to a contribution from patients with generalized MG but not from patients with only ocular disease. Homozygosity for Glu27 was negatively associated with both the presence of beta2-AR antibodies and severity of disease. Moreover, acetylcholine receptor (AChR) antibodies were more often present in patients being homozygous for Gln27. Our results imply that homozygosity for Arg16 confers susceptibility to generalized MG, and that certain polymorphisms at amino acid position 27 are associated with subgroups of patients.     

血清生长分化因子15水平与慢性淋巴细胞白血病发生风险的关联研究

目的 采用两样本孟德尔随机化研究方法探讨血清生长分化因子15(GDF15)水平与慢性淋巴细胞白血病(CLL)发生之间的关联。方法 基于欧洲人群血清GDF15和CLL的全基因组关联研究公开数据库,筛选与血清GDF15水平相关的遗传变异位点作为工具变量,采用逆方差加权法评估遗传学预测的血清GDF15浓度与CLL发生的关联,采用最大似然比法进行敏感性分析,采用MR-Egger回归探讨工具变量潜在多效性。结果 研究共纳入3个单核苷酸多态位点作为工具变量,逆方差加权法结果显示,血清GDF15水平与CLL发生风险之间存在负相关,GDF15浓度每升高一个标准差(SD),CLL发生风险降低33%(95%置信区间:2%～54%)(P=0.039)。敏感性分析得到了一致的结果。此外,MR-Egger回归未发现存在多效性。结论 本研究结果提示,在欧洲人群中,血清GDF15水平与CLL发生之间可能存在负相关,仍需大样本人群研究及体内外实验进一步阐明GDF15在CLL发生发展中的作用及其潜在生物学机制。     

ABCB4基因突变合并巨细胞病毒感染致婴儿胆汁淤积症的诊治分析并文献复习

目的探讨ABCB4基因突变合并巨细胞病毒(CMV)感染致婴儿胆汁淤积症(IC)患儿的临床特征、基因检测结果和诊治方案。 方法选择2019年8月3日,于中山大学附属第七医院就诊并确诊为ABCB4基因突变合并CMV感染致IC的1例婴儿(女性,生后9个月)为研究对象。回顾性分析其临床病例资料,包括临床特征、实验室检查结果及基因检测结果。同时,检索国内外数据库中ABCB4基因突变所致IC患儿的相关文献,并进行文献复习。本研究遵循的程序符合2013年新修订的《世界医学协会赫尔辛基宣言》要求。 结果本例IC患儿在本院诊治结果如下。①病史采集：系G₂P₂,足月顺产,外观无异常,否认新生儿黄疸病史,生后2个月龄时出现皮肤及巩膜呈暗绿色,伴反复呕奶,当地医院治疗并诊断为胆汁淤积性肝病、CMV感染和泌尿系统感染,抗病毒治疗2周后好转出院。出院时,其血清总胆汁酸(sTBA)为152.8 μmol/L,CMV-DNA<4×10² copies/mL,口服熊去氧胆酸胶囊10 mg/(kg·d)治疗后,皮肤暗绿色逐渐消退,大、小便正常。出院后定期监测肝功能,sTBA、γ-谷氨酰转肽酶(GGT)仍然较正常值增高。②实验室检查：血清CMV免疫球蛋白(Ig)G抗体呈阳性、CMV IgM抗体呈阴性,CMV-DNA<55×10² copies/mL。基因检测结果：患儿及其父亲均携带ABCB4基因杂合变异。治疗结果：经口服熊去氧胆酸胶囊10 mg/(kg·d)及谷胱甘肽片0.1 g/次× 3次/d治疗后,对患儿定期复查sTBA、GGT。随访到18个月龄时,其各项指标逐渐恢复正常范围。③文献复习结果：共计检索到8篇国内外报道的因ABCB4基因突变引起IC相关文献,纳入14例IC患儿,均被诊断为进行性家族性肝内胆汁淤积3型(PFIC3),伴肝大,sTBA、GGT水平升高等。14例IC患儿中,共检测到ABCB4基因突变位点20个。其中,9例IC患儿接受熊去氧胆酸治疗,7例随访结果显示临床症状及实验室检查指标有所好转。 结论携带ABCB4基因突变,可引起IC。对于sTBA升高、肝酶异常的病因不明确、治疗效果不佳IC患儿,建议完善基因检测进一步排查ABCB4基因突变所致胆汁淤积症。     

Preliminary study of single nucleotide polymorphisms of PRPS2 gene in overproducing type of gouty patients

目的 :探讨编码人磷酸核糖焦磷酸合成酶亚单位 2的基因 PRPS2单核苷酸多态性与产生过剩型痛风患者的关系。方法 :利用聚合酶链反应扩增健康人和产生过剩型痛风患者 PRPS2基因全部外显 (包括外显子与内含子交界区 )的片段 ,采用多荧光标记的 PCR单链构象多态性分析技术对扩增的片段进行了筛选 ,对筛选到的片段进行序列测定 ,并与正常序列进行对照分析。结果 :在 PRPS2基因的第一个外显子区发现了一个 SNP( exon1+45A/G) ,第六个内含子区发现了一个 SNP ( intron6+12G/A) ,健康人与患者间的频率比较分别为 P =0 .0 96和 P =0 .2 73。结论 :提供了 PRPS2基因 SNP的数据库信息 ,为研究痛风发病机制提供了新的途径。