Polymorphisms of microsomal triglycedde transfer protein in different hepatitis B virus-infected patients

AIM: To identify the two polymorphisms of microsomal triglyceride transfer protein (MTP) gene in the Chinese population and to explore their correlation with both hepatitis B virus (HBV) self-limited infection and persistent infection.METHODS: A total of 316 subjects with self-limited HBV infection and 316 patients with persistent HBV infection (195 subjects without familial history),matched with age and sex,from the Chinese Han population were enrolled in this study.Polymorphisms of MTP at the promoter region -493 and at H297Q were determined by the allele specific polymerase chain reaction (PCR).RESULTS: The ratio of males to females was 2.13:1 for each group and the average age in the self-limited and chronic infection groups was 38.36 and 38.28 years,respectively.None of the allelic distributions deviated significantly from that predicted by the Hardy-Weinberg equilibrium.There was a linkage disequilibrium between H297Q and -493G/T(D'=0.77).As the X2 test was used,the genotype distribution of MTP-493G/T demonstrated a significant difference between the self-limited infection group and the entire chronic group or the chronic patients with no family history (X2=8.543,P=0.015 and X2=7.199,P=0.019).The allele distribution at the MTP-493 position also demonstrated a significant difference between the study groups without family history (X2=6.212,P=0.013).The T allele emerged as a possible protective factor which may influence the outcomes of HBV infection (OR: 0.59; 95% CI: 0.389-0.897).CONCLUSION: The polymorphism of the MTP gene,T allele at -493,may be involved in determining the HBV infection outcomes,of which the mechanism needs to be further investigated.     

Polymorphisms of microsomal triglyceride transfer protein in different hepatitis B virus-infected patients

AIM： To identify the two polymorphisms of microsomal triglyceride transfer protein （MTP） gene in the Chinese population and to explore their correlation with both hepatitis B virus （HBV） self-limited infection and persistent infection.
METHODS： A total of 316 subjects with self-limited HBV infection and 316 patients with persistent HBV infection （195 subjects without familial history）, matched with age and sex, from the Chinese Han population were enrolled in this study. Polymorphisms of MTP at the promoter region -493 and at H297Q were determined by the allele specific polymerase chain reaction （PCR）.
RESULTS： The ratio of males to females was 2.13：1 for each group and the average age in the self-limited and chronic infection groups was 38.36 and 38.28 years, respectively. None of the allelic distributions deviated significantly from that predicted by the Hardy-Weinberg equilibrium. There was a linkage disequilibrium between H297Q and -493G/T （D＇ = 0.77）. As the χ^2 test was used, the genotype distribution of MTP-493G/T demonstrated a significant difference between the self-limited infection group and the entire chronic group or the chronic patients with no family history （χ^2 = 8.543, P = 0.015 and χ^2 = 7.199, P = 0.019）. The allele distribution at the MTP-493 position also demonstrated a significant difference between the study groups without family history （χ^2 = 6.212, P = 0.013）. The T allele emerged as a possible protective factor which may influence the outcomes of HBV infection （OR： 0.59; 95% CI： 0.389-0.897）. CONCLUSION： The polymorphism of the MTP gene, T allele at -493, may be involved in determining the HBV infection outcomes, of which the mechanism needs to be further investigated.     

A functional polymorphism in the promoter region of the microsomal triglyceride transfer protein (MTP -493G/T) influences lipoprotein phenotype in familial hypercholesterolemia

The microsomal triglyceride transfer protein (MTP) has a key function in intracellular apolipoprotein (apo) B lipidation and secretion of very low density lipoprotein (VLDL). A recently discovered functional polymorphism in the promoter of the MTP gene (-493G/T) affects the plasma concentration of low density lipoprotein (LDL) cholesterol and the VLDL distribution between large and small particle species in healthy men. This phenotype is likely to be explained by an effect on VLDL synthesis. Against this background, we studied the effect of the MTP-493G/T polymorphism in a large cohort (217 men and 211 women) with heterozygous familial hypercholesterolemia (FH). A 40% to 50% lower serum triglyceride level was observed in homozygous carriers of the MTP-493 T allele (T/T, 0.93+/-0.34; G/T, 1.54+/-1.40; and G/G, 1.56+/-1.24 mmol/L; T/T vs G/T P=0.04, T/T vs G/G P=0.02). In contrast to the situation in healthy subjects, the MTP promoter polymorphism did not have a significant effect on the LDL cholesterol levels in FH subjects, although the same trend was observed (T/T, 7.31+/-1.87; G/T, 7. 80+/-2.12; and G/G, 7.91+/-2.31 mmol/L, NS). Adjustment for the apo E gene polymorphism by inclusion of subjects homozygous for the apo E3 allele only revealed a reciprocal high density lipoprotein cholesterol-elevating effect (T/T, 1.41+/-0.73; G/T, 1.18+/-0.27; and G/G, 1.16+/-0.29 mmol/L; T/T vs G/T P=0.06, T/T vs G/G P=0.04). This effect seemed to be sex-specific because it was accounted for by the female patients. In conclusion, the LDL cholesterol-lowering effect of the rare MTP gene promoter variant (MTP-493T) present in healthy subjects is shifted to a triglyceride-lowering effect in FH. These data suggest that the MTP gene has a role in modulating the clinical phenotype of FH.     

Association of the -1438 G/A and 102 T/C polymorphism of the 5-Ht2A receptor gene with irritable bowel syndrome 5-Ht2A gene polymorphism in irritable bowel syndrome

GOALS: The aim of this study is to investigate whether there were any association between the 102 T/C and -1438 G/A polymorphisms of the 5-HT2A receptor gene and IBS, and abdominal pain, anxiety and depression. BACKGROUND: Genes involved in serotonin (5-HT) metabolism are good candidates for the pathogenesis of irritable bowel syndrome (IBS). Recently, a silent polymorphism in the 5-HT2A receptor gene was identified that is defined by a T to C transition at position 102. Also, a novel G to A base change at position -1438 of the promoter region has been detected in 5-HT2A receptor gene. STUDY: Fifty-four patients with IBS diagnosed according to the Rome 1 criteria and 107 healthy individuals were included in the study. PCR was used to amplify a 468-bp (G-->A) and 342-bp (T-->C) fragment of genomic DNA containing the polymorphism. Hospital anxiety and depression scale was used to assess the risk of depression and anxiety. Severity of chronic abdominal pain was determined by visual analogue scale (VAS). RESULTS: It was shown that there was a high incidence of homozygote C allele of the 102T/C polymorphism (%22.2; OR: 7.89, P = 0.04) and homozygote A allele of the -1438 G/A promoter region (%%37; OR: 11.14, P = 0.01) in patients with IBS. The risk of having an anxiety disorder was 83.3% in patients with C/C genotype, which was higher than other allele carrying patients, and overall mean (%52.7). (chi = 8.56, P = 0.014). The patients with T/T genotype had a VAS score of 54.93 +/- 2.59 mm, which was significantly higher than that of the patients with other genotypes (p1 = 0.02, p2 = 0.001). CONCLUSION: This study suggests that the patients with homozygote C allele of the 102 T/C polymorphisms or homozygote A allele of the -1438 G/A polymorphism of the 5-HT2A receptor gene, have a high risk of IBS. On the other hand, T/T genotype of 102 T/C polymorphism may be associated with more severe pain in patient with IBS.     

Polymorphism in microsomal triglyceride transfer protein: a link between liver disease and atherogenic postprandial lipid profile in NASH?

Nonalcoholic fatty liver disease (NAFLD) is emerging as an independent cardiovascular risk factor, but mechanism(s) linking fatty liver to atherosclerosis are unknown. Microsomal triglyceride transfer protein (MTP) -493 G/T polymorphism modulates circulating lipid and lipoprotein levels in different subsets and has been linked to NAFLD. The impact of MTP -493 G/T polymorphism, adipokines, and diet on postprandial lipoprotein profile and liver disease was assessed in nonalcoholic steatohepatitis (NASH). Plasma lipids, triglyceride-rich lipoprotein subfractions, high-density lipoprotein-C (HDL-C), and oxidized low-density lipoprotein (LDL) after an oral fat load were cross-sectionally correlated to MTP -493 G/T polymorphism, dietary habits, adipokines, and liver histology in 29 nonobese nondiabetic patients with NASH and 27 healthy controls. The severity of liver histology, the magnitude of triglycerides (Tg), free fatty acid (FFA), and LDL-conjugated diene responses, and the fall in HDL-C and apoA1 were significantly higher in NASH G/G (66% of patients) than in the other genotypes, despite similar adipokine profile and degree of insulin resistance. Postprandial large intestinal very-low-density lipoprotein (VLDL) subfraction A increases independently predicted Tg (beta=0.48; P=.008), FFA (beta=0.47; P=0.010), HDL-C (beta=0.42; P=0.009), and LDL-conjugated diene (beta=0.52; P=0.002) responses. VLDL A apoB48 response was independently associated with liver steatosis (OR: 2.4; CI 1.7-9.6; P=0.031). Postprandial LDL-conjugated diene response predicted severe necroinflammation (OR: 3.3; CI 1.4-9.7; P=0.016) and fibrosis (OR: 2.8; CI 1.0-8,5; P=0.030); postprandial apoA1 fall predicts severe fibrosis (OR: 2.1; CI: 1.5-6.1; P=0.015). CONCLUSION: MTP -493 G/T polymorphism may impact NASH by modulating postprandial lipemia and lipoprotein metabolism; homozygous GG carriers have a more atherogenic postprandial lipid profile than the other genotypes, independently of adipokines and insulin resistance.     

Promoter polymorphism of transforming growth factor-β1 gene and ulcerative colitis

AIM： To elucidate the possible difference in two promoter polymorphisms of the transforming growth factor-β1 （TGF-β1） gene （-800G 〉 A, -509C 〉 T） between ulcerative colitis （UC） patients and normal subjects.
METHODS： A total of 155 patients with established ulcerative colitis and 139 normal subjects were selected as controls. Two single nucleotide polymorphisms within the promoter region of TGF-β1 gene （-509C 〉 T and -800G 〉 A） were genotyped using PCR-RFLP. RESULTS： There was a statistically significant difference in genotype and allele frequency distributions between UC patients and controls for the -800G 〉 A polymorphism of the TGF-β1 gene （P 〈 0.05）. The frequency of the TGF-β1 gene polymorphism at position -800 showed that the AA genotype and the allele A frequencies significantly differed between the patients and healthy controls （P 〈 0.05）. At position -509, there was no statically significant difference in genotype and allele frequency between the patients and control subjects.
CONCLUSION： The results of our study indicate that there is a significant difference in both allele and genotype frequency at position -800G 〉 A of TGF-β1 gene promoter between Iranian patients with UC and normal subjects.     

Promoter polymorphism of transforming growth factor-β1 gene and ulcerative colitis

AIM: To elucidate the possible difference in two promoter polymorphisms of the transforming growth factor-β1 (TGF-β1) gene (-800G > A, -509C > T)between ulcerative colitis (UC) patients and normal subjects.METHODS: A total of 155 patients with established ulcerative colitis and 139 normal subjects were selected as controls. Two single nucleotide polymorphisms within the promoter region of TGF-β1 gene (-509C > T and -800G > A) were genotyped using PCR-RFLP.RESULTS: There was a statistically significant difference in genotype and allele frequency distributions between UC patients and controls for the -800G > A polymorphism of the TGF-β1 gene (P < 0.05). The frequency of the TGF-β1 gene polymorphism at position -800 showed that the AA genotype and the allele A frequencies significantly differed between the patients and healthy controls (P <0.05). At position -509, there was no statically significant difference in genotype and allele frequency between the patients and control subjects.CONCLUSION: The results of our study indicate that there is a significant difference in both allele and genotype frequency at position -800G > A of TGF-β1 gene promoter between Iranian patients with UC and normal subjects.     

环氧化酶-2基因启动子区多态性与结直肠癌的易感性

目的:探讨环氧化酶-2(cyclooxygenase-2,COX-2)基因启动子区的-1195(G/A,rs689466)及3’非翻译区的8473(T/C,rs5275)2个位点的基因多态性与结直肠癌(colorectal cancer,CRC)发病风险的相关性.方法:采用病例-对照研究,利用聚合酶链式反应和限制性片段长度多态性(polymerase chain reaction-restrictive fragment length polymorphism,PCR-RFLP)分析方法,对343例CRC患者和340例健康人的COX-2基因的2个位点的多态性进行检测,采用SPSS11.0软件包统计分析各位点的基因型分布和等位基因频率.结果:COX-2-8473位点多态性的各基因型频率在病例组及对照组中分布均无显著差异(P>0.05),但COX-2-1195位点多态性的基因型频率在二组中分布有显著性差异(P<0.001),结果显示CRC患者COX-2-1195AG基因型在病例组的频率较对照组显著增高(校正后OR=2.23;95%CI:1.50-3.32),AA基因型在病例组中的频率亦较对照组高(校正后OR=2.46;95%CI:1.51-4.02),A等位基因携带者在病例组中的频率高于对照组(校正后OR=2.27;95%CI:1.55-3.34).各基因型分布在结肠癌及直肠癌中的分布无显著性差异(P>0.05).COX-2-1195A等位基因与淋巴结转移及TNM分期有显著相关性.结论:COX-2-1195位点AG/AA基因型是CRC的风险因素,且与CRC的淋巴结转移及TNM分期相关.     

Microsomal triglyceride transfer protein (MTP) -493G/T gene polymorphism contributes to fat liver accumulation in HCV genotype 3 infected patients

Summary. (A) A reduced activity of microsomal triglyceride transfer protein (MTP), a key enzyme of assembly/secretion of lipoproteins, is related to HCV steatosis. Host genetic background may influence development of steatosis. The aim of the study was to investigate the association between MTP‐493 G/T gene polymorphism, fat liver accumulation and fibrosis progression in HCV infected patients. A total of 102 naïve patients with liver biopsy proven chronic hepatitis C were evaluated for MTP‐493 G/T gene polymorphism, HCV RNA, HCV genotype, HOMA‐IR, serum adiponectin, TNF‐α and serum lipid levels. HCV genotype 3 infected patients carrying the T allele of the MTP gene polymorphism showed higher degree of steatosis than those carrying GG genotype (3.45 ± 0.37 vs 1.30 ± 0.45, respectively; P < 0.001). MTP‘T’ allele carriers also had higher HCV RNA serum levels (P < 0.01) and hepatic fibrosis (P < 0.001). Irrespective of MTP genotype, patients with HCV genotype 3 had lower levels of cholesterol, ApoB, HDL and LDL. In HCV genotype non‐3 infected patients no parameters were associated with MTP gene polymorphism. In conclusion the presence of T allele of MTP‐493G/T gene polymorphism predisposes patients infested with HCV genotype 3 to develop higher degree of fatty liver accumulation.     

Microsomal triglyceride transfer protein gene polymorphism strongly influences circulating malondialdehyde-modified low-density lipoprotein

Microsomal triglyceride transfer protein (MTP) plays a critical role in the assembly of lipoproteins. Therefore, we studied whether MTP gene polymorphisms are associated with atherosclerosis-promoting parameters, especially metabolic profiles and endothelial function, in healthy young men. One hundred one healthy men (mean age, 30.3 years) were studied. We analyzed the 2 promoter polymorphisms (−493G/T and −400A/T) of the MTP gene. Linkage disequilibrium analysis revealed a significant but incomplete linkage disequilibrium between the 2 polymorphisms (D' = 0.74). The −493T allele carriers (n = 26) showed marked increases in their levels of malondialdehyde-modified low-density lipoprotein (mean value, 135 vs 99 U/L in the G/G carriers; P = .003) and triglycerides (2.15 vs 1.16 mmol/L, P = .014), and reduced low-density lipoprotein particle size (259.2 vs 264.3 nm, P = .023), whereas there was no difference in apolipoproteins, insulin, adiponectin, homocysteine, folate, and endothelial function assessed using ultrasound measurement of brachial artery flow-mediated vasodilation. In contrast, the −400T allele carriers (n = 61) showed a reduced endothelial function (P = .044), accompanied by elevated apolipoprotein B levels in subjects with higher triglyceride levels. These results indicate that both promoter polymorphisms may be associated with the development of atherosclerosis and cardiovascular diseases, but that the mechanism responsible may be different.     

Impact of lipoprotein lipase gene polymorphisms on ulcerative colitis

INTRODUCTION Inflammatory bowel disease (IBD), characterized by chronic recurrent inflammation of the intestinal tract, includes two common forms: Crohn’s disease (CD) and ulcerative colitis (UC). For both forms, the etiology is unclear, but likely to be…     

Effect of the microsomal triglyceride transfer protein -493 G/T polymorphism and type 2 diabetes mellitus on LDL subfractions

Genetic variation in the microsomal triglyceride transfer protein (MTP) affects the secretion pattern and plasma concentration of apolipoprotein (aopB)-containing lipoproteins and a common functional -493 G/T polymorphism has been reported to influence plasma lipids levels. Recent data suggest that carriers of the T allele might be more sensitive to detrimental factors such as features of the insulin resistance syndrome. Since type 2 diabetes is associated with obesity and insulin resistance, the present study investigated the effect of this polymorphism on plasma lipids, apoB and LDL subfractions in 281 Chinese type 2 diabetic subjects and 364 non-diabetic controls. The frequency of the rare T allele was 0.162 and 0.126 in subjects with and without diabetes respectively. There were no differences in the effect of the polymorphism on plasma lipids and apoB in the two groups. However, the TT genotype was associated with a higher concentration of small dense LDL-III than the GT or GG variants in the diabetic subjects (P=0.01) whereas no such effect was observed in the controls. In the diabetic patients, age, plasma triglyceride and the MTP genotype were independent determinants of LDL-III concentrations in linear regression analysis (R(2)=10%, P=0.04) whereas in the controls, only plasma triglyceride and age were important determinants (R(2)=15%, P=0.01). In conclusion, the -493 G/T polymorphism only has a minor effect on LDL subfraction pattern in Chinese and the effect is only apparent in the presence of type 2 diabetes.     

Angiotensinogen gene haplotype is associated with the prevalence of Japanese non-alcoholic steatohepatitis

Aim: Non-alcoholic steatohepatitis (NASH) patients frequently have hypertension, which is considered to be an important predictive factor for the subsequent development of hepatic fibrosis. The renin-angiotensin system is also known to contribute to the progression of NASH. Various types of functional single-nucleotide polymorphisms (SNPs) involved in the development of NASH have been proposed. Angiotensinogen (AGT) gene SNPs related to cardiovascular diseases have been reported. We aimed to evaluate the involvement of the AGT gene haplotype in Japanese NASH patients. Methods: Previously described genotypes of SNPs of the AGT gene, rs4762 C/T polymorphism (T207M), rs699 C/T polymorphism (T268M), and rs7079 C/A polymorphism (C11537A), were determined in 124 Japanese biopsy-proven NASH patients and 150 healthy volunteers (controls). Results: The allele and genotype frequencies in rs4762 and rs699 SNPs in NASH patients were similar to those in controls, while the frequency of the A allele and A/- genotype in rs7079 SNPs were much higher in NASH patients than in controls. In addition, the 3-SNP haplotype CTA was significantly over-represented in NASH patients compared with controls. Regarding clinical features of NASH patients, diastolic blood pressures in patients with the CTA/- genotype were much higher than in patients with other genotypes. Conclusions: We found a 3-SNP haplotype of the AGT gene that is involved in the development of NASH and influences hypertension in NASH patients. These results provide new insight into the therapy of NASH patients with the CTA haplotype using ACE inhibitors or angiotensin II type 1 receptor blockers.     

Microsomal triglyceride transfer protein polymorphism (−493G/T) is associated with hepatic steatosis in patients with chronic hepatitis C

Background: Hepatic steatosis may promote progression of chronic hepatitis C (CHC). Microsomal triglyceride transfer protein (MTP) is required for assembly and secretion of ApoB lipoprotein and is implicated in hepatitis C virus (HCV)‐related steatosis. The MTP ?493G/T polymorphism may promote liver fat accumulation, but its role in HCV‐related steatosis is still unclear. Methods: Two hundred ninety‐eight CHC patients were studied and genotyped for MTP ?493G/T variants. Hepatic MTP mRNA expression and activity were determined in a subgroup. Results: Patients with grades 2/3 steatosis were older, had a higher body mass index (BMI), more advanced fibrosis and lower MTP mRNA expression and carried more often HCV genotype 3 and the MTP T allele. Age, BMI, HCV‐3 and MTP T allele [odds ratio (OR) 2.05; 95% confidence interval (CI) 1.2–3.53; P=0.009] were independent risk factors for steatosis grades 2/3, and in HCV genotype non‐3 patients, the MTP T allele was the strongest predictor for steatosis grade 2/3 (OR 2.17; 95% CI 1.22–3.86; P=0.008). Moreover, TT carriers had higher high‐density lipoprotein (65.6±14.6 vs 56.1±16.2 mg/dl; P=0.003) and apolipoprotein AI (1.80±0.3 vs 1.60±0.3 g/L; P=0.005) levels than G allele carriers. Conclusions: Chronic hepatitis C patients with the MTP ?493T allele reveal higher grades of steatosis, indicating a relevant contribution to liver fat accumulation, particularly in HCV non‐3 patients.     

细胞毒T淋巴细胞相关抗原4基因多态性与溃疡性结肠炎

目的炎症性肠病的发病与T细胞过度活化有关,细胞毒T淋巴细胞相关抗原4（CTLA-4）是重要的T细胞活化负性调节因子.本课题研究CTLA-4基因启动子区-1722位点（T/C）及-1661位点（A/G）多态性与中国汉族人群中溃疡性结肠炎（UC）的相关性.方法采用PCR-限制性片段长度多态性方法,对87例中国汉族UC患者和116例正常对照者进行CTLA-4基因-1722位点和-1661位点多态性检测.结果UC患者CTLA-4基因-1661位点A/G＋G/G基因型频率,-1661位点G等位基因频率显著高于正常对照组（34.5%比15.5%,P=0.002,OR=2.865,95%CI=1.467～5.596;19.0%比8.2%,P=0.002,OR=2.624,95%CI=1.435～4.796）;而在-1722位点的基因型频率、等位基因频率与对照组比较差异无统计学意义（P＞0.05）.结论CTLA-4基因启动子区-1661位点G等位基因与中国汉族UC存在显著相关性.     

CTLA4 gene and Graves' disease: association of Graves' disease with the CTLA4 exon 1 and intron 1 polymorphisms,but not with the promoter polymorphism

OBJECTIVE: Recent studies have shown that Graves' disease (GD) is linked to and associated with alleles of the cytotoxic T lymphocyte antigen-4 (CTLA4) locus. However, the true pathogenic polymorphism(s) at this locus remains uncertain. Moreover, the association studies of the promoter CTLA4(-318)C/T polymorphism in white GD populations have produced conflicting results. Therefore, we have analysed three CTLA4 single nucleotide polymorphisms, including promoter CTLA4(-318)C/T, exon 1 CTLA4(49)A/G and intron 1 CTLA4(1822)C/T in our GD cohort from the UK. PATIENTS AND METHODS: We studied 301 white patients with GD and 349 healthy ethnically matched local controls. Amongst GD probands, 129 had significant thyroid-associated orbitopathy (TAO; NOSPECS class III or worse). The CTLA4(-318)C/T, CTLA4(49)A/G and CTLA4(1822)C/T polymorphisms were genotyped by using the restriction enzymes MseI, Bst71I and HaeIII, respectively. RESULTS: We found no association between GD and alleles of CTLA4(-318)C/T. GD was found to be associated with the G allele of CTLA4(49)A/G[P = 5.9 x 10(-6), odds ratio (OR) 1.65] and the T allele of CTLA4(1822)C/T (P = 7.7 x 10(-6), OR 1.64). The frequencies of these alleles were significantly higher in GD probands with significant TAO than in those without TAO (G allele: P = 0.001, OR 1.68; T allele: P = 0.001, OR 1.70). CONCLUSIONS: The promoter CTLA4(-318)C/T polymorphism is not in linkage disequilibrium with the pathogenic polymorphism(s) at the CTLA4 locus. The alleles of both the exon 1 CTLA4(49)A/G and the intron 1 CTLA4(1822)C/T polymorphisms are associated with GD, which is stronger in patients with TAO.     

白细胞介素-2基因多态性与慢性乙型肝炎的相关性

目的 探讨白细胞介素-2(IL-2)基因多态性与慢性乙型肝炎的相关性,以及对HBVDNA水平的影响.方法 应用聚合酶链反应-限制性片段长度多态性分析和DNA测序的方法检测155例慢性乙型肝炎患者和170名健康对照者的IL-2基因-385T/G、+114T/G单核苷酸多态性位点基因型,血清HBV DNA测定采用荧光定量PCR技术.结果 IL-2基因+114T/G多态性在慢性乙型肝炎组和正常人群中的频率分布差异无统计学意义.IL-2基因-385T/G多态性在两组人群中的频率分布差异有统计学意义,X2=7.377,P<0.05.等位基因频率的相对风险分析发现,G等位基因携带者患慢性乙型肝炎的风险是T等位基因的1.490倍(OR=1.490,95%CI:1.085-2.046);进一步比较慢性乙型肝炎患者IL一2基因多态性与HBV DNA复制的关系,发现高水平HBVDNA(≥1×10<'3>拷贝/ml)组-385G等位基因携带者分布频率明显高于低水平HBV DNA组(<1×10<'3>拷贝/ml),X2=6.051,P=0.014,差异有统计学意义.结论 IL-2基因-385T/G多态性可能与HBV具有相关性,其中G等位基因可能是慢性乙型肝炎的遗传易感基因,携带G等位基因的个体可能更利于HBV DNA的复制.     

Association of asthma severity and bronchial hyperresponsiveness with a polymorphism in the cytotoxic T-lymphocyte antigen-4 gene

OBJECTIVES: Cytotoxic T-lymphocyte antigen (CTLA)-4 is a homolog of CD28, which is expressed only on activated T cells. It binds to accessory molecule B7 and mediates T-cell-dependent immune response. Signaling through CTLA-4 may down-regulate type 1 T-helper cell proliferation; moreover, some studies suggest that CTLA-4 might also deliver a positive signal to type 2 T-helper cell activation. Disruption of this delicate balance of immune regulation may lead to autoimmune diseases or atopic diseases. To evaluate the possible role of CTLA-4 polymorphisms in bronchial asthma, we investigated the association between polymorphisms (exon 1 +49 A/G, promoter -318 C/T) and atopy, asthma severity, and bronchial hyperresponsiveness in bronchial asthma patients and a group of healthy control subjects. PATIENTS: Eighty-eight asthmatic patients and 88 healthy control subjects were studied. MEASUREMENTS AND RESULTS: Asthma severity assessment, methacholine challenge, allergy skinprick test, and serum total IgE measurements were performed. The genotypes of the CTLA-4 promoter (-318 C/T) and exon 1 (+49 A/G) in all subjects were determined using the polymerase chain reaction and restriction fragment length polymorphism. The CTLA-4 promoter (-318 C/T) polymorphism was shown to be associated with asthma severity, but not with asthma, atopy, or bronchial hyperresponsiveness. A significant association was found between severe asthma and the T allele (p = 0.037). The CTLA-4 exon 1 (+49 A/G) polymorphism was shown to be associated with bronchial hyperresponsiveness, but not with asthma, atopy, or asthma severity. Asthmatic patients of the GG genotype had more hyperresponsive airways than those with the AG or AA genotype (p = 0.019). CONCLUSIONS: The CTLA-4 promoter (-318 C/T) T allele may serve as a clinically useful marker of severe asthma. The CTLA-4 exon 1 (+49 A/G) polymorphism may have a disease-modifying effect in asthmatic airways.