Apolipoprotein E polymorphism is associated with susceptibility to schizophrenia among Saudis

Introduction

Apolipoprotein E (APOE) genotypes influence the phenotype of several neurodegenerative disorders including Alzheimer''s and Parkinson disease and may affect schizophrenia pathogenesis. This study was undertaken to determine the association between APOE gene polymorphisms and schizophrenia in the Saudi population.

Material and methods

APOE allele and genotype frequencies were studied in 380 Saudi subjects including schizophrenia patients and matched controls using polymerase chain reaction (PCR) and reverse-hybridization techniques.

Results

The frequencies of the APOE allele ε2 and genotypes ε2/ε3 and ε2/ε4 were significantly higher in the schizophrenia patients as compared to controls, suggesting that the ε2 allele and its heterozygous genotypes may increase the susceptibility to schizophrenia. In contrast, the frequencies of the ε3 allele and ε3/ε3 genotype were lower in patients as compared to controls, suggesting a protective effect of APOE ε3 for schizophrenia. This study indicated that APOE ε4 was differentially associated with schizophrenia depending on the symptoms as the frequency of the ε4 allele was significantly higher in schizophrenia patients with positive symptoms. By contrast, no significant association between APOE ε4 and schizophrenia patients with negative symptoms was observed. Genotypes ε2/ε2 and ε4/ε4 were absent in patients and controls. Moreover, the age of onset was significantly lower in patients with the APOE ε2/ε3 genotype. There was no significant difference in the frequencies of APOE alleles and genotypes between male and female schizophrenia patients.

Conclusions

The results of this study clearly show that APOE alleles and genotypes are associated with risk of developing schizophrenia and early age of onset in Saudis.     

Interleukin-17A gene polymorphism is associated with susceptibility to gastric cancer

We conducted a study to investigate the role of three common SNPs in the IL-17A and IL-17F genes (rs2275913G>A, rs3748067C>T and rs763780T>C) in the development of gastric cancer, and their interaction with H.pylori infection. A total of 326 patients with gastric cancer and 326 control subjects were consecutively recruited between May 2012 and May 2014. Genotyping of IL-17A rs2275913G>A and rs3748067C>T and IL-17F rs763780T>C was performed in a 384-well plate format on the Sequenom MassARRAY platform. By logistic regression analysis, individuals carrying the GA and AA genotypes of IL-17 rs2275913G>A were significantly associated with an increased risk of gastric cancer when compared with GG genotype, and the adjusted Ors (95% CI) were 1.46 (1.03-2.06) for GA genotype and 2.57 (1.51-4.43) for AA genotype. We observed that the GA+AA genotype of rs2275913 was associated with an increased risk of gastric cancer among H.pylori infection subjects (OR=2.21, 95% CI=1.29-3.79). In conclusion, we found that there was a significant association between L-17A rs2275913G>A polymorphism and increased gastric cancer risk, especially in H.pylori infection subjects.     

MMP-1 promoter gene polymorphism and susceptibility to chronic periodontitis in a Chinese population

A single nucleotide polymorphism in the promoter region of -1607 bp of the human MMP-1 gene has been found to be associated with an increased risk of various inflammatory diseases and cancer metastasis. This study aimed to evaluate the association between the MMP-1 promoter gene polymorphism and chronic periodontitis susceptibility and/or severity in a Chinese population. Genomic DNA was obtained from whole blood samples in 60 Chinese subjects with chronic periodontitis and 50 periodontally healthy subjects as controls. MMP-1 promoter fragment was amplified by polymerase chain reaction, and the polymorphism was analyzed by restriction endonuclease cleavage. In the control subjects, the 2G allele was observed a frequency of 49%, while in severely diseased patients, the 2G allele was seen in 73.4%. The individuals with the 2G allele seem to be approximately three times at greater risk for developing the severe chronic periodontitis (chi(2) = 12.148, P = 0.000). The genotype of 2G/2G was found in 58.5% of the severe periodontitis and 24% of the control group (chi(2) = 11.779, P = 0.003). This study suggests that a single nucleotide polymorphism in the MMP-1 promoter region of -1607 bp may be associated with severe chronic periodontitis in a Chinese population.     

MASP2 gene polymorphism is associated with susceptibility to hepatitis C virus infection

Hepatitis C virus (HCV) has become a major public health issue and is prevalent in most countries. We examined several MASP2 functional polymorphisms in 104 Brazilian patients with moderate and severe chronic hepatitis C using the primers set to amplify the region encoding the first domain (CUB1), a critical region for the formation of functional mannan-binding lectin (MBL)/MBL-associated serine proteases (MASP)-2 complexes, and the fifth domain (CCP2), which is essential for C4 cleavage of the MASP2 gene. We identified five single nucleotide polymorphisms in patients and controls: p. R99Q, p. D120G, p.P126L, p.D371Y, and p.V377A. Our results show that the p.D371Y variant (c.1111 G > T) is associated with susceptibility to HCV infection (p = 0.003, odds ratio = 6.33, 95% confidence interval = 1.85-21.70). Considered as a dominant function for the T allele, this variant is associated with high plasma levels of the MASP-2 in hepatitis C patients (p < 0.001). However, further functional investigations are necessary to understand the degree of involvement between MASP2 and the HCV susceptibility.     

CCR5 Delta32 polymorphism: associated with gallbladder cancer susceptibility

Inflammation of gallbladder is an established risk factor for gallbladder cancer (GBC) pathogenesis. Chemokine receptors play crucial role in antitumour immunity and are involved in inflammation and pathogenesis of cancers. Present study was aimed to examine the role of CCR5 Δ32 polymorphism in conferring genetic susceptibility to GBC. Present case–control study included 144 proven GBC patients and 210 healthy controls. Genotyping was done by polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) method. Statistically significant difference was observed in distribution of CCR5+/Δ32 genotype ( P  = 0.028) [odds ratio (OR) = 2.850; 95% confidence interval (CI) = 1.1–7.2] and CCR5 Δ32 allele ( P  = 0.012) (OR = 3.145, 95% CI = 1.2–7.7) in GBC patients which was conferring high risk. Stratification of GBC patients showed significant association of CCR5+/Δ32 genotype and CCR5 Δ32 allele with GBC patients with and without gallstones. Analysis based on age of onset and gender suggested significant association of CCR5 Δ32 allele with early onset (<50 years) of the disease but only marginal influence of gender in CCR5 Δ32 -mediated risk of cancer. Risk was further modulated by tobacco usage and significantly increased risk was observed in tobacco users with CCR5+/Δ32 genotype. In conclusion, CCR5+/Δ32 genotype and CCR5 Δ32 allele confer significant risk for GBC particularly in patients with early onset and tobacco usage. Role of CCR5+/Δ32 polymorphism in GBC susceptibility is independent of gallstone formation.     

A polymorphism in human TLR2 is associated with increased susceptibility to tuberculous meningitis

Tuberculous meningitis (TBM) results from the haematogenous dissemination of Mycobacterium tuberculosis from the lung to the brain. Dissemination is believed to occur early during infection, before the development of adaptive immunity. Toll-like receptor 2 (TLR2) mediates recognition of M. tuberculosis and initiates the innate immune response to infection. We hypothesized that polymorphisms in the TLR2 gene influence bacterial dissemination and the development of TBM. A case-control study was designed to test the hypothesis. Cases of bacteriologically confirmed pulmonary tuberculosis (TB) (n=183) and TBM (n=175), and cord blood controls (n=389) were enrolled in Vietnam. TLR2 genotype 597CC was associated with susceptibility to TB (odds ratio (OR)=2.22, 95% confidence interval (CI): 1.23-3.99). The association was found with meningeal rather than pulmonary TB (TBM vs control, OR=3.26, 95% CI: 1.72-6.18), and was strongest when miliary TB was found on chest radiography (controls vs TBM with miliary TB, OR=5.28, 95% CI: 2.20-12.65). Furthermore, the association increased with the severity of neurologic symptoms (grade I TBM, OR=1.93, 95% CI: 0.54-6.92; grade II, OR=3.32, 95% CI: 0.84-13.2; and grade III, OR=5.70, 95% CI: 1.81-18.0). These results demonstrate a strong association of TLR2 SNP T597C with the development of TBM and miliary TB and indicate that TLR2 influences the dissemination of M. tuberculosis.     

肥大细胞Toll样受体4在人慢性牙周炎牙龈组织中的表达

 目的：观察人慢性牙周炎牙龈组织中肥大细胞Toll样受体4（Toll-like receptor 4, TLR4）的表达,并探讨其在牙周炎发病中的可能作用。方法: 将68例自愿接受本研究的牙周炎患者按照牙周炎的病变程度分成3组：轻度牙周炎组（23例）、重度牙周炎组（25例）和正常对照组（20例）。取牙龈组织标本,4%中性甲醛液固定48 h以上。制作牙龈组织的连续切片,HE染色,光学显微镜下观察各实验组牙龈组织的组织学改变;免疫组化法染色观察各实验组牙龈组织TLR4的表达;免疫荧光双染色法观察TLR4在肥大细胞中的表达。结果： (1)与正常对照组相比,各慢性牙周炎组牙龈组织中TLR4的表达及TLR4在肥大细胞中的表达均显著升高（P<005）;(2)重度牙周炎组牙龈组织中TLR4表达的数量及TLR4在肥大细胞中的表达明显高于轻度牙周炎组（P<005）。结论：TLR4在牙龈组织中的表达及在肥大细胞中的表达量随着牙周炎的炎症程度加重而增加,提示TLR4,特别是肥大细胞TLR4可能在慢性牙周炎的发病和疾病进程中起着重要的作用。     

Periodontopathogens levels and clinical response to periodontal therapy in individuals with the interleukin-4 haplotype associated with susceptibility to chronic periodontitis

Periodontitis is an inflammatory disease that results from an interaction between dental biofilm agents and the host immune-inflammatory response. Periodontopathogenic organisms, such as Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola, as well as the host’s susceptibility, represented by the host’s genetic makeup, are the key factors that influence this complex disease. Recently, we identified haplotypes in the IL4 gene that were associated with chronic periodontitis (CP). This study aimed to evaluate whether subjects with different IL4 haplotypes (TCI/CCI and TTD/CTI) would be differentially colonized by periodontopathogens and whether they would respond differently to non-surgical periodontal therapy. Thirty-nine patients carrying the IL4 haplotype of genetic susceptibility to CP (IL4+) or protection against CP (IL4?) were evaluated. Those groups were further subdivided into individuals with CP (CP IL4+ or CP IL4?) and those that were periodontally healthy (H) (H IL4+ or H IL4?). CP patients were submitted to non-surgical periodontal therapy. Clinical and microbiological analyses were performed considering the data at baseline and 45 and 90 days after periodontal therapy. Periodontopathogens levels were evaluated by absolute quantitative polymerase chain reaction (qPCR). The baseline data revealed that the total levels of periodontopathogens were higher in the CP IL4+ than in the CP IL4? groups. Clinical analyses revealed that the periodontal therapy was equally effective, independent of the subject’s IL4 genetic load. The TCI/CCI IL4 haplotype, previously associated with genetic susceptibility to CP, was also associated with increased levels of periodontopathogenic bacteria, but this genetic background did not influence the response to non-surgical periodontal treatment.     

CD14 promoter polymorphism -159C>T is associated with susceptibility to chronic Chlamydia pneumoniae infection in peripheral blood monocytes

Chlamydia pneumoniae uses peripheral blood monocytes (PBMC) for systemic dissemination and has been linked to atherogenesis by inflammation mediated via TLR2/4 and CD14. We found 12.8% of 610 coronary artery disease (CAD) patients of Central European background to be chronically infected with C. pneumoniae based on the repeated detection of chlamydial DNA in PBMC. Among those the -159C>T CD14 promoter polymorphism was more frequent (OR 1.7, 95% CI 1.08-2.65, P=0.0224) than among C. pneumoniae-negative subjects matched for age and gender. The Arg753Gln TLR2 and Asp299Gly TLR4 polymorphisms were not related to chlamydial infection. Susceptibility for chronic chlamydial infection of PBMC in CAD patients appears associated with the CD14-159C>T promoter polymorphism encoding for enhanced CD14 expression.     

白细胞介素1B-511多态性与侵袭性牙周炎的关系

目的研究中国人群中IL-1B-511位点单核苷酸多态性(single nucleotide polymorphism,SNP)与侵袭性牙周炎(aggressive periodontitis,AgP)之间的关系.方法提取122名AgP患者和95名健康对照者外周静脉血基因组DNA,应用聚合酶链反应-限制性片段长度多态性的方法,分析IL-1B-511位点SNP与AgP的关联性.结果男性AgP组杂合基因型的频率较男性健康对照组升高并有统计学意义(P=0.048);A2 基因型/等位基因A2与吸烟联合作用显著增加了AgP的易感性(基因型:P=0.022;等位基因:P=0.006).结论IL-1B-511位点的SNP可能与中国人群中男性个体的AgP易感性有关;该位点的SNP与吸烟可能对AgP的易感性具有联合效应.     

Inherited susceptibility to insulin-dependent diabetes is associated with HLA-DR1, while DR5 is protective

Of the HLA allelic associations with insulin-dependent diabetes (IDD) reported to date. DR3 and DR4 have been the most positive and DR2 the most negative. In 952 Caucasian proband patients reported here, only 57 or 6% had no DR3 or DR4 alleles. When these 57 patients were compared to 249 Caucasian controls similarly lacking DR3 and DR4 antigens, there were excesses of DR1 (P = 0.13) and DRW8 (P = 0.01) and deficiencies of DR2 (P = 0.03) and DR5 (P = 0.03) in the patient group. The most common phenotype in this group of patients was DR1/DR7 (12.3%). Only four DR-homozygous patients involving alleles other than DR3 and DR4 were found by genotyping, and all were DR1 homozygotes. Among 506 patients wuth DR3/DRX or DR4/DRX phenotypes, DR1 was more frequent (P = 0.001; Bonferronni P = 0.006), and DR2 (P = 0.001) and DR5 (P = 0.001) less frequent than 243 HLA-matched controls. Of 187 patients with a single DR3 and no DR4, DR1 was more frequent (P = 0.02), with DR2 (P = 0.001) and DR5 (P = 0.02) less frequent than 94 HLA DR-compatible controls. Among 319 patients with a single DR4 but no DR3, DR1 was again more frequent (P = 0.01) and DR2 (P = 0.001) and DR5 (P = 0.001) less frequent than 149 HLA-matched controls. We conclude that DR1 is an additional risk DR allele for IDD to that of DR3 and DR4, and DR5 an additional protective DR allele to that of DR2.     

Toll-like receptor 2 Arg677Trp polymorphism is associated with susceptibility to tuberculosis in Tunisian patients

Toll-like receptor 2 (TLR2) is critical in the immune response to mycobacteria. Herein, we report that the frequency of a human TLR2 Arg677Trp polymorphism (C2029T nucleotide substitution) in tuberculosis patients in Tunisia is significantly higher than in healthy controls (P < 0.0001). This finding suggests that this polymorphism could be a risk factor for tuberculosis.     

NLRC4 inflammasome has a protective role on inflammatory bone resorption in a murine model of periodontal disease

There is virtually no information on the role of NLRC4 inflammasome on bone resorption and inflammation associated with periodontitis. Bacterial-associated experimental periodontitis was induced in wild-type (WT) and Nlrc4-KO C57BL/6 mice. 3 μL of a 1 × 10⁹ UFC/mL PBS suspension of heat-killed Gram-negative bacteria were injected (3x/week for 4 weeks) directly into the gingival tissues of WT and Nlrc4-KO mice (n = 6/genotype). Control animals were injected bilaterally (3x/week for 4 weeks) in the same sites with the same volume of the PBS vehicle. Alveolar bone resorption was quantified by μCT. Inflammatory infiltrate in the gingival tissues was assessed qualitatively in H&E-stained slides and by the detection of a pan-leukocyte marker (CD45) and a neutrophil marker (Ly6G) using immunofluorescence. Modulation of Rankl, Mmp-13, Tnf-a, Il-6 and Il-10 expression in the gingival tissues was determined by RT-qPCR. Osteoclastogenesis was assessed in vivo by biochemical staining for TRAP. The relevance of NLRC4 for RANKL-induced osteoclastic differentiation and activity was investigated in vitro using bone marrow-derived macrophages from WT and Nlrc4-KO mice. Bone resorption was significantly greater in Nlrc4-KO mice; however there were no differences between WT and Nlrc4-KO mice on osteoclast numbers and on the inflammatory infiltrate. In vitro, osteoclast activity was significantly enhanced in Nlrc4-deficient macrophages; whereas RANKL-induced differentiation was not affected. Expression of the selected candidate genes was also similarly increased by the induction of experimental periodontal disease, except for the expression of Tnf-alpha and Il-10, which was already significantly higher in the gingival tissues of Nlrc4-KO mice. We conclude that NLRC4 inflammasome has a protective role on inflammatory bone resorption in this experimental model. Furthermore, the bone-sparing effect may be related with the modulation of osteoclast activity.     

HLA基因多态性与慢性粒细胞和急性淋巴细胞白血病易感性的关联分析

HLA基因在个体差异中是控制人体特异性免疫应答和决定疾病易感性的重要基因。大量的研究表明,HLA基因与慢性粒细胞白血病(chron ic myelogenous leukem ia,CML)和急性淋巴细胞白血病(acute lymphob lastic leukem ia,ALL)的发病密切相关[1~3],并在不同的人种和区域中存在差异。找出这种关联及差异的遗传因素,对于确定致病基因,明确致病机制都非常重要。本文就CML和ALL患者与HLA基因分布频率的相关性进行研究。1材料与方法1·1材料:选择江苏地区的CML患者73例,其中男42例,女31例,年龄4~50岁;ALL患者50例,其中男29例,女21例,年龄5~…     

A single-nucleotide polymorphism in ANK1 is associated with susceptibility to type 2 diabetes in Japanese populations

To identify a novel susceptibility locus for type 2 diabetes, we performed an imputation-based, genome-wide association study (GWAS) in a Japanese population using newly obtained imputed-genotype data for 2 229 890 single-nucleotide polymorphisms (SNPs) estimated from previously reported, directly genotyped GWAS data in the same samples (stage 1: 4470 type 2 diabetes versus 3071 controls). We directly genotyped 43 new SNPs with P-values of <10(-4) in a part of stage-1 samples (2692 type 2 diabetes versus 3071 controls), and the associations of validated SNPs were evaluated in another 11 139 Japanese individuals (stage 2: 7605 type 2 diabetes versus 3534 controls). Combined meta-analysis using directly genotyped data for stages 1 and 2 revealed that rs515071 in ANK1 and rs7656416 near MGC21675 were associated with type 2 diabetes in the Japanese population at the genome-wide significant level (P < 5 × 10(-8)). The association of rs515071 was also observed in European GWAS data (combined P for all populations = 6.14 × 10(-10)). Rs7656416 was in linkage disequilibrium to rs6815464, which had recently been identified as a top signal in a meta-analysis of East Asian GWAS for type 2 diabetes (r(2) = 0.76 in stage 2). The association of rs7656416 with type 2 diabetes disappeared after conditioning on rs6815464. These results indicate that the ANK1 locus is a new, common susceptibility locus for type 2 diabetes across different ethnic groups. The signal of association was weaker in the directly genotyped data, so the improvement in signal indicates the importance of imputation in this particular case.     

Gene polymorphism in transforming growth factor‐beta codon 10 is associated with susceptibility to Giardiasis

Secretory immunoglobulin A (S‐IgA) antibodies have a central role in anti‐Giardial defence. It has been demonstrated that transforming growth factor‐beta1 (TGF‐β1) stimulates B lymphocytes to produce and secrete S‐IgA. We sought to determine the association between TGF‐β1 polymorphism (T+869C) with susceptibility to Giardiasis. The TGF‐β1 genotypes and levels of salivary (S‐IgA) were analysed in individuals with Giardiasis (97 symptomatic and 57 asymptomatic) and controls (n = 92). Individuals with symptomatic Giardiasis had the lowest levels of S‐IgA compared to individuals in asymptomatic Giardiasis and control groups (97%, 73% and 43%, <1 g L^?1, respectively, P = 0.002). The frequency of allele C and CC genotypes of TGF‐β1 polymorphism was significantly higher among symptomatic patients than asymptomatic and control groups. Logistic regression analysis demonstrated that the individuals homozygous for allele C of TGF‐β1 had a significantly higher risk for symptomatic Giardiasis with odds ratio of 2.76 (95% CI: 3.88, 1.71, P = 0.007). Among the participants with TT genotype per cent of individuals with S‐IgA level of more than 1 g L^?1 was almost twice the percentage in CC genotype individuals (14% versus 7% respectively P = 0.01). Our data suggest that CC genotype of TGF‐β1 polymorphism at codon 10 is associated with occurrence of Giardiasis.     

TYK2 rs34536443 polymorphism is associated with a decreased susceptibility to endometriosis-related infertility

Introduction

Tyrosine kinase 2 gene (TYK2) is part of the janus kinase (JAK) that binds to the type I interferon-α receptor (IFNAR) on the cell surface of IFN-producing cells, and have crucial importance in the etiology of autoimmune and inflammatory diseases. Many polymorphisms of the TYK2 gene have been identified, and recently, a number of case–control studies were conducted to investigate the association of these polymorphisms with autoimmune and inflammatory diseases, with conflicting results. Based on these observations, we hypothesized that the TYK2 polymorphisms (rs34536443, rs2304256, rs280523, rs12720270 and rs12720356) might be involved in the pathogenesis of endometriosis and/or infertility.

Methods

Genetic association study comprising 275 infertile women with endometriosis, 92 women with idiopathic infertility and 307 fertile women as controls. TYK2 polymorphisms were identified by TaqMan PCR. Genotype distribution, allele frequency and haplotype analysis of the TYK2 polymorphisms were performed. A p-value <0.05 was considered significant.

Results

Single-marker analysis revealed that TYK2 rs34536443 was significantly associated with protection against endometriosis-related infertility, especially in moderate/severe disease (p = 0.002; OR = 0.24, 95% IC = 0.09–0.62). No difference was found considering the infertile group without endometriosis. No associations were found considering rs2304256, rs280523, rs12720270 and rs12720356 either for endometriosis-related infertility group or idiopathic infertility group. Haplotype analysis of five TYK2 polymorphisms identified a haplotype “CTATG” associated with protection against endometriosis-related infertility, especially in moderate/severe disease (p = 0.027).

Conclusion

This is the first study to report an association between TYK2 polymorphisms and endometriosis and/or infertility. These findings require replication in other populations but suggest the TYK2 rs34536443 polymorphisms and “CTATG” haplotype can be associated with a decreased susceptibility to endometriosis-related infertility in Brazilian women.     

A CA repeat polymorphism of the IFN-gamma gene is associated with susceptibility to type 1 diabetes.

Recent studies have shown that loci outside the HLA region are involved in determining susceptibility to type 1 diabetes. Polymorphisms in the coding and noncoding regions of the genes encoding cytokines may be involved in modulating the immune response to self and nonself antigens. There is increasing evidence that an imbalance and disruption of the Thl and Th2 T cell subsets play a key role in the development of experimental and clinical type 1 diabetes. The aim of this study was to investigate the frequency of a CA dinucleotide repeat polymorphism in the interferon-gamma (IFN-gamma) gene (IFNG) and a C(-590)T polymorphism of the interleukin-4 (IL-4) gene in 236 Caucasoid patients with type 1 diabetes. There was a highly significant increase in the 3/3 IFNG genotype in the patients compared with normal healthy controls (34.3% vs. 13.5%, p<0.0001) as well as a significant increase in allele 3 of the IFNG locus in the patients compared with controls (51.9% vs. 31.7%, p<0.00001). In contrast, no significant differences were found in the frequency of the C(-590)T IL-4 polymorphism between patients and controls. These results suggest that polymorphisms of the IFNG gene may modify the function of this proinflammatory mediator and the response to pancreatic islet beta cells.     

A CXCL2 tandem repeat promoter polymorphism is associated with susceptibility to severe sepsis in the Spanish population

Sepsis describes a complex clinical syndrome resulting from a systemic inflammatory response to bacteria. Functional studies in animal models of sepsis have catalogued CXCL2 as a candidate gene for the development of the disease. We hypothesized that CXCL2 polymorphisms may confer susceptibility to sepsis and performed an association study using 178 severe sepsis patients and 357 population-based controls. We selected two polymorphisms from the promoter of the gene (-437A/G and -665(AC)n), and analyzed whether haplotypes or single loci were associated with disease susceptibility. An overall test of differentiation showed that haplotype distribution was not different between cases and controls (P=0.407). Likewise, -437A/G was not associated with disease susceptibility (heterozygote odds ratio (OR) 0.68 (0.47-1.03), and homozygote OR 0.86 (0.56-1.32); P=0.706). However, for the -665(AC)n, we found that the 24+/-1 repeat alleles were associated with susceptibility (heterozygote OR 2.82 (1.10-7.24), and homozygote OR 3.65 (1.41-9.43); P=0.0006). This association remained significant when using a multiple logistic regression analysis (OR 2.23; 95% confidence intervals (95% CI) 1.22-4.03; P=0.008) and after a genomic control adjustment (P=0.017). Although replicate studies and functional assays are needed, these results suggest that CXCL2 gene variants may contribute to the development of severe sepsis.     

ALOX5 variants associated with susceptibility to human pulmonary tuberculosis

The 5-lipoxygenase (ALOX5)-derived lipid mediators leukotrienes and lipoxins have regulatory functions in inflammation by modulating activities of immune cells and cytokine production. Recently, it was shown in ALOX5-/- mice that host control of Mycobacterium tuberculosis is regulated by 5-lipoxygenase (5-LO). ALOX5 polymorphisms were genotyped in 1916 sputum-positive patients with pulmonary tuberculosis (TB) from Ghana and in 2269 exposed, apparently healthy controls. Polymorphisms of a variable number of tandem repeats (VNTR) of the ALOX5 promoter and of the exonic non-synonymous variant g.760G>A were analysed by fragment length determination and fluorescence resonance energy transfer, respectively, and DNA sequencing. Mycobacterial lineages of >1400 isolates were differentiated biochemically and genetically. Carriers of one variant (n repeats not equal 5) and one wild-type VNTR allele (n = 5) or of the exonic allele g.760A had a higher risk of TB [P(corrected) = 0.026, odds ratio (OR) 1.19 (95% CI 1.04-1.37) and P(corrected) = 0.026, OR 1.21 (95% CI 1.04-1.41), respectively]. The association of the exonic variant was stronger in infections caused by the mycobacterial lineage M. africanum West-African 2 [P(corrected) = 0.024, OR 1.70; (95% CI 1.2-2.6)]. Determination of haplotypes revealed the strongest associaton with TB for the 'non-5/760A' haplotype compared with the 'non-5/760G' haplotype (P = 0.003, OR 1.50). Our observation of an association of ALOX5 variants with susceptibility to TB contributes evidence of the importance of 5-LO products to the regulation of immune responses to M. tuberculosis.