Inhibitor kappa B-alpha (IkappaB-alpha) promoter polymorphisms in UK and Dutch sarcoidosis

Polymorphisms in NF-κB pathway genes & their association with risk of lung cancer in the Chinese population

Objective:

To investigate the association of NFKB1 -94 ins/del ATTG, NFKBIA -826C>T and NFKBIA -881A>G polymorphisms with risk of lung cancer in a Chinese population.

Methods:

Genotyping of the polymorphisms were performed on 1,436 subjects (718 cases and 718 controls) by using PCR-RFLP technique, followed by DNA sequencing.

Results:

We found a significant risk reduction associated with heterozygous ins/del (OR=0.705, 95% CI=0.566-0.878, P=0.002) and variant del/del (OR=0.342, 95% CI=0.221-0.528, P<0.001) genotypes of the NFKB1 polymorphism. In contrast, the heterozygous and variantgenotypes of theNFKBIA polymorphisms showed association with increased lung cancer risk (NFKBIA -826 CT,OR=1.256, 95%CI=1.004-1.572, P=0.046; TT,OR=1.773, 95% CI=1.131-2.778, P=0.013; NFKBIA -881 AG,OR=1.277, 95% CI=1.023-1.599, P=0.031; GG,OR=1.801, 95% CI=1.169-2.775, P=0.008). Several genotypic combinations of the three polymorphisms also showed significant association with lung cancer risk. The risk association of NFKB1 polymorphism remained significant when analyses were done according to gender and smoking status (P<0.05). The significance of NFKBIA risk association was not observed when gender-specific analyses were made (P>0.05), while only NFKBIA -881 GG genotype showed significant risk association among smokers when analyzed according to smoking status (P=0.032).

Conclusions:

Polymorphisms in NFKB1 and NFKBIAgenes were associated with risk of lung cancer.

Association between polymorphisms in selected inflammatory response genes and the risk of prostate cancer

Inflammation represents an important event which facilitates prostate carcinogenesis. Genetic variations in inflammatory response genes could affect the level and function of the protein products, resulting in the differential prostate cancer risk among carriers of different variants. This study attempted to investigate the association of IL-4 rs2243250, IL-6 rs10499563, IL-8 rs4073, as well as NFKBIA rs2233406 and rs3138053 polymorphisms with prostate cancer risk in the Chinese population. Genotyping of the polymorphisms was performed by using polymerase chain reaction-restriction fragment length polymorphism technique on 439 prostate cancer patients and 524 controls, and the association of each polymorphic genotype with prostate cancer risk was evaluated by using logistic regression analysis based on allele, heterozygous, and homozygous comparison models, with adjustment to age and smoking status. We showed that the C allele of IL-4 rs2243250 polymorphism could increase prostate cancer risk (heterozygous comparison model: odds ratio [OR] =1.434, 95% confidence interval [CI] =1.092–1.881, P=0.009; homozygous comparison model: OR =2.301, 95% CI =1.402–3.775, P=0.001; allele comparison model: OR =1.509, 95% CI =1.228–1.853, P<0.001). On the other hand, the C allele of rs10499563 polymorphism could decrease prostate cancer risk (heterozygous comparison model: OR =0.694, 95% CI =0.525–0.918, P=0.010; homozygous comparison model: OR =0.499, 95% CI =0.269–0.926, P=0.028; allele comparison model: OR =0.692, 95% CI =0.553–0.867, P=0.001). No association was observed for the other polymorphisms. In conclusion, IL-4 rs2243250 and IL-6 rs10499563 polymorphisms could serve as potential predictive biomarkers for prostate cancer risk in the Chinese population.

Polymorphisms in NFKB1 and NFKBIA Genes Modulate the Risk of Developing Prostate Cancer among Han Chinese

Background

Nuclear factor kappa B (NF-κB) pathway proteins play an important role in modulating inflammation and other carcinogenic processes. Polymorphisms within NF-κB pathway genes may influence cancer risk. This study aimed to examine the association between NFKB19-4 ATTG ins→del, NFKBIA 3′ UTR A→G, -826CT and -881AG polymorphisms and prostate cancer risk among Chinese.

Material/Methods

The polymorphisms were genotyped via PCR-RFLP technique on 936 prostate cancer patients and 936 population-based healthy controls. Logistic regression model was used to measure the risk association present.

Results

With the exception of NFKBIA 3′ UTR polymorphism, the heterozygous and mutant genotypes of the other polymorphisms were significantly associated with prostate cancer risk. For NFKB1 polymorphism, a decreased risk was observed, with adjusted OR: 0.69; 95% CI: 0.44, 0.98; P=0.01 (heterozygous) and adjusted OR: 0.60; 95% CI: 0.37, 0.91; P=0.02 (mutant). NFKBIA -826CT and -881AG polymorphisms were in complete linkage disequilibrium and shared the same risk association, with adjusted OR: 1.34; 95% CI: 1.09, 1.62; P=0.02 (heterozygous) and adjusted OR: 2.83; 95% CI: 1.79, 4.50; P=0.01 (mutants). Interestingly, the impact of the NFKB1 polymorphism was not present in nonsmokers and younger (<60 years) subjects (P<0.05).

Conclusions

In conclusion, polymorphisms in NFKB1 and NFKBIA genes may modulate the risk of developing prostate cancer among Chinese.

Gender-specific association of NFKBIA promoter polymorphisms with the risk of sporadic colorectal cancer

The inhibitory protein IκBα, encoded by the NFKBIA gene, plays an important role in regulating the activity of nuclear factor-kappa B, a transcription factor which has been implicated in the initiation and progression of cancers. This study aimed to evaluate the association of NFKBIA -826C>T (rs2233406) and -881A>G (rs3138053) polymorphisms with the risk of sporadic colorectal cancer (CRC) in Malaysian population. A case-control study comprising 474 subjects (237 CRC patients and 237 cancer-free controls) was carried out. The polymorphisms were genotyped from the genomic DNA of the study subjects employing PCR-RFLP, followed by DNA sequencing. The association between the polymorphic genotypes and CRC risk was evaluated by deriving odds ratios (ORs) and 95 % confidence intervals (CIs) using unconditional logistic regression analysis. The two polymorphisms were in complete and perfect linkage disequilibrium (D' = 1.0, r (2) = 1.0). Overall, no statistically significant CRC risk association was found for the polymorphisms (P > 0.05). A similar lack of association was observed when the data were stratified according to ethnicity (P > 0.05). However, stratification by gender revealed a significant inverse association between the heterozygous genotype of the polymorphisms and the risk of CRC among females (OR 0.53, 95 % CI 0.29-0.97, P = 0.04), but not among males (P > 0.05). In conclusion, the heterozygous genotype of the polymorphisms could contribute to a significantly decreased CRC risk among females, but not males, in the Malaysian population.

Functional genetic variation in NFKBIA and susceptibility to childhood asthma, bronchiolitis, and bronchopulmonary dysplasia

Respiratory diseases are the most frequent chronic illnesses in babies and children. Although a vigorous innate immune system is critical for maintaining lung health, a balanced response is essential to minimize damaging inflammation. We investigated the functional and clinical impact of human genetic variants in the promoter of NFKBIA, which encodes IκBα, the major negative regulator of NF-κB. In this study, we quantified the functional impact of NFKBIA promoter polymorphisms (rs3138053, rs2233406, and rs2233409) on promoter-driven protein expression, allele-specific and total NFKBIA mRNA expression, IκBα protein expression, and TLR responsiveness; mapped innate immune regulatory networks active during respiratory syncytial virus infection, asthma, and bronchopulmonary dysplasia; and genotyped and analyzed independent cohorts of children with respiratory syncytial virus infection, asthma, and bronchopulmonary dysplasia. Genetic variants in the promoter of NFKBIA influenced NFKBIA gene expression, IκBα protein expression, and TLR-mediated inflammatory responses. Using a systems biology approach, we demonstrated that NFKBIA/IκBα is a central hub in transcriptional responses of prevalent childhood lung diseases, including respiratory syncytial virus infection, asthma, and bronchopulmonary dysplasia. Finally, by examining independent pediatric lung disease cohorts, we established that this immunologically relevant genetic variation in the promoter of NFKBIA is associated with differential susceptibility to severe bronchiolitis following infection with respiratory syncytial virus, airway hyperresponsiveness, and severe bronchopulmonary dysplasia. These data highlight the importance of negative innate immune regulators, such as NFKBIA, in pediatric lung disease and begin to unravel common aspects in the genetic predisposition to bronchopulmonary dysplasia, bronchiolitis, and childhood asthma.

Effects of NFKB1 and NFKBIA gene polymorphisms on hepatocellular carcinoma susceptibility and clinicopathological features

BACKGROUND

Constitutive activation of nuclear factor (NF)-κB is frequently observed in hepatocellular carcinoma (HCC). The current study examined associations of polymorphisms within promoter regions of NFKB1 encoding NF-κB1 and NFKBIA encoding IκBα with the susceptibility of developing HCC and clinicopathological characteristics of the tumors.

METHODOLOGY AND PRINCIPAL FINDINGS

Genetic polymorphisms of NFKB1 and NFKBIA were analyzed by a real-time polymerase chain reaction (PCR) in 135 HCC patients and 520 healthy controls. The genotypic frequency of the NFKB1 -94 Ins polymorphism in HCC patients was significantly higher than that of the controls (adjusted odds ratio (AOR) = 2.23; 95% confidence interval (CI) 1.32∼3.77). No statistical significance was observed for the distribution frequency of the NFKBIA --519 C/T, -826 C/T, or -881 A/G genotype and haplotype polymorphisms between HCC patients and controls. Furthermore, female HCC patients carrying the NFKB1 -94 Ins polymorphism were associated with lower clinical stages and smaller tumor sizes.

CONCLUSIONS

Our results indicate that the NFKB1 -94 Ins promoter polymorphism increased the risk of HCC, and may be applied as a predictive factor for the clinical stage and tumor size in female HCC patients.

Effects of NFKB1 and NFKBIA gene polymorphisms on susceptibility to environmental factors and the clinicopathologic development of oral cancer

BACKGROUND

Oral cancer, which is the fourth most common cancer in Taiwanese men, is associated with environmental carcinogens. The possibility that genetic predisposition in nuclear factor-kappa B (NF-κB)-signaling pathways activation is linked to the development of oral squamous cell carcinoma (OSCC) requires investigation. The current study examines associations between polymorphisms within promoter regions of NFKB1 encoding NF-κB1 and NFKBIA encoding IkappaBalpha (IκBα) with both the susceptibility to develop OSCC and the clinicopathological characteristics of the tumors.

METHODOLOGY/PRINCIPAL FINDINGS

Genetic polymorphisms of NFKB1 and NFKBIA were analyzed by a real-time polymerase chain reaction (real-time PCR) for 462 patients with oral cancer and 520 non-cancer controls. We found that NFKB1 -94 ATGG1/ATGG2, -94 ATGG2/ATGG2, and the combination of -94 ATGG1/ATGG2 and ATGG2/ATGG2 genotypes NFKBIA -826 T (CT+TT) and -881 G (AG+GG) allelic carriages, were more prevalent in OSCC patients than in non-cancer participants. Moreover, we found that NFKB1 or NFKBIA gene polymorphisms seem to be related to susceptibility to develop oral cancer linked to betel nut and tobacco consumption. Finally, patients with oral cancer who had at least one -519 T allele of the NFKBIA gene were at higher risk for developing distant metastasis (P<.05), compared with those patients CC homozygotes.

CONCLUSIONS

Our results suggest that NFKB1 -94 ATTG2, NFKBIA -826 T, and -881 G alleles are associated with oral carcinogenesis. The combination of NFKB1 or NFKBIA gene polymorphisms and environmental carcinogens appears related to an increased risk of oral cancer. More importantly, the genetic polymorphism of NFKBIA -519 might be a predictive factor for the distal metastasis of OSCC in Taiwanese.

[Sarcoidosis and genetics]

Familial features of sarcoidosis and observations in monozygotic twins affected by the condition suggest the presence of a genetic predisposition. Various genetic associations have been described with genes coding for proteins involved in immune regulation in particular at the level of interaction between T-lymphocyte and antigen presenting cell. We review the various genetic targets described with techniques ranging from classic human lymphocyte antigen genotype to genome wide linkage scans. The 6p21 region has been highlighted, which includes relevant genes such as MHC class II, BTNL2 and TNFα. These studies show that the genetics of sarcoidosis are complex, that patient sub-groups exist, which may explain some of the heterogeneity in the results of genetic studies and that the interactions between genetic and environmental factors remains to be elucidated.

Polymorphisms of nuclear factor-κB family genes are associated with development of multiple myeloma and treatment outcome in patients receiving bortezomib-based regimens

BACKGROUND

The nuclear factor-κB pathway is an important signaling pathway activated in multiple myeloma cells. Bortezomib inhibits nuclear factor-κB activation and is an important antimyeloma agent. Nevertheless, patients treated with this drug eventually relapse. We hypothesized that the nuclear factor-κB pathway may be associated with multiple myeloma and patients' responses to bortezomib.

DESIGN AND METHODS

In this study we analyzed 26 polymorphism sites of nuclear factor-κB family member genes, IKBα, NFKB2, and TRAF3, in 527 unrelated Chinese Han subjects (252 with multiple myeloma and 275 controls) using a Sequenom MassARRAY genotyping assay, and examined the outcome of 83 patients treated with a bortezomib-based regimen.

RESULTS

Single nucleotide polymorphisms in the TRAF3 rs12147254 A allele and a specific haplotype 1 of TRAF3 [GAACAG] are associated with a decreased risk of multiple myeloma (odds ratio 0.709, P<0.001, and odds ratio 0.543, P<0.0001), while TRAF3 haplotype 4 [GGACAG] was associated with an increased risk of development of multiple myeloma (odds ratio 2.099, P=0.001). Moreover, the TRAF3 rs11160707 GA+AA genotype was significantly associated with a better progression-free survival (P=0.018). Patients with the NFKB2 rs12769316 GA+AA genotype had a superior overall survival (P=0.020), while those with the rs1056890 CT+TT genotype had an inferior overall survival (P=0.037). In an exploratory analysis, patients with the GA+AA/CC/GG genotype at the rs12769316, rs1056890, and rs11160707 sites had a significantly superior overall survival compared to patients with a wild-type genotype (P=0.007). In the multivariable analysis, TRAF3 rs11160707 was found to be an independent favorable factor for progression-free survival (hazard ratio 0.428, P=0.028).

CONCLUSIONS

Nuclear factor-κB family member gene polymorphisms play a role in the development of multiple myeloma and in the response to bortezomib therapy.

Defective feedback regulation of NF-kappaB underlies Sjogren's syndrome in mice with mutated kappaB enhancers of the IkappaBalpha promoter

Feedback regulation of transcription factor NF-kappaB by its inhibitor IkappaBalpha plays an essential role in control of NF-kappaB activity. To understand the biological significance of IkappaBalpha-mediated feedback regulation of NF-kappaB, we generated mice harboring mutated kappaB enhancers in the promoter of the IkappaBalpha gene (IkappaBalpha(M/M)) to inhibit NF-kappaB-regulated IkappaBalpha expression. Here, we report that these mutant mice are defective in NF-kappaB-induced expression of IkappaBalpha. This defective feedback regulation of NF-kappaB by IkappaBalpha not only altered activity of NF-kappaB, but also the expression of NF-kappaB-regulated genes. As a result, IkappaBalpha(M/M), the homozygous knock-in mice with mutated kappaB enhancers in the IkappaBalpha promoter, acquire shorten life span, hypersensitivity to septic shock, abnormal T-cell development and activation, and Sjögren's Syndrome. These findings therefore demonstrate that the IkappaBalpha-mediated feedback regulation of NF-kappaB has an essential role in controlling T-cell development and functions, provide mechanistic insight into the development of Sjögren's Syndrome, and suggest the potential of NF-kappaB signaling as a therapeutic target for Sjögren's Syndrome and other autoimmune diseases.

Inhibitor IkappaBalpha promoter functional polymorphisms in patients with rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammation disease that may involve extra-articular organs in addition to joints. Many proinflammatory cytokines are involved in the inflammatory process of RA. IkappaBalpha conjugates with NF-kappaB and is a key player in regulation of the inflammatory process. We carried out experiments to define the effect of different promoter polymorphisms on the transcriptional activities of IkappaBalpha promoter and the development of RA.

METHODS

Different IkappaBalpha promoter reporters were constructed and were examined in human mononuclear cells, THP-1 cells. One hundred forty patients and 115 healthy controls were recruited from the Kaohsiung Medical University Hospital.

RESULTS

The activities of IkappaBalpha promoter constructs with -826C, -550A, -519T, and -826T, -550A, -519T genotypes were expressed at one half the activity level of other constructs. Promoter constructs containing the sites -550A/T and -519T had a reduced risk of rheumatoid arthritis. The odds ratio of -826C/T genotype was significantly associated with an increase of risk in causing rheumatoid arthritis, whereas -826T/T genotype was associated only with a slightly increased risk of RA, but without statistical significance (odds ratio = 1.2; 95% confidence interval, 0.4-3.8).

CONCLUSION

The increase of T allele was associated with a significant increased risk and the tendency to the pathogenesis of RA. The association between IkappaBalpha promoter polymorphisms and disease severity of rheumatoid arthritis is partly due to different transcriptional activities of IkappaBalpha promoter and the activation of NF-kappaB.

Association of polymorphism in genes encoding kappaB inhibitors (IkappaB) with susceptibility to and phenotype of Graves' disease: a case-control study

Background

Genes related to the nuclear factor-κB (NF-κB), a key transcription factor involved in regulation of immune responses, are interesting candidates for association studies in autoimmune disorders. The aim of this study was to investigate an association of polymorphisms in two genes encoding NF-κB inhibitors: IKBL (encoding inhibitor of κB-like) and NFKBIA (encoding κB inhibitor α), withsusceptibility to and phenotype of Graves' disease (GD).

Methods

A population-based, case-control association study comprising 481 patients with GD and 455 healthy controls was performed. We analyzed 3 single nucleotide polymorphisms (SNPs) in IKBL [promoter region -62T/A substitution (rs2071592), intron 1 C/T substitution (rs2071591) and exon 4 T/C substitution (rs3130062)] and 3 SNPs in NFKBIA [G/A substitution in 3' untranslated region (rs696) and two promoter region polymorphisms -297C/T (rs2233409) and -826C/T (rs2233406)] by the PCR-restriction fragment length polymorphism (RFLP) method.

Results

The two SNPs in IKBL (rs2071592 and rs2071591) were in a strong linkage disequilibrium (D' = 0.835) and the AT haplotype was associated with susceptibility to GD (p < 10^-4, OR = 1.61 [95%CI:1.21-2.14]). Moreover subgroup analysis revealed a gen-gen interaction between the investigated IKBL haplotype and HLA-DRB1*03 allele (p < 10^-4). The investigated NFKBIA SNPs were not associated with susceptibility to GD. However, when correlated with phenotype, the -297T (rs2233409) and -826T (rs2233406) alleles were associated with the development of clinically evident ophthalmophaty (p = 0.004, p_c = 0.07, OR = 1.65 [95%CI: 1.18-2.38] and p = 0.002, p_c = 0.036, OR = 1.67 [95%CI: 1.20-2.36], respectively).

Conclusion

Our results suggest that SNPs in genes encoding NF-κB inhibitors may contribute to the development and clinical phenotype of GD.

IkappaBalpha gene promoter polymorphisms are associated with hepatocarcinogenesis in patients infected with hepatitis B virus genotype C

Genetic predisposition of nuclear factor-kappa B (NF-κB)-signaling pathways linking inflammation to hepatitis B virus (HBV)-induced hepatocellular carcinoma (HCC) remains unresolved. We conducted a case–control study to determine the associations of the polymorphisms within the promoter regions of NFKB1 encoding NF-κB1 and NFKBIA encoding IkappaBalpha with the development of HCC. A total of 404 healthy controls, 482 non-HCC subjects with HBV infection and 202 patients with HCC were included. NFKB1 −94ATTG2 allele and GG allele in the 3′-untranslated region of NFKBIA were more prevalent in HCC patients than in the healthy controls. NFKBIA −826CT and NFKBIA −881AG allelic carriages were more prevalent in HCC patients than in the non-HCC subjects with HBV infection. The estimated haplotype frequency of NFKBIA promoter −881G−826T−519C was significantly higher in the patients with HCC than in the HBV-infected subjects without HCC (odds ratio = 3.142, P = 0.002). As compared with the HBV-infected subjects without HCC, NFKBIA −826 T and NFKBIA −881AG allelic carriages were only associated with HCC risk in the subjects with HBV genotype C. The association of NFKBIA −881AG allelic carriage with HCC risk was not affected by liver cirrhosis (LC) status, alanine aminotransferase level and hepatitis B e antigen status. By multivariate regression analysis, NFKB1 −94ATTG2, NFKBIA −826T, NFKBIA −881AG and HBV genotype C were independently associated with an increased risk of HCC. In conclusion, NFKB1 −94ATTG2 allele and haplotype −881G−826T−519C in NFKBIA promoter were associated with hepatocarcinogenesis. NFKBIA −826T and −881AG were associated with the risk of HCC in the subjects infected with HBV genotype C.

Variation in IL7R predisposes to sarcoid inflammation

Sarcoidosis is a chronic granulomatous disorder characterized by a massive influx of Th1 lymphocytes. Both naive and memory T cells express high levels of interleukin 7 receptor-alpha (IL7R alpha), encoded by the IL7R gene. The purpose of this study was to investigate the role of the IL7R gene region in susceptibility to sarcoidosis. Six common single-nucleotide polymorphisms (SNPs) spanning IL7R were genotyped and analyzed in 475 sarcoidosis patients and 465 healthy controls. Replication of one significant associated SNP was carried out in 206 independent sarcoidosis patients, 127 controls and 126 patients with Löfgren's disease. The rs10213865 SNP was associated with sarcoidosis (P=0.008), and in silico analysis showed a complete linkage (r(2)=1, D'=1) with a functional nonsynonymous coding SNP in exon 6 (rs6897932, T244I). Combined analysis of 663 individuals with sarcoidosis and 586 controls (homozygous carriers of risk allele, P=5 x 10(-4), odds ratio=1.49 (1.19-1.86)) provided strong statistical support for a genuine association of IL7R with the risk of sarcoidosis. In addition, we report the same trend between variation in the IL7R gene and patients with Löfgren's disease, suggesting that variation in IL7R may confer general risk for developing granulomatous lung disease.

Polymorphic variation in NFKB1 and other aspirin-related genes and risk of Hodgkin lymphoma

We found that regular use of aspirin may reduce the risk of Hodgkin lymphoma (HL), a common cancer of adolescents and young adults in the United States. To explore possible biological mechanisms underlying this association, we investigated whether polymorphic variation in genes involved in nuclear factor-kappaB (NF-kappaB) activation and inhibition, other inflammatory pathways, and aspirin metabolism influences HL risk. Twenty single nucleotide polymorphisms (SNP) in seven genes were genotyped in DNA from 473 classical HL cases and 373 controls enrolled between 1997 and 2000 in a population-based case-control study in the Boston, Massachusetts, metropolitan area and the state of Connecticut. We selected target genes and SNPs primarily using a candidate-SNP approach and estimated haplotypes using the expectation-maximization algorithm. We used multivariable logistic regression to estimate odds ratios (OR) for associations with HL risk. HL risk was significantly associated with rs1585215 in NFKB1 (AG versus AA: OR, 2.1; 95% confidence interval, 1.5-2.9; GG versus AA: OR, 3.5; 95% confidence interval, 2.2-5.7, Ptrend=1.7x10(-8)) and with NFKB1 haplotypes (Pglobal=6.0x10(-21)). Similar associations were apparent across categories of age, sex, tumor EBV status, tumor histology, and regular aspirin use, although statistical power was limited for stratified analyses. Nominally significant associations with HL risk were detected for SNPs in NFKBIA and CYP2C9. HL risk was not associated with SNPs in IKKA/CHUK, PTGS2/COX2, UDP1A6, or LTC4S. In conclusion, genetic variation in the NF-kappaB pathway seems to influence risk of HL. Pooled studies are needed to detect any heterogeneity in the association with NF-kappaB across HL subgroups, including aspirin users and nonusers.

Immune interventions of human diseases through toll-like receptors

Toll-like receptors (TLRs) are the immune sensors for infections, triggering robust innate immune activation followed by protective adaptive immunity against various infectious diseases. Recent evidence, however, has suggested that TLRs are involved in the pathogenesis of many diseases, including not only infectious diseases but also autoimmune diseases, allergy and atherosclerosis. Therefore, prophylactic or therapeutic application of TLR-based immune interventions should be potent, but their safety must be demonstrated using experimental animal models as well as human resources, including analysis of single nucleotide polymorphisms. Here, we focus on recent advances in understanding of the protective and pathogenic roles of TLRs in human diseases.

IκB Genetic Polymorphisms and Invasive Pneumococcal Disease

RATIONALE

Increasing evidence supports a key role for the transcription factor nuclear factor (NF)-kappaB in the host response to pneumococcal infection. Control of NF-kappaB activity is achieved through interactions with the IkappaB family of inhibitors, encoded by the genes NFKBIA, NFKBIB, and NFKBIE. Rare NFKBIA mutations cause immunodeficiency with severe bacterial infection, raising the possibility that common IkappaB gene polymorphisms confer susceptibility to common bacterial disease.

OBJECTIVES

To determine whether polymorphisms in NFKBIA, NFKBIB, and NFKBIE associate with susceptibility to invasive pneumococcal disease (IPD) and thoracic empyema.

METHODS

We studied the frequencies of 62 single-nucleotide polymorphisms (SNPs) across NFKBIA, NFKBIB, and NFKBIE in individuals with IPD and control subjects (n=1,060). Significantly associated SNPs were then studied in a group of individuals with thoracic empyema and a second control group (n=632).

MEASUREMENTS AND MAIN RESULTS

Two SNPs in the NFKBIA promoter region were associated with protection from IPD in both the initial study group and the pneumococcal empyema subgroup. Significant protection from IPD was observed for carriage of mutant alleles at these two loci on combining the groups (SNP rs3138053: Mantel-Haenszel 2x2 chi2=13.030, p=0.0003; odds ratio [OR], 0.60; 95% confidence interval [CI], 0.45-0.79; rs2233406: Mantel-Haenszel 2x2 chi2=18.927, p=0.00001; OR, 0.55; 95% CI, 0.42-0.72). An NFKBIE SNP associated with susceptibility to IPD but not pneumococcal empyema. None of the NFKBIB SNPs associated with IPD susceptibility.

CONCLUSIONS

NFKBIA polymorphisms associate with susceptibility to IPD. Genetic variation in an inhibitor of NF-kappaB therefore not only causes a very rare immunodeficiency state but may also influence the development of common infectious disease.

Inhibitor kappaB-alpha haplotype GTC is associated with susceptibility to acute respiratory distress syndrome in Caucasians

OBJECTIVE

The nuclear factor (NF)-kappaB regulates inflammatory responses and plays important roles in the pathogenesis of acute respiratory distress syndrome (ARDS). Inhibitor kappaB-alpha (NFKBIA) inhibits NF-kappaB and controls its activities. The objective was to determine whether polymorphisms in NFKBIA gene would be associated with ARDS development.

DESIGN

Prospective cohort of adults with clinical risk factors for ARDS.

SETTING

Hospital system.

PATIENTS

Patients were 1,210 critically ill Caucasian patients meeting study criteria for a defined risk factor for ARDS who were enrolled and prospectively followed for 60 days; 382 had ARDS, and 828 were controls.

INTERVENTIONS

Genetic polymorphisms in the NFKBIA promoter (-881A/G, -826C/T, -297C/T) were determined using TaqMan techniques.

MEASUREMENTS AND MAIN RESULTS

The three polymorphisms were in Hardy-Weinberg equilibrium. No individual genotype was significantly associated with ARDS development. In contrast, haplotypes of NFKBIA were globally associated with ARDS development (p = .02, degree of freedom = 2). The frequency of haplotype GTC (-881G/-826T/-297C) was significantly higher among ARDS patients (7.4%) than that among controls (5.2%) (p = .03). Crude analysis showed that the haplotype GTC was significantly associated with higher risks of ARDS in the whole cohort compared with the common haplotype ACC (-881A/-826C/-297C) (odds ratio [OR], 1.47; 95% confidence interval [CI], 1.03-2.09; p = .03), especially among male subjects (OR, 1.90; 95% CI, 1.20-2.97; p < .01). After adjustment for covariates, the haplotype GTC remained significantly associated with increased risk of ARDS in the whole cohort (OR, 1.66; 95% CI, 1.09-2.53; p = .02), particularly among male patients (OR, 1.98; 95% CI, 1.16-3.40; p = .02) and among subjects with direct pulmonary injury (OR, 1.75; 95% CI, 1.04-2.95; p = .04).

CONCLUSIONS

The haplotype GTC of NFKBIA gene is associated with higher risk of ARDS in Caucasians, particularly in male patients and in patients with direct lung injury.

Genetics of sarcoidosis: candidate genes and genome scans

Human leukocyte antigen class II allele associations and T-cell receptor beta chain bias in sarcoidosis suggest a specific disease-triggering antigen exposure in a genetically susceptible host. The cause of sarcoidosis has been elusive, but genetics provides one of the few promising avenues to further our understanding. We review the association studies and genome scans used to identify the genes involved in sarcoidosis.

Racial and ethnic disparities in sarcoidosis: from genetics to socioeconomics

Sarcoidosis is a multisystem granulomatous disease of unknown cause that occurs worldwide. The clinical expression of sarcoidosis varies by race. These racial differences may be the result of genetic and socioeconomic factors. Many of these genetic associations are race-specific in that they are found in either African Americans or whites but not both. Socioeconomic differences may also explain the racial disparities between African American and white patients with sarcoidosis. Finally, the phenotypic differences be-tween races may relate to an interaction between genetics and socioeconomic factors. The influences of genetics and socioeconomic status on the development and phenotypic expression of sarcoidosis will be better understood as the mechanisms of disease development are uncovered.

Toll-like receptor (TLR) 4 polymorphisms are associated with a chronic course of sarcoidosis

The aetiology of sarcoidosis, an inflammatory granulomatous multi-system disorder, is unclear. It is thought to be the product of an unknown exogenous antigenic stimulus and an endogenous genetic susceptibility. Toll-like receptors (TLR) are signal molecules essential for the cellular response to bacterial cell wall components. Lipopolysaccharide (LPS), for example, binds to TLR 4. Two different polymorphisms for the TLR4 gene (Asp299Gly and Thr399Ile) have been described recently. This leads to a change in the extracellular matrix function of TLR4 and to impaired LPS signal transduction. We genotyped a total of 141 Caucasian patients with sarcoidosis and 141 healthy unrelated controls for the Asp299Gly and Thr399Ile polymorphisms in the TLR4 gene. The mutations were identified with polymerase chain reaction followed by restriction fragment length polymorphism (RFLP) analysis. Among sarcoidosis patients the prevalence for each Asp299Gly and Thr399Ile mutant allele was 15.6% (22/141). In the control group the prevalence was 5.67% (8/141) (P = 0.07). In the subgroup of patients with acute sarcoidosis there was no difference in the control group (P = 0.93), but there was a highly significant association between patients with a chronic course of sarcoidosis and TLR4 gene polymorphisms (P = 0.01).

Haplotypic structure across the I kappa B alpha gene (NFKBIA) and association with multiple myeloma

Polymorphisms in NFKBIA may be important in pre-disposition to and outcome after treatment, of multiple myeloma (MM). The NFKBIA gene product, IkappaBalpha, binds to NF-kappaB preventing its activation and is important in mediating resistance to apoptosis in B-cell lymphoproliferative diseases. This study investigates eight polymorphisms across the NFKBIA gene in large patient and control populations. Significant differences in the frequency of particular polymorphisms were noted between patients and controls. A risk haplotype [GCCTATCA] for MM was also identified (P=0.006). Analysis of the genetics of NFKBIA may lead to associations with disease progression and survival and thus more personalized therapy.

Sarcoidosis is associated with a truncating splice site mutation in BTNL2

Sarcoidosis is a polygenic immune disorder with predominant manifestation in the lung. Genome-wide linkage analysis previously indicated that the extended major histocompatibility locus on chromosome 6p was linked to susceptibility to sarcoidosis. Here, we carried out a systematic three-stage SNP scan of 16.4 Mb on chromosome 6p21 in as many as 947 independent cases of familial and sporadic sarcoidosis and found that a 15-kb segment of the gene butyrophilin-like 2 (BTNL2) was associated with the disease. The primary disease-associated variant (rs2076530; P(TDT) = 3 x 10(-6), P(case-control) = 1.1 x 10(-8); replication P(TDT) = 0.0018, P(case-control) = 1.8 x 10(-6)) represents a risk factor that is independent of variation in HLA-DRB1. BTNL2 is a member of the immunoglobulin superfamily and has been implicated as a costimulatory molecule involved in T-cell activation on the basis of its homology to B7-1. The G --> A transition constituting rs2076530 leads to the use of a cryptic splice site located 4 bp upstream of the affected wild-type donor site. Transcripts of the risk-associated allele have a premature stop in the spliced mRNA. The resulting protein lacks the C-terminal IgC domain and transmembrane helix, thereby disrupting the membrane localization of the protein, as shown in experiments using green fluorescent protein and V5 fusion proteins.

The same IkappaBalpha mutation in two related individuals leads to completely different clinical syndromes

Both innate and adaptive immune responses are dependent on activation of nuclear factor kappaB (NF-kappaB), induced upon binding of pathogen-associated molecular patterns to Toll-like receptors (TLRs). In murine models, defects in NF-kappaB pathway are often lethal and viable knockout mice have severe immune defects. Similarly, defects in the human NF-kappaB pathway described to date lead to severe clinical disease. Here, we describe a patient with a hyper immunoglobulin M-like immunodeficiency syndrome and ectodermal dysplasia. Monocytes did not produce interleukin 12p40 upon stimulation with various TLR stimuli and nuclear translocation of NF-kappaB was impaired. T cell receptor-mediated proliferation was also impaired. A heterozygous mutation was found at serine 32 in IkappaBalpha. Interestingly, his father has the same mutation but displays complex mosaicism. He does not display features of ectodermal dysplasia and did not suffer from serious infections with the exception of a relapsing Salmonella typhimurium infection. His monocyte function was impaired, whereas T cell function was relatively normal. Consistent with this, his T cells almost exclusively displayed the wild-type allele, whereas both alleles were present in his monocytes. We propose that the T and B cell compartment of the mosaic father arose as a result of selection of wild-type cells and that this underlies the widely different clinical phenotype.