Interleukin-1 Gene Cluster Research Articles

Polymorphism of Interleukin-1 Gene Cluster in Polish Patients with Acute Coronary Syndrome.

Background and objectives: Some experimental studies demonstrated adverse modulation of atherothrombosis by interleukin-1beta (IL-1b). To assess the relationship between the five most common variants of three polymorphisms of the IL1b gene cluster and the complexity of coronary atherosclerosis expressed in Gensini Score (GS), and the age of onset of the first acute coronary syndrome (ACS), we assessed the patients (pts) hospitalized due to ACS in this aspect. Materials and Methods: 250 individuals were included. The single nucleotide polymorphisms of IL1b gene: transition T/C at -31 position, C/T at -511, and those of IL1 receptor antagonist gene (IL1RN)—variable number of tandem repeats allele 1, 2, 3, or 4—were determined by PCR. GS was calculated from the coronary angiogram performed at the index ACS. The impact of the presence of T or C and allele 1 to 4 at the investigated loci on the mean GS, GS greater than 40, mean age of onset of ACS, and the fraction of pts over 60 years of age at ACS were compared between the five most common genotype variants. Results: The five most common variants were present in 203 pts (81.2%). Patients with pair 22 in ILRN had the lowest rate and those with pair 12 had the highest rate of ACS before 60 years of age (29.4 vs. 67.8%; p = 0.004). GS > 40 entailed an eight-fold increase of risk, as observed when pts with one T allele at locus -31 were compared with carriers of 2 or no T allele at this locus: OR 8.73 [CI95 4.26–70.99] p = 0.04. Conclusion: Interleukin-1 beta is subject to frequent genetic variability and our results show a potential relationship of this polymorphism with the extent of coronary atherosclerosis and age at the first ACS.

Interleukin-1 Gene Variability and Plasma Levels in Czech Patients with Chronic Periodontitis and Diabetes Mellitus.

Recent studies have suggested a bidirectional relationship between chronic periodontitis (CP) and diabetes mellitus (DM). Immunoregulatory factors such as cytokines play an important role in etiopathogenesis of both diseases. The aim of this study was to analyze variability in interleukin-1 (IL-1) gene cluster and IL-1β plasma levels in patients with CP, DM, and a combination of both diseases. A total of 1016 individuals participating in this case-control study—225 healthy controls, 264 patients with CP, 132 with type 1 diabetes (T1DM), and 395 patients with type 2 diabetes (T2DM)—were genotyped using methods based on polymerase chain reaction for IL-1 gene polymorphisms (IL-1A (−889C/T, rs1800587), IL-1B (+3953C/T, rs1143634), and IL-1RN (gene for IL-1 receptor antagonist, IL-1RA, 86 bp tandem repeats in intron 2)). Levels of IL-1β were measured by Luminex methods in subgroups of controls, CP, T1DM + CP, and T2DM + CP subjects. Although no significant associations were found in the genotype and allele frequencies of IL-1A (−889C/T), significant differences in the allele frequencies of IL-1B (+3953C/T) were observed between controls and CP patients (P < 0.05). In T1DM patients, IL-1RN∗S “short” allele and IL-1RN 12 genotype were significantly less frequent than those in controls (P < 0.01). In haplotype analysis, TTL haplotype decreased the risk of CP development (P < 0.01), whereas CCS and CTL haplotypes (P < 0.01 and P < 0.05) were associated with T1DM. Although IL-1β levels were measured significantly higher in mononuclear cells after stimulation by mitogens, HSP70, or selected periodontal bacteria than in unstimulated cells, IL-1 genotypes did not correlate with circulating IL-1β levels. In the Czech population, significant associations between the IL-1B polymorphism with CP and the IL-1RN variant with T1DM were found. Haplotype analysis suggests that variability in IL-1 gene cluster may be one of the factors in the CP and T1DM pathogenesis, although single variants of these polymorphisms are not substantial for protein production.

Identification of an immune modulation locus utilising a bovine mammary gland infection challenge model

Inflammation of the mammary gland following bacterial infection, commonly known as mastitis, affects all mammalian species. Although the aetiology and epidemiology of mastitis in the dairy cow are well described, the genetic factors mediating resistance to mammary gland infection are not well known, due in part to the difficulty in obtaining robust phenotypic information from sufficiently large numbers of individuals. To address this problem, an experimental mammary gland infection experiment was undertaken, using a Friesian-Jersey cross breed F2 herd. A total of 604 animals received an intramammary infusion of Streptococcus uberis in one gland, and the clinical response over 13 milkings was used for linkage mapping and genome-wide association analysis. A quantitative trait locus (QTL) was detected on bovine chromosome 11 for clinical mastitis status using micro-satellite and Affymetrix 10 K SNP markers, and then exome and genome sequence data used from the six F1 sires of the experimental animals to examine this region in more detail. A total of 485 sequence variants were typed in the QTL interval, and association mapping using these and an additional 37 986 genome-wide markers from the Illumina SNP50 bovine SNP panel revealed association with markers encompassing the interleukin-1 gene cluster locus. This study highlights a region on bovine chromosome 11, consistent with earlier studies, as conferring resistance to experimentally induced mammary gland infection, and newly prioritises the IL1 gene cluster for further analysis in genetic resistance to mastitis.

The Allele 2 of the VNTR Polymorphism in the Gene That Encodes a Natural Inhibitor of IL-1β, IL-1RA Is Favorably Associated With Chronic Otitis Media.

Objectives Chronic otitis media (COM) is followed by irreversible tissue damage and destruction of the middle ear structures, with the possibility of complications under the maintenance of inflammation. Inflammatory mediators such as cytokines play a crucial role in the initial stage of inflammation. The aim of this study was to evaluate the association of the polymorphisms in two innate immunity/inflammation cascade genes from interleukin-1 (IL-1) gene cluster with COM with regard to cholesteatoma.Methods In the cross-sectional case-control study, DNA samples were collected from 189 patients with COM and 119 controls from a population of Serbia. The +3953 C/T (rs1143634), TaqI polymorphism in interleukin-1 beta (IL-1β) gene and 86 bp variable number tandem repeat (VNTR, rs2234663) polymorphism in the IL-1 receptor antagonist (IL-1RA) gene were analyzed by polymerase chain reaction.Results The IL-1β TaqI polymorphism was not significantly different in patients compared with the control group. The significant difference between patients and controls was observed for both, genotype and allele frequencies of IL-1RA VNTR polymorphism (chi-square P<0.01). We found that carriers of IL-1RA allele 2 (odds ratio, 0.47; 95% confidence interval, 0.29 to 0.76; P=0.004) have a favorable association with COM, using multivariate logistic analysis that included both polymorphisms, age and sex. The IL-1RA allele frequency distribution was significantly different with regard to cholesteatoma.Conclusion The carriers of allele 2 of VNTR IL-1RA polymorphism had a decreased odds ratio for COM, which is in agreement with findings in other inflammatory disease and its previous association with higher IL-1RA levels. Possible down-regulation of IL-1 mediated proinflammatory signaling pathways via IL-1RA in COM as well as results of our study should be further investigated and replicated.

Association of Interleukin-1 Gene cluster polymorphisms with coronary slow flow phenomenon.

Objective:Coronary slow flow phenomenon (CSFP) is characterized by the decreased rate of contrast progression in epicardial coronary arte-ries in the absence of significant coronary stenosis. Mounting evidence has showed a significant association between inflammation and CSFP severity. This study aimed to evaluate possible associations between interleukin-1 receptor antagonist (IL-1ra) gene variable number tandem repeat (VNTR), IL-1β -511 single nucleotide (SNP), and IL-1β+3954 SNP mutations with CSFP.Methods:Forty-eight patients with CSFP and 62 controls with angiographically normal coronary arteries were prospectively enrolled in the study. Genotypes were assessed using the polymerase chain reaction (PCR)-based restriction fragment length polymorphism (PCR-RFLP) technique.Results:Homozygote genotype for allele 2 of+3954 C>T 2/2 genotype was significantly more frequent in patients with CSFP than in the control group, whereas 1/2 genotype was more frequent in the control group (35.4% versus 14.5% for 2/2 genotype and 25% versus 35.5% for 1/2 genotype in CSFP and control groups, respectively, X2=6.6; p=0.04). The allelic frequency of allele 2 of this polymorphism was significantly higher in the CSFP group than in the control group (47.9% versus 28.6% in the control group, X2=5.6; p=0.02). However, there was no significant difference with regard to genotype or allelic frequencies of IL-1ra VNTR or IL-1β -511 SNP polymorphisms between patients with CSFP and controls.Conclusion:IL-1β+3954 SNP mutations are significantly more common in patients with CSFP. It may suggest that the tendency for inflammation may contribute to the presence of this phenomenon.

Interleukin 1 gene polymorphism and susceptibility to disease.

The Interleukin 1 (IL-1) family plays a central role in the generation and regulation of inflammatory responses, in both innate and adaptive immunity. Although the IL-1 molecules are traditionally considered to be classical proinflammatory cytokines, their functions are not restricted to inflammation, and they have also been shown to play a key role in a wide range of additional physiological and pathological functions, including learning modulation, sleep, pregnancy, depression, appetite, hematopoiesis, metabolism, and many others. Since their effect as cytokines and regulators of inflammation is so pleiotropic, any shift of the biological balance between agonistic and antagonistic signals has the potential to cause disease. Here, we consider the genetic influence of interleukin-1 gene polymorphism in the context of susceptibility to human diseases. We review known single nucleotide polymorphisms (SNP) of IL-1 genes linked to human diseases, and suggest how exploring biological effects of IL-1 gene cluster polymorphism may lead to new directions in understanding and diagnostic of disease and effective treatment.

Interleukin-1 Gene Cluster Polymorphisms and Their Association with Coronary Artery Disease: Separate Evidences from the Largest Case-Control Study amongst North Indians and an Updated Meta-Analysis.

Several researchers have reported significant association of numerous single nucleotide polymorphisms (SNPs) residing in the interleukin-1 (IL-1) gene cluster with coronary artery disease (CAD). However, their association status amongst North Indian ancestry (NIA) have never been systematically assessed. Despite a published meta-analysis on this subject, their association status worldwide as well as amongst different major ancestral subgroups still remains unclear. We therefore decided to prospectively test the association of 11 IL-1 gene cluster SNPs with CAD, vide a case-control study amongst a cohort of NIA and attempted to validate our results with the help of an updated meta-analysis of all relevant published association studies. Included studies were segregated into ancestral subgroups and association statuses for each subgroup were determined. A total of 323 cases and 400 healthy, age and sex matched controls belonging to NIA were prospectively enrolled and subsequently genotyped for 11 selected IL-1 gene cluster SNPs. Although results for none of the evaluated IL-1 gene cluster SNPs reached the adjusted level of significance (p<0.0045), clear trends of association were seen for IL1B -511 C>T and IL1RN 86bp VNTR in several of the constructed genetic models (p range = 0.01–0.044 and 0.005–0.034 respectively). The presence of >1, ‘T’ (minor) allele of IL1B -511 C>T in a genotype seemed to provide protection against CAD (OR = 0.62, p = 0.044), while the presence of >1, ‘C’ (major) allele seemed to increase the risk of CAD (OR = 1.36, p = 0.041). The minor allele (allele 2) of IL1RN 86bp VNTR and its homozygous genotype (2/2 genotype) also seemed to carry an increased risk for CAD (OR = 1.62, p = 0.005 and OR = 2.25, p = 0.031 respectively). On the other hand, several haplotype combinations constructed out of IL1B and IL1RN gene variants clearly showed statistically significant associations with CAD (p<0.0045). Our meta-analysis was conducted for 8 previously assessed IL-1 SNPs. We included 53 different studies which involved a total sample of 26,210 (13,982 cases and 12,228 controls). Our pooled results concurred with the findings of our case-control study and was not able to deduce any statistically significant associations for any of the 8 studied SNPs (p>0.05). Subgroup analysis, however, yielded interesting results, where significant differences in association statuses were seen for IL1A +4845 G>T, IL1B -511 C>T, IL1RN 86bp VNTR and IL1RN +8006 T>C for select ancestral subgroups. The hints of associations deduced for subjects belonging to NIA in our case-control study for both IL1B -511 C>T and IL1RN 86bp VNTR were duly validated vide significant p values seen for NIA in all three genetic models (OR range = 0.62–0.76, p range = 0.01–0.04 and OR range = 1.51–2.25, p range = 0.004–0.04 respectively). On the other hand, Mixed Ancestry (MA) subgroup carrying IL1B -511 C>T, IL1RN 86bp VNTR or IL1RN +8006 T>C polymorphisms seemed to enjoy significant protection against CAD. A few other ancestral subgroups also demonstrated significant associations for a few of the studied SNPs vide one of the three genetic models. Clinical interpretation of derived results is however recommended.

Association of interleukin-1 gene cluster polymorphisms and haplotypes with multiple sclerosis in an Iranian population

Multiple sclerosis (MS) is a multi-factorial autoimmune disease of the central nervous system. The exact etiology of MS is still unknown. Due to the important roles that cytokines play as mediators in immune and inflammatory responses, we have evaluated the association of IL-1 gene cluster polymorphisms and haplotypes with MS susceptibility in 306 unrelated MS patients and 312 healthy matched controls. A significant association was found for the IL-1β +3953 T allele [OR=1.43, 95% CI (1.14–1.79), P value=0.002, Pc=0.01] and for IL-1β +3953 T/T genotype and MS risk [OR=1.92, 95% CI (1.25–2.96), P value=0.005, Pc=0.01]. Interestingly, the genotypes of the polymorphisms remained significant under recessive, co-recessive and dominant models. However, no significant differences were found between MS patients and controls in the genotype and allele frequencies of the IL-1β −511, −31 and IL-1Ra polymorphisms. Haplotype analysis for IL-1β −31 and IL-1β −511, with moderate linkage disequilibrium (LD), using the EM algorithm revealed a significant global association of haplotype differences between the two groups. Lower presence of two haplotypes (H3: C-T and H4: T-C) was observed in the MS patients than healthy controls. However, after applying Bonferroni's correction the differences were not significant. To our knowledge, this is the first study reporting the association of the IL-1β +3953 gene polymorphism and MS susceptibility.

Association analysis of the IL-1 gene cluster polymorphisms with aggressive and chronic periodontitis in the Algerian population

ObjectiveThere is strong evidence that genetic as well as environmental factors affect the development of periodontitis. Various studies suggest that genetic polymorphisms of the interleukin-1 (IL-1) genes are associated with an increased risk of developing the pathogenesis. The aim of the present study was to investigate the possible relationship between two polymorphisms of IL-1 gene cluster IL-1B (C+3954T) (rs1143634) and IL-1A (C−889T) (rs1800587) SNPs and the aggressive and chronic periodontitis risk in a case control study in Algerian population. Methods279 subjects were recruited and received a periodontal examination: 128 healthy controls and 151 cases. From cases, 91 patients were having a chronic disease whereas 60 subjects with aggressive form. All these subjects were genotyped for IL-1A (C−889T) and IL-1B (C+3954T) polymorphisms using TaqMan real time PCR technology. Frequencies of IL-1 alleles, genotypes and the haplotypes were also examined. ResultsSignificant differences were found in the carriage rate of both minor alleles of the IL-1A (C−889T) and IL-1B (C+3954T) polymorphisms of aggressive periodontitis cases compared with healthy controls (OR [95%CI]=1.61 [1.03–2.49], p=0.03), (OR [95%CI]=1.69 [1.09–2.63], p=0.01), respectively. The result did not reach significance with the chronic form. ConclusionThe studied polymorphisms of the IL-1 genes appear to be associated with susceptibility to aggressive periodontitis (AgP) in the Algerian population.

Interleukin-1 Gene Cluster Polymorphisms and its Haplotypes may Predict the Risk to Develop Cervical Cancer in Tunisia.

Our study aimed to evaluate the association between IL-1α (4845 G/T), IL-1β (-511C/T) and IL-1RN (VNTR) polymorphisms and risk of cervical cancer. This case-control study investigates three polymorphisms in 130 patients and 260 controls by PCR-restriction fragment length polymorphism (RFLP). The IL-1RN (VNTR) A1/A3 genotype appear as a cervical cancer risk factor (p = 0.048; OR = 2.92; 95 % CI = 1.00-8.74), moreover, the L/2* decreased the risk (p = 0.011; OR = 0.47; 95 % CI = 0.25-0.88) and may be a protective factor against this pathology. Stratified analysis according to the FIGO stage subgroup revealed that the IL-1β-511 T/T genotype and T allele may be a protective factors against cervical cancer development for patients with early stage (p = 0.030; OR = 0.46; 95 % CI = 0.22-0.96) (p = 0.020; OR = 0.68; 95 % CI = 0.48-0.97). However, for the patients with advanced FIGO stage, IL-1RN-VNTR L/2* genotype appear as a protective factor for this pathology (p = 0.023; OR = 0.29; 95 % CI = 0.08-0.99). The (G-T-L) haplotype showed a significant decreased frequency in cervical cancer patients as compared to controls (p = 0.032; OR = 0.53; 95 % CI = 0.29-0.95). In contrast, the (T-T-2*) combination appear a risk factor for the development of cervical cancer (p = 0.018; OR = 1.57; 95 % CI = 1.07-2.30). Our study suggested that IL1 cluster polymorphisms and haplotypes may be a genetic risk factor for cervical cancer.

A study of the interleukin-1 gene cluster polymorphisms and inflammatory external root resorption in replanted permanent teeth.

To investigate whether single nucleotide polymorphisms (SNPs) within the interleukin-1 gene cluster (IL1) are associated with the occurrence and severity of inflammatory external root resorption (IERR) after replantation of avulsed permanent teeth. Indexes of IERR were radiographically assessed in 182 mature replanted permanent teeth from 146 patients at the onset of endodontic therapy. DNA was extracted from buccal mucosa cells and genotyped using TaqMan probes-based assays for the SNPs IL1A -889C/T (rs 180058), IL1B +3954C/T (rs1143634) and IL1RN +2018C/T (rs419598). Teeth were grouped into two categories: IERR absent to mild (indexes ≤ 4) and moderate to severe IERR (indexes > 4). Genetic variations in the IL1 gene cluster were tested for their effect on the occurrence and extension of IERR using the GEE model (generalized estimation equation). Patient's age at the moment of injury, timing of pulpectomy, extra-alveolar period and storage condition of the avulsed teeth was included as possible confounders. No association was found between SNPs IL1A -889C/T, IL1B +3954C/T (rs1143634) and IL1RN +2018C/T (rs419598) and IERR indexes. Timing of pulpectomy (OR 3.5 IC 95% 2.0-6.2 P < 0.001) and patient's age at the moment of trauma (OR 0.29 IC 95% 0.12-0.67 P = 0.004) significantly affected the risk of developing severe IERR. While timing of pulpectomy and patient's age at the moment of trauma were confirmed as important risk factors, SNPs within the IL1 gene cluster did not affect the susceptibility for IERR after replantation of permanent teeth.

Influence of Interleukin-1 Gene Cluster Polymorphisms on the Susceptibility and Outcomes of Acute Stroke in Egyptian Patients

Interleukin-1 (IL-1) has pleiotropic actions in the central nervous system. A growing corpus of evidence has indicated an important role of this cytokine in the development of brain damage following cerebral ischemia. The objective of this study is to investigate the influence of IL-1 cluster gene polymorphisms on the susceptibility of acute stroke and its outcomes in Egyptian patient. 320 patients with new or recurrent stroke [176 with atherothrombotic cerebral infarction, 79 with intracerebral hemorrhage (ICH), and 65 with subarachnoid hemorrhage (SAH)] and 320 controls were included in the study. IL-1b -511, IL-1a -889, and IL-1RN VNTR polymorphisms were analyzed using polymerase chain reaction-restriction fragment length polymorphism. Serum level of IL-1 was measured by enzyme linked immunosorbent assay. All patients were followed for neurological and functional impairments 7 days, 1, 3 and 6 months after the onset of the stroke. We found that IL-1b -511 gene polymorphisms were significantly increased in patients with atherothrombotic, intracerebral, and SAH. Subjects with IL-1a -889 CT and TT genotypes were significantly more likely to have atherothrombotic infarction. Both IL-1b -511, IL-1a -889 genes polymorphisms were significantly more likely to have severe neurological and functional impairment, while IL-1RN 2/2 genotype was significantly decreased in atherothrombotic infarction and ICH groups and showed less severe neurological and functional impairments 7 days, 1, 3, and 6 months after the onset of the stroke compared with carriers of the IL1RN 1/1 and 1/2 genotypes. We concluded that IL-1 cluster gene polymorphisms were associated with risk of acute stroke. IL-1b, IL-1a gene polymorphisms were associated with more severe functional and neurological impairments, while IL-1RN VNTR polymorphisms were associated with good outcomes.

Interleukin-6, interleukin-1 gene cluster and interleukin-1 receptor polymorphisms in Iranian patients with juvenile systemic lupus erythematosus.

Juvenile systemic lupus erythematosus (JSLE) is a polygenic, autoimmune disorder of unknown origin. As proinflammatory cytokines, including interleukin-6 (IL-6) and the interleukin-1 (IL-1) family, seem to contribute to the pathogenesis of JSLE, this investigation was performed to assess the associations of particular single nucleotide polymorphisms (SNPs) of IL-6 and IL-1 genes in a case-control study. Fifty nine JSLE cases were recruited for this study as the patient group, and were compared against 140 healthy, unrelated, control subjects. Using the polymerase chain reaction with the sequence-specific primer method, genotyping was carried out for the IL-6 gene at positions -174 and nt565, as well as the IL-1α gene at position -889, the IL-1β gene at positions -511 and +3962, the interleukin-1 receptor (IL-1R) gene at position Pst-I 1970, and the interleukin-1 receptor antagonist (IL-1Ra) gene at position Mspa-I 11100. RESULTS of the analyzed data revealed a remarkable, positive association for the promoter sequence of the IL-1β gene at position -511 for T/T in the patient group compared with healthy controls (P value, 0.03). Furthermore, a significant negative association was found between the T/C genotype at the same position on the IL-1β gene in juvenile SLE (P value, 0.03). cytokine gene polymorphisms might play a role in the pathophysiology of JSLE. Particular IL-1 gene variants could affect individual susceptibility to JSLE.

Long-range DNA interactions at the IL-1/IL-36/IL-37 gene cluster (2q13) are induced by activation of monocytes

The interleukin-1 gene cluster occupies a 360kb region of chromosome 2q13 and contains nine homologous genes. These include agonists and antagonists of the parallel IL-1 and IL-36 systems, and IL1F7, the gene encoding IL-37. As the genes of the cluster are structurally and functionally related and have similar mRNA kinetics, we have sought evidence for gene induction-specific looping of chromatin in the IL-1 cluster by chromatin conformation capture (3C).We show here that IL1A, IL1B and IL1F7 regulatory regions come in close proximity in LPS stimulated cells but not in resting human monocytes. This suggests that IL1A, IL1B and IL1F7 are likely transcribed by the same transcription factory.One cardinal function of transcriptional Locus Control Region (LCR) is bringing map-distant activated genes into close physical proximity within the transcription factory. Our data show distant intergenic DNA segments are also in close proximity to the regulatory regions of the three genes. This may indicate that they are co-regulated and raise the possibility of a LCR within the cluster.

Genetic variants in theIL1Agene region contribute to intestinal-type gastric carcinoma susceptibility in European populations

The most studied genetic susceptibility factors involved in gastric carcinoma (GC) risk are polymorphisms in the inflammation-linked genes interleukin 1 (IL1) B and IL1RN. Despite the evidence pointing to the IL1 region, definite functional variants reproducible across populations of different genetic background have not been discovered so far. A high density linkage disequilibrium (LD) map of the IL1 gene cluster was established using HapMap to identify haplotype tagSNPs. Eighty-seven SNPs were genotyped in a Portuguese case-control study (358 cases, 1,485 controls) for the discovery analysis. A replication study, including a subset of those tagSNPs (43), was performed in an independent analysis (EPIC-EurGast) containing individuals from 10 European countries (365 cases, 1284 controls). Single SNP and haplotype block associations were determined for GC overall and anatomopathological subtypes. The most robust association was observed for SNP rs17042407, 16Kb upstream of the IL1A gene. Although several other SNP associations were observed, only the inverse association of rs17042407 allele C with GC of the intestinal type was observed in both studies, retaining significance after multiple testing correction (p = 0.0042) in the combined analysis. The haplotype analysis of the IL1A LD block in the combined dataset revealed the association between a common haplotype carrying the rs17042407 variant and GC, particularly of the intestinal type (p = 3.1 × 10(-5) ) and non cardia localisation (p = 4.6 × 10(-3) ). These results confirm the association of IL1 gene variants with GC and reveal a novel SNP and haplotypes in the IL1A region associated with intestinal type GC in European populations.

Cytokine gene polymorphisms associate with microbiogical agents in periodontal disease: our experience.

Periodontics has evolved from a simplistic model to a more complex interplay between infection and host response. Genetic factors have been a new addition to the list of risk factors for periodontal diseases. The processes leading to destruction and regeneration of the destroyed tissues are of great interest to both researchers and clinicians.The selective susceptibility of subjects for periodontitis has remained an enigma and wide varieties of risk factors have been implicated for the manifestation and progression of periodontitis. Emerging pathway models suggest that gene-environment interactions are etiologically important in disease pathogenesis. The current practical utility of genetic knowledge in periodontitis is limited.Allelic variants at multiple gene loci probably influence periodontitis susceptibility. The pro-inflammatory cytokine interleukin-1 (IL-1) is a key modulator of host responses to microbial infection and a major modulator of extracellular matrix catabolism and bone resorption, and polymorphisms in the IL-1 gene cluster have been associated with an increased risk of developing severe adult periodontitis.The aim of this study was to test if polymorphisms of genes of IL-1α+4845 and IL-1β +3954 were linked with periodontitis, in a case-control study population, delimited to a specific geographic area, in association with microbiological findings.The polymorphisms observed in IL-1α+4845 and IL-1β+3954 single nucleotide polymorphisms (SNPs), was significantly different among the study groups (healthy controls, mild, moderate and severe periodontitis with p<0.05, d.f.=1.We found a significant correlation between the severe form of periodontitis and the presence of composite genotype (p < 0.05, d.f.=1, calculated among healthy vs. severe). Furthermore a statistically significant association between the presence of bacteria and periodontitis was detected (p<0.05, d.f.=1). In the current investigation findings were concordant with literature observations.

Correlation of tumor necrosis factor-β and interleukin-1 gene cluster polymorphism with susceptibility to bacteremia in patients undergoing kidney transplantation

Background Bacteremia remains a significant cause of morbidity and mortality after kidney transplantation. This study was conducted to investigate whether the polymorphisms of tumor necrosis factor (TNF)-β, interleukin (IL)-1β, and IL-1 receptor antagonist (IL-1ra) gene predicted the susceptibility to bacteremia within the first 6 months after kidney transplantation. Methods Subjects comprised 82 infected kidney transplant recipients and 60 non-infected kidney transplant recipients. Bacteremia was diagnosed in 16 of the 82 infected recipients. Genomic DNA from these 142 kidney transplant recipients was extracted from peripheral blood leukocytes. Regions containing the NcoI polymorphic site at position +252 of TNF-β gene and the AvaI polymorphic site at position -511 of IL-1β gene were amplified by polymerase chain reaction (PCR) and subsequently digested with NcoI and AvaI restriction enzymes, respectively. The polymorphic regions within intron 2 of IL-1ra gene containing variable numbers of a tandem repeat (VNTR) of 86 base pairs were amplified by PCR. Results Genotypic and allelic frequencies were similar between infected recipients and non-infected ones. Individual locus analysis showed that recipient TNF-β and IL-1ra gene polymorphisms were not associated with the presence of bacteremia (P=0.684 and P=0.567, respectively). However, genotype analysis revealed that recipient IL-1β-511CC genotype was strongly associated with susceptibility to develop bacteremia (P=0.003). Recipient IL-1β-511CC genotype (odds ratio 5.242, 95% confidence intervals 1.645-16.706, P=0.005) independently predicted the risk for bacteremia within the first 6 months after kidney transplantation. Conclusions These findings indicate a critical role of IL-1β gene polymorphisms in susceptibility to bacteremia after kidney transplantation, which may be useful to screen for patients at higher risk for post-transplant bacteremias. Thus, the identified individuals can benefit from preventive treatment and a less potent immunosuppressive regimen.

Genetic Association of Tumor Necrosis Factor-β, Interleukin-10, and Interleukin-1 Gene Cluster Polymorphism With Susceptibility to Pneumonia in Kidney Transplant Recipients

IntroductionPneumonia remains a significant cause of morbidity and mortality after kidney transplantation. The present study was therefore conducted to investigate whether or not the polymorphisms of tumor necrosis factor (TNF)β, interleukin (IL)-10, IL-1β, and IL-1 receptor antagonist (IL-1ra) gene predicted the susceptibility to pneumonia within the first year after kidney transplantation. MethodsSubjects comprised 33 kidney transplant recipients with pneumonia and 63 noninfected kidney transplant recipients. Genomic DNA from these 96 kidney transplant recipients was extracted from peripheral blood leukocytes. The regions containing the NcoI polymorphic site at position +252 of TNFβ gene, the RsaI polymorphic site at position −592 of IL-10 gene, and the AvaI polymorphic site at position −511 of IL-1β gene were amplified by polymerase chain reaction (PCR) and subsequently digested with NcoI, RsaI, and AvaI restriction enzyme, respectively. The polymorphic regions with intron 2 of the IL-1 ra gene (IL-1 RN) containing variable numbers of a tandem repeat of 86 base pairs, were amplified by PCR. ResultsUnivariate analysis showed that recipient IL-10, IL-1β, and IL-1 RN polymorphisms were not associated with the presence of pneumonia (P = .589, .940, and .286, respectively). However, compared with GG genotype, recipient TNFβ +252AA + AG genotype was significantly associated with susceptibility to pneumonia (P = .006). Age of 45 years or older was not significantly associated with susceptibility to develop pneumonia but had a tendency to develop it (P = .119). After adjusting for age of 45 years or older, recipient TNFβ+252 AA + AG genotype (odds ratio = 5.366, 95% confidence intervals = 1.470 − 19.589, P = .011) independently predicted the risk for pneumonia within the first year after kidney transplantation in the multivariate analysis. ConclusionThese results suggested that recipient TNFβ gene polymorphism may be useful in predicting pneumonia, hence identifying individuals who could benefit from preventive treatment and a less potent immunosuppression regimen.

Interleukin-1 gene cluster and IL-1 receptor polymorphisms in Iranian patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease of unknown etiology with a complex pathogenesis involving multiple genetic and environmental contributions. Single-nucleotide polymorphisms (SNPs) in cytokine genes are associated with higher or lower cytokine activity, which can alter the susceptibility to certain diseases or their clinical outcomes. We investigated SNPs of the IL-1 family in Iranian SLE patients and normal individuals. We obtained blood samples from 207 SLE patients and 213 healthy controls. Cytokine genotyping was performed by polymerase chain reaction with sequence-specific primers. The following SNPs were assessed: IL-1A rs1800587, IL-1B rs16944 and rs1143634, IL-1R1 rs2234650 and IL-1RN rs315952. The frequency of the IL-1RN rs315952 CT genotype was significantly lower among patients with SLE compared with healthy controls (OR = 0.63, 95 % CI = 0.42-0.95; P < 0.05 relative to reference genotype and OR = 0.62, CI = 0.42-0.93; P < 0.05 relative to homozygous genotypes). For all other studied alleles and genotypes, there were no significant differences concerning genotype frequencies between patients and controls. A significant increase in IL-1RN rs315952 T allele frequency was noted in patients with a hematologic manifestation (OR = 1.75; 95 % CI = 1.07-2.84; P = 0.033). Polymorphism in IL-1RN rs315952 was significantly associated with SLE in Iranian patients, rs315952CT genotype being a protective factor. We found that IL-1RN rs315952 T allele frequency was significantly higher in patients with hematologic manifestations. Variation at this locus may affect IL-1 receptor antagonist activity, supporting the hypothesis that altered or imbalanced IL1 production may affect the risk of developing SLE.

The Interleukin-1 Gene Cluster Polymorphisms Are Associated with Takayasu's Arteritis in Mexican Patients

Takayasu's arteritis (TA) is a chronic inflammatory arteritis of unknown etiology involving mainly the aorta and its major branches. The interleukin (IL) 1β and IL-1 receptor antagonist have been playing an important role as regulators of inflammation. We investigated whether the polymorphisms at the IL-1B and IL-1RN gene cluster were associated with the genetic susceptibility to develop TA. We analyzed the IL-1B, IL-1F10.3, and IL-1RN polymorphisms in a sample of 58 TA patients, and 248 clinically healthy unrelated Mexican individuals by 5' exonuclease TaqMan polymerase chain reaction. Polymorphic haplotypes were constructed after linkage disequilibrium analysis. We found increased frequencies of different polymorphisms (C allele and TC genotype of IL-1F10.3; TT genotype of IL-1RN.4; C allele and TC genotype of IL-1RN6.1; G allele of IL-1RN6.2 and haplotypes "1T" and "1C" of IL-RN VNTR and IL-1RN6.1) in the group of TA when compared to healthy controls. On the other hand, decreased frequency of IL-1-511 TC genotype was found in the TA group compared to controls. IL-1B and IL-1RN gene polymorphisms could be involved in the risk of developing TA in the Mexican population. These associations were independent of the affected vessels.