Relevance of interleukin 1 receptor antagonist intron 2 polymorphism in Italian MS patients

Relapsing-remitting multiple sclerosis: A profile of interleukine-1 gene cluster polymorphisms in Iraqi patients

In this case-control study, 68 relapsing-remitting multiple sclerosis (RRMS) patients and 133 control were genotyped for IL1A-889 (rs1800587), IL1B-511 (rs16944), IL1B+3962 (rs1143634), IL1R1pst11970 (rs2234650) and IL1RNmspa1 11,100 (rs315952) variants. Sequence-specific-primer-polymerase-chain-reaction was the genotyping method. Logistic regression analysis demonstrated protective effects of IL1B-511, IL1R1pst11970 and IL1RNmspa1 11,100 against MS incidence, while no association was found with IL1A-889 and IL1B+3962 variants. Allele frequencies showed no significant gender, medication or expanded disability status scale-associated variation. Haplotype analysis suggested 4.31-fold increased odds for MS in subjects with C-T-C-C-T haplotype of the respective loci. In conclusion, IL-1 gene variants influence MS susceptibility in Iraqi population.

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.

Involvement of the IL-1 system in experimental autoimmune encephalomyelitis and multiple sclerosis: Breaking the vicious cycle between IL-1β and GM-CSF

Multiple sclerosis (MS) is an autoimmune disease that affects hundreds of thousands of people worldwide. Given the autoimmune nature of the disease, a large part of the research has focused on autoreactive T and B cells. However, research on the involvement of myeloid cells in the pathophysiology of MS has received a strong and renewed attention over the recent years. Despite the multitude of inflammatory mediators involved in innate immunity, only a select group of cytokines are absolutely critical to the development of CNS autoimmunity, among which is interleukin (IL)-1. While the importance of the IL-1 system in experimental autoimmune encephalomyelitis (EAE) and MS has been recognized for about 20years, it is only recently that we have begun to understand that IL-1 plays multifaceted roles in disease initiation, development, amplification and chronicity. Here, we review the recent findings showing an implication of the IL-1 system in EAE and MS, and introduce a model that highlights how IL-1β and granulocyte-macrophage colony-stimulating factor (GM-CSF) are interacting together to create a vicious feedback cycle of CNS inflammation that ultimately leads to myelin and neuronal damage.

Immunopathogenesis and immunotherapeutic approaches in multiple sclerosis

Multiple sclerosis is an organ-specific autoimmune disease, characterized pathologically by cell-mediated inflammation, demyelination and variable degrees of axonal loss. Although inflammation is considered central to the pathogenesis of multiple sclerosis, to date, the only licensed and hence widely used multiple sclerosis immunotherapies are interferon-beta, glatiramer acetate and mitoxantrone. This review discusses the immunopathogenesis of multiple sclerosis, focusing on a number of emerging immunotherapies. A number of new approaches likely to manipulate the immunopathogenesis of multiple sclerosis and which may ultimately allow for the development of more effective immunotherapy are also highlighted.

Multiple sclerosis: association with the interleukin-1 gene family polymorphisms in the Turkish population

BACKGROUND

Multiple Sclerosis (MS) is a neurodegenerative disease. It involves inflammation and demyelination. Since cytokines play an important role in the development of MS, genes encoding cytokines such as the Interleukin (IL)-1 family are candidate genes for MS susceptibility.

OBJECTIVE

To determine the relationship between IL-1 gene family and MS in the Turkish population.

METHODS

A total of 409 MS patients and 256 healthy controls were included in the study. IL-1A -889 (rs1800587), IL-1 RN variable number tandom repeat (VNTR), IL-1B -511 (rs 16944) and IL-1B +3953 (rs 1143634) polymorphisms were investigated from the genomic DNA, obtained via blood samples.

RESULTS

No association was found between IL-1A and IL-1RN polymorphisms and susceptibility to MS. However, we have found significantly decreased frequency of IL-1B -511 genotype (p = 0.004) in MS patients compared to controls. In addition, there was a significant association between IL-1B -511 (1/2) genotype and early onset MS (EOMS) (p = 0.0001).

CONCLUSIONS

Individuals with the 2/2 genotype of IL-1B -511 have significantly decreased incidence of MS, suggesting a protective role for this genotype in the Turkish population. Additionally, IL-1B -511 (1/2) genotype was determined as a possible risk factor for EOMS.

Association of interleukin-1 gene polymorphisms with multiple sclerosis: a meta-analysis

BACKGROUND

Dysregulated levels of interleukin-1 (IL-1) were observed in patients with multiple sclerosis (MS). Previous studies have provided conflicting evidence implicating the IL-1 gene polymorphisms in MS risk.

METHODS

A meta-analysis of 16 case-control studies involving 3,482 cases and 3,528 controls was conducted to evaluate this association.

RESULTS

No association was found between the IL-1α -889 (rs1800587), IL-1α +4,845 (rs17561), IL-1β -511 (rs16944), IL-1β +3,953 (rs1143634), IL-1ra variable number tandem repeat (VNTR) polymorphisms and MS risk. However, in subgroup analyses for the IL-1ra VNTR polymorphism, we found that individuals carrying the 2 allele had a 32 % increased risk for bout-onset MS (relapsing remitting and secondary progressive MS) when compared to the LL homozygotes (OR = 1.32, 95 % CI = 1.06-1.66, P (z) = 0.014).

CONCLUSION

Common variants in the IL-1 region are not associated with MS risk but our data suggest that the IL-1ra VNTR polymorphism might be associated with bout-onset MS subtype.

Genetics for understanding and predicting clinical progression in multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a dys-immune disease of the central nervous system with highly variable and unpredictable long-term outcome.

STATE OF THE ART

In the early 1970s association between HLA alleles and MS was established. Very recently, the power of Genome Wide Association Studies (GWAS) enabled the identification of several loci involved in immune functions as genetic risk factors in MS. Recent data suggest that common genetic variations might modulate the clinical phenotype of MS through a regulation of key pathophysiological pathways.

PERSPECTIVES

Identification of modifier genes might offer an opportunity to explore new relevant therapeutic targets and early prognostic markers. To date, studies of modifier genes in MS are numerous but results are still unclear. This research field may now benefit from large cohorts of patients available for association studies.

CONCLUSION

In this context, we propose a review of epidemiological and association studies of genetic modifying effect in MS.

INTERLEUKIN-1 RECEPTOR ANTAGONIST GENE POLYMORPHISM AND TRADITIONAL CLASSIFICATION IN OBESE WOMEN

Cytokines appear to be the major regulators of adipose tissue metabolism. Interleukin- 1 receptor antagonist (IL-1ra) serum levels are increased in human obesity, and are under strong genetic control. The hypothesis was tested that the IL-1ra gene might be a candidate for obesity. Furthermore, the relationship was investigated between Sasang constitution and IL-1ra polymorphism. The frequency of a penta-allelic 86-bp tandem repeat (VNTR) in the intron 2 of IL-1ra gene in 67 lean (BMI<25 kg/m2), 133 overweight (BMI 25-29.9 kg/m2) and 61 obese (BMI>or=30 kg/m2) otherwise healthy Korean subjects was investigated. Total fat mass and percentage body fat were determined by dual-energy X-ray absorptiometry. Subjects were discriminated into four types by QSCC II program as well as clinical data (weight, height, blood pressure, etc.); Teaeumin, Taeyangin, Soyangin, and Soeumin. Genomic DNA was extracted and used for polymerase chain reaction-based genotyping of IL-1ra. The genotypic, or allelic distribution did not differ markedly between the three groups. The relative risk of being obese in comparison with lean was twofold increased in allele 2 carriers, although it was not statistically significant. Carriers of the allele 2 did not show a significant difference in physical and clinical characteristics. However, the relative risk of being obese in comparison with lean was increased in Taeumin subjects (p=.050), and so was in IL-1ra A2- carriers (p=.047). No relationship was found between the IL-1ra polymorphism and BMI in Korean women, but the authors first attempted to find an association among IL-1ra polymorphism, obesity, and Sasang constitution.

An investigation of susceptibility loci in benign, aggressive and primary progressive multiple sclerosis in Northern Irish population

OBJECTIVE

To investigate the possibility that susceptibility loci in multiple sclerosis (MS) have a role in determining the disease outcome in Northern Ireland population.

BACKGROUND

The Genetic Analysis of Multiple Sclerosis in Europeans (GAMES) initiative and follow-up refined analysis identified 15 candidate susceptibility loci within the Northern Irish population for MS. We aimed to investigate the 12 most significant markers for their role in disease outcome.

METHODS

Cases with probable or definite MS (Poser criteria) were classified as benign onset (Kurtzke Expanded Disability Status Scale [EDSS]<or=3.0 at 10 years), aggressive (Kurtzke EDSS>or=6.0 by 10 years), or primary progressive MS. All cases were Caucasian of Northern Irish origin. DNA was extracted from venous blood, microsatellite markers were amplified using polymerase chain reaction and typed using fluorescent fragment analysis. Allele frequencies were compared statistically using a chi-squared test with allowance for multiple comparisons (critical P<0.0042); significant markers were further analyzed by CLUMP (critical P<0.0014).

RESULTS

Two microsatellite markers were significant: D3S1278 (Chr 3q13, P<0.001) and tumor necrosis factor (TNF)-alpha (Chr 6p21, P<0.001). A further three markers were significant in our preliminary analysis suggesting a trend toward impact on disease outcome; D4S432 (Chr 4p16, P=0.001), D2S347 (Chr 2q14, P=0.003), and D19S903 (Chr 19p13, P=0.003).

CONCLUSIONS

This is the first study to suggest a role for TNF-alpha in the disease outcome in MS. Larger replication studies need to be performed to assess the role of markers D4S432, D2S347, and D19S903.

The genetics of clinical outcome in multiple sclerosis

Multiple sclerosis (MS) is a common inflammatory disease of the central nervous system (CNS), the clinical course of which varies considerably between patients. Genetic complexity and interactions with as yet unknown environmental factors have hindered researchers from fully elucidating the aetiology of the disease. In addition to influencing disease susceptibility, epidemiological evidence suggests that genetic factors may affect phenotypic expression of the disease. Genes that affect clinical outcome may be more effective therapeutic targets than those which determine susceptibility. We present in this review a comprehensive survey of the genes (both MHC- and non-MHC-related) that have been investigated for their role in disease outcome in MS. Recent studies implicating the role of the genotype and epistatic interactions in the MHC in determining outcome are highlighted.

Association of polymorphisms in CTLA-4, IL-1ra and IL-1beta genes with multiple sclerosis in Serbian population

We have investigated separate as well as combined influence of IL-1beta TaqI, IL-1ra VNTR and CTLA-4 + 49 A/G polymorphisms on susceptibility, clinical course and progression of MS in 162 Serbian patients. We found significant independent relative risk for MS susceptibility in noncarriers of IL-1ra allele 2 (OR = 2.2, CI = 1.3-3.7, p = 0.003) and CTLA-4 + 49 AA genotype (OR = 2.0, CI = 1.2-3.5, p = 0.01) as well as their combined effect (OR = 4.4, CI = 2.0-9.7, p = 0.0003). Our result supports the significant and combined effect of IL-1ra VNTR and CTLA-4 polymorphisms on MS justifying the need for further haplotype analysis in different populations.

Postoperative pain, morphine consumption, and genetic polymorphism of IL-1beta and IL-1 receptor antagonist

Interleukin-1 beta (IL-1beta) and its endogenous IL-1 receptor antagonist (IL-1Ra) play an important role in inflammatory response and in pain modulation. It has recently been shown that polymorphism of the IL-1beta and IL-1Ra genes may account for variation in the production of these cytokines. The present study examined the hypothesis that polymorphism of IL-1beta and IL-1Ra genes is involved in pain sensitivity and morphine consumption in the immediate postoperative period. Genetic polymorphism was determined in 76 women undergoing transabdominal hysterectomy. The genotype of IL-1Ra was determined using PCR amplification of the variable number of tandem repeats (VNTR) of 86 base pair (bp) in intron 2, while for IL-1beta the cytosine to thymine transition at codon -511 of the promoter was determined by PCR. Morphine consumption and pain scores were evaluated in the first postoperative 24 h. The study group was divided based on morphine consumption to three sub-groups: low morphine consumers (LMC) (<28 mg/24 h), medium morphine consumers (MMC) (28-38 mg/24 h), and high morphine consumers (HMC) (>38 mg/24 h). Patients consuming the least amount of morphine postoperatively showed significant lower pain scores. IL-1Ra genetic polymorphism of the MMC group was significantly different compared to the other two groups. No difference in IL-1beta gene polymorphism was found among the three sub-groups. Since IL-1Ra polymorphism is known to affect the levels of both IL-1Ra and IL-1, cytokines associated with modulation of pain sensitivity and morphine analgesia, it is suggested that IL-1Ra genetic polymorphism may contribute to the variation in postoperative morphine consumption.

MS treatment: new perspectives

Immunomodulating and immunosuppressive treatments for multiple sclerosis patients are directed against the inflammatory process and are only partially effective. This partial failure could be explained by mechanisms of axonal damage at least partially independent from acute or chronic inflammation. This suggests that there is a need for better use of available treatments and the necessity of alternative new therapeutic options to halt disease progression and enhance recovery mechanisms. Concerning actual treatments, two strategies are quite interesting: early treatment and combination therapy. The former approach is based on converging epidemiological, immunological and pathological studies and is proved by some recent clinical trials. The second one is under evaluation on ongoing clinical trials. Progress in understanding the mechanisms of T cell activation, inactivation and modulation has been translated into new therapeutic strategies aiming at inducing selective immunosuppression. Such an approach is now tested in phase II-III clinical trials.

Multiple sclerosis genetics: leaving no stone unturned

Compelling epidemiologic and molecular data indicate that genes play a primary role in determining who is at risk for developing multiple sclerosis (MS), how the disease progresses, and how someone responds to therapy. The genetic component of MS etiology is believed to result from the action of allelic variants in several genes. Their incomplete penetrance and moderate individual effect probably reflects epistatic interactions, post-transcriptional regulatory mechanisms, and significant environmental influences. Equally significant, it is also likely that locus heterogeneity exists, whereby specific genes influence susceptibility and pathogenesis in some individuals but not in others. With the aid of novel analytical algorithms, the combined study of genomic, transcriptional, proteomic, and phenotypic information in well-controlled study groups will define a useful conceptual model of pathogenesis and a framework for understanding the mechanisms of action of existing therapies for this disorder, as well as the rationale for novel curative strategies.

Genotypes and haplotypes in the IL-1 gene cluster: analysis of two genetically and diagnostically distinct groups of Alzheimer patients

Increased risk of Alzheimer's disease (AD) has been associated with polymorphisms in the IL-1 gene cluster, and in particular with the IL-1alpha-889 T/T genotype. However, this association is still unclear, and needs further investigation. In order to clarify the role of these polymorphisms in the complex pathogenesis of AD we examined genotype and haplotype frequencies of the two C-to-T SNPs at position -889 and -551 in the IL-1alpha and IL-1beta genes, respectively, and of the 86 bp VNTR intron-2 polymorphisms in the IL-1Ra gene. The analysis was performed in two genetically and diagnostically distinct groups of sporadic AD from Italy and the USA. In the Italian group a significant association between the IL-1alpha-889 T/T genotype and AD (OR=3.022, 95% CI: 1.001-9.119) was found, whereas no difference was found in the group from the USA. Results were also compared with previously published studies that analyzed the same IL-1 polymorphisms in AD. In both groups, the analysis of the estimated haplotypes shows that AD patients and controls who carry the IL-1beta-511 C allele, were also more frequently carriers of the IL-1Ra 1 allele (haplotypes -C-1). The total frequency of the two -C-1 haplotypes (C-C-1 plus T-C-1) was about one half of the total frequency of the eight estimated haplotypes. This was confirmed by significant linkage disequilibrium between these two loci in both the Italian and USA groups. In the Italian group a weak association of the T-C-2 haplotype with the disease (OR=1.648, 95% CI: 1.519-1.788) was also found, whereas in the USA group no difference was found. Although ours and other published data on different samples of Caucasian and non-Caucasian AD show a great heterogeneity in the frequencies of the IL-1alpha-889, the IL-1beta-511 and the IL-1Ra VNTR gene polymorphisms, we confirm the role of the IL-1alpha-889 T/T genotype as a risk factor for sporadic AD, and show the presence of an allelic association between IL-1beta C and IL-1Ra 1 alleles in both the Italian and the USA groups, confirmed by the presence of significant levels of linkage disequilibrium between these two loci.

The interleukin-1 gene family in multiple sclerosis susceptibility and disease course

Multiple sclerosis (MS) is a chronic disease of presumed autoimmune origin with a considerable polygenic influence. We have previously observed that a specific allele combination in genes of the interleukin-1 (IL-1) family influenced the progression rate in MS. We have considerably expanded our patient population (492 MS patients and 228 controls). In the present study, we investigated the role of the IL-IA--889, IL-1B--511, IL-1B f3953 and IL-1RN VNTR gene polymorphisms in MS. In addition, we performed preliminary analyses on longitudinal magnetic resonance imaging (MRI) data. We found no associations between the polymorphisms and susceptibility to MS or clinical features. In addition, we observed no significant effect of the polymorphisms on brain or lesion volumes, Based on our data and those from the literature, one can conclude that there is currently no evidence to support a role for the IL-1 genes in MS.

Polymorphism of interleukin-1 receptor antagonist gene and obesity

BACKGROUND

Cytokines appear to be major regulators of adipose tissue metabolism. Interleukin-1 receptor antagonist (IL-1ra) serum concentrations are increased in human obesity, and are under strong genetic control. We tested the hypothesis that the IL-1ra gene might be a candidate for obesity.

METHODS

We investigated the frequency of a penta-allelic 86-bp tandem repeat (VNTR) in the intron 2 of IL-1ra gene in 52 lean (body mass index (BMI) <25 kg/m(2)), 133 overweight (BMI 25-29.9 kg/m(2)) and 76 obese (BMI > or =30.0 kg/m(2)) otherwise healthy Korean women. Total fat mass and percent body fat were determined by dual-energy X-ray absorptiometry. Genomic DNA was extracted and used for polymerase chain reaction-based genotyping of IL-1ra.

RESULTS

Carriers of the allele 2 did not show a significant difference in physical and clinical characteristics. The genotypic, or allelic distribution did not differ markedly between the three groups. The relative risk of being obese in comparison with lean group tended to be higher in allele 2 carriers, but not significantly.

CONCLUSIONS

We found no relationship between the IL-1ra polymorphism and BMI in Korean women.

Interleukin (IL)-1 gene polymorphisms: relevance of disease severity associated alleles with IL-1beta and IL-1ra production in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is an autoimmune disorder, with a considerable genetic influence on susceptibility and disease course. Cytokines play an important role in MS pathophysiology, and genes encoding various cytokines are logical candidates to assess possible associations with MS susceptibility and disease course. We previously reported an association of a combination of polymorphisms in the interleukin (IL)-1B and IL-1 receptor antagonist (IL-1RN) genes (i.e. IL-1RN allele 2+/IL-1B(+3959)allele 2-) with disease severity in MS. Extending this observation, we investigated whether IL-1beta and IL-1ra production differed depending on carriership of this gene combination.

METHODS

Twenty MS patients and 20 controls were selected based upon carriership of the specific combination. In whole blood, in vitro IL-1beta and IL-1ra production was determined by enzyme-linked immunosorbent-assay after 6 and 24 h of stimulation with lipopolysaccharide.

RESULTS

Carriers of the specific combination produced more IL-1ra, especially in MS patients, although not significantly. IL-1ra production was significantly higher in individuals homozygous for IL-1RN allele 2. In patients, Il-1ra production was higher and IL-1beta production lower compared with controls. In primary progressive patients, the IL-1beta /IL-1ra ratio was significantly lower than in relapsing-remitting patients.

CONCLUSION

Our results suggest higher in vitro IL-1ra production in carriers of IL-1RN allele 2, with an indication of an allelic dose-effect relationship.

Neuroinflammation and anti-inflammatory therapy for Alzheimer's disease

Neuroinflammation is now recognized as a prominent feature in Alzheimer's pathology and a potential target for therapy aimed at treatment and prevention of disease. This review provides a synopsis of current information about cellular and molecular mediators involved in Alzheimer's neuroinflammation as well as interactions between these mediators that influence pathology. Anti-inflammatory therapies, particularly nonsteroidal anti-inflammatory drugs, are considered from experimental and clinical perspectives and potential mechanisms underlying their apparent benefits are discussed. Finally, possible protective effects of the inflammatory response in Alzheimer's are described. Taken all together, evidence presented in this review suggests a scheme for Alzheimer's pathogenesis, with neuroinflammation playing a crucial role influencing and linking beta-amyloid deposition to neuronal damage and clinical disease.

The balance between IL-1 and IL-1Ra in disease

IL-1 is an important mediator of inflammation and tissue damage in multiple organs, both in experimental animal models of disease and in human diseases. The IL-1 family consists of two agonists, IL-1alpha and IL-1beta, two receptors, biologically active IL-1RI and inert IL-1RII, and a specific receptor antagonist, IL-1Ra. The balance between IL-1 and IL-1Ra in local tissues plays an important role in the susceptibility to and severity of many diseases. An allelic polymorphism in the IL-1Ra gene has been associated with a variety of human diseases primarily of epithelial and endothelial cell origin. This association may be secondary to an imbalance in the IL-1 system with enhanced production of IL-1beta and reduced production of the major intracellular isoform of IL-1Ra. Treatment of RA with daily subcutaneous injections of recombinant IL-1Ra protein has been shown to be efficacious. Gene therapy approaches with IL-1Ra are being evaluated for the treatment of RA and other human diseases.

Interleukin 1 genotypes in multiple sclerosis and relationship to disease severity

We studied the association between clinical outcome in MS and allelic variants single nucleotide polymorphisms (SNPs) of interleukin-1alpha (IL-1alpha), IL-1beta and a variable number tandem repeat (VNTR) in IL-1 receptor antagonist (IL-1RN). A total of 377 patients with MS were studied. Significant associations between IL-1 genotypes and clinical outcome were found using logistic regression after correction for gender, onset age and disease duration. The same trends were subsequently demonstrated in a second independent group of 67 primary progressive patients. Our results suggest that genetically determined immunomodulation mediated by IL-1 influences long-term prognosis in multiple sclerosis (MS).

Genetics of multiple sclerosis: linkage and association studies

Multiple sclerosis (MS) is a demyelinating autoimmune disease of the central nervous system caused by an interplay of environmental and genetic factors. The only genetic region that has been clearly demonstrated by linkage and association studies to contribute to MS genetic susceptibility is the human leukocyte antigen (HLA) system. The majority of HLA population studies in MS have focused on Caucasians of Northern European descent, where the predisposition to disease has been consistently associated with the class II DRB1*1501-DQA1*0102-DQB1*0602 haplotype. A positive association with DR4 was detected in Sardinians and in other Mediterranean populations. Moreover DR1, DR7, DR11 have been found to be protective in several populations. Systematic searches aimed at identifying non-HLA susceptibility genes were undertaken in several populations by means of linkage studies with microsatellite markers distributed across the whole genome. The conclusion of these studies was that there is no major MS locus, and genetic susceptibility to the disease is most likely explained by the presence of different genes each conferring a small contribution to the overall familial aggregation. The involvement of several candidate genes was tested by association studies, utilizing either a population-based (case control) or a family-based (transmission disequilibrium test) approach. Candidate genes were selected mainly on the basis of their involvement in the autoimmune pathogenesis and include immunorelevant molecules such as cytokines, cytokine receptors, immunoglobulin, T cell receptor subunits and myelin antigens. With the notable exception of HLA, association studies met only modest success. This failure may result from the small size of the tested samples and the small number of markers considered for each gene. New tools for large scale screening are needed to identify genetic determinants with a low phenotypic effect. Large collaborative studies are planned to screen several thousands of patients with MS with several thousands of genetic markers. The tests are increasingly based on the DNA pooling procedure.

Estrogen receptor gene polymorphism and multiple sclerosis in Japanese patients: interaction with HLA-DRB1*1501 and disease modulation

We investigated PvuII and XbaI polymorphism in the estrogen receptor gene (ERG) and HLA-DRB1*1501 positivity in 116 conventional multiple sclerosis (MS) patients and 101 healthy controls in a Japanese population. Logistic analysis revealed independent associations of [P] allele in the profiles for PvuII (p=0.0005, adjusted odds ratio (aOR)=3.17) and DRB1*1501 (p=0.0089, aOR=2.61) with conventional MS. Synergistic elevated risk of MS due to interaction between the [P] allele and HLA-DRB1*1501 allele was found among female patients (odds ratio=16.0; 95% CI=3.99-63.8, p<0.0001). The [P] allele-positive patients with disease duration of more than 5 years had a significantly higher progression index (PI) of disability (p=0.0230) and a worse ranked MS severity score (p=0.0152) than their non-[P] counterparts.

Production of IL-1beta and IL-1Ra as risk factors for susceptibility and progression of relapse-onset multiple sclerosis

Interleukin-1beta (IL-1beta) is present in multiple sclerosis (MS) lesions. Interleukin-1 receptor antagonist (IL-1Ra) moderates the induction of experimental autoimmune encephalomyelitis (EAE). Here, we show that families that are characterized by high IL-1beta over IL-1Ra production ratio are at 2.2-fold (95% CI, 1.0-4.8; p=0.05) increased risk to have a patient relative with relapse-onset MS than families with a low ratio. It is also related to the reduction of volumetric magnetization transfer ratio (MTR) histogram height, a measure of parenchymal integrity (p=0.04). Those families who combine a high IL-1beta over IL-1Ra ratio with a high tumor necrosis factor (TNF) over IL-10 production ratio have a 6.2-fold (95% CI, 1.8-21; p=0.002) increased risk. Innate production of IL-1beta and IL-1Ra is not related to the outcome of primary progressive MS. Taq1 polymorphism in the IL-1beta gene and the variable number of tandem repeats (VNTR) polymorphism of 86-base pairs within the IL-1Ra gene cannot explain these findings.

Interleukin-1 beta exerts a myriad of effects in the brain and in particular in the hippocampus: analysis of some of these actions

The realization, in the past decade or so, that bidirectional communication between the central nervous system and the immune system was likely has sparked an explosion of interest in the roles certain cytokines, particularly the proinflammatory cytokine interleukin-1 beta (IL-1 beta), might play in the brain. The observation that IL-1 type I receptor was expressed in highest density in the hypothalamus was of significance in identifying a role for IL-1 beta in neuroendocrine modulation. However, the finding that receptor expression was also high in the hippocampus, an area of the brain which plays a pivotal role in memory and learning, has led to uncovering a role for IL-1 beta in cognitive function. There is now a great deal of evidence suggesting that IL-1 beta plays a significant role in hippocampal synaptic function, and the possibility that IL-1 beta may trigger some of the detrimental changes in certain neurodegenerative diseases is currently being assessed. The review addresses some of the issues relating to the role of IL-1 beta in the brain, specifically in the hippocampus.

Identifying disease modifying genes in multiple sclerosis

Evidence is mounting that genetic variation influences not only susceptibility to multiple sclerosis (MS), but also its course and severity. Identification of disease modifying genes, however, poses unique challenges, especially on how to classify the course and outcome of the disease in ways that may be relevant to analysis of biological factors that might be influenced by genes. The power of the statistical approaches to detect small effects of individual genes in complex disorders such as MS is problematic, and approaches to estimate power must be appropriate for the data. Nonetheless, using contemporary schemes of classification, genetic variants that influence disease course have been found; in fact, a small number have been confirmed to influence disease course in two or more independent studies. This review addresses strategies relevant to identification of disease modifying genes in MS, and summarizes and critically evaluates the current state of knowledge in this area.

IL-1 genes in myasthenia gravis: IL-1A -889 polymorphism associated with sex and age of disease onset

Myasthenia gravis (MG) is a multifactorial autoimmune disease of the neuromuscular junction. We investigated the relation between four polymorphisms of the interleukin (IL)-1 gene cluster on 2q12-22, and MG susceptibility and clinical features in a large cohort of individuals. No polymorphism was associated with MG susceptibility. However, the IL-1A -889 CC genotype was associated with early disease onset (p=0.0044) in the whole MG group and the subgroup of CC males developed MG about 18 years earlier than males carrying other IL-1A -889 genotypes (p=0.022). This finding suggests that IL-1A is a disease modifier in MG, or is in linkage disequilibrium with an unknown locus on chromosome 2.

Analysis of an interferon-gamma gene dinucleotide-repeat polymorphism in Nordic multiple sclerosis patients

The proinflammatory cytokine interferon (IFN)-gamma has been shown to influence the course of multiple sclerosis (MS). The IFN-gamma (IFNG) contains a multiallelic dinucleotide repeat in intron 1. To investigate whether alleles at this locus influence susceptibility to MS, we performed linkage and familial association analyses on 100 sibling pairs from four Nordic countries, and case-control association analysis on 220 intermediately disabled sporadic MS patients and 266 controls. To determine the effect of the polymorphism on disease outcome, we compared genotype frequencies in the most and least disabled octiles of a total cohort of 913 cases. We also measured IFN-gamma mRNA levels in unstimulated peripheral blood mononuclear cells from 46 MS patients and 27 controls grouped according to IFNG intron 1 genotype. Both nonparametric linkage analysis and transmission disequilibrium testing of the 100 sibling pairs produced negative results. Genotype frequencies for intermediate-MS patients did not differ significantly from those for controls; nor did genotype frequencies in the benign-MS octile differ significantly from those in the severe-MS octle. Comparison of IFN-gamma mRNA levels in genotype-conditioned subgroups revealed no significant differences. Thus, alleles at the IFNG intron 1 dinucleotide repeat appear to affect neither MS susceptibility and severity nor IFN-gamma mRNA expression in vivo.

A study of interleukin-1 cluster genes in susceptibility to and severity of multiple sclerosis

In this explorative study, interleukin-1 (IL-1) receptor antagonist (IL-1RA; polymorphism of variable number of tandem repeats: VNTR), IL-1alpha (-889), IL-1beta (-511) and IL-1beta (+3953) polymorphisms were studied in relation to susceptibility to and severity of multiple sclerosis (MS), in 93 MS patients and 400 normal controls. No associations were found for any polymorphisms, alone or in combination. However, in our MS cohort, females were found to be IL-1RA allele 2 carriers more frequently than males (33/49 vs. 16/44, p = 0.0028). Using a cohort of 109 controls, IL-1RA allele 2 carriers were more frequently women with MS than control women (33/49 vs. 23/43, odds ratio (OR) = 2.19, 95% confidence interval (CI) 1.02-4.72, p = 0.043, P(C) = ns). The data suggest that the IL-1 cluster genes make no major contribution to MS, but the tentative association between IL-1RA allele 2 and susceptibility of MS in women warrants further studies.

Multiple sclerosis: genomic rewards

A large body of immunologic, epidemiologic, and genetic data indicate that tissue injury in multiple sclerosis (MS) results from an abnormal immune response to one or more myelin antigens that develops in genetically susceptible individuals after exposure to an as-yet undefined causal agent. The genetic component of MS etiology is believed to result from the action of several genes of moderate effect. The incomplete penetrance of MS susceptibility alleles probably reflects interactions with other genes, post transcriptional regulatory mechanisms, and significant nutritional and environmental influences. Equally significant, it is also likely that genetic heterogeneity exists, meaning that specific genes influence susceptibility and pathogenesis in some affects but not in others. Results in multiplex MS families confirm the genetic importance of the MHC region in conferring susceptibility of MS. Susceptibility may be mediated by the class II genes themselves (DR, DQ or both), related to the known function of these molecules in the normal immune response, e.g. antigen binding and presentation and T cell repertoire determination. The possibility that other genes in the MHC or the telomeric region of the MHC are responsible for the observed genetic effect cannot be excluded. The data also indicate that although the MHC region plays a significant role in MS susceptibility, much of the genetic effect in MS remains to be explained. Some loci may be involved in the initial pathogenic events, while others could influence the development and progression of the disease. The past few years have seen real progress in the development of laboratory and analytical approaches to study non-Mendelian complex genetic disorders and in defining the pathological basis of demyelination, setting the stage for the final characterization of the genes involved in MS susceptibility and pathogenesis. Their identification and characterization is likely to define the basic etiology of the disease, improve risk assessment and influence therapeutics.

Biological role of interleukin 1 receptor antagonist isoforms

The interleukin 1 receptor antagonist (IL1Ra) family of molecules now includes one secreted isoform (sIL1Ra) and three intracellular isoforms (icIL1Ra1, 2, and 3). Extensive evidence indicates that the sole biological function of sIL1Ra seems to be to competitively inhibit IL1 binding to cell-surface receptors. Although intracellular IL1Ra1 may be released from keratinocytes under some conditions, the intracellular isoforms of IL1Ra may carry out additional as yet poorly defined roles inside cells. Maintenance of a balance between IL1 and IL1Ra is important in preventing the development or progression of inflammatory disease in certain organs. Both the secreted and intracellular isoforms of IL1Ra contribute to maintenance of this balance. An allelic polymorphism in intron 2 of the IL1Ra gene (IL1RN*2) predisposes to the development or severity of a variety of human diseases largely of epithelial cell origin. Both the impaired production of IL1Ra and the overproduction of IL1beta are related to the presence of this allele. Restoration of the balance between IL1Ra and IL1 through a variety of approaches is a therapeutic goal in specific chronic inflammatory diseases.

Predictive value of interleukin 1 gene polymorphisms for surgery

OBJECTIVES

To determine the influence of interleukin 1alpha (IL1alpha), IL1beta, and IL1 receptor antagonist gene polymorphisms on disease outcome as assessed by the need for major joint surgery within 15 years of diagnosis.

PATIENTS AND METHODS

50 patients with rheumatoid arthritis (RA) who required major joint surgery (hip, knee, or shoulder arthroplasty) within a 15 year period of disease diagnosis and 50 patients with RA with disease duration greater than 15 years and no major surgery were recruited together with 66 normal west of Scotland controls. Genomic DNA and polymerase chain reaction were used to determine polymorphisms in the genes for IL1alpha, IL1beta, and IL1 receptor antagonist. For all patients with RA recruited to the study, HLA-DR beta1 gene status was recorded as was the erythrocyte sedimentation rate (ESR) at the first ever clinic visit.

RESULTS

No difference in the allele frequencies or genotypes of the IL1alpha and IL1 receptor antagonist gene polymorphisms was found between the controls and patients with RA, with or without previous surgery. IL1beta allele 2 was overrepresented in patients with RA who had undergone surgery compared with patients who had not (40% v 27%, chi(2)=4, 1df, p=0.04). ESR at the first ever clinic visit was significantly higher in those carrying allele 2 (36 mm/1st h v 22 mm/1st h, p=0.04). When patients, with or without previous surgery, who did not carry two disease associated HLA-DR beta1 alleles were compared, an increase in allele 2 was observed in the surgery cohort (42% v 25%, chi(2)=4.8, 1df, p=0.03).

CONCLUSIONS

Patients who require major joint surgery were found to carry the IL1beta allele 2 more often than expected. Patients with this allele also had a higher initial ESR. This may be useful in predicting early surgery in patients who do not carry two disease associated HLA-DR beta1 alleles. Although these findings are interesting, further functional and epidemiological studies to confirm these observations are required.

Association of two variants in IL-1beta and IL-1 receptor antagonist genes with multiple sclerosis

We studied the putative association of a C-->T polymorphism in exon-5 of IL-1beta and an 85 bp tandem repeat in intron-4 of IL-1 receptor antagonist (IL-1ra) genes with susceptibility to or outcome of MS. DNA from 122 cases from a population-based cohort in Olmsted County, MN who were previously categorized for disease severity and temporal course and 244 ethnically-matched controls were analyzed. There was no association between either polymorphism and disease susceptibility. Allele-2 of IL-1beta and allele-3 of the IL-1ra polymorphisms were associated with a favorable outcome (P=0.023 and P=0.030).

Polymorphisms in the IL-1 receptor antagonist gene VNTR are possible risk factors for juvenile idiopathic inflammatory myopathies

Although HLA-DRB1 and -DQA1 alleles have been associated with adult and juvenile idiopathic inflammatory myopathies (JIIM), they only partially account for the genetic risk for these autoimmune disorders. Because IL-1alpha and IL-1beta, and the anti-inflammatory competitive inhibitor, IL-1 receptor antagonist (IL-1Ra), have been implicated in the pathogenesis of myositis, we assessed the role of variable number tandem repeat (VNTR) polymorphisms of the IL-1Ra gene (IL-1RN) in the aetiology of JIIM: IL-1RN VNTR polymorphisms were performed on 250 JIIM patients and 471 race-matched controls and were correlated with clinical characteristics. The IL-1RN A1 allele, associated with increased proinflammatory activity, was found to be a risk factor for Caucasians with JIIM (96.0% carriage rate versus 90.2% in race-matched controls, Pcorr = 0.037, odds ratio (OR) = 2.5, confidence interval (CI) = 1.1-5.8), but not for African-Americans, in whom the A3 allele was a possible risk factor (7.0% versus 1.1% in race-matched controls, Pcorr = 0.07, OR = 6.5, CI = 1.1-40.3). IL-1RN genotypes did not correlate with circulating levels of IL-1Ra, which were higher in patients than in controls. The polymorphic IL-1RN locus could be the first non-MHC genetic risk factor identified for JIIM, and different alleles may confer susceptibility for different ethnic groups.

Interleukin 1 receptor antagonist (IL-1ra) in multiple sclerosis

The autoimmune nature of multiple sclerosis introduces cytokine genes as logical candidates for the loci determining susceptibility to the disease, and/or influencing disease progression. Working on this principle, several groups have investigated the relevance of polymorphism in the interleukin 1 receptor antagonist gene (IL1RN) but with conflicting results. In an effort to clarify this situation, we typed the functionally significant variable number of tandem repeat (VNTR) polymorphism from intron 2 of IL1RN in 536 simplex families with multiple sclerosis. In order to improve the information extracted from these families, we also typed a closely mapped single nucleotide polymorphism (SNP) from the promoter of IL1B (the gene for IL-1beta). Disease associations were assessed by transmission disequilibrium testing (TDT), alone and after haplotype construction. There was highly significant (P</=2.48.10(-16)) linkage disequilibrium (LD) between the two polymorphisms studied, illustrating that LD adjacent to an SNP can be considerably more extensive than has recently been suggested. None of the alleles from the VNTR, the SNP or their haplotype showed statistically significant evidence for association. We stratified patients for current disability status but using this manoeuvre found no evidence that either of the polymorphisms influences disease severity. Combining the available data on the IL1RN VNTR suggests that any effect of this gene on susceptibility to multiple sclerosis, or its progression is, at best, small.

Why treat early multiple sclerosis patients?

Class 1 clinical trials demonstrated that immunomodulatory treatments (interferon beta and glatiramer acetate) reduce the disease activity and the accumulation of disability in relapsing remitting multiple sclerosis. Moreover interferon beta-1b also had similar positive effects in secondary progressive multiple sclerosis. The magnitude of these clinical effects was modest, but the reduction of inflammatory activity, as revealed by magnetic resonance imaging, was marked. Converging evidence from new pathological studies and new magnetic resonance techniques, characterized by increased pathological specificity, has shown that already in the early phases of the disease inflammatory activity determines irreversible axonal damage. Moreover, the amount of inflammatory activity at the clinical presentation of the disease has some value in predicting long-term disability. Taken together, these data indicate that patients may benefit from early treatment; the positive results of the Controlled High Risk Subjects Avonex Multiple Sclerosis Prevention Study support this conclusion.

Susceptibility to multiple sclerosis: interplay between genes and environment

Multiple sclerosis is a complex trait of unknown etiology. Epidemiological data have shown that susceptibility to multiple sclerosis is determined by both genetic and environmental factors. It is unknown whether the clinical subcategories of multiple sclerosis are separate diseases with separate etiologies and causes. Recent theories of the pathogenesis of multiple sclerosis and candidate genes are discussed. Other potential nonchromosomal factors involved in multiple sclerosis susceptibility such as mitochondrial DNA and viral factors such as Chlamydia pneumoniae are reviewed.

An evaluation of interleukin genes fails to identify clear susceptibility loci for multiple sclerosis

Differential expression of interleukins may influence susceptibility to inflammatory diseases such as MS. IL-1a production is increased in MS patients during acute relapse, IL-2 receptor (IL-2R) secretion correlates with disease activity in several inflammatory disorders and is variable in MS. Both IL-4 and IL-10 expression vary significantly with relapse/remission in MS and IL-9 is postulated to inhibit steroid-induced apoptosis. To examine the influence of interleukin (IL) genes on MS susceptibility and clinical course, gene association studies using separate polymorphic microsatellite markers for il-1 alpha, il-2, il-2r beta, il-4 il-9 and il-10 were performed, incorporating 150-177 relapsing-remitting or secondary progressive MS (RR/SPMS) patients, 100-110 primary progressive (PPMS) patients and 152-210 controls. No significant differences existed in allele frequencies between either MS group and controls for any of the interleukin microsatellite markers studied, nor were statistically significant differences observed in PPMS vs. RR/SPMS for any marker. These data indicate that the IL-1 alpha, IL-2, IL-2R beta, IL-4, IL-9 and IL-10 genes are unlikely to be susceptibility loci for MS in this population.

Association study of a new polymorphism in the PECAM-1 gene in multiple sclerosis

Genetic polymorphisms of immunorelevant genes may modulate occurrence or clinical features of multifactorial diseases. PECAM-1 is an adhesion molecule crucial for transmigration of cells from blood to tissues, but its genetic contribution to multifactorial diseases has never been investigated. We have identified and characterized a tetranucleotide repeat polymorphism within the third intron of PECAM-1. In a cohort of healthy controls (HC), we found 10 alleles. An assessment of the association of this polymorphism with multiple sclerosis (MS) showed similar allele and genotype frequencies in HC and MS patients as well as in MS patients differing for the gravity of their disease course. We conclude that although potentially able to affect organ-specific autoimmune diseases, this new PECAM-1 polymorphism, does not seem to contribute to the genetic background of MS.