Interleukin-10 microsatellite polymorphisms and IL-10 locus alleles in rheumatoid arthritis susceptibility

Genomic variants associated with age at diagnosis of childhood-onset type 1 diabetes

Age at diagnosis (AAD) of Type 1 diabetes (T1D) is determined by the age at onset of the autoimmune attack and by the rate of beta cell destruction that follows. Twin studies found that T1D AAD is strongly influenced by genetics, notably in young children. In young UK, Finnish, Sardinian patients AAD-associated genomic variants were previously identified, which may vary across populations and with time. In 1956 children of European ancestry born in mainland France in 1980-2008 who declared T1D before 15 years, we tested 94 T1D-associated SNPs for their association with AAD using nonparametric Kruskal-Wallis test. While high-risk HLA genotypes were not found to be associated with AAD, fourteen SNPs located in 12 non-HLA loci showed a strong association (2.9 × 10-12 < P < 1.4 × 10-3 after FDR correction). Four of these loci have been associated with AAD in previous cohorts (GSDMB, IL2, TNFAIP3, IL1), supporting a partially shared genetic influence on AAD of T1D in the studied European populations. In contrast, the association of 8 new loci CLEC16A, TYK2, ERBB3, CCR7, FCRL3, DNAH2, FGF3/4, and HPSE2 with AAD is novel. The 12 protein-coding genes located within these loci are involved in major immune pathways or in predisposition to other autoimmune diseases, which suggests a prominent role for these genes in the early immune mechanisms of beta cell destruction.

Treatment of Type II Collagen-Induced Rat Rheumatoid Arthritis Model by Interleukin 10 (IL10)-Mesenchymal Stem Cells (BMSCs)

BACKGROUND Rheumatoid arthritis model (CIA) rats were treated by tail vein injection of IL-10-modified bone marrow mesenchymal stem cells (BMSCs) to investigate its feasibility and intrinsic molecular mechanism. MATERIAL AND METHODS The CIA rat model was established by induction type II collagen, and IL-10-modified BMSCs was established by transfecting BMSCs with adenovirus. IL-10-modified BMSCs were used to treat the CIA rats. The therapeutic effect was evaluated by measuring the changes in body weight, ankle swelling, and forced swimming time, as well as observation of synovial hyperplasia and cartilage tissue repair by HE staining. Western blot analysis and ELISA were used to detect gene expression. RESULTS After 4 weeks and 8 weeks of treatment with IL10-BMSCs, the body weight, swelling value, resting time, and forced swimming struggle time of CIA rats were significantly higher than those of BMSCs-treated and -untreated CIA rats (P<0.05). Compared to BMSCs-treated CIA model rats, after treatment with IL10-BMSCs, the repair rate of osteoarticular cartilage was higher and the inhibition of synovial proliferation was better, and serum IL-17, IL-1ß, and TNF-alpha levels were lower. We found that the protein level of SIRT1 in peripheral blood mononuclear cells was lower, the protein level in spleen was higher, and phosphorylation of p65 protein in peripheral blood mononuclear cells was reduced. CONCLUSIONS The efficacy of tail vein injection of IL-10-modified BMSCs in treatment of CIA rats was superior to that of BMSCs alone, which may be related to the more pronounced suppression of IL-10-modified BMSCs in peripheral blood inflammation and spleen immune response.

Putative IL-10 Low Producer Genotypes Are Associated with a Favourable Etanercept Response in Patients with Rheumatoid Arthritis

Outcome predictors of biologic therapeutic drugs like TNF inhibitors are of interest since side effects like serious infections or malignancy cannot be completely ruled out. Response rates are heterogeneous. The present study addressed the question whether in patients with rheumatoid arthritis (RA) interleukin-10 (IL-10) promoter genotypes with potential relevance for IL-10 production capacity are associated with response to long-term treatment with etanercept. Caucasian RA patients that, according to the EULAR criteria, responded well (n = 25), moderately (n = 17) or not (n = 8) to etanercept therapy (median 36 months, range 4–52), and 160 matched controls were genotyped for the IL-10 promoter SNPs -2849 G>A (rs6703630), -1082 G>A (rs1800896), -819 C>T (rs1800871) and -592 C>A (rs1800872). Haplotypes were reconstructed via mathematic model and tested for associations with disease susceptibility and therapy response. We identified the four predominant haplotypes AGCC, GATA, GGCC, and GACC in almost equal distribution. Patients that responded well carried the putative IL-10 low producer allele -2849 A or the haplotypes AGCC and GATA (RR 2.1 and 4.0, respectively; 95% CI 1.1–4.0 and 1.1–14.8), whereas an unfavourable response was associated with carriage of the putative high producer haplotype GGCC (RR 1.9, 95% CI 1.1–3.3). No significant associations of alleles or haplotypes with disease susceptibility were observed. In RA, a low IL-10 production which is genetically determined rather by haplotypes than by SNPs may favour the response to etanercept treatment. Iatrogenic blockade of TNF may reveal proinflammatory effects of its endogeneous antagonist IL-10. Further studies are needed to correlate these genetic findings to direct cytokine measurements.

Oral interleukin-10 alleviates polyposis via neutralization of pathogenic T-regulatory cells

Immune dysregulation drives the pathogenesis of chronic inflammatory, autoimmune, and dysplastic disorders. While often intended to address localized pathology, most immune modulatory therapies are administered systemically and carry inherent risk of multiorgan toxicities. Here, we demonstrate, in a murine model of spontaneous gastrointestinal polyposis, that site-specific uptake of orally administered IL10 microparticles ameliorates local and systemic disease to enhance survival. Mechanistic investigations showed that the therapeutic benefit of this treatment derived from neutralization of disease-promoting FoxP3(+)RoRγt(+)IL17(+) pathogenic T-regulatory cells (pgTreg), with a concomitant restoration of FoxP3(+)RoRγt(-)IL17(-) conventional T-regulatory cells (Treg). These findings provide a proof-of-principle for the ability of an oral biologic to restore immune homeostasis at the intestinal surface. Furthermore, they implicate local manipulation of IL10 as a tractable therapeutic strategy to address the inflammatory sequelae associated with mucosal premalignancy.

IL-10 -1082 SNP and IL-10 in primary CNS and vitreoretinal lymphomas

OBJECTIVES

Most primary central nervous system lymphomas (PCNSLs) and primary vitreoretinal lymphomas (PVRLs) are B-cell lymphomas that produce high levels of interleukin (IL)-10, which is linked to rapid disease progression. The IL-10 (-1082) G → A polymorphism (IL-10 SNP) is associated with improved survival in certain non-CNS lymphoma patients. PDCD4 is a tumor suppressor gene and upstream regulator of IL-10. This study examined the correlation between the IL-10 SNP, PDCD4 mRNA expression, and IL-10 expression (at transcript and protein levels) in these lymphoma cells.

MATERIALS AND METHODS

Single-nucleotide polymorphism (SNP)-typing at IL-10 (-1082) was performed after microdissecting cytospun PVRL cells from 26 specimens. Vitreal IL-10 and IL-6 levels were measured by ELISA. PCNSL cells from 52 paraffin-embedded sections were microdissected and SNP typed on genomic DNA. RT-PCR was performed to analyze expression of IL-10 and PDCD4 mRNA. IL-10 (-1082) SNP typing was performed on blood samples of 96 healthy controls. We measured IL-10 (-1082) SNP expression in 26 PVRLs and 52 PCNSLs and examined its relationship with IL-10 protein and gene expression, respectively.

RESULTS

More PVRL patients expressed one copy of the IL-10 ( -1082 )  G → A SNP with the GA genotype compared to controls. The frequencies of the three genotypes (AA, AG, GG) significantly differed in PVRL versus controls and in PCNSL versus controls. In PVRLs, the vitreal IL-10/IL-6 ratio was higher in IL-10 (-1082) AG and IL-10 (-1082) AA patients, compared to IL-10 (-1082) GG patients. IL-10 mRNA expression was higher in IL-10 (-1082) AG and IL-10 (-1082) AA PCNSLs, compared to IL-10 (-1082) GG PCNSLs. No correlation was found between IL-10 and PDCD4 expression levels in 37 PCNSL samples.

CONCLUSIONS

PVRL and PCNSL patients had similar IL-10 (-1082) A allele frequencies, but genotype distributions differed from healthy controls. The findings suggest that the IL-10 (-1082) A allele is a risk factor for higher IL-10 levels in PVRLs and PCNSLs. Higher IL-10 levels have been correlated with more aggressive disease in both PVRLs and PCNSLs, making this finding an important and potentially clinically significant observation.

Hepatitis C virus spontaneous clearance: immunology and genetic variance

Hepatitis C virus (HCV) infection is one of the most common chronic viral infections in the world. Approximately 80-90% of acutely infected individuals develop persistent infection, which is a major risk for liver cirrhosis and liver cancer. However, a small portion of patients (10-20%) clear the virus. Clinical outcomes of HCV infection are determined by the interplay between the host immune response, and viral and environmental factors. In regulating immune responses, cytokines play an indispensable role that controls the underlying pathogenesis and the resulting outcome of HCV infection. Cytokines themselves are manipulated by polymorphisms in their genes. In fact, the majority of genetic variants that apparently confer a significant risk for chronic HCV infection have been localized in genes involved in cytokine synthesis and the ultimate immune response. So far, treatment strategies for HCV infection have remained controversial. Genotyping of different polymorphisms will aid clinical decision making for both current standard and personalized care. Genotyping can potentially be useful for future integration of other agents, which provides an opportunity for clinicians to personalize treatment regimens for HCV patients. This review summarizes findings of different studies on host immune responses after HCV infection and the association between cytokine gene polymorphisms and the likelihood of HCV clearance.

The -1082A/G polymorphism in the Interleukin-10 gene and the risk of rheumatoid arthritis: a meta-analysis

A large number of studies have shown that the -1082A/G polymorphism (rs1800896) in the Interleukin-10 gene (IL-10) is implicated in the susceptibility to rheumatoid arthritis (RA). However, the results are inconsistent and inconclusive. The aim of this study is to analyze the association between the -1082A/G polymorphism in the IL-10 gene and the RA risk by meta-analysis. A total of 1480 cases and 1413 controls in 10 case-control studies were included in this meta-analysis. The results indicated that the G allele carriers (GG+GA) had a 25% decreased risk of RA, when compared with the homozygote AA (odds ratio (OR)=0.75, 95% confidence interval (CI): 0.59-0.93). In the analysis in Europeans, significant decreased risks were associated with the G allele carriers (OR=0.73 and 95% CI: 0.57-0.93 for GG+GA vs. AA). The results from this meta-analysis provide evidence for the association between the IL-10 -1082A/G polymorphism and the risk of RA. To further evaluate gene×gene and gene×environment interactions between the polymorphisms in the IL-10 gene and RA risk, more studies with large groups of patients are required.

An intracytoplasmic IL-10 receptor variant permits rapid reduction in STAT3 activation

Within the interleukin-10 receptor 1 (IL10R1) gene, two common variants are associated with certain diseases: single-nucleotide polymorphism 3 (SNP3), a serine-138 to glycine mutation is in linkage disequilibrium with SNP4, a glycine-330 to arginine mutation, both of which are considered loss-of-function alleles. However, the molecular consequence of G330R is unknown. We investigated possible roles of G330R on the dynamics of IL10R1 surface expression and signal transducer and activator of transduction (STAT) phosphorylation. HeLa cells expressing the respective IL10R1 haplotype were stimulated with IL-10. Significant reduction of IL10R1 surface expression was observed after ligand binding. Receptor expression remained low on continuous incubation with IL-10. In contrast, when treated with an IL-10 pulse, IL10R1 surface expression returned to its resting state within 3-9 h irrespective of the haplotype. STAT3 was rapidly phosphorylated both in cells with wild-type (WT) or variant IL10R1, and maintained phosphorylated when cells were cultured with IL-10. On IL-10 pulse, however, STAT3 phosphorylation declined rapidly in cells expressing IL10R1-G330R but not IL10R1-WT or S138G. Similar dynamics were observed with STAT1 phosphorylation at Tyr701. No differences in janus kinase 1 (JAK1) activation were observed in cells with WT or variant IL10R1. Our results indicate that IL10R1-G330R does not alter surface expression but duration of STAT phosphorylation, indicating that the position of G330 is important in stabilizing the STAT signal.

Associations between interleukin-10 polymorphisms and susceptibility to rheumatoid arthritis: a meta-analysis

The aim of this study was to determine whether the interleukin-10 (IL-10) polymorphisms confer susceptibility to rheumatoid arthritis (RA). A meta-analysis was conducted on the associations between the IL-10 -1082 G/A, -592 C/A, -892 C/T and IL-10.R polymorphisms and RA using; (1) allele contrast, (2) the recessive model, (3) the dominant model, and (4) the additive model. A total of 16 studies (19 comparisons) involving 2647 RA patients and 3383 controls were considered in the meta-analysis. Meta-analysis of the IL-10 -1082 G/A polymorphism showed no association with RA in the study subjects, or in European or Asian subjects. However, meta-analysis of the -1082 G allele in 4 studies in Hardy-Weinberg equilibrium showed a significant association with RA (OR=1.217, 95% CI=1.027-1.442, P=0.0236). In contrast, meta-analysis of the C allele, the CC genotype, and of the CC versus the AA genotype of the IL-10 -592 C/A polymorphism showed significant associations with RA. The overall ORs of the associations between the C allele and RA were 0.684 and 0.758 (95% CI=0.494-0.946, P=0.022; 95% CI=0.475-1.210, P=0.045) in all study subjects and Asians. Meta-analysis of the CC+CT versus TT genotype and of the CC versus TT genotype of the IL-10 -892 C/T polymorphism revealed significant associations with RA. The overall OR of the association between the C allele carrier and RA was 0.552 (95% CI=0.375-0.812, P=0.003). No association was found between the IL10.R2 alleles and RA. This meta-analysis suggests that the IL-10 -592 C/A polymorphism confers susceptibility to RA in Asians and that the IL-10 -1082 G/A and -892 C/T polymorphisms are associated with RA susceptibility. These findings suggest the IL-10 genes confer susceptibility to RA.

Cell type-specific regulation of IL-10 expression in inflammation and disease

IL-10 plays an essential part in controlling inflammation and instructing adaptive immune responses. Consequently, dysregulation of IL-10 is linked with susceptibility to numerous infectious and autoimmune diseases in mouse models and in humans. It has become increasingly clear that appropriate temporal/spatial expression of IL-10 may be the key to how IL-10 contributes to the delicate balance between inflammation and immunoregulation. The mechanisms that govern the cell type- and receptor-specific induction of IL-10, however, remain unclear. This is due largely to the wide distribution of cellular sources that express IL-10 under diverse stimulation conditions and in a variety of tissue compartments. Further complicating the issue is the fact that human IL-10 expression patterns appear to be under genetic influence resulting in differential expression and disease susceptibility. In this review, we discuss the cellular sources of IL-10, their link to disease phenotypes and the molecular mechanisms implicated in IL-10 regulation.

Dynamic DNA methylation patterns across the mouse and human IL10 genes during CD4+ T cell activation; influence of IL-27

IL-10 plays a critical role in controlling inflammation and the anti-inflammatory functions of IL-10 are regulated based on its coordinated expression from various cellular sources, most notably T cells. Although nearly all CD4+ subpopulations can express IL-10, surprisingly little is known about the molecular mechanisms which control IL-10 induction, particularly in humans. To examine the regulation of human IL-10 expression, we created the hIL10BAC transgenic mouse. As previously reported, we observed conservation of myeloid-derived IL-10 expression but found that human IL-10 was only weakly expressed in splenic CD4+ T cells from hIL10BAC mice. Since DNA methylation is an important determinant of gene expression profiles, we assessed the patterns of DNA methylation in the human and mouse IL10 genes in naïve and activated CD4+ T cells. Across mouse and human IL10 there were no obvious patterns of CpG methylation in naïve CD4+ T cells following polyclonal activation. Overall however, the human IL10 gene had significantly higher levels of DNA methylation. Interestingly, coculture with the IL-10-inducing cytokine IL-27 lead to a site-specific reduction in methylation of the mouse but not human IL10 gene. Demethylation was specifically localized to an intronic site adjacent to a known regulatory region. Our findings indicate that while the mouse and human IL10 genes undergo variable changes in DNA methylation during CD4+ T cell activation, IL-27 appears to influence DNA methylation in a particular intronic region thus associating with IL-10 expression.

Gene polymorphisms of interleukin-4, interleukin-10 and transforming growth factor-beta in Graves' disease

Among genetic factors that may contribute to the development and progression of Graves' disease (GD) and its complications are polymorphisms in the genes encoding cytokines. The association between GD and the following polymorphisms in anti-inflammatory cytokines was studied in 107 patients with GD and 140 healthy controls: IL-4 (-1098T/G, -590T/C, -33C/T), IL-10 (-1082A/G, -819C/T, -592C/A) and TGF-beta (+869T/C, +915G/C). The following alleles and genotypes were significantly (P < 0.01 after correction for multiple testing) more frequent among patients: the IL-4 -1098G allele and GG genotype (OR = 3.12 and 105.00, respectively), IL-4 -33T allele and TT genotype (OR = 2.52 and 118.83, respectively), IL-10 -1082G allele and GG genotype (OR = 2.16 and 6.40, respectively), IL-10 -819T allele, TC and TT genotype (OR = 2.60, 3.68 and 6.76, respectively), IL-10 -592A allele, AC and AA genotype (OR = 2.41, 2.89 and 5.68, respectively), TGF-beta +869C allele and CC genotype (OR = 2.24 and 6.21, respectively), and TGF-beta +915C allele, CG and CC genotype (OR = 7.81, 11.80 and 20.40, respectively). The only allele and genotype with a lower frequency in patients were IL-4 -590T allele and TC genotype (OR = 0.47 and 0.08, respectively; P < 0.01). In conclusion, this study highlighted the importance of anti-inflammatory cytokine gene polymorphisms in susceptibility to GD.

A human IL10 BAC transgene reveals tissue-specific control of IL-10 expression and alters disease outcome

Interleukin (IL)-10 is an immunoregulatory cytokine that is produced by diverse cell populations. Studies in mice suggest that the cellular source of IL-10 is a key determinant in various disease pathologies, yet little is known regarding the control of tissue-specific human IL-10 expression. To assess cell type-specific human IL-10 regulation, we created a human IL-10 transgenic mouse with a bacterial artificial chromosome (hIL10BAC) in which the IL10 gene is positioned centrally. Since human IL-10 is biologically active in the mouse, we could examine the in vivo capacity of tissue-specific human IL-10 expression to recapitulate IL-10-dependent phenotypes by reconstituting Il10(-/-) mice (Il10(-/-)/hIL10BAC). In response to LPS, Il10(-/-)/hIL10BAC mice proficiently regulate IL-10-target genes and normalize sensitivity to LPS toxicity via faithful human IL-10 expression from macrophages and dendritic cells. However, in the Leishmania donovani model of pathogen persistence, Il10(-/-)/hIL10BAC mice did not develop the characteristic IL-10(+)IFN-gamma(+)CD4 T cell subset thought to mediate persistence and, like Il10(-/-) mice, cleared the parasites. Furthermore, the IL-10-promoting cytokine IL-27 failed to regulate transgenic human IL-10 production in CD4(+) T cells in vitro which together suggests that the hIL10BAC encodes for weak T cell-specific IL-10 expression. Thus, the hIL10BAC mouse is a model of human gene structure and function revealing tissue-specific regulatory requirements for IL-10 expression which impacts disease outcomes.

The role of interleukin-10 promoter polymorphisms in primary Sjogren's syndrome

OBJECTIVE

To determine the impact of a broad spectrum of different polymorphisms within the interleukin-10 (IL-10) promoter gene on disease susceptibility to primary Sjogren's syndrome (pSS), clinical manifestations, and autoantibody production.

METHODS

We genotyped 111 unrelated German Caucasian patients with pSS and 145 healthy controls for the single nucleotide polymorphisms (SNPs) at positions -2849, -2776, -2769, -2763, -1349, -1082, -851, -819, -657, and -592 and for the microsatellites IL10.R and IL10.G. Allele and haplotype distributions were compared between patients and controls and between subgroups of patients with different clinical and laboratory findings.

RESULTS

We found no significant differences in the allele or haplotype frequencies between pSS patients and healthy controls. After Bonferroni correction we found a significant association of the ACC haplotype (at the -1082, -819, and -592 loci) with immunoglobulin (Ig)A antibodies to anti-alpha-fodrin.

CONCLUSION

Overall we found no associations of IL-10 promoter polymorphisms with the susceptibility to pSS in our cohort. The finding that the production of IgA anti-alpha-fodrin antibodies is associated with polymorphisms within the IL-10 promoter region suggests a genetic contribution to the generation of these antibodies.

Pharmacogenetics of anti-TNF treatment in patients with rheumatoid arthritis

TNF-blocking strategies are widely used in the treatment of rheumatoid arthritis (RA). Three anti-TNF agents are registered for use in RA: etanercept, infliximab and adalimumab. Although anti-TNF therapy is very effective in controlling disease activity and slowing down radiological damage, prolonged response is only seen in approximately 70% of the patients. The causes for nonresponse in the remaining patients have not yet been elucidated. Pharmacogenetic studies focusing on genes involved in RA etiology (and/or progression) and in the pharmacokinetics of TNF-blocking agents have identified markers associated with anti-TNF treatment outcome. In the future, more exhaustive, less hypothesis-driven search strategies are expected to discover additional markers. Identification of these markers might be viewed as the first step towards tailored TNF-blocking therapy for patients with RA. Nevertheless, replication and large prospective studies will be needed to demonstrate the validity of the identified genetic markers before implementation into daily clinical practice.

The interleukin-10-1082 'A' allele and abdominal aortic aneurysms

BACKGROUND

Abdominal aortic aneurysms (AAA) are caused by inflammatory processes in the wall of the aorta resulting in degradation of structural proteins. This inflammatory process is mediated, in part, by cytokines, and interleukin-10 (IL-10) is a predominantly anti-inflammatory cytokine. A single nucleotide polymorphism in the promoter region of the IL-10 gene that affects transcription has been associated with AAA in a small study. The aim of this study was to determine whether this polymorphism is associated with AAA and also examine its effect on the growth of small AAA.

METHODS AND RESULTS

A case control study was performed. A total of 389 patients with AAA and 404 healthy controls were recruited. IL-10-1082 polymorphisms were determined by polymerase chain reaction-based methods. In the case of patients with small AAA (<5.5 cm), serial size measurements were recorded to determine mean growth rate. There was a statistically significant difference both in allele and genotype frequencies between the case and control groups with the IL-10-1082 'A' allele being more common in the AAA group (P = .006). In the AAA group, genotype frequencies were as follows: GG 84, GA 201, and AA 104. In the control group, the genotype frequencies were GG 118, GA 205, and AA 81. The odds ratio for the 'A' allele as a risk factor for AAA was 1.50 (95% confidence interval 1.09 to 2.07). Regression modeling revealed that the IL-10-1082 genotype was, however, not independently associated with AAA if age, tobacco use, hypertension, and history of coronary or peripheral artery disease was taken into account. There was a trend towards lower plasma IL-10 level in IL-10 AA carriers, but the IL-10 'A' allele did not have any discernible effect on the growth of small AAA.

CONCLUSIONS

This study demonstrates that the IL-10-1082 'A' allele is associated with AAA, although this association is likely to be secondary to an association between IL-10-1082 genotype and other markers of cardiovascular disease rather than AAA per se.

Association of interleukin-6 and interleukin-10 genotypes with radiographic damage in rheumatoid arthritis is dependent on autoantibody status

Objective

Recent evidence has highlighted a major genetic contribution to radiographic damage in rheumatoid arthritis (RA). The objective of this study was to determine whether genetic variants in the loci for interleukin-1 (IL-1), IL-6, IL-10, protein tyrosine phosphatase N22 (PTPN22), and selenoprotein S are associated with radiographic damage.

Methods

Modified Larsen scores of radiographic damage were determined in a cross-sectional population of patients with RA (n = 964). Rheumatoid factor (RF) and anti–cyclic citrullinated peptide (anti-CCP) were also assayed. The Kruskal-Wallis nonparametric test was used to compare median radiographic damage scores across genotype groups, followed by the Cuzick nonparametric test for trend to assess gene-dose effects.

Results

An allele-dose association of IL-6 −174G with increasing radiographic damage was present (P = 0.005), but only in patients who were RF positive (P = 0.004) or anti-CCP positive (P = 0.01). Patients with the IL-10 −592CC genotype had more extensive radiographic damage than did those with the AC or AA genotype (P = 0.006), but this was observed only among patients who were RF negative (P = 0.002) or anti-CCP negative (P = 0.002). However, RF status and anti-CCP status were not associated with the IL-6 or IL-10 genotype. No other genetic associations were detected, apart from a marginal association of PTPN22 +1858T with increased radiographic damage.

Conclusion

The reported associations of IL-6 −174G with high IL-6 production and IL-10 −592 with low IL-10 production and our own results support a role of genetically determined dysregulated cytokine production in disease severity. The lack of association of these genotypes with RF and anti-CCP antibody status suggests that they act downstream of autoantibody production. We conclude that IL-6 and IL-10 genotypes may be useful in predicting disease severity in autoantibody-positive and autoantibody-negative patients, respectively.

Polymorphisms of interferon-γ, interleukin-10, and interleukin-12 genes in myasthenia gravis

To assess the involvement of polymorphisms in genetic susceptibility to myasthenia gravis (MG), this study analyzed four polymorphisms of interferon (IFN)-gamma, interleukin (IL)-10, and IL-12 genes in 115 patients and 204 healthy controls (HC). IFNG +874T carriers were less frequent in MG, in patients with anti-acetylcholine receptor (AChR) (63%) and anti-titin (56.2%) antibodies compared with HC (p = 0.01 for all, OR: 0.5, 0.5, and 0.4, respectively). The presence of thymoma was also associated with lower frequency of IFNG +874T allele (p = 0.018, OR = 0.34). At IL10, -2763A allele was found to be slightly more frequent in MG and in patients with anti-AChR than in HC group (p = 0.05, OR = 1.7, p = 0.036, OR = 1.83). However, these associations did not remain significant after correction for multiple comparisons. IL12B allele distribution was not different among groups. These data suggest that some cytokine gene polymorphisms may contribute to susceptibility to or antibody production in MG. These findings need to be replicated in further studies.

Impact of aboriginal ethnicity on HCV core-induced IL-10 synthesis: interaction with IL-10 gene polymorphisms

The host immune response is a critical determinant in viral infection outcome. Epidemiological studies indicate that North American indigenous peoples are more resistant to chronic HCV infection than other populations. Due to the prominence of IL-10 in chronic HCV infection, we investigated the genetic tendency to produce IL-10 in Caucasian (CA) and First Nation (FN) populations. Peripheral blood mononuclear cells (PBMCs) from CA subjects had a greater tendency to produce IL-10 defined by allelic polymorphisms, as well as genotypes and haplotypes, at the -1082, -819, and -592 positions of the IL-10 promoter. More importantly, we directly evaluated the influence of ethnicity on the ability of HCV core protein to induce IL-10 synthesis and found significantly higher IL-10 production by PBMCs isolated from healthy CA subjects compared with FN subjects. Further examination of the underlying relationship between core-induced IL-10 with the high, intermediate, and low phenotypes at the -1082, -819, and -592 position revealed that spontaneous and core-induced IL-10 synthesis tended to interact negatively with defined polymorphisms. This was particularly evident for the FN cohort, in which the relationship was strengthened by a stronger interaction of core with the low-IL-10-producing phenotypes. As with previous studies, concanavalin A induced IL-10 synthesis from the CA cohort positively associated with defined genetic phenotypes.

CONCLUSION

Cells from FN subjects had a reduced capacity to produce IL-10 in response to HCV core protein, suggesting that reduced susceptibility of FN immunity to virally induced IL-10 synthesis might contribute to epidemiological observations of enhanced HCV clearance.

A hallmark of balancing selection is present at the promoter region of interleukin 10

As an anti-inflammatory mediator IL10 is beneficial in certain contexts and deleterious in others. As increased production of IL10 favours protection against inflammatory disease, whereas low production promotes elimination of foreign pathogens by the host, we investigated the possible influence of balancing selection at this locus. We began by resequencing 48 European and 48 African chromosomes across 2.2 kb of the IL10 promoter region, and compared this with four neighbouring gene regions: MK2, IL19, IL20 and IL24. Analysis of nucleotide diversity showed a positive Tajima's D-test for IL10 in Europeans, of borderline statistical significance (1.89, P=0.05). Analysis of F(st) values showed significant population divergence at MK2, IL19, IL20 and IL24 (P<0.01) but not at IL10. Taken together, these findings are consistent with the hypothesis that balancing selection has played a role in the evolution of polymorphisms in the IL10 promoter region.

The association of -627 interleukin-10 promoter polymorphism in Chinese patients with systemic lupus erythematosus

The objective of the study is to examine whether interleukin-10 (IL-10) promoter polymorphism is a marker of susceptibility of systemic lupus erythematosus (SLE) in Chinese patients in Taiwan. The study included 119 Chinese patients with SLE. One hundred unrelated healthy individuals living in central Taiwan served as control subjects. Each polymorphism was detected as a result of a polymerase chain reaction (PCR)-based restriction analysis. The PCR product length was determined to be 412 bp (CC) whereas two fragments of 236 and 176 bp were determined to be excisable lengths (AA). The relationship between the IL-10 gene polymorphism and clinical manifestations of SLE was evaluated. For the genotype and allelic frequency, there were statistically significant differences between the SLE patients and the normal control subjects (p=0.007 and 0.003, respectively). But we did not detect any association of carriage rate of the IL-10 polymorphism and the normal control subjects (p=0.077). Furthermore, we did not detect any association of IL-10 genotype with antinuclear antibody, malar rash, photosensitivity, discoid lupus, mucosal ulcer, arthritis, serositis, hematology, immunology, involvement of central nervous system, and renal disease involvement in the SLE patients. The significant relation of -627 IL-10 genotype and allelic frequency with SLE implies that the IL-10 gene polymorphism can serve as a candidate gene marker for further study in patients with SLE in Taiwan.

IL-10 promoter -1082 polymorphism is associated with elevated IL-10 levels in control subjects but does not explain elevated plasma IL-10 observed in Sjögren's syndrome in a Hungarian cohort

The aim of this study was to investigate the frequency of the -1082 polymorphism of the interleukin-10 (IL-10) gene and the soluble IL-10 levels in Hungarian primary Sjögren's syndrome (SS) patients. Ninety-nine SS patients and 135 healthy volunteers were examined. Samples were analysed by the PCR restriction fragment length polymorphism method, and IL-10 plasma levels were assessed by a commercial enzyme-linked immunosorbent assay. IL-10 plasma levels were higher in the primary SS patients (36.4 +/- 57.5 pg/ml, n = 99) compared with the healthy subjects (9.9 +/- 20.3 pg/ml, n = 135, P = 10(-6)). The elevated IL-10 phenotype of SS patients was not associated with increased G allele frequency as reported earlier, while in the control group, we found higher IL-10 levels among the subjects who were carriers of the GG genotype (17.7 +/- 23.2 pg/ml) as compared with the other two genotype carriers (AA 8.98 +/- 16.5 and GA 8.5 +/- 21.1 pg/ml, P = 0.01). Our data do not support previous observations indicating an association between deregulated IL-10 secretion in SS and higher G allele frequency. However, the results clearly demonstrate that GG homozygosity is associated with elevated IL-10 levels in apparently healthy subjects, but this cannot account for the IL-10-related specific disease features observed in SS. Thus, other genetic factors contribute to the clinical spectrum of this heterogeneous disease at least in the Hungarian population.

Interleukin-10-1082 promoter polymorphism in association with cytokine production and sepsis susceptibility

OBJECTIVE

To investigate the -1082 (A/G) polymorphism in the promoter of the IL-10 gene in terms of IL-10 production from stimulated peripheral blood mononuclear cells (PBMC) and to evaluate the relationship of this polymorphism with susceptibility to severe sepsis and the outcome of the disease.

DESIGN

Case-control study.

SETTING

Research laboratory of Molecular Biology and Immunology and University Hospital ICU, Faculty of Medicine, Trakia University.

PATIENTS

A total of 53 healthy volunteers and 33 patients in ICU meeting the criteria for severe sepsis were included.

MEASUREMENTS AND RESULTS

The amplification refractory mutation system PCR was used for IL-10-1082 polymorphism detection. Isolated PBMC were stimulated with either C3-binding glycoprotein (C3bgp), lipopolysaccharide (LPS), phytohemagglutinin (PHA),or pokeweed mitogen (PWM). IL-10 production was measured in culture supernatants. The AA genotype was associated with lower IL-10 production in LPS-, PHA- or PWM-stimulated healthy PBMC. Patients with severe sepsis had significant elevation of A allele, compared with healthy controls (74.2% vs 52.8%; p=0.0062). Carriage of at least one copy of IL-10-1082 G allele in sepsis patients and in healthy controls resulted in a statistically significant increase in IL-10 production from stimulated PBMC. Surviving sepsis patients had a significant decrease of IL-10-1082 allele G frequency, compared with controls (17% vs 47.2%; p=0.012). An association between increased IL-10 production and poor outcome from sepsis was observed.

CONCLUSION

The A allele of the -1082 polymorphism in the interleukin-10 gene promoter is associated with sepsis susceptibility, whereas G allele is associated with higher stimulated interleukin-10 production and increased mortality in severe sepsis.

Analysis of IL10 haplotypic associations with severe malaria

We investigated the association between severe malaria and genetic variation of IL10 in Gambian children, as several lines of evidence indicate that IL10 is protective against severe malaria and that IL10 production is genetically determined. We began by identifying five informative SNPs in the Gambian population that were genotyped in a combined case-control and intrafamilial study including 654 cases of severe malaria, 579 sets of parents and 459 ethnically matched controls. No significant associations were identified with individual SNPs. One haplotype of frequency 0.11 was strongly associated with protection against severe malaria in the case-control analysis (odds ratio 0.52, P=0.00002), but the transmission disequilibrium test in families showed no significant effect. These findings raise the question of whether IL10 associations with severe malaria might be confounded by foetal survival rates or other sources of transmission bias.

Association of interleukin 10 haplotype with low bone mineral density in Korean postmenopausal women

Osteoporosis is a disease characterized by exaggerated loss of bone mass, with as much as 50 to 85% of the variation in bone mineral density (BMD) commonly accepted as being genetically determined. Although intensive studies have attempted to elucidate the genetic effects of polymorphisms on BMD and/or osteoporosis in several genes, the genes involved are still largely unknown. The possible associations of genetic variants in five-candidate genes (IL10, CCR3, MCP1, MCP2 and GC) with spinal BMD were investigated in Korean postmenopausal women (n = 370). Fourteen SNPs in five candidate genes were genotyped, and the haplotypes of each gene constructed. The associations of adjusted spinal BMD by age, year since menopause (YSM) and body mass index (BMI), with genetic polymorphisms, were analyzed using multiple regression models. Genetic association analysis of Korean postmenopausal women revealed that IL10 -592A > C and/or IL10 ht2 were associated with decreased bone mass, whereas no significant associations were observed with all polymorphisms in other genes. The levels of spinal BMD in individuals bearing the IL10 -592CC genotype were lower (0.78 +/- 0.16) than those in others (0.85 +/- 0.17) (P = 0.02), and the BMD of IL10 ht2 bearing individuals were also lower (0.82 +/- 0.15) than those in others (0.85 +/- 0.17) (P = 0.04). Our results suggest that variants of IL10 might play a role in the decreased BMD, although additional study might need to be followed-up in a more powerful cohort.

Interleukin-10 promoter polymorphism in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease in which interleukin (IL)-10 plays an important role. There are, however, controversial reports that IL-10 promoter polymorphism may be an independent marker of susceptibility and severity of RA. The aim of the present study was to examine the IL-10 promoter polymorphism in patients with RA. We examined 95 patients with rheumatoid arthritis diagnosed according to the criteria of the American College of Rheumatology. Polymerase chain reaction amplification was used for analysis of the promoter polymorphism of the IL-10 gene. In RA patients, the prevalence of genotypes encoding high expression of IL-10 was observed. Nevertheless, there was no association between IL-10 genotypes and age at disease diagnosis, disease activity in a physician's global assessment, and joint and extra-articular involvement. There was also no correlation between IL-10 polymorphism and disease activity parameters--erythrocyte sedimentation rate, C-reactive protein, number of swollen and tender joints, and duration of morning stiffness. We suggest that IL-10 promoter polymorphism is not a genetic risk factor for RA activity.

Human interleukin-19 and its receptor: a potential role in the induction of Th2 responses

Interleukin-19 (IL-19) is a newly discovered member of the IL-10 family of ligands whose function is presently undefined. We recently described its cloning and initial characterization and in so doing, noted that the induction of IL-19 by LPS in human monocytes was down-regulated by interferon-gamma (IFN-gamma) and up-regulated by IL-4. This preliminary observation led us to speculate that IL-19 may play a role in the Th1/Th2 system and we examined this hypothesis further. Our results suggested that IL-19 is able to influence the maturation of human T-cells. CD4+ T-cells resulting from SEB stimulation in the presence of IL-19 contained a higher proportion of IL-4 producing cells than those developing in the absence of IL-19. This observation was complimented by the observation that fewer IFN-gamma cells accrued in the presence of IL-19, thereby suggesting that IL-19 altered the balance of Th1/Th2 cells in favour of Th2. Furthermore, in whole PBMC cultures, IL-19 up-regulated IL-4 and down-regulated IFNgamma in a dose-dependent manner. These results are presented here in review format, in the context of an overall discussion of IL-19 and its receptor.

Understanding the genetic contribution to rheumatoid arthritis

PURPOSE OF REVIEW

The identification of the genetic variants that mediate the risk for susceptibility and severity of rheumatoid arthritis will allow the development of new drug targets and also increase the ability to predict disease course. Technical and methodologic progress has fueled the advances in this field.

RECENT FINDINGS

The second risk factor for rheumatoid arthritis, the PTPN22 polymorphism, has been identified. This genetic variant regulates the threshold of T cell activation. Intriguingly, this variant is a risk factor for diabetes as well. Moreover, it has been shown that multiple genetic variants in one pathway (both in a transcription factor, RUNX-1, as in the transcription factor binding site of RUNX1 in the SLC22A4 gene) can each confer very small risks but by gene-gene interactions can confer a ninefold risk for rheumatoid arthritis. These genetic risk factors have been found to confer risk for multiple autoimmune diseases. Phenotype-genotype interactions were described by the enhanced prevalence of a rheumatoid arthritis-specific autoantibody (anti-cyclic citrullinated peptide antibodies) in rheumatoid arthritis patients that harbor the rheumatoid arthritis-associated human leukocyte antigen class II genes, the shared epitope alleles. An environmental factor, smoking was demonstrated to confer risk for rheumatoid arthritis, especially in patients positive for both shared epitope and rheumatoid arthritis-specific anti-cyclic citrullinated peptide antibodies.

SUMMARY

Two new pathways, T cell receptor signaling and a hematopoietic-specific signal transduction pathway, have been discovered that allow future pharmacologic interventions. The description of the new genetic risk factors and the interaction with environmental triggers as well as phenotypic features are gradually expanding the ability to predict disease susceptibility and course.

Autoantibodies to citrullinated proteins in rheumatoid arthritis: clinical performance and biochemical aspects of an RA-specific marker

Rheumatoid arthritis (RA) is a common, systemic autoimmune disease of which the exact etiology is not known. In the past 10 years, substantial progress has been made in the identification of the antigens specifically recognized by the autoantibodies of RA patients. A central factor in this respect is citrullination, a form of post-translational modification that is strongly associated with autoimmunity in RA. Here, we summarize and discuss our current knowledge on (i) autoantibody systems in RA, (ii) the occurrence of peptidylarginine deiminases and (iii) citrullinated proteins in natural and diseased environments, and (iv) genetic factors involved in RA that may influence the generation and presentation of citrullinated proteins and the resulting antibody production against these modified proteins. Citrullination of proteins may play a key role in the initiation and/or the progression of RA. The onset of citrulline-specific autoimmunity in RA is probably mediated by both environmental and genetic factors, and future studies will learn whether therapeutic intervention at the level of citrullination may provide new possibilities to treat RA.

Polymorphisms of interleukin 4 receptor gene and interleukin 10 gene are not associated with Graves' disease in the UK

Graves' disease (GD) is an autoimmune disorder of the thyroid gland and both environmental and genetic factors contribute to disease aetiology. Cytokines, such as interleukin 4 (IL-4) and interleukin 10 (IL-10), are involved in the immune response and may be implicated in the autoimmune disease process. Associations have been reported between single nucleotide polymorphisms (SNPs) of IL-10 and the Ile50Val polymorphism of the IL-4 receptor gene (IL-4R) gene and atopy and autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. The autoimmune diseases cluster within families and susceptibility genes may overlap between the different disorders. Therefore, we investigated 5 SNPs (-592C/A, -657G/A, - 819C/T, -1349A/G, and -2013G/A) in the promoter region of the IL-10 and the Ile50Val polymorphism (A/G) in the IL-4R in a large UK population based case-control dataset with GD. No association was found between the polymorphisms studied and GD and no significant differences were found in genotype or allele frequencies between the patients and control subjects. We conclude these polymorphisms of IL-10 and IL-4R previously associated with other immune mediated diseases, do not confer susceptibility to GD in white Caucasians in the United Kingdom.

Mosaics of gene variations in the Interleukin-10 gene promoter affect interleukin-10 production depending on the stimulation used

Interleukin-10 (IL-10), a cytokine involved in many aspects of the immune response shows interindividual variations in their expression. However, genetic variations of the 5'-flanking region of the IL-10 gene (PIL-10) are poorly characterised with respect to different stimuli. New extended haplo- and genotypes are identified present at differing frequencies in three geographically separated populations. Their influence on IL-10 expression have been assessed in vitro after stimulation of leukocytes with lipopolysaccharide (LPS), dibutyryl-cAMP or following immortalisation with Epstein-Barr virus (lymphoblastoid cell line (LCL)). Interindividual differences of IL-10 production were found to be related to single-nucleotide polymorphisms (SNP) haplotype -6752/-6208 in LCLs (P<0.02), and for haplotypes comprising SNPs -6752/-6208/-3538 after LPS stimulation (P<0.03). Carriers of the IL10.G microsatellite with 22, 24 or 26 dinucleotide repeats linked with the -1087G SNP, exhibited the highest levels of IL-10 expression. Contrasting IL-10 secretion patterns were found for IL10.R microsatellite alleles characterised by 15 dinucleotide repeats: after LPS stimulation this allele was associated with high IL-10 production (P<0.007), but with low IL-10 levels in LCLs (P< 0.038). Thus, the effects of mosaics of genetic elements in the PIL-10 on the capacity of leukocytes to produce IL-10 depend on the agent inducing IL-10 expression.

Interleukin 10 promoter microsatellite polymorphisms are associated with response to long term treatment with etanercept in patients with rheumatoid arthritis

OBJECTIVES

To analyse the association of interleukin 10 (IL10) promoter polymorphisms, which have been shown to be related to IL10 secretion capacity, with the response to long term treatment with etanercept in patients with rheumatoid arthritis (RA).

METHODS

Fifty patients with active RA were treated for up to 4 years (median 39 months, range 3-52) with stable doses of etanercept as monotherapy. Treatment response was assessed as defined by the EULAR criteria in an intention to treat analysis, with the last observation carried forward. IL10 promoter microsatellite polymorphisms IL10.R and IL10.G were genotyped by fragment length analysis in patients and 189 healthy controls matched for ethnicity, age, and sex. Haplotypes were reconstructed using a method based on bayesian, coalescent theory with the PHASE software.

RESULTS

IL10 microsatellite polymorphisms were not associated with susceptibility to RA. When patients with good treatment response (n = 25) were compared with patients with moderate (n = 17) or no response (n = 8), a significantly different distribution of the prevailing alleles R2, R3 and G9, G13, respectively, became evident. Good treatment response was associated with carriage of the R3 allele or R3-G9 haplotype, whereas the allele G13 and the haplotype R2-G13 predominated in patients with moderate or no response.

CONCLUSION

Genotyping of the IL10 promoter microsatellites may be useful in predicting the clinical response to etanercept in patients with RA. The high prevalence of the presumptive IL10 low producer allele R3 in patients with a favourable response suggests that IL10 promotes disease activity in RA under the specific condition of tumour necrosis factor antagonism.

An elevated level of IL-10- and TGFbeta-secreting T cells, B cells and macrophages in the synovial membrane of patients with reactive arthritis compared to rheumatoid arthritis

A relative high secretion level of IL-10 and a low secretion of TNF-alpha has been described in the synovial fluid and peripheral blood of patients with reactive arthritis (ReA), possibly contributing to the persistence of bacteria. The role of TGF-beta is less clear. We investigated these cytokines in the synovial membrane of patients with ReA and rheumatoid arthritis (RA) and tried to identify their cellular source. We used sections from the synovial membrane of 4 ReA and 4 RA patients which were double stained with immunofluorescence antibodies against cell surface markers for T cells (CD3), macrophages (CD68) and B cells (CD20) in combination with antibodies against intracellular cytokines TNF-alpha, IFN-gamma, TGF-beta, IL-4 and IL-10, and quantified these using a fluorescence microscope. A lower number of TNF-alpha-secreting cells were found in ReA compared to RA: CD3+: 1.78 +/- 0.54% versus 5.02% +/- 0.47% (p = 0.034). CD68+: 2.86 +/- 0.52 versus 5.37 +/- 0.53% (p = 0.034), CD20+ : 3.02 +/- 0.42% versus 3.58 +/- 0.48% (p > 0.05). A higher number of IL-10 positive cells were found in ReA compared to RA: CD3+: 3.27 +/- 1.5% versus 1.13 +/- 0.50% (p = 0.034), CD68+ 1.23 +/- 0.75% versus 0.83 +/- 0.35% (p > 0.05), CD20+: 3.70 +/- 1.6% versus 1.6 +/- 1.1% (p > 0.05). A difference between ReA and RA was also found for TGF-beta+ T cells: CD3+ 7.86 + 1.5% versus 1.78 + 0.35% (p = 0.032); CD20+: 7.91 + 2.1% versus 2.1 + 2.8% (p > 0.05), CD68+: 7.81% + 1.24% versus 2.12 + 0.28% (p = 0.032). In conclusion, we saw a different cytokine secretion pattern in the synovial membrane of ReA and RA. For T cells in ReA we found a cytokine secretion profile typical for T regulatory cells 1 (Tr1), with an elevated level of IL-10- and TGF-beta-secreting cells. Whether this is due to a more general difference in TNF-alpha, IL-10 or TGF-beta production which is genetically determined or regulated by T cells remains to be determined.

Simultaneous analysis of interleukin-10 gene microsatellites and single-nucleotide polymorphisms in parallel with tumour necrosis factor and interferon-gamma short tandem repeats by fluorescence-based polymerase chain reaction

Different cytokine genotypes exist in the population, for example, as a result of selective pressure of infectious diseases. It may be that specific cytokine genotypes that are beneficial by creating a 'proinflammatory' phenotype predispose to severe inflammatory disease with worse clinical outcome. There is individual variation in the production of certain cytokines in relation to their genotypes. IL-10, IFN-gamma and TNF-alpha are key components in the regulation of immune responses and the balance of their expression levels is predictive in certain diseases. To describe cytokine genotypes, a one-tube PCR reaction was developed to analyse simultaneously DNA sequence variations of cytokine genes IL-10, IFN-gamma, and TNF. This multiplex PCR approach was used to provide genotypic data for two geographically independent donor groups from Germany and Gabon. Significant differences were obtained for the majority of sequence variations comparing both populations. However, the SNPs within the 5'-flanking region of the IL-10 gene at position -1087 and -6208 are comparable in their genic and genotypic behaviour. Comparing allelic and genotypic disequilibrium between pairs of loci revealed different association patterns for both populations according to the geographical polymorphism. This assay may improve immunogenetic studies in disease, characterized by disbalanced IL-10, IFN-gamma and TNF-alpha expression.

No relationship of -627 interleukin-10 promoter polymorphism in Chinese patients with rheumatoid arthritis

The aim of this study was to examine whether -627 interleukin-10 (IL-10) promoter polymorphism is a marker of susceptibility to or severity of rheumatoid arthritis (RA) in Chinese patients in Taiwan. The study included 198 Chinese patients with RA. One hundred unrelated healthy individuals living in central Taiwan served as the control subjects. The relationship between IL-10 gene polymorphism and clinical manifestations of RA was evaluated. For the genotype, allelic frequency, and carriage rate of IL-10 polymorphism, there were no statistically significant differences found between patients and controls. Furthermore, we did not detect any association of IL-10 genotype with rheumatoid factor (RF), extra-articular involvement, or bone erosion in the RA patients. The lack of association of -627 IL-10 gene polymorphism with RA and the clinical findings in our study implies that the IL-10 gene polymorphism cannot serve as a candidate gene marker for screening RA patients.

IL10 gene polymorphisms are associated with asthma phenotypes in children

IL10 is an anti-inflammatory cytokine that has been found to have lower production in macrophages and mononuclear cells from asthmatics. Since reduced IL10 levels may influence the severity of asthma phenotypes, we examined IL10 single-nucleotide polymorphisms (SNPs) for association with asthma severity and allergy phenotypes as quantitative traits. Utilizing DNA samples from 518 Caucasian asthmatic children from the Childhood Asthma Management Program (CAMP) and their parents, we genotyped six IL10 SNPs: 3 in the promoter, 2 in introns, and one in the 3' UTR. Using family-based association tests, each SNP was tested for association with asthma and allergy phenotypes individually. Population-based association analysis was performed with each SNP locus, the promoter haplotypes and the 6-loci haplotypes. The 3' UTR SNP was significantly associated with FEV(1) as a percent of predicted (FEV(1)PP) (P=0.0002) in both the family and population analyses. The promoter haplotype GCC was positively associated with IgE levels and FEV(1)PP (P=0.007 and 0.012, respectively). The promoter haplotype ATA was negatively associated with lnPC(20) and FEV(1)PP (P=0.008 and 0.043, respectively). Polymorphisms in IL10 are associated with asthma phenotypes in this cohort. Further studies of variation in the IL10 gene may help elucidate the mechanism of asthma development in children.

Genes and gene polymorphisms associated with periodontal disease

The scientific literature during the last ten years has seen an exponential increase in the number of reports claiming links for genetic polymorphisms with a variety of medical diseases, particularly chronic immune and inflammatory conditions. Recently, periodontal research has contributed to this growth area. This new research has coincided with an increased understanding of the genome which, in turn, has permitted the functional interrelationships of gene products with each other and with environmental agents to be understood. As a result of this knowledge explosion, it is evident that there is a genetic basis for most diseases, including periodontitis. This realization has fostered the idea that if we can understand the genetic basis of diseases, genetic tests to assess disease risk and to develop etiology-based treatments will soon be reality. Consequently, there has been great interest in identifying allelic variants of genes that can be used to assess disease risk for periodontal diseases. Reports of genetic polymorphisms associated with periodontal disease are increasing, but the limitations of such studies are not widely appreciated. While there have been dramatic successes in the identification of mutations responsible for rare genetic conditions, few genetic polymorphisms reported for complex genetic diseases have been demonstrated to be clinically valid, and fewer have been shown to have clinical utility. Although geneticists warn clinicians on the over-enthusiastic use and interpretation of their studies, there continues to be a disparity between the geneticists and the clinicians in the emphasis placed on genes and genetic polymorphism associations. This review critically reviews genetic associations claimed for periodontal disease. It reveals that, despite major advances in the awareness of genetic risk factors for periodontal disease (with the exception of periodontitis associated with certain monogenetic conditions), we are still some way from determining the genetic basis of both aggressive and chronic periodontitis. We have, however, gained considerable insight into the hereditary pattern for aggressive periodontitis. Related to our understanding that it is autosomal-dominant with reduced penetrance comes a major clinically relevant insight into the risk assessment and screening for this disease, in that we appreciate that parents, offspring, and siblings of patients affected with aggressive periodontitis have a 50% risk of this disease also. Nevertheless, we must exercise caution and proper scientific method in the pursuit of clinically valid and useful genetic diagnostic tests for chronic and aggressive periodontitis. We must plan our research using plausible biological arguments and carefully avoid the numerous bias and misinterpretation pitfalls inherent in researching genetic associations with disease.

Idiopathic thrombocytopenic purpura in adults

Immune thrombocytopenic purpura (ITP) is an organ-specific autoimmune disorder in which platelets opsonized by antiplatelet antibodies are destroyed by the reticuloendothelial system. As a result the peripheral blood platelet count is low; if sufficiently severe, it may lead to bruising and mucocutaneous bleeding. The disorder may occur in adults and in children; in the former the disease affects primarily females, whereas the childhood type affects the sexes equally. For most individuals the disorder is minor, requiring little treatment, but patients with more severe forms of the disease require therapy to elevate the platelet count to a safe level to prevent serious bleeding. Therapies include corticosteroids, intravenous immunoglobulin, splenectomy, and immunosuppressive agents. Because there have been few trials in ITP, there is little evidence to guide treatment, and all the treatments may have adverse effects in terms of morbidity and mortality. The American Society of Hematology and British Committee for Standards in Haematology guidelines provide a framework for management but nonetheless are based on little evidence. In this paper the authors review the management of ITP in adults, children, and pregnant women and highlight some of the novel therapies being explored in this disorder, in addition to some of the ongoing laboratory research exploring the mechanisms underlying the disease.

Genetics in rheumatoid arthritis

This chapter reviews the latest original research on the genetics of rheumatoid arthritis (RA), with a focus on its relevance for the clinical rheumatologist. The following questions will be dealt with in order to appreciate the recent progress in this field. * Why is a knowledge of genetics useful for an understanding of the pathogenesis of RA? * Is a knowledge of genetic risk factors relevant for day-to-day clinical practice? * What methods are used for identifying genetic risk factors? * Which genetic regions have been identified in susceptibility to RA? * What risk factors have been identified? * What are the future prospects and research agenda?

Molecular genetics in the pediatric intensive care unit

Molecular genetics and genomics have become highly relevant tools in the field of pediatric critical care medicine. The most immediate examples involve the use of molecular genetics as routine diagnostic tests (eg, detection of herpes simplex virus by PCR). Perhaps the most exciting and promising examples involve the research efforts based in these fields, which hold the potential to gain novel insight regarding the complex mechanisms involved in critical illness. Ultimately, the generation of more comprehensive and fundamental knowledge can lead to the design of more effective and specific therapeutic strategies.

Association of the -2849 interleukin-10 promoter polymorphism with autoantibody production and joint destruction in rheumatoid arthritis

OBJECTIVE

To analyze the -2849 A/G interleukin-10 (IL-10) promoter polymorphism, which is associated with high (AG/GG) and low (AA) IL-10 production, in a cohort of rheumatoid arthritis (RA) patients and controls in order to gain a better understanding of its role in the incidence and progression of RA.

METHODS

Allele frequencies of the promoter polymorphism -2849 A/G and carriage rates were compared in 283 RA patients, 413 patients with other rheumatic diseases, and 1,220 healthy controls. The rate of joint damage and baseline levels of IgG and IgM rheumatoid factors and anti-citrullinated peptide antibodies were measured and were correlated with the IL-10 gene polymorphism. Furthermore, the correlation between the invasiveness of fibroblast-like synoviocytes (FLS) and the -2849 IL-10 genotype was tested.

RESULTS

The IL-10 genotype was not associated with the incidence of RA, but instead, correlated with disease progression, as determined by the extent of joint destruction. A higher rate of joint destruction was observed in patients with the genotype associated with high IL-10 production. Since FLS are thought to be involved in joint destruction, we analyzed IL-10 genotypes in conjunction with FLS invasiveness. Although adenoviral gene transfer of IL-10 to FLS inhibited their invasiveness, no differences were observed in vitro in the FLS from RA patients who were -2849 non-G carriers compared with those who were G carriers. Instead, patients with the -2849 AG/GG genotype, which is associated with high IL-10 production, had higher autoantibody titers at baseline.

CONCLUSION

The -2849 IL-10 promoter polymorphism is associated with autoantibody production and subsequent joint damage in RA.

Interleukin-10 therapy--review of a new approach

Interleukin (IL)-10 is an important immunoregulatory cytokine produced by many cell populations. Its main biological function seems to be the limitation and termination of inflammatory responses and the regulation of differentiation and proliferation of several immune cells such as T cells, B cells, natural killer cells, antigen-presenting cells, mast cells, and granulocytes. However, very recent data suggest IL-10 also mediates immunostimulatory properties that help to eliminate infectious and noninfectious particles with limited inflammation. Numerous investigations, including expression analyses in patients, in vitro and animal experiments suggest a major impact of IL-10 in inflammatory, malignant, and autoimmune diseases. So IL-10 overexpression was found in certain tumors as melanoma and several lymphomas and is considered to promote further tumor development. Systemic IL-10 release is a powerful tool of the central nervous system to prevent hyperinflammatory processes by activation of the neuro-endocrine axis following acute stress reactions. In contrast, a relative IL-10 deficiency has been observed and is regarded to be of pathophysiological relevance in certain inflammatory disorders characterized by a type 1 cytokine pattern such as psoriasis. Recombinant human IL-10 has been produced and is currently being tested in clinical trials. This includes rheumatoid arthritis, inflammatory bowel disease, psoriasis, organ transplantation, and chronic hepatitis C. The results are heterogeneous. They give new insight into the immunobiology of IL-10 and suggest that the IL-10/IL-10 receptor system may become a new therapeutic target.

The interrelationship of maternal stress, endocrine factors and inflammation on gestational length

Preterm birth rates continue to rise in the United States despite the advent of tocolytic agents and the identification of risk factors for preterm birth, such as vaginal infection and a shortened cervix. Although improvement in gestational-age-related survival of preterm infants has occurred as a result of the use of antenatal corticosteroids, neonatal surfactant therapy, and regionalization of perinatal care, there has been no reduction in the incidence of preterm birth. Recently, investigators have appreciated that the etiology of preterm birth is heterogeneous, perhaps accounting for one reason for the failure of current interventions to improve pregnancy outcome. Both abnormal maternal hormonal homeostasis and intrauterine inflammatory responses appear to contribute to a significant proportion of the cases of preterm birth, and the interaction of the maternal endocrine and immunologic systems may contribute to the pathophysiology of this condition. An important modulator of endocrine and immune function is perceived emotional and social stress. Maternal stress has been strongly associated with preterm birth, but the links between maternal stress and resultant aberrations of maternal endocrine and immune function remain difficult to quantify and investigate. However, new insights into the role of perceived maternal stress on gestational length suggest that specific interventions to alleviate stress could contribute to an increase in gestational length and a decrease in the risk for preterm birth. This review addresses the role of maternal stress on the regulation of maternal hormone and inflammatory responses and how aberrations in these systems may lead to preterm birth.

Genetic polymorphisms in Spanish rheumatoid arthritis patients: an association and linkage study

HLA polymorphism accounts only for approximately one-third of the genetic predisposition to rheumatoid arthritis (RA). To investigate the role of other loci in the susceptibility to RA, we have performed an analysis of several polymorphisms in genes of immune-related function: IL-10 -1082, -819, -592 promoter single nucleotide polymorphisms (SNPs), IL-10G and IL-10R microsatellites, IL-6 -622 promoter SNP, FcgammaRIIIA Val/Phe-158 polymorphism, IL-1 receptor antagonist VNTR, and the IKBL+738 T/C mutation. The analysis has been performed on a case-control study and also on RA trios. IL-10G12 was found to be associated with RA in the case-control study (18% in RA patients vs 9% in controls: P=0.001; pc<0.05). This allele was also more often transmitted than not transmitted (10 vs 5). No other allele in the present study is found to be associated to RA. Our data suggest that most of the loci studied play no major role in the susceptibility to RA, the IL-10 gene being the sole exception.

Interleukin-10 promoter haplotypes are differently distributed in the Brazilian versus the Dutch population

The frequency of five different single nucleotide polymorphisms of the promoter interleukin-10 (IL-10) gene (-3575, -2849, 2763, -1082, -819) was compared between two healthy populations, one originating from the Netherlands and one from Rio de Janeiro, Brazil. A total of 321 Caucasian Dutch individuals and 293 Brazilians, grouped as Afro-Brazilians and Euro-Brazilians, were genotyped using PCR-RFLP. The frequencies of the genotypes in the Brazilian population were different (P<0.05) from the frequencies in the Dutch population in all but one (-2763) genotype. The comparison of genotype frequencies between Afro- and Euro-Brazilians did not demonstrate any differences. The haplotype combination of the most-distant three polymorphisms showed strong linkage disequilibrium. All eight possible combinations were observed in Brazilians, but only seven in Dutch Caucasians. The haplotype frequencies were also significantly different between Brazilians when compared with Dutch and also between Euro-Brazilians and Dutch. No differences were observed in haplotype frequencies between Afro-Brazilians and Euro-Brazilians. The -3575T/-2849G/-2763C is more frequent, while the AAA haplotype was much less represented in the Brazilian than in the Dutch population. The haplotype TAC, which was described in African-Americans, was observed only in Brazilians, almost exclusively among those of European origin. The results corroborate the data indicating that the Brazilian population exhibits a genetic admixture of Africans, Europeans, and Amerindians, and the data may serve as a background for clinical and immunological studies involving the IL-10 locus.

Influence of interleukin-10 polymorphisms on interleukin-10 expression and survival in critically ill patients

OBJECTIVE

To determine the functionality of identified polymorphisms in the promoter and upstream regions of the interleukin-10 gene in terms of release of interleukin-10 from lipopolysaccharide-stimulated whole blood from healthy volunteers and to evaluate the relationship of interleukin-10 polymorphisms to interleukin-10 release, development of sepsis, and mortality in critically ill patients.

DESIGN

Observational study.

SETTING

The academic unit of anesthesia and intensive care, university laboratories, and ten-bed general intensive care unit in a university teaching hospital.

SUBJECTS

A total of 132 healthy volunteers plus 67 consecutive critically ill patients recruited within 24 hrs of admission to the intensive care unit, regardless of diagnosis.

MEASUREMENTS

Plasma interleukin-10 levels were measured by enzyme-linked immunosorbent assay. Single nucleotide polymorphisms were detected by restriction fragment length polymorphism analysis. Dinucleotide repeat polymorphisms were identified after polymerase chain reaction using a DNA size analyzer.

MAIN RESULTS

Stimulated interleukin-10 release in critically ill patients was significantly lower than in healthy subjects (p < .0001). In addition, in the patients who developed sepsis, interleukin-10 release at admission to the intensive care unit was significantly lower than in patients who did not subsequently develop sepsis (median [range] 1.47 [0.13-6.90] ng/mL compared with 4.93 [0.03-16.80] ng/mL, p = .001). The A allele of the single nucleotide polymorphism at -592 base pairs was associated with lower interleukin-10 release and higher mortality in critically ill patients. Other polymorphisms were not linked to interleukin-10 release, sepsis, or mortality.

CONCLUSIONS

The A allele of the -592 base pair single nucleotide polymorphism in the interleukin-10 gene is associated with lower stimulated interleukin-10 release and increased mortality. Further investigations are required to determine the nature of the functionality and the potential diagnostic and therapeutic aspects of this marker.

Genetic epidemiology of rheumatoid arthritis

Building on the spectacular success of molecular genetics in defining the biological basis of many rare single gene disorders over the past decade, epidemiologists have turned their attention to unravelling the complex genetic mysteries of common disorders, such as rheumatoid arthritis (RA). As a prelude to any such endeavour it is obviously important to establish that there is a significant genetic component to the disease. The classical approaches of twin and other family recurrence risk studies, coupled with prevalence studies in different ethnic and migrant populations, have been used to estimate the environmental and genetic contributions to RA. However, developing a consensus on these estimates has proved difficult, thereby providing an early warning to the unwary investigator that the road to gene discovery in RA is likely to be a rough ride.