Interleukin-10 promoter polymorphism in psoriasis

Inflammation: A Mediator Between Hypertension and Neurodegenerative Diseases

Hypertension is the most prevalent and modifiable risk factor for stroke, vascular cognitive impairment, and Alzheimer's disease. However, the mechanistic link between hypertension and neurodegenerative diseases remains to be understood. Recent evidence indicates that inflammation is a common pathophysiological trait for both hypertension and neurodegenerative diseases. Low-grade chronic inflammation at the systemic and central nervous system levels is now recognized to contribute to the physiopathology of hypertension. This review speculates that inflammation represents a mediator between hypertension and neurodegenerative diseases, either by a decrease in cerebral blood flow or a disruption of the blood-brain barrier which will, in turn, let inflammatory cells and neurotoxic molecules enter the brain parenchyma. This may impact brain functions including cognition and contribute to neurodegenerative diseases. This review will thus discuss the relationship between hypertension, systemic inflammation, cerebrovascular functions, neuroinflammation, and brain dysfunctions. The potential clinical future of immunotherapies against hypertension and associated cerebrovascular risks will also be presented.

T helper-2 cytokine/regulatory T-cell gene polymorphisms and their relation with risk of psoriasis in a South Indian Tamil cohort

BACKGROUND

Psoriasis is known to be associated with an up-regulation of T-helper (Th)-1 & Th-17 cytokines and a relative down-regulation of Th-2 and T-regulatory (T-reg) cytokines. Certain allelic variants of these cytokine genes may alter Th1/Th17 and Th2/T-reg balance and may be associated with the risk of psoriasis. Hence we aimed to determine the association of IL-4 (rs2243250), IL-10 (rs1800871 and rs1800896) and FOXP3 (rs3761548) gene polymorphisms with risk of psoriasis in South Indian Tamils.

METHODS

A total of 360 cases of psoriasis and 360 healthy controls were recruited. The polymorphism in IL-4 (rs2243250) & IL-10 (rs1800871) were typed by ARMS-PCR and IL-10 (rs1800896) & FOXP3 (rs3761548) were typed by TaqMan 5'allele discrimination assay.

RESULTS

We observed that IL-4 (rs2243250) had a reduced risk of psoriasis, while the IL-10 (rs1800871) conferred an increased susceptibility to psoriasis, as compared with controls. However, IL-10 (rs1800896) and FOXP3 (rs3761548) gene polymorphisms were not associated with psoriasis risk. The plasma IL-4 levels was not different between the cases and controls, however the heterozygous CT genotype demonstrated significant high IL-4 levels. Plasma IL-10 levels were significantly increased in cases compared to controls, however none of the genotypes were associated with the plasma IL-10 levels.

CONCLUSION

Our results suggest that IL-4 (rs2243250) polymorphism is protective against psoriasis, while IL-10 (rs1800871) polymorphism confers increased risk of psoriasis in South Indian Tamils. Detection of these genetic variants as predictive risk factors may lead to the selection of patient-tailored therapy to maximize the effectiveness of therapy.

Impact of genetic polymorphisms on paediatric atopic dermatitis

In order to investigate whether polymorphisms of genes encoding some factors of innate and adaptive immunity play a role in the development of, or protection against atopic dermatitis (AD) and condition its severity, we genotyped 33 candidate genes and 47 single nucleotide polymorphisms (SNPs) using Custom TaqMan Array Microfluidic Cards and an ABI 7900HT analyser (Applied Biosystems, Foster City, CA, USA). The study involved 104 children with AD (29 with mild-to-moderate and 75 with severe disease; 42 girls; mean age ± SD, 5.8 ± 3.3 years) and 119 healthy controls (49 girls; mean age, 4.8 ± 3.0 years). IL10-rs1800872T, TG and MBL2-rs500737AG were all significantly more frequent among the children with AD ( P = 0.015, P = 0.004 and P = 0.030), whereas IL10-rs1800896C and TC were more frequent in those without AD ( P = 0.028 and P = 0.032). The VEGFA-rs2146326A and CTLA4-rs3087243AG SNPs were significantly more frequent in the children with mild/moderate AD than in those with severe AD ( P = 0.048 and P = 0.036). IL10-rs1800872T and TG were significantly more frequent in the children with AD and other allergic diseases than in the controls ( P = 0.014 and P = 0.007), whereas IL10-rs1800896TC and C were more frequent in the controls than in the children with AD and other allergic diseases ( P = 0.0055 and P = 0.0034). These findings show that some of the polymorphisms involved in the immune response are also involved in some aspects of the development and course of AD and, although not conclusive, support the immunological hypothesis of the origin of the inflammatory lesions.

Mononuclear phagocytes of the intestine, the skin, and the lung

Tissues that are in direct contact with the outside world face particular immunological challenges. The intestine, the skin, and the lung possess important mononuclear phagocyte populations to deal with these challenges, but the cellular origin of these phagocytes is strikingly different from one subset to another, with some cells derived from embryonic precursors and some from bone marrow-derived circulating monocytes. Here, we review the current knowledge regarding the developmental pathways that control the differentiation of mononuclear phagocytes in these barrier tissues. We have also attempted to build a theoretical model that could explain the distinct cellular origin of mononuclear phagocytes in these tissues.

Polymorphisms of IL-10 gene in patients infected with HCV under antiviral treatment in southern Brazil

Interleukin-10 (IL-10) is a cytokine that plays an important role in the regulation of the immune system. Gene polymorphisms of IL-10 have been associated with the different expression levels of this cytokine. In hepatitis C virus infection, IL-10 appears to interfere with the progression of disease, viral persistence and the response to therapy. This study investigated genetic variability in the IL-10 gene promoter between patients infected with hepatitis C virus (HCV) and healthy individuals, associating the frequency of polymorphisms with different aspects of viral infection. This is a case-control study with 260 patients who were infected with HCV and 260 healthy individuals. Genotyping of the polymorphisms was performed using the technique of amplification refractory mutation system PCR (ARMS-PCR) for regions of the IL-10 gene promoter (-1082 G/A, -819 C/T, -592 C/A). The frequencies of alleles and genotypes related to polymorphisms in the IL-10 gene promoter showed a higher frequency of the G allele and genotype GG in the -1082 region between the infected group and the control group (p=0.005 and p=0.001, respectively), whereas the AA genotype was significantly more frequent in the control group. The frequencies of the haplotypes GTA and GCC were higher in the group of infected individuals, whereas the haplotype ATA was more frequent in the healthy group (p<0.006). It was also observed that the genotypes GG and AG in the region -1082 were significantly more frequent among patients infected with HCV who were in advanced stages of fibrosis and cirrhosis (p=0.042). No association was observed between polymorphisms of IL-10 and sustained virologic response (SVR).

[Psoriasis: physiopathology and immunogenetics]

Psoriasis is a multifactorial disease that involves genetic, immunological and environmental factors. During the last decade, several studies by genome scan on families or cases/controls helped to highlight more than ten loci "PSORS" located on different chromosomes and containing several candidate genes. Psoriasis appears as a genetic disease that follows the mixed model with the involvement of a major gene (PSORS1) and a set of minor genes with a variable penetrance depending on the locus. Genetic data have focused on the involvement of the immune system in the pathogenesis of psoriasis. It is now accepted that psoriasis is an immunological disease involving the response profiles TH1 and TH17. Much remains to be done to better elucidate the mechanisms involved in the genesis of psoriatic lesions to find new therapeutic targets.

Interleukin-10 inhibits lipopolysaccharide induced miR-155 precursor stability and maturation

The anti-inflammatory cytokine interleukin-10 (IL-10) is essential for attenuating the inflammatory response, which includes reducing the expression of pro-inflammatory microRNA-155 (miR-155) in lipopolysaccharide (LPS) activated macrophages. miR-155 enhances the expression of pro-inflammatory cytokines such as TNFα and suppresses expression of anti-inflammatory molecules such as SOCS1. Therefore, we examined the mechanism by which IL-10 inhibits miR-155. We found that IL-10 treatment did not affect the transcription of the miR-155 host gene nor the nuclear export of pre-miR-155, but rather destabilized both pri-miR-155 and pre-miR-155 transcripts, as well as interfered with the final maturation of miR-155. This inhibitory effect of IL-10 on miR-155 expression involved the contribution of both the STAT3 transcription factor and the phosphoinositol phosphatase SHIP1. This is the first report showing evidence that IL-10 regulates miRNA expression post-transcriptionally.

Sleep loss and cytokines levels in an experimental model of psoriasis

Up to 80% of people develop a cutaneous condition closely connected to their exposure to stressful life events. Psoriasis is a chronic recurrent inflammatory skin disorder with multifactorial etiology, including genetic background, environmental factors, and immune system disturbances with a strong cytokine component. Moreover, psoriasis is variably associated with sleep disturbance and sleep deprivation. This study evaluated the influence of sleep loss in the context of an animal model of psoriasis by measuring cytokine and stress-related hormone levels. Male adult Balb/C mice with or without psoriasis were subjected to 48 h of selective paradoxical sleep deprivation (PSD). Sleep deprivation potentiated the activities of kallikrein-5 and kallikrein-7 in the skin of psoriatic groups. Also, mice with psoriasis had significant increases in specific pro-inflammatory cytokines (IL-1β, IL-6 and IL-12) and decreases in the anti-inflammatory cytokine (IL-10) after PSD, which were normalized after 48 h of sleep rebound. Linear regression showed that IL-2, IL-6 and IL-12 levels predicted 66% of corticosterone levels, which were selectively increased in psoriasis mice subject to PSD. Kallikrein-5 was also correlated with pro-inflammatory cytokines, explaining 58% of IL-6 and IL-12 variability. These data suggest that sleep deprivation plays an important role in the exacerbation of psoriasis through modulation of the immune system in the epidermal barrier. Thus, sleep loss should be considered a risk factor for the development of psoriasis.

Is interleukin-10 gene polymorphism a predictive marker in HCV infection?

The clinical outcome of hepatitis C virus (HCV) infection varies between individuals - from spontaneous viral clearance and persistence without complication, to chronic hepatitis, cirrhosis and hepatocellular carcinoma. Also patterns of response to interferon-based anti-HCV therapy are different from person to person. This diversity may be affected by host genetic factors, including alterations in genes encoding cytokines. Interleukin-10, as an anti-inflammatory cytokine and immune response modulator, may influence on HCV infection susceptibility as well as spontaneous and treatment-induced HCV eradication. Moreover, it is stated that IL-10 has antifibrotic properties and play a role in progression of liver disease. This review summarized studies on interleukin-10 gene polymorphisms (mainly promoter SNPs at positions -1082(G/A), -819(C/T) and -592(C/A)), which may determine IL-10 production, regarding susceptibility to HCV infection, course of HCV-related liver disease (fibrosis, cirrhosis, hepatocellular carcinoma, ALT abnormalities), spontaneous viral elimination as well as hepatitis C treatment outcomes. Analysis of hereby summarized studies shows that it is difficult to unambiguously determine the importance of IL-10 polymorphism as a predictor of clinical outcome of hepatitis C and response to anti-HCV therapy before its beginning. Thus, future larger studies need to address these issues. Continuation of studies on interleukin-10 polymorphisms as well as identification of other candidate predictive markers in HCV infection has important practical implications and there is a chance that may contribute to reduce the scale of hepatitis C problem.

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.

Interleukin-19: multiple roles in immune regulation and disease

First reported in 1999, IL-19 remains a mystery in many ways. Despite appearing in many genome scans and candidate gene studies, and having been searched for specifically as part of the IL-10 family, its function is still to be defined. Nonetheless, a pattern of Th2 promotion is coalescing from this nebulous body of work, supported by increasing evidence for a role in asthma. Similarly, a clear but less intuitive role as a subtle immunomodulator is emerging in psoriasis and chronic inflammatory disorders in general. Indeed, several human diseases and their animal models have highlighted a role for IL-19. Key questions remain, relating to the nature of its receptor, its function (if any) on leukocytes and how its effects are distinguished by the cell from those of IL-20 and IL-24. In this review, I shall attempt to bring together a summary of the known work - disparate as it may be - as well as presenting a picture of these two important clinical disorders and the potential involvement of this somewhat enigmatic cytokine.

The angiotensin-converting enzyme insertion/deletion and the endothelin -134 3A/4A gene polymorphisms in patients with chronic plaque psoriasis

BACKGROUND

Psoriasis is a common chronic inflammatory skin disease. Vasoactive peptides such as endothelin-1 (ET-1) and bradykinin have previously been implicated in the pathogenesis of chronic plaque psoriasis. The angiotensin-converting enzyme (ACE) gene carries a 287-base pair insertion/deletion (I/D) gene polymorphism, which is associated with plasma concentrations of bradykinin-degrading ACE. A functional polymorphism (EDN1 -134 3A/4A) in the gene encoding ET-1 has been shown to affect ET-1 expression. The purpose of the present study was thus to investigate a hypothesized association between these gene polymorphisms and the presence of chronic plaque psoriasis.

METHODS

The present case-control study comprised 207 patients with chronic plaque psoriasis (136 with early onset and 71 with late onset disease) and 182 control subjects. Genotypes of EDN1 and ACE were determined by a 5' exonuclease assay (Taqman).

RESULTS

The prevalence of the homozygous ACE II genotype was significantly higher in patients with early-onset psoriasis than among control subjects (30.9% vs 19.2%, P = 0.016), yielding an odds ratio of 1.88 [95% confidence interval (CI): 1.12-3.15] for early-onset disease. For late-onset psoriasis, presence of the ACE II genotype was associated with a non-significant odds ratio 1.54 (95% CI: 0.81-2.92). As for the EDN1 -134 3A/4A gene polymorphism, no significant differences in genotype distributions were found between patients with either early- or late-onset psoriasis and control subjects (EDN1 -134 4A/4A: 9.6% in early-onset and 5.6% late-onset psoriasis vs 7.7% in controls; P > 0.05).

CONCLUSIONS

Our data suggest that homozygosity for the ACE I allele may affect susceptibility to early-onset psoriasis.

Psoriasis: genetic associations and immune system changes

Psoriasis is a common inflammatory skin disease characterized by infiltration of inflammatory cells into the epidermis and altered keratinocyte differentiation. Psoriasis is currently thought of as a T-cell mediated 'Type-1' autoimmune disease. Gene expression changes in psoriasis lesions have been well documented, and strongly support an important role for tumor necrosis factor and interferon gamma signal pathways in its pathogenesis. The strongest genetic determinant of psoriasis identified to date lies within the class I region of the multiple histocompatibility locus antigen cluster, although its low penetrance implicates a requirement for other genetic risk factors. Multiple genome-wide linkage and an increasing number of association studies have been carried out, leading to multiple linkage peaks, and the identification of potential low risk variants. A number of these variants lie within genes encoding components of the immune system. However, the functional relationships between predisposing genetic variation is unclear, and presumably involves genetic susceptibility factors affecting both immune cell activation and keratinocyte differentiation. The interaction of environmental trigger factors with genetic effects is also not understood, but provide further evidence for the complex basis of this disease.

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.

Interleukin-10 haplotype associated with total serum IgE in atopic dermatitis patients

BACKGROUND

The genetic background of atopic dermatitis (AD) is not clearly understood. Interleukin (IL)-10 is a powerful Th-2 cell cytokine produced by lymphoid cells that exerts its function by inhibiting macrophage/monocyte and T-cell lymphocyte replication and secretion of inflammatory cytokines [IL-1, tumour necrosis factor-alpha (TNFA), IL-6, IL-8 and IL-12].

OBJECTIVE

In an effort to discover additional polymorphism(s) in genes whose variant(s) have been implicated in total immunoglobulin E (IgE) level in AD patients, we scrutinized the single nucleotide polymorphisms (SNPs) in the IL10 gene as a potent candidate for contributing to the level of IgE in serum.

METHODS

We recruited 334 AD patients and assayed their serum total IgE levels using the LIPA-200 system. Four SNPs in the IL10 gene were genotyped using the single-base extension (SBE) method. Logistic regression analyses were performed with single polymorphisms and haplotypes (ht) to determine their association with the level of serum total IgE.

RESULTS

Genetic association analysis of total serum IgE in AD patients revealed that one of the IL10 ht, IL10-ht2, was associated with decreased serum total IgE in gene dose-dependent manner (P = 0.02-0.001).

CONCLUSIONS

It was predicted that the inhibition of innate immunity by increased IL-10 production in IL10-ht2-bearing individuals might be associated with decreased total serum IgE levels among AD patients. The greater effects of IL10 ht on decreased total serum IgE levels suggest that the effect of IL-10 polymorphism might be the result of a combined genotype (ht) rather than single polymorphisms.

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.

Polymorphisms in the interleukin-20 gene: relationships to plaque-type psoriasis

We analyzed the frequency of single-nucleotide polymorphisms (SNPs) at positions -1053 (rs 2981572), 1380 (rs 2981573), 1462 (rs 2232360), and 3978 (rs 1518108) of the human interleukin-20 (IL-20) gene by tetraprimer ARMS-PCR method. A significant association between patients with psoriasis and the G allele at position -1053 (P<0.05) was established. The pairwise linkage disequilibrium (LD) matrix showed that the nearly complete LD was present within the polymorphisms at positions -1053, 1380, and 1462 of the IL-20 gene. We found that patients with plaque psoriasis had a higher frequency of the HT3 GAA haplotype (P<0.01, OR 2.341, 95% CI: 1.346-4.074) compared to the control group. Likewise, the HT3 GAA haplotype was associated with an increased risk of early-onset psoriasis (P<0.01, OR 2.305, 95% CI: 1.285-4.132), late onset of disease (P<0.01, OR 2.542, 95% CI: 1.266-5.102), familial psoriasis (P<0.02, OR 2.220, 95% CI: 1.249-3.945), and sporadic disease (P<0.01, OR 2.523, 95% CI: 1.390-4.580). Our data indicate that IL-20 gene polymorphisms should have a role in determining susceptibility to plaque-type psoriasis. The possible role of the studied SNPs in the regulation of the expression of IL-20 is unknown yet and needs further studies.

Association of insertion/deletion polymorphism of the angiotensin-converting enzyme gene with psoriasis

BACKGROUND

Genetic factors are likely to be of fundamental importance in the pathogenesis of psoriasis. There are reports concerning the induction or/and exacerbation of psoriasis by angiotensin-converting enzyme (ACE) inhibitors, which have been attributed to the ACE inhibitor-induced augmentation of kinin levels in skin. However, to the best of our knowledge there has been no molecular genetic study investigating whether ACE insertion/deletion (I/D) polymorphism may contribute to the genetic background in psoriasis.

OBJECTIVES

To assess the role of ACE I/D polymorphism in psoriasis.

METHODS

A group of 86 patients with psoriasis and 154 control subjects were analysed for ACE I/D polymorphism by polymerase chain reaction.

RESULTS

The distribution of ACE I/D polymorphism and allele frequencies in psoriatic patients was not significantly different from controls. Further analyses of psoriasis patients showed that ACE I/D polymorphism was not associated with age at onset of disease, clinical type of psoriasis or gender. However, the frequency of the I allele was significantly higher in patients with a positive family history of psoriasis than in those with no family history (sporadic psoriasis) (48% vs. 32%; P =0.03). In addition, the I allele was found significantly more frequently in type I psoriasis patients (onset < 40 years and positive family history) than in type II psoriasis patients (onset >/= 40 years, no family history) (48% vs. 27%; P = 0.04).

CONCLUSIONS

Our results suggest that the presence of the I allele may confer susceptibility to development of psoriasis in individuals from psoriatic families.

Recent insights into the immunopathogenesis of psoriasis provide new therapeutic opportunities

Chronic and excessive inflammation in skin and joints causes significant morbidity in psoriasis patients. As a prevalent T lymphocyte-mediated disorder, psoriasis, as well as the side effects associated with its treatment, affects patients globally. In this review, recent progress is discussed in the areas of genetics, the immunological synapse, the untangling of the cytokine web and signaling pathways, xenotransplantation models, and the growing use of selectively targeted therapies. Since psoriasis is currently incurable, new management strategies are proposed to replace previous serendipitous approaches. Such strategic transition from serendipity to the use of novel selective agents aimed at defined targets in psoriatic lesions is moving rapidly from research benches to the bedsides of patients with this chronic and debilitating disease.

Recent insights into the immunopathogenesis of psoriasis provide new therapeutic opportunities

Chronic and excessive inflammation in skin and joints causes significant morbidity in psoriasis patients. As a prevalent T lymphocyte-mediated disorder, psoriasis, as well as the side effects associated with its treatment, affects patients globally. In this review, recent progress is discussed in the areas of genetics, the immunological synapse, the untangling of the cytokine web and signaling pathways, xenotransplantation models, and the growing use of selectively targeted therapies. Since psoriasis is currently incurable, new management strategies are proposed to replace previous serendipitous approaches. Such strategic transition from serendipity to the use of novel selective agents aimed at defined targets in psoriatic lesions is moving rapidly from research benches to the bedsides of patients with this chronic and debilitating disease.

The role of interleukin 10 in the pathogenesis and potential treatment of skin diseases

Interleukin 10 (IL-10) is a key cytokine produced by a multitude of immune effector cells and possesses distinct regulatory effects on immune functioning in the skin. In this article we report the current understanding of the immunobiology of IL-10 and identify the role of IL-10 in cutaneous infection as well as in autoimmune and neoplastic processes. We reviewed the literature to examine the function of IL-10 in different cutaneous disorders. IL-10 can influence and potentially treat T1/T2 differentiation, antigen-presenting cell functioning, antigen-presenting cell-mediated T-cell activation, and T-cell, B-cell, and mast cell growth and differentiation that is aberrant in various disease processes. The literature consensus is that the multitude of effects of IL-10 contribute to the pathogenesis of different skin disorders. In certain circumstances IL-10 could represent novel therapeutic approaches to treating cutaneous diseases.

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should be acquainted with the role of IL-10 in many infectious diseases, autoimmune skin disease, inflammatory processes, and malignancy. Its possible role in the resolution of various skin diseases should be better understood.

Psoriasis Is Not Associated with IL-12p70/IL-12p40 Production and IL12B Promoter Polymorphism

Psoriasis is a type-1 T cell-mediated, chronic inflammatory disease. Since interleukin (IL)-12p70 promotes the development of type-1 T cells, we investigated whether psoriasis is associated with an increased production of this cyctokine by blood cells. Results revealed that the production of IL-12p70 by cells of psoriasis patients stimulated by 1 and 10 ng per mL, but not 100 ng per mL of lipopolysaccharide (LPS) was higher (p=0.03) than that by cells of healthy volunteers. The production of IL-12p40 by patients cells upon stimulation with 0.1 ng per mL LPS, but not higher concentrations, was higher (p=0.02) than that by cells of healthy volunteers. No association between IL-12p70 production by blood cells and the severity of psoriasis was observed, nor was there a difference in the LPS-stimulated production of this cytokine between cells of the early and late onset type of patients. The frequencies of the various genotypes for the promoter region of the gene encoding IL-12p40 (IL12B) did not differ between psoriasis patients and controls. No association was observed between the various IL12B promoter genotypes and the LPS-stimulated production of IL-12p70 or IL-12p40 by blood cells. Together, psoriasis is not associated with a promoter polymorphism in the IL12B gene nor with the production of IL-12p70 by LPS-stimulated blood cells.

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.

IL-10 promoter polymorphisms influence disease severity and course in psoriasis

We analyzed three single-nucleotide polymorphisms (SNPs) at the interleukin-10 (IL-10) 5' flanking region (positions -1082 A/G, -819 C/T and -592 C/A) in an association case-control study involving 248 patients with plaque type of psoriasis and 148 unrelated healthy volunteers using ARMS (amplification refractory mutation system)-PCR (Polymerase Chain Reaction) method. No difference was found in the frequencies of haplotype distribution between healthy controls and patients with psoriasis. There were no significant differences in the IL-10 haplotype distribution depending on the age of onset and family history of psoriasis. However, the results of our study demonstrate that the IL-10 haplotype has a role in determining severity and course of plaque type of psoriasis. IL-10 ACC haplotype (P<0.05) is likely to be defining lower activity of disease (PASI</=20; extent</=10%) and ATA haplotype is likely to be associated with persistent eruption (P<0.01). As ACC haplotype is suggested to be associated with high IL-10 secretion and ATA is related to low IL-10 secretion, potential differences in the IL-10 secretion levels might contribute the differences in the clinical course of psoriasis.

Interleukin-10 promoter polymorphism IL10.G and familial early onset psoriasis

BACKGROUND

The anti-inflammatory cytokine interleukin (IL)-10 is considered to play a major role in the pathophysiology of psoriasis, which is characterized by an IL-10 deficiency. Systemic administration of IL-10 has been shown to be an effective therapy for psoriasis. The IL-10 promoter region contains a highly polymorphic microsatellite (IL10.G) and in a recent case-control study the IL10.G13 (144 bp) allele was found to be associated with familial early onset psoriasis (type 1 psoriasis) having a susceptible effect.

OBJECTIVES

As it is essential in multifactorial diseases to replicate findings before definite conclusions can be drawn, we decided to perform a follow-up study and to follow a genetic approach analysing allele transmission in families with a positive family history of psoriasis.

METHODS

We studied 137 nuclear families (trio-design) comprising 456 individuals and genotyped the IL10.G marker. For comparison we also genotyped the microsatellite tn62 as a reference marker of the major psoriasis susceptibility locus on chromosome 6p21 (PSORS1). In the present study allele transmission was evaluated using the family-based association test (FBAT) and GENEHUNTER 2.0 based on the transmission/disequilibrium test.

RESULTS

The G13 allele (144 bp) had a frequency of 24%, was present in 88 families and clearly showed an even transmission (FBAT, P = 0.753). In contrast, allele 3 (IL10.G9) (136 bp) had a frequency of 39%, was present in 110 families and was transmitted in 43 trios and remained untransmitted in 67 trios (FBAT, P = 0.026), thus showing preferential nontransmission. For the HLA-linked tn62-marker we obtained a P-value of 0.00027 for allele 4 in the same study group.

CONCLUSIONS

In conclusion, we failed to confirm the susceptible effect of the G13 allele, but provide the first data for a protective effect of allele 3 (IL10.G9) for familial psoriasis. Our results suggest that the IL10.G polymorphism is not a major locus, but acts as a minor locus.

Cytokine gene polymorphisms in atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) and psoriasis are genetically determined inflammatory skin disorders characterized by abnormal cytokine production. From association studies there is evidence that functionally relevant cytokine gene polymorphisms contribute to the genetic basis of psoriasis. Association studies in AD have mostly been limited to polymorphisms of T-helper 2-type cytokines, which dominate in acute AD lesions. Unexpectedly, the results of recent genome scans indicate linkage of AD to psoriasis susceptibility loci. Therefore, AD may also be influenced by genes that modulate cutaneous inflammation independently from atopic mechanisms.

OBJECTIVES

To investigate further the role of cytokine gene polymorphisms in AD.

METHODS

Polymorphisms in the genes encoding tumour necrosis factor-alpha (TNFA-238 G/A, -308 G/A), interleukin (IL)-1beta (IL1B-511 T/C, +3953 T/C), IL-6 (IL6-174 C/G), IL-10 (IL10-1082 A/G) and the IL-1 receptor antagonist (IL1RN intron 2) were investigated in German patients with AD (n = 94) and in healthy nonatopic individuals (n = 214) by polymerase chain reaction-based methods and direct cycle sequencing.

RESULTS

No association was found between AD and any of the polymorphisms analysed. This is in contrast to the recently described association between psoriasis and the TNFA-238 and IL1B-511 polymorphisms.

CONCLUSIONS

Our data indicate that cytokine gene polymorphisms may act as specific markers of inflammatory skin diseases rather than contribute to a general disposition towards cutaneous inflammation.

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.

Interleukin-10 promoter polymorphisms and susceptibility to skin squamous cell carcinoma after renal transplantation

After organ transplantation, susceptibility to cancer is multifactorial, especially for skin carcinomas. Risk factors may include genetic susceptibilities, such as the control of cytokine production. Interleukin-10 is a cytokine that is implicated in tumorigenesis, and it has been shown that polymorphisms in its gene promoter correlate with differential amounts of production. The aim of this study was to investigate a possible association between interleukin-10 gene promoter polymorphisms and the occurrence of skin carcinomas after renal transplantation. Seventy kidney transplant recipients who developed a squamous cell carcinoma or a basal cell carcinoma were examined for polymorphisms in the interleukin-10 gene promoter using polymerase chain reaction based methods. Single base pair mutations were studied at positions -1082, -819, and -592. These patients were compared to 70 healthy controls and to 70 matched renal transplant recipients without cancer. The interleukin-10 secretion capability was tested in a subgroup of 40 of these patients by in vitro stimulation of peripheral mononuclear cells. Interleukin-10 genotypes and haplotypes were differently distributed in kidney transplant recipients who developed a skin carcinoma, but especially a squamous cell carcinoma, with an increased frequency of the GCC haplotype and a decreased frequency of the ATA haplotype. Subsequently, we found a shift in the predicted phenotypes from the low production phenotype to the high production phenotype. Secretion of interleukin-10 was strongly correlated to the production predicted phenotype, and tended to be higher in patients who developed a squamous cell carcinoma than in the others. These results indicate that interleukin-10 gene polymorphisms and interleukin-10 production capability may contribute to the development of skin squamous cell carcinomas after renal transplantation.

Mechanistic perspectives on sulfonamide-induced cutaneous drug reactions

PURPOSE OF REVIEW

Idiosyncratic drug reactions continue to limit the therapeutic utility of sulfonamide drugs because of their associated morbidity and mortality. Cutaneous reactions are the predominant reasons for withdrawal of such drugs from use in patients. As a consequence of the recognized metabolic and immunologic capability of the skin, an understanding of the pathogenic role of this tissue in the development of sulfonamide-induced cutaneous drug reactions may provide insight into the mechanisms and risk factors for these and other adverse drug events.

RECENT FINDINGS

In the present review we discuss currently available mechanistic information, including issues related to drug bioactivation and adduct formation, immunoresponsiveness, and immune dysregulation, for the development of sulfonamide-induced (delayed-type) cutaneous drug reactions. The potential application of findings from several related areas of research are also discussed within the context of the pathogenesis of these cutaneous reactions.

SUMMARY

Despite progress, numerous unresolved issues support the testing of novel hypotheses, the search for additional risk factors, and the need for a global approach, including links between laboratory and clinical paradigms. These issues must be addressed if we are to gain an understanding of the mechanistic bases for these cutaneous drug reactions.

Immunomodulation by interleukin-10 therapy decreases the incidence of relapse and prolongs the relapse-free interval in Psoriasis

The ability of interleukin-10 therapy to reduce the severity of exacerbated psoriasis has been demonstrated recently. Considering the immunobiologic properties of this cytokine we investigated the effects of long-term interleukin-10 application on the immune system and duration of psoriasis remission. We performed a placebo-controlled, double-blind, phase II trial using interleukin-10 in patients with chronic plaque psoriasis in remission. Patients received subcutaneous injections with either interleukin-10 (10 microg per kg body weight; n = 7) or placebo (n = 10) three times per week until relapse or study termination after 4 months. The treatment was well tolerated. In the placebo group almost all patients (90%) showed a relapse during the observation period. In contrast to this, only two of seven patients (28.6%) relapsed in the interleukin-10-treated group. Kaplan-Meier analysis revealed a significantly lower relapse incidence in the interleukin-10 than in the placebo group (p = 0.02). The mean relapse-free interval time was 101.6 +/- 12.6 d in the interleukin-10 group in comparison with 66.4 +/- 10.4 d in the placebo group. Immunologic activity of interleukin-10 application was indicated by an increase in soluble interleukin-2 receptor plasma levels and higher ex vivo interleukin-4 secretion capacities. Remarkably, a significant negative correlation was demonstrated between the interleukin-4 secretion capacity and Psoriasis Area and Severity Index score (r = -0.36, p < 0.01). Our data suggest that interleukin-10 therapy is immunologic effective, decreases the incidence of relapse and prolongs the disease-free interval in psoriasis. Its value should be further determined in larger trials and for the prevention of re-exacerbation of other inflammatory disorders with a similar immunologic profile.