Dysregulation of interleukin-10 production in relatives of patients with systemic lupus erythematosus

The cytokine network type I IFN-IL-27-IL-10 is augmented in murine and human lupus

IL-10 is elevated in the autoimmune disease systemic lupus erythematosus (SLE). Here, we show that conventional dendritic cells (cDCs) from predisease lupus-prone B6.NZM Sle1/Sle2/Sle3 triple congenic (TCSle) mice produce more IL-10 than wild-type congenic cDCs upon TLR stimulation, and this overproduction is prevented by blocking the type I IFN receptor (IFNAR) with specific Abs. Priming wild-type cDCs with type I IFN mimics the IL-10 overproduction of TCSle cDCs. The MAPK ERK is more phosphorylated in lupus cDCs, partially contributing to IL-10 overproduction. Moreover, we found that TCSle cDCs express higher levels of IL-27 upon TLR7/TLR9 stimulation, and IFNAR blockade reduced IL-27 levels in TCSle cDCs. These results suggest that dysregulated type I IFNs in cDCs contribute to the increased IL-10 and IL-27 in SLE. Since IL-27 neutralization did not inhibit TLR-induced IL-10 production, we propose that type I IFNs enhanced IL-10 in TCSle cDCs independently from IL-27. Moreover, RNA sequencing analysis of a cohort of SLE patients reveals higher gene expression of these cytokines in SLE patients expressing a high IFN signature. Since IL-27 and IL-10 have both pro- and anti-inflammatory effects, our results also suggest that these cytokines can be modulated by the therapeutic IFN blockade in trials in SLE patients and have complex effects on the autoimmune response.

Discerning Risk of Disease Transition in Relatives of Systemic Lupus Erythematosus Patients Utilizing Soluble Mediators and Clinical Features

OBJECTIVE

Systemic lupus erythematosus (SLE) and other autoimmune diseases cause significant morbidity. Identifying populations at risk of developing SLE is essential for curtailing irreversible inflammatory damage. The aim of this study was to identify factors associated with transition to classified disease that would inform our understanding of the risk of SLE.

METHODS

Previously identified blood relatives of patients with SLE, who had <4 American College of Rheumatology (ACR) classification criteria for SLE at baseline, were enrolled in this follow-up study (n = 409 unaffected relatives). Participants provided detailed family, demographic, and clinical information, including the SLE-specific portion of the Connective Tissue Disease Screening Questionnaire (SLE-CSQ). Serum and plasma samples were tested for the presence of lupus-associated autoantibodies and 52 soluble mediators. Generalized estimating equations (GEEs) were applied to identify factors predictive of disease transition.

RESULTS

Of the 409 unaffected relatives of SLE patients, 45 (11%) had transitioned to classified SLE at follow-up (mean time to follow-up 6.4 years). Relatives who transitioned to SLE displayed more lupus-associated autoantibody specificities and higher SLE-CSQ scores (P < 0.0001) at baseline than did relatives who did not transition. Importantly, those who had developed SLE during the follow-up period also had elevated baseline plasma levels of inflammatory mediators, including B lymphocyte stimulator, stem cell factor (SCF), and interferon-associated chemokines (P ≤ 0.02), with concurrent decreases in the levels of regulatory mediators, transforming growth factor β (TGFβ), and interleukin-10 (P ≤ 0.03). GEE analyses revealed that baseline SLE-CSQ scores or ACR scores (number of ACR criteria satisfied) and plasma levels of SCF and TGFβ, but not autoantibodies, were significant and independent predictors of SLE transition (P ≤ 0.03).

CONCLUSION

Preclinical alterations in levels of soluble mediators may predict transition to classified disease in relatives of SLE patients. Thus, immune perturbations precede SLE classification and can help identify high-risk relatives for rheumatology referral and potential enrollment in prevention trials.

Correlation of circulating CD27high plasma cells and disease activity in systemic lupus erythematosus

CD27 is a useful marker in assessing the number of circulating B cells and B cell subsets because it permits one step identification of the major B cell compartments, CD27- naïve and CD27+ memory B cells as well as CD27high plasma cells. Abnormalities in the distributionof CD27+ B cell subsets are useful in assessing disease activity in patients with systemic lupus erythematosus(SLE). In particular, the frequencyof CD27high plasma cells significantly correlates with lupus activity in both children and adults with SLE. Conventional immunosuppressive therapies affect the number of CD27- naive B cells and CD27high plasma cells, but do not target CD27+ memory B cells. These results suggest that disease flares may relate to the retention of CD27+ memory B cells after conventional immunosuppressive therapy and that new therapies that target these cells specifically may offer new opportunities to induce remission in SLE.

T follicular helper cells, T follicular regulatory cells and autoimmunity

CD4(+)T follicular helper (Tfh) cells are recognized as a distinct T-cell subset, which provides help for germinal center (GC) formation, B-cell development and affinity maturation, and immunoglobulin class switching, as an indispensable part of adaptive immunity. Tfh cell differentiation depends on various factors including cell-surface molecule interactions, extracellular cytokines and multiple transcription factors, with B-cell lymphoma 6 (Bcl-6) being the master regulator. T follicular regulatory (Tfr) cells are also located in the GC and share phenotypic characteristics with Tfh cells and regulatory T cells, but function as negative regulators of GC responses. Dysregulation of either Tfh or Tfr cells is linked to the pathogenesis of autoimmune diseases such as systemic lupus erythematosus. This review covers the basic Tfh and Tfr biology including their differentiation and function, and their close relationship with autoimmune diseases.

Evaluating the association of interleukin-10 gene promoter -592 A/C polymorphism with lupus nephritis susceptibility

Background

Interleukin-10 (IL-10) is an important immunoregulatory cytokine. There are few studies evaluating the association between IL-10 and lupus nephritis (LN). The aim of this study was to evaluate the association of IL-10 gene promoter -592 A/C with LN susceptibility.

Methods

The study was conducted on 84 patients with systemic lupus erythematosus (SLE). Patients were divided into LN group (Group I, 48 patients) and non-LN group (Group II, 36 patients). The -592 A/C polymorphisms in IL-10 promoter gene were determined by polymerase chain reaction and restriction fragment length polymorphism in both groups. IL-10 was determined by enzyme-linked immunosorbent assay. Frequencies of the genotypes were compared between LN and non-LN patients and among LN patients with different pathologic classes.

Results

There was a significant increase in serum level of IL-10 (P = 0.001) in Group I compared with Group II and significant positive correlation between serum IL-10 and SLE disease activity index (r = 0.466, P = 0.001) in Group I. There were no significant differences in the distribution of the IL-10 gene promoter -592 A/C genotypes or the allele frequencies between Groups I and II. There was no significant difference between AC/CC and AA genotypes with SLE disease activity index, proteinuria, hematuria, anti-double-stranded DNA, and IL-10 in Group I. There was no significant difference in the distribution of AC and CC genotypes among different pathologic LN classes.

Conclusion

IL-10 suggested to play a role in pathogenesis and development of LN. However, the promoter -592 A/C of IL-10 gene suggested to be not associated with serum IL-10 levels or LN susceptibility. In addition, it appears that promoter -592 A/C of IL-10 gene not associated with LN activity or the pathologic classes of LN.

Interleukin-10 paradox: A potent immunoregulatory cytokine that has been difficult to harness for immunotherapy

Interleukin-10 (IL-10) is arguably the most potent anti-inflammatory cytokine. It is produced by almost all the innate and adaptive immune cells. These cells also serve as its targets, indicating that IL-10 secretion and action is highly regulated and perhaps compartmentalized. Consistent with this notion, various efforts directed at systemic administration of IL-10 to modulate autoimmune diseases (type 1 diabetes, multiple sclerosis, rheumatoid arthritis, psoriasis) have produced conflicting and largely inconsequential effects. On the other hand, IL-10 can promote humoral immune responses, enhancing class II expression on B cells and inducing immunoglobulin (Ig) production. Consequently, the high IL-10 level in systemic lupus erythematosus (SLE) patients is considered pathogenic and its blockade ameliorates the disease. In this perspective, we review preclinical findings and results of recent clinical studies using exogenous IL-10 to treat the aforementioned autoimmune diseases. In addition, given the limited success of IL-10 supplementation, we suggest that future studies should be expanded beyond modulating the delivery modes to include developing new strategies to protect and replenish the endogenous sources of IL-10. As an example, we provide evidence that aberrant Fas-mediated deletion of IL-10-producing B cells subverts the immunoregulatory role of IL-10 in autoimmune diabetes and that modulation of the Fas pathway preserves the IL-10-producing B cells and completely protects NOD mice from developing the disease.

Association of interleukin-10 promoter haplotypes with disease susceptibility and IL-10 levels in Mexican patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is the prototype autoimmune rheumatic disease. The etiology of this disease is incompletely understood; however, environmental factors and genetic predisposition are involved. Cytokine-mediated immunity plays a crucial role in the pathogenesis of SLE. We investigate the association of interleukin-10 (IL-10) promoter polymorphisms and their haplotypes in SLE patients from the western Mexico. One hundred and twenty-five SLE patients fulfilling the 1997 ACR criteria and 260 unrelated healthy subjects (HS), both Mexican mestizos, were genotyped for IL-10 -1082A>G, -819C>T, and -592C>A polymorphisms. Haplotypes were inferred using the expectation-maximization algorithm, then allele and haplotype distributions were compared between patients and HS, as well as patients with different clinical variables. We identified at -1082, -819, and -592 four predominant haplotypes ACC (43.70 % in patients vs 46.55 % in HS), ATA (21.45 vs 22.97 %), GCC (16.28 vs 14.21 %), and GTA (14.12 vs 14.12 %). The ATC haplotype was more frequent in SLE respect to HS, suggesting a risk effect (3.23 vs 1.05 %; OR 3.55, CI 1.14-11.11; p = 0.0293). SLE patient carriers of -592 CC genotype as well as the dominant model of inheritance showed higher sIL-10 respect to AA genotype, suggesting that -592 C allele is associated with increased production of the cytokine (p < 0.05). The ACC haplotype had higher IL-10 serum levels and higher values of Mexican version of the Systemic Lupus Erythematosus Disease Activity Index compared with the other haplotype carriers; however, no association was found regarding autoantibodies. Our data suggest that the IL-10 promoter haplotypes play an important role in the risk of developing SLE and influence the production of IL-10 in Mexican population. Nevertheless, further studies are required to analyze the expression of mRNA as well as to investigate the interacting epigenetic factors that could help to define the true contribution of this marker in SLE pathogenesis.

Association of extended interleukin-10 promoter haplotypes with disease susceptibility and manifestations in German patients with systemic lupus erythematosus

OBJECTIVES

Associations of interleukin-10 (IL-10) promoter single nucleotide polymorphisms (SNPs) and their haplotypes with systemic lupus erythematosus (SLE) are unclear. We extended the analysis of established proximal IL-10 promoter haplotypes to a more distal SNP with functional capacity.

METHODS

Two hundred and ten German caucasian SLE patients fulfilling the ACR criteria and 160 ethnically, age and sex matched controls were genotyped for IL-10 -2849 G > A, -1082 A > G, -819 T > C and -592 C > A. Haplotypes were reconstructed via a mathematical model, then allele and haplotype distributions were compared between patients and controls and patients with different disease manifestations.

RESULTS

We detected at -2849, -1082, -819 and -592 the four predominant haplotypes GGCC (22% in patients vs. 29% in controls), AGCC (24% vs. 21%), GACC (30% vs. 25%) and GATA (24% vs. 24%). GGCC was underrepresented in SLE patients, suggesting a protective effect (odds ratio (OR) 0.67, 95% confidence interval (CI) 0.48-0.94). AGCC was found significantly more frequently in patients with pathognomonic anti-dsDNA antibodies (26% vs. 15%; OR 1.98, 95% CI 1.04-3.75). As compared to patients with glomerulonephritis type V (WHO classification), the presumptive IL-10 high producer allele -2849 G was found significantly more often in patients with GN type III/IV (93% vs. 60%; OR 8.7, 95% CI 1.59-47.15).

CONCLUSION

Our data confirm that the complexity of the IL-10 promoter evokes the need for a meticulous analysis of its haplotypic structure in order to specify disease associations, particularly under functional aspects, thereby shedding light on the pathophysiology of SLE.

Preferential binding to Elk-1 by SLE-associated IL10 risk allele upregulates IL10 expression

Immunoregulatory cytokine interleukin-10 (IL-10) is elevated in sera from patients with systemic lupus erythematosus (SLE) correlating with disease activity. The established association of IL10 with SLE and other autoimmune diseases led us to fine map causal variant(s) and to explore underlying mechanisms. We assessed 19 tag SNPs, covering the IL10 gene cluster including IL19, IL20 and IL24, for association with SLE in 15,533 case and control subjects from four ancestries. The previously reported IL10 variant, rs3024505 located at 1 kb downstream of IL10, exhibited the strongest association signal and was confirmed for association with SLE in European American (EA) (P = 2.7×10⁻⁸, OR = 1.30), but not in non-EA ancestries. SNP imputation conducted in EA dataset identified three additional SLE-associated SNPs tagged by rs3024505 (rs3122605, rs3024493 and rs3024495 located at 9.2 kb upstream, intron 3 and 4 of IL10, respectively), and SLE-risk alleles of these SNPs were dose-dependently associated with elevated levels of IL10 mRNA in PBMCs and circulating IL-10 protein in SLE patients and controls. Using nuclear extracts of peripheral blood cells from SLE patients for electrophoretic mobility shift assays, we identified specific binding of transcription factor Elk-1 to oligodeoxynucleotides containing the risk (G) allele of rs3122605, suggesting rs3122605 as the most likely causal variant regulating IL10 expression. Elk-1 is known to be activated by phosphorylation and nuclear localization to induce transcription. Of interest, phosphorylated Elk-1 (p-Elk-1) detected only in nuclear extracts of SLE PBMCs appeared to increase with disease activity. Co-expression levels of p-Elk-1 and IL-10 were elevated in SLE T, B cells and monocytes, associated with increased disease activity in SLE B cells, and were best downregulated by ERK inhibitor. Taken together, our data suggest that preferential binding of activated Elk-1 to the IL10 rs3122605-G allele upregulates IL10 expression and confers increased risk for SLE in European Americans.

Interleukin-10 promoter polymorphisms and expression in Thai children with juvenile systemic lupus erythematosus

Interleukin (IL)-10 expression is regulated by its promoter and correlated with the activity of adult-onset lupus (systemic lupus erythematosus (SLE)). As the pathogenesis of adult-onset SLE may differ from SLE with the age at onset <18 years old (juvenile SLE or JSLE), we evaluated polymorphisms at positions −1082A/G, −819T/C and −592A/C of the IL-10 promoter and serum IL-10 levels in 71 patients with JSLE. Disease activity was determined by the SLE disease activity index (SLEDAI). Active SLE was defined by SLEDAI ≥6 and inactive SLE was defined by SLEDAI equal to zero. The mean age was 14.5 ± 2.8 years. Nephritis occurred in 57 patients. In JSLE patients, −592 CC and −819 CC were identified with a higher frequency than in controls with the odds ratio (OR) of 2.75 (95% confidence interval (CI) 1.11–6.81, p = 0.04). GCC increased the susceptibility to nephritis in patients with JSLE (OR 2.16, 95% CI 1.07–4.35, p = 0.03). Serum IL-10 levels were significantly higher in 20 JSLE patients with active disease than in 27 patients with inactive disease and in 15 healthy children ( p < 0.001). In conclusion, IL-10 expression was upregulated in active JSLE. The −819 CC and −592 CC genotypes increased the susceptibility to JSLE and GCC increased the susceptibility to nephritis.

A regulatory role for IL-10 receptor signaling in development and B cell help of T follicular helper cells in mice

IL -10 is widely accepted as a survival, proliferation, and differentiation factor for B cells. However, IL-10 deficiency accelerates disease progression as the result of autoantibody production in many autoimmune disease models. It was demonstrated that T follicular helper cells (T(FH) cells) play a key role in helping B cells that are secreting Abs. In this study, we demonstrated a regulatory role for IL-10R signaling on the development and B cell help function of T(FH) cells in vitro and in vivo. IL-1R subunit β-deficient (Il10rb(-/-)) Th cells were able to differentiate more readily into T(FH) cells, as well as secrete more IL-21 and IL-17 compared with wild-type Th cell-derived T(FH) cells. Increased IL-21 and IL-17 contributed to the enhanced B cell help functions of T(FH) cells. Further experiments demonstrated that IL-6 and IL-23 from dendritic cells in Il10rb(-/-) mice contributed to the differentiation of naive Th cells into T(FH) cells, as well as the generation of IL-21- and IL-17-producing T(FH) cells. Our results provide useful information for clarifying the immunoregulatory mechanisms associated with IL-10 deficiency in certain autoimmune disease models. This information could also be of benefit for the development of vaccines.

Systemic lupus erythematosus monocytes are less responsive to interleukin-10 in the presence of immune complexes

OBJECTIVE

Systemic lupus erythematosus (SLE) is a systemic inflammatory disease characterized by autoantibody production and immune complex deposition. The level of interleukin-10 (IL-10), predominantly an antiinflammatory cytokine, is paradoxically elevated in patients with SLE. The aim of this study was to examine the hypothesis that the antiinflammatory function of IL-10 is impaired in monocytes from patients with SLE with long-term exposure to immune complexes.

METHODS

CD14+ monocytes were isolated from healthy donors and patients with SLE. Cultured CD14+ cells were treated with heat-aggregated human IgG (325 μg/ml) in the presence or absence of IL-10 (20 ng/ml). To study gene expression, RNA was extracted 3 hours after treatment. To study cytokine production, supernatants were harvested after 8 hours. To study IL-10 signaling, cell lysates were obtained from CD14+ cells treated with human IgG (325 μg/ml) for 1 hour followed by IL-10 (20 ng/ml) treatment for 10 minutes. Western blot analysis was used to assess STAT-3 phosphorylation. All experiments were performed in pairs.

RESULTS

When stimulated with human IgG, SLE monocytes produced more tumor necrosis factor α (TNFα) and IL-6 than did control cells. The suppressive effect of IL-10 on human IgG-induced TNFα and IL-6 production was lower in SLE monocytes compared with control monocytes, although IL-10 receptor expression was similar in SLE and control monocytes. Human IgG suppressed IL-10 receptor expression and altered IL-10 signaling in control monocytes. Like SLE monocytes, interferon-α (IFNα)-primed control monocytes stimulated with human IgG were also less responsive to IL-10.

CONCLUSION

Human IgG and IFNα modulate IL-10 function. In SLE monocytes, which are considered to be IFNα primed and persistently exposed to immune complexes, responses to IL-10 are abnormal, limiting the antiinflammatory effect of this cytokine.

Anticytokine therapies in systemic lupus erythematosus

The dysfunctional immune response that characterizes systemic lupus erythematosus (SLE) associates with an unbalanced production of soluble mediators that are crucial in promoting and sustaining chronic inflammation. The successful use of biologics in several autoimmune diseases has led to studies in SLE aimed at contrasting the proinflammatory responses that contribute to tissue and organ damage in the disease. Several approaches have been developed and tested as potential therapeutic agents in SLE in preclinical studies and in clinical trials. This article provides an overview on antibody-based approaches in SLE that, although preliminary, have the potential to expand the current therapeutic possibilities in the disease.

Regulation of interleukin-10 gene expression in macrophages engulfing apoptotic cells

Apoptosis and the rapid clearance of apoptotic cells (ACs) by professional or nonprofessional phagocytes are normal and coordinated processes that ensure controlled cell growth and stress response with nonpathological outcomes. Uptake of ACs by phagocytes is thought to suppress autoimmune responses through the release of anti-inflammatory cytokines such as interleukin-10 (IL-10), transforming growth factor-beta (TGF-beta), and inhibition of proinflammatory cytokines. The production of pro- and anti-inflammatory cytokines by phagocytes is highly regulated as part of an intrinsic mechanism to prevent inflammatory and autoimmune reactions in a physiological state. Production of IL-10 by phagocytes during clearance of ACs is critical to ensuring cellular homeostasis and suppression of autoimmunity. The molecular mechanism whereby IL-10 production is induced by ACs is only beginning to be understood. This review summarizes our recent work in this aspect of an essential physiological and homeostatic process.

IL-10 and TNFalpha genotypes in SLE

The production of two regulators of the inflammatory response, interleukin 10 (IL-10) and tumor necrosis factor α (TNFα), has been found to be deeply deregulated in SLE patients, suggesting that these cytokines may be involved in the pathogenesis of the disease. Genetic polymorphisms at the promoter regions of IL-10 and TNFα genes have been associated with different constitutive and induced cytokine production. Given that individual steady-state levels of these molecules may deviate an initial immune response towards different forms of lymphocyte activation, functional genetic variants in their promoters could influence the development of SLE. The present review summarizes the information previously reported about the involvement of IL-10 and TNFα genetic variants on SLE appearance, clinical phenotype, and outcome. We show that, in spite of the heterogeneity of the populations studied, the existing knowledge points towards a relevant role of IL-10 and TNFα genotypes in SLE.

Anti-ribosomal phosphoprotein autoantibody triggers interleukin-10 overproduction via phosphatidylinositol 3-kinase-dependent signalling pathways in lipopolysaccharide-activated macrophages

Anti-ribosomal phosphoprotein autoantibodies have been shown to be significantly associated with multiple manifestations of systemic lupus erythematosus (SLE). High levels of interleukin-10 (IL-10) have been demonstrated to contribute to lupus susceptibility and severity. In this study, we investigated the molecular mechanisms of anti-ribosomal phosphoprotein monoclonal antibody (anti-P mAb)-induced autoimmune responses. Anti-P mAb promoted IL-10 overproduction in a dose- and time-dependent manner in both lipopolysaccharide (LPS)-activated RAW 264.7 cells and primary human macrophages. Anti-P mAb enhanced phosphorylation of Akt (PKB; protein kinase B), extracellular signal regulated kinase 1/2 (ERK1/2) and c-Jun NH2-terminal kinase 1/2 (JNK1/2), while phosphorylation of p38 remained unaltered. Furthermore, anti-P mAb decreased glycogen synthase kinase 3 (GSK3) activity and reduced the phosphorylation of I kappaB alpha in LPS-activated macrophages. The Syk, phosphatidylinositol 3-kinase (PI3K), protein kinase C (PKC), JNK and ERK signalling pathways involved in anti-P mAb-triggered IL-10 secretion were also confirmed using various pharmacological inhibitors. In addition, nuclear factor (NF)-kappaB had negative regulatory effects on anti-P mAb-triggered IL-10 secretion. Using reporter plasmids containing the nuclear factor binding sites of NF-kappaB, cAMP-enhanced activation protein 1 (AP-1), serum response element (SRE) or cyclic AMP response element (CRE), treatment of anti-P mAb led to activation of the corresponding factors that bind to the AP-1 site, SRE and CRE in the LPS-activated macrophages. Furthermore, by transfection with reporter plasmids bearing various lengths of the IL-10 promoter, the AP-1 binding site, SRE and CRE were shown to be required for anti-P mAb-induced effects. Collectively, our results provide a molecular model for anti-P mAb-induced IL-10 overproduction in LPS-activated macrophages, which may play a role in the pathogenesis of SLE.

Interleukin-10 promoter polymorphisms in patients with systemic lupus erythematosus from the Canary Islands

The purpose of this study was to examine whether several allelic variants in the polymorphic interleukin (IL)-10 promoter region were related with an increased risk of developing systemic lupus erythematosus (SLE) in Spanish patients from Canary Islands. Microsatellites (MS) at positions -4000 and -1200 (IL10R and IL10G, respectively) and single nucleotide polymorphisms (SNPs) (MS) at positions -1082G/A, -819C/T and -592C/A of the IL-10 promoter were analysed in patients with SLE and healthy controls from Canary Islands (Spain). We found that SNPs but not MS were associated with SLE. The GCC haplotype frequency was significantly higher in SLE patients (0.43) than in healthy donors (0.33) [P = 0.02; OR = 1.50 (95% CI = 1.06-2.14)], whereas the ACC haplotype was less represented in patients (0.28 vs. 0.37) [P = 0.02; OR = 0.64 (95% CI = 0.44-0.92)]. To assess the functional role of genotypes, serum IL-10 levels from patients and controls were quantified by ELISA. Also, the lipopolysaccharide-induced IL-10 secretion by monocytes from healthy controls was evaluated in vitro. Serum IL-10 levels were higher in patients [median (interquartile range) = 2.8 pg/mL (1.8-4.2)] than in controls [0.9 pg/mL (0-3.5)] (P = 0.02), but no association was observed between serum IL-10 levels or lipopolysaccharide-induced IL-10 secretion and the IL-10 promoter haplotypes. These data suggest that the IL-10 promoter haplotype that produces higher levels of cytokine is associated with SLE in patients from Canary Islands.

Susceptibility to sequelae of human ocular chlamydial infection associated with allelic variation in IL10 cis-regulation

Trachoma, an infectious disease of the conjunctiva caused by Chlamydia trachomatis, causes scarring and blindness in some infected individuals but not others. In an African community where trachoma is endemic, we have previously identified an IL10 haplotype that is associated with increased risk of scarring complications. Here we examine the hypothesis that the risk haplotype (H-RISK) affects levels of IL10 expression in the conjunctiva during active trachoma infection. To overcome potential genetic and environmental confounders we used the method of allele-specific quantification, which involved identifying subjects in the community who had active trachoma and were also heterozygous for the H-RISK. We find that there is allelic variation in cis-regulation of IL10 in the conjunctiva during active trachoma, with the H-RISK generating relatively more IL10 transcripts than other haplotypes in this population (average difference in IL10 allelic transcripts in the conjunctiva of heterozygous individuals infected with C. trachomatis of 23% (95% confidence interval: 14-32%, P < 0.0001). These findings provide a plausible functional explanation for the observed genetic association, and support the hypothesis that an excessive IL10 response to C. trachomatis infection is a risk factor for scarring and blindness.

Differential expression in lupus-associated IL-10 promoter single-nucleotide polymorphisms is mediated by poly(ADP-ribose) polymerase-1

Systemic lupus erythematosus (SLE) is a complex, multifactorial autoimmune disease characterized by the dysregulation of T and B cells that leads to hyperactivity of B cells and production of autoantibodies, and involves both environmental and genetic factors. Interleukin-10 (IL-10) is a candidate susceptibility gene in SLE. In particular, three IL-10 promoter single-nucleotide polymorphisms (SNPs; -1082A/G, -819T/C and -592A/C) are strongly associated with the pathogenesis of SLE. We found that the homozygous GCC haplotype linked to greater SLE severity confers higher IL-10 gene transcriptional activity than the ATA haplotype in macrophages that encounter apoptotic cells, because of the differential DNA binding to the -592 SNP by a nuclear protein uniquely induced by apoptotic cells. We identified this protein as poly(ADP-ribose) polymerase-1, confirmed its physiological role and characterized its molecular properties in modulating IL-10 production during phagocytosis of apoptotic cells. This study unveils a novel direct link between DNA damage repair/apoptosis pathways and IL-10-mediated immune regulation.

Interleukin-10-secreting type 1 regulatory T cells in rodents and humans

Interleukin-10 (IL-10)-secreting T regulatory type 1 (Tr1) cells are defined by their specific cytokine production profile, which includes the secretion of high levels of IL-10 and transforming growth factor-beta(TGF-beta), and by their ability to suppress antigen-specific effector T-cell responses via a cytokine-dependent mechanism. In contrast to the naturally occurring CD4+ CD25+ T regulatory cells (Tregs) that emerge directly from the thymus, Tr1 cells are induced by antigen stimulation via an IL-10-dependent process in vitro and in vivo. Specialized IL-10-producing dendritic cells, such as those in an immature state or those modulated by tolerogenic stimuli, play a key role in this process. We propose to use the term Tr1 cells for all IL-10-producing T-cell populations that are induced by IL-10 and have regulatory activity. The full biological characterization of Tr1 cells has been hampered by the difficulty in generating these cells in vitro and by the lack of specific marker molecules. However, it is clear that Tr1 cells play a key role in regulating adaptive immune responses both in mice and in humans. Further work to delineate the specific molecular signature of Tr1 cells, to determine their relationship with CD4+ CD25+ Tregs, and to elucidate their respective role in maintaining peripheral tolerance is crucial to advance our knowledge on this Treg subset. Furthermore, results from clinical protocols using Tr1 cells to modulate immune responses in vivo in autoimmunity, transplantation, and chronic inflammatory diseases will undoubtedly prove the biological relevance of these cells in immunotolerance.

Association of apoptosis-related microsatellite polymorphisms on chromosome 1q in Taiwanese systemic lupus erythematosus patients

Apoptosis is important in the pathogenesis of systemic lupus erythematosus (SLE). Several genome-wide scan studies have suggested chromosome 1q as a genetic susceptibility locus for SLE. This study investigated the association of apoptosis-related genes on chromosome 1q, Fas ligand (FasL), interleukin (IL)-10 and poly(ADP-ribose) polymerase (PARP), promoter microsatellite multi-allelic polymorphisms with SLE susceptibility and clinical characteristics in Taiwan. This study recruited 237 SLE patients and 304 healthy controls. FasL, IL-10 and PARP promoter microsatellite polymorphisms were genotyped employing gene scan. IL-10, located on 1q31-32, emerged as a significant susceptibility gene locus in Taiwanese SLE (T4 statistic = 0.01). IL-10 CA21 allele was the most common allele of 15 identified in Taiwanese, displaying skewed distribution of susceptibility in Taiwanese SLE patients. Conversely, the IL-10 CA20 allele showed a protective effect of SLE susceptibility. Additionally, the IL-10 CA26 allele displayed a negative significant association with ascites and IL-10 CA25 allele increased the occurrence of the anti-cardiolipin IgM antibody. This study identified five alleles of FasL and nine alleles of PARP of microsatellite polymorphisms in Taiwanese patients. FasL and PARP alleles displayed no skewing distribution between Taiwanese SLE patients and controls. However, FasL GT15 and PARP CA17 allele demonstrated a high discoid rash presentation (T4 statistic 0.01 and 0.03, respectively) and PARP CA12 allele displayed a significant association with anti-cardiolipin IgM antibody production (T4 statistic 0.02). IL-10, FasL and PARP microsatellite polymorphisms exhibited significant associations with SLE susceptibility and/or clinical characteristics in Taiwanese patients. Thus, SLE is a complex and multiple genetics determined autoimmune disease. Chromosome 1q23-42 is an important genetic locus for further SLE subphenotype susceptibility study.

Polymorphisms of complement receptor 1 and interleukin-10 genes and systemic lupus erythematosus: a meta-analysis

A number of studies have tested the association of the complement receptor 1 (CR1) and Interleukin-10 (IL10) polymorphisms with systemic lupus erythematosus (SLE), but reported conflicting results. The aim of the study is to explore whether the CR1 and IL10 genes are associated with SLE susceptibility. We surveyed studies on the CR1 and IL10 polymorphisms and SLE using comprehensive Medline search and review of the references. A meta-analysis was conducted in a fixed effects model or random effects model based on between-study heterogeneity. Eighteen comparisons from 13 studies were included in the CR1 meta-analysis and a total of 16 separate comparisons were used for the IL10 meta-analysis. The CR1 meta-analysis showed no significant association of the CR1 functional polymorphisms with SLE. In contrast, the S structural variant of the CR1 showed a significant association (OR=1.544, 95% CI, 1.217-1.959, P<0.001). Stratification by ethnicity indicated that the CR1 S variant was associated with SLE in Caucasians (OR=1.667, 95% CI, 1.193-2.357, P=0.003). The IL10 meta-analysis showed a significant association between SLE and the G11 allele of IL10.G (OR=1.279, 95% CI; 1.027-1.593, P=0.028) in whole populations, and IL10 promoter -1082G allele was associated with SLE in Asians (OR=1.358, 95% CI; 1.015-1.816, P=0.039). In conclusion, the CR1 meta-analysis revealed the association of the S structural variant of the CR1 with SLE and the IL10 meta-analysis showed the association of IL10.G11 allele and SLE in whole populations and the association between promoter -A1082G polymorphism and SLE in Asians.

Risk of trachomatous scarring and trichiasis in Gambians varies with SNP haplotypes at the interferon-gamma and interleukin-10 loci

Experimental evidence implicates interferon gamma (IFNgamma) in protection from and resolution of chlamydial infection. Conversely, interleukin 10 (IL10) is associated with susceptibility and persistence of infection and pathology. We studied genetic variation within the IL10 and IFNgamma loci in relation to the risk of developing severe complications of human ocular Chlamydia trachomatis infection. A total of 651 Gambian subjects with scarring trachoma, of whom 307 also had potentially blinding trichiasis and pair-matched controls with normal eyelids, were screened for associations between single-nucleotide polymorphisms (SNPs), SNP haplotypes and the risk of disease. MassEXTEND (Sequenom) and MALDI-TOF mass spectrometry were used for detection and analysis of SNPs and the programs PHASE and SNPHAP used to infer haplotypes from population genetic data. Multivariate conditional logistic regression analysis identified IL10 and IFNgamma SNP haplotypes associated with increased risk of both trachomatous scarring and trichiasis. SNPs in putative IFNgamma and IL10 regulatory regions lay within the disease-associated haplotypes. The IFNgamma +874A allele, previously linked to lower IFNgamma production, lies in the IFNgamma risk haplotype and was more common among cases than controls, but not significantly so. The promoter IL10-1082G allele, previously associated with high IL10 expression, is in both susceptibility and resistance haplotypes.

Genetics of systemic lupus erythematosus: how far have we come?

There are two primary mechanisms for studying the genetic forces at work in systemic lupus erythematosus (SLE). Several groups have collected large numbers of pedigrees in which multiple family members have SLE for use in linkage studies. These linkage studies serve to isolate areas of the genome in which susceptibility genes lie. Other groups have taken a more direct approach of investigating genes that might contribute to disease pathogenesis in sets of lupus subjects and matched controls. These association studies are accumulating in greater numbers as the technology to determine the genotype at a given locus becomes more accessible. This article discusses the results of both types of studies.

Genetics of lupus nephritis

Susceptibility to lupus nephritis is the end-result of complex interactions between polymorphic genetic factors involved in the regulation of immune responses. In humans, genome-wide screens and candidate-gene analyses led to the identification of several loci containing potential targets (FcgammaRIIa, PTPN22, PD-1, IL-10) for physiopathological research and therapeutic interventions. In mice, the generation of congenic mice, bearing in a normal genetic background one single disease-associated locus, greatly improved our understanding of the mechanisms mediating the genetic contribution to the disease. In the future, the identification of disease-associated genes will open new perspectives for the development of more targeted therapies of lupus nephritis.

Familial aggregation of systemic lupus erythematosus, rheumatoid arthritis, and other autoimmune diseases in 1,177 lupus patients from the GLADEL cohort

OBJECTIVE

To determine whether there is familial aggregation of systemic lupus erythematosus (SLE) and/or other autoimmune diseases in SLE patients and to identify clinical differences between patients with and those without familial autoimmunity.

METHODS

We interviewed members of the Grupo Latinoamericano de Estudio del Lupus Eritematoso (GLADEL) inception cohort of 1,214 SLE patients to ascertain whether they had relatives with SLE and/or other autoimmune diseases. Identified relatives were studied. Familial aggregation was tested using reported highest and intermediate population prevalence data for SLE, rheumatoid arthritis (RA), or all autoimmune diseases, and studies were performed to identify the genetic model applicable for SLE.

RESULTS

We identified 116 first-, second-, or third-degree relatives with SLE, 79 with RA, 23 with autoimmune thyroiditis, 3 with scleroderma, 1 with polymyositis, and 16 with other autoimmune diseases, related to 166 of the 1,177 SLE patients in the GLADEL cohort who agreed to participate. Forty-two SLE patients had 2 or more relatives with an autoimmune disease. We found a lambda(sibling) of 5.8 and 29.0 for SLE and of 3.2-5.3 for RA, when comparing with their reported high or intermediate population prevalence, respectively. We also found familial aggregation for autoimmune disease in general (lambda(sibling) = 1.5) and determined that for SLE, a polygenic additive genetic model, rather than a multiplicative one, is applicable.

CONCLUSION

In SLE there is familial aggregation of SLE, RA, and autoimmune disease in general. A polygenic additive model applies for SLE. American Indian-white Mestizo SLE patients and those with higher socioeconomic level were more likely to have familial autoimmunity.

Pregnancy, cytokines, and disease activity in systemic lupus erythematosus

OBJECTIVE

To evaluate levels of selected cytokines and soluble receptors involved in the humoral immune response during pregnancy in systemic lupus erythematosus (SLE) patients.

METHODS

Seventeen consecutive SLE patients and 8 matched healthy controls were prospectively studied during pregnancy. Sera were obtained within the last 3 months prior to pregnancy; at 9, 17, and 29 weeks of pregnancy; and at 1 month after delivery. Serum levels of interleukin-10 (IL-10), interleukin-6 (IL-6), and soluble tumor necrosis factor receptors p55 (sTNFR I) and p75 (sTNFR II) were evaluated. SLE activity was measured by the European Consensus Lupus Activity Measurement score modified for pregnancy.

RESULTS

IL-10 serum levels were found to be higher (P <0.0001) in patients than in controls before conception, and still higher (P <0.0001) in SLE patients during gestation, without intertrimester changes. In SLE patients, IL-6 serum levels did not increase in the third trimester of pregnancy, as was observed in controls (P=0.011). No significant differences between SLE patients and controls were found in either sTNFR I or II levels or profiles before and during pregnancy. IL-10 and sTNFR I levels were significantly higher during pregnancy and postpartum in SLE patients with active disease (P=0.03 and P=0.01, respectively).

CONCLUSION

The levels of some cytokines involved in the humoral immune response seem to be modified in the peripheral circulation of pregnant SLE patients. The most relevant modifications are the lower than expected increase of IL-6 in the third trimester of gestation and persistently high levels of IL-10 during pregnancy.

[Pathogenic mechanisms of autoimmune diseases]

BACKGROUND

Auto-immune diseases are a fascinating but poorly understood group of diseases.

MAJOR POINTS

In this review, we will consider genetic susceptibility to auto-immune diseases, initiation of autoreactivity and changes in pathologic processes. Recent physiopathological hypotheses are detailed with clinical examples.

PERSPECTIVES

A better knowledge of the physiopathological mechanisms would allow the development of more efficacious treatments.

Association of interleukin-10 promoter polymorphisms with systemic lupus erythematosus

Several lines of evidence suggest interleukin-10 gene (IL-10) is a candidate gene in susceptibility to systemic lupus erythematosus (SLE). We investigated the association of IL-10 promoter single-nucleotide polymorphisms (SNPs) (-3575T/A, -2849G/A, -2763C/A, -1082A/G, -819T/C and -592A/C) and microsatellites (IL10.R, IL10.G) with SLE in 554 Hong Kong Chinese patients and 708 ethnically matched controls. Six haplotypes (hts) were identified from the SNPs. The genotype distribution of the ht1 (T-C-A-T-A), which is associated with low IL-10 production, was different in patients and controls (P=0.009). The homozygous genotype of non-ht1 was significantly increased in patients (P=0.009, odds ratio (OR)=1.80, 95% CI: 1.15-2.82). The frequency of IL10.G4 of IL10.G was also significantly increased in patients (P=0.017, OR=2.53, 95% CI: 1.18-5.40). We found that the homozygous non-ht1 combined with short allele (CA repeat number < or =21) of IL10.G has a dose-dependent effect on SLE susceptibility: non-ht1/non-ht1 with homozygous short allele showed a higher OR (OR=4.11, 95% CI: 1.27-13.2, P=0.018) of association with SLE than the genotype of non-ht1/non-ht1 with heterozygous short/long allele (OR=2.98, 95% CI: 1.26-7.07, P=0.013) and homozygous long allele (OR=1.05, 95% CI: 0.62-1.78, P=0.848). The frequency of non-ht1 was significantly increased in patients with serositis (P<0.0001, OR=2.42, 95% CI: 1.55-3.80). In conclusion, the high expression promoter genotype is associated with SLE in Chinese.

Immunology of cutaneous lupus erythematosus

The cause and effect between ultraviolet light and cutaneous lupus erythematosus (CLE) is clear. In LE patients indeed, photosensitivity is one of the major diagnostic criteria of the systemic form of lupus erythematosus. This strong clinical association has led to the postulate that abnormal photosensitivity participates in the pathogenesis of cutaneous lesions in LE. What is not clear is how the ultraviolet radiation (UVR) induces cutaneous lesions in susceptible individuals despite the fact that profound effects of UVR on the cellular components of the skin have been extensively studied. The whole scenario is complicated by the relationship between sunlight and the cutaneous immune system. Pronounced effects of UVR on the cutaneous immune response further complicate the understanding of photosensitivity in LE. In addition, the network of cutaneous cytokines, chemokines, and adhesion molecules has become increasingly intricate, thus contributing to the genetic substrate of each individual, and to the tremendous complexity of the pathogenesis of CLE.

Immunoregulatory defects in patients with systemic lupus erythematosus in clinical remission

Little is known about the immune system of patients with systemic lupus erythematosus (SLE) during periods of silent disease. To address this issue we analysed lymphoid populations andcytokine production of mononuclear cells obtained from SLE patients in remission. We studied 43 patients with inactive disease, 10 with active disease and 30 controls. Remission was defined as at least 1 year during which lack of clinical disease activity permitted withdrawal of all treatment. Remission length ranged from 1 to 30 years. Flow cytometry and ELISA were used to study lymphoid populations (CD4, CD8 and CD19) and cytokine production (IL-2, 4, 10, 12 and 18). Patients with short remission periods (up to 15 years) exhibited an increased percentage of B cells; production of IL-2, IL-10 and IL-12 was decreased; production of IL-18 was increased. Interestingly, patients from groups with long time of inactive disease had corrected most alterations, but had an impaired IL-18 expression. IL-12 production correlated strongly with the length of the remission period (r = 0.7565). The immune system of patients with inactive lupus has partially corrected the disturbances present during disease activity. This is accomplished gradually, sometimes until counter-regulatory alterations are developed. This may allow patients to remain without disease activity.

Functional cooperation of simian virus 40 promoter factor 1 and CCAAT/enhancer-binding protein beta and delta in lipopolysaccharide-induced gene activation of IL-10 in mouse macrophages

Previous studies have revealed that LPS can activate transcription of the IL-10 gene promoter through an SV40 promoter factor 1 (Sp1) binding site in mouse macrophage RAW264.7. In this study, we determined that, in addition to Sp1, C/EBPbeta and delta were also involved in LPS-induced gene expression of IL-10. By transient transfection with 5'-deletion mutants of the IL-10 promoter, we found that there were two LPS-responsive elements in the promoter of the mouse IL-10 gene. Analysis of these two regions by gel shift assay suggested that Sp1 and C/EBPbeta and delta were bound to these two regions, respectively. By site-directed mutagenesis, we found that disruption at both the Sp1 and C/EBP binding sites almost completely blocked the LPS response. By gel shift assay and Western blotting, we found that the DNA binding complex and protein expression of C/EBPbeta and delta were increased by LPS treatment, but these results were not found for Sp1. Overexpression of C/EBPbeta or C/EBPdelta, respectively, activated the promoter of the IL-10 gene, and they were enhanced by LPS. Coimmunoprecipitation experiments in intact cells indicated that LPS stimulated interaction between Sp1 and C/EBPbeta and delta. These results suggested that the interaction between Sp1 and C/EBPbeta and delta induced by LPS cooperatively activated expression of the IL-10 gene. The increase of C/EBPbeta and delta proteins and the enhancement of transactivation activity of C/EBPbeta and delta by LPS treatment, at least in part, explain the activation of IL-10 gene expression.

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.

Correlation between circulating CD27high plasma cells and disease activity in patients with systemic lupus erythematosus

OBJECTIVE

Disease activity in systemic lupus erythematosus (SLE) is usually assessed with complex disease activity scores comprising a variety of different parameters. In order to determine whether SLE disease activity correlates with abnormal B lymphocyte activity, B cell subsets were analyzed, and their relationship to clinical and humoral measures of disease activity was assessed.

METHODS

The distribution of B cell subsets was determined by fluorescence-activated cell sorting analysis and assessed in relation to the autoantibody profile, disease activity measured by the SLE Disease Activity Index (SLEDAI) and the European Consensus Lupus Activity Measure scores, disease duration, and therapy.

RESULTS

The number and frequency of CD27(high) plasma cells were significantly correlated with the SLE disease activity indices and with the titer of anti-double-stranded DNA (anti-dsDNA) autoantibodies. Circulating B cell subsets were not influenced by age or sex, but appeared to relate to the duration of disease and the therapeutic regimen, with the number and frequency of CD27(high) plasma cells increasing and those of CD27- naive B cells decreasing over time. Patients were divided into those with a SLEDAI score of 0-8 (low disease activity) and those with SLEDAI score >8 (high disease activity). Patients with high disease activity had an increased frequency of both CD19+ B cells and CD27(high) plasma cells. By using a nonparametric data sieving algorithm, we observed that these B cell abnormalities provided predictive values for nonactive and active disease of 78.0% and 78.9%, respectively. The predictive value of the B cell abnormalities (78.9%) was greater than that of the humoral/clinical data pattern (71.4%), including anti-dsDNA antibody levels, circulating immune complexes, increased erythrocyte sedimentation rate, mucocutaneous involvement, and acute renal involvement.

CONCLUSION

Flow cytometric monitoring of B cell subsets in the peripheral blood provides new insights into abnormalities of B cell function in SLE and may also be a diagnostically valuable option for monitoring the activity of this autoimmune disease.

Increased T-lymphocyte apoptosis/necrosis and IL-10 producing cells in patients and their spouses in Icelandic systemic lupus erythematosus multicase families

The objective of this study was to evaluate apoptosis and production of IL-10 in SLE patients, their spouses and first-degree relatives in Icelandic SLE multicase families. Previously, increased IL-10 production has been found in all three groups. As IL-10 has been found to induce apoptosis in SLE, the percentage of lymphocytes undergoing apoptosis was evaluated, as well as the possible correlation between apoptosis and IL-10 production. Apoptosis and IL-10 production were studied in SLE patients (n = 12) from SLE multicase families and their spouses (n = 12) and a matched control group of healthy individuals (n = 10). The proportion of T and B lymphocytes undergoing apoptosis at 0, 24, 48 and 72 h was detected by flow cytometry using Annexin V and PI staining and the rate of apoptosis was calculated. IL-10 production was studied simultaneously by ELISpot analysis of freshly isolated peripheral blood mononuclear cells. In addition, T lymphocyte apoptosis at t = 0 was investigated in a group of non-household first-degree relatives (n = 10) and controls (n = 10). Antinuclear and antilymphocyte antibodies were analysed in all the groups. The SLE patients as a group had a significantly increased percentage of T lymphocytes in apoptosis at 0 and 48 h and a significantly higher number of IL-10 producing cells as compared with the healthy controls (P = 0.03, 0.02 and 0.03, respectively). The spouses also had significantly increased percentage of T lymphocytes in apoptosis (t = 0) and a significantly higher number of IL-10-producing cells when compared with healthy controls (P = 0.01 and 0.02, respectively). There were no significant differences between the patients and their spouses. For apoptosis of B lymphocytes no difference was found between the groups. The SLE patients as a group had the highest rate of apoptosis. No correlation between the degree and rate of apoptosis and the number of IL-10-producing cells was detected. The first-degree relatives did not have increased percentage of T lymphocytes undergoing apoptosis at t = 0 compared with healthy controls. The SLE patients had higher titres of ANA compared with the other groups. No correlation was detected between the ANA titre and the percentage of lymphocytes undergoing apoptosis. There was no correlation between disease activity as measured by SLEDAI and apoptosis. In conclusion, our results suggest that environmental factors common to both SLE patients and their spouses are associated both with the increased apoptosis and increased spontaneous production of IL-10, thus providing support for the notion that both environmental and genetic factors influencing apoptosis are of importance for the development of SLE.

The role of interleukin-10 in autoimmune disease: systemic lupus erythematosus (SLE) and multiple sclerosis (MS)

Interleukin-10 (IL-10) is an immunoregulatory cytokine that plays a crucial role in inflammatory and immune reactions. It has potent anti-inflammatory and immunosuppressive activities on myeloid cell functions which forms a solid basis for its use in acute and chronic inflammatory diseases. Here, we discuss the role of IL-10 in autoimmune diseases and examine its beneficial effects in cellular-based autoimmune diseases such as multiple sclerosis (MS) or its involvement in humoral-based autoimmune diseases such as systemic lupus erythematosus (SLE). Inhibition of the immune stimulatory activities of IL-10 may provide novel approaches in the treatment of humoral autoimmune diseases, infectious diseases and cancer.

Recent advances in the genetics of systemic lupus erythematosus

In recent years, we have witnessed an explosion in our understanding of the biology of SLE through the study of lupus-prone mice and the identification and subsequent narrowing of the genomic intervals likely responsible for SLE in human beings. The data from these efforts support the hypothesis that multiple genes contribute to disease susceptibility. Clearly, there is no single locus operating in all families multiplex for SLE, and the degree of ethnic and genetic heterogeneity seems to be quite significant. In this respect, the genetics of SLE resemble those of many other complex genetic diseases. The list of candidate genes and pathways (see Table 1) implicated in the pathogenesis of SLE is expanding at a rapid rate. Understanding how alterations in these genes and pathways lead to the lupus phenotype is the primary objective of future genetic studies in SLE.

Longitudinal study of interleukin-10, tumor necrosis factor-alpha, anti-U1-snRNP antibody levels and disease activity in patients with mixed connective tissue disease

OBJECTIVE

To investigate the levels and relationship between IL-10, TNF-alpha, anti-U1snRNP antibodies and disease activity in longitudinally collected serum samples from patients with mixed connective tissue disease (MCTD).

METHODS

Six patients followed for 17-138 months were investigated with ELISA for estimation of cytokine levels and antibodies to the different epitopes of the U1snRNP. Disease activity was assessed by systemic lupus activity measure (SLAM).

RESULTS

IL-10 and TNF-alpha levels fluctuated with time in at least half of the patients. Three patients had increased IL-10 levels and two had increased TNF-alpha in all samples. There was no correlation between cytokine levels and disease activity or clinical manifestations. All patients had increased levels of antibodies to the main components of the U1snRNP. Both antibody levels and disease activity decreased with time. A correlation between TNF-alpha and U1snRNP antibody levels were observed in five patients.

CONCLUSIONS

Increased and fluctuating levels of IL-10 or TNF-alpha without correlation to disease activity were observed in MCTD patients. In some patients increased cytokine levels were observed over several years irrespective of disease activity indicating that they could be constitutively increased in these individuals.

Maintenance of NF-kappaB activation in T-lymphocytes and a naive T-cell population in autoimmune-prone (NZB/NZW)F(1) mice by feeding a food-restricted diet enriched with n-3 fatty acids

We have previously shown that feeding a fish oil (FO) supplemented diet in combination with 40% food restriction (FO/FR) has a greater impact on extending life span in lupus-prone (NZB x NZW)F1 mice than either FO ad libitum (FO/AL) or corn oil food restricted (CO/FR) alone. Lupus disease is associated with increased Th-2 (i.e., IL-6 and IL-10) cytokine production and reduced IL-2 production and NF-kappaB activation. We hypothesized that the mechanism of action by which FO/FR increases life span may involve alterations in T-lymphocyte signaling and subsequent cytokine production. To test this hypothesis, we isolated and then stimulated splenic T-lymphocytes ex vivo with anti-CD3 and -CD28 monoclonal antibodies. We report here that CO/FR and FO/FR and to a lesser extent FO/AL offset disease-associated losses in Th-1 cytokine production, CD69 expression, and NF-kappaB activation in splenic T-lymphocytes activated ex vivo. Similarly, CO/FR and FO/FR prevented the disease-dependent rise in Th-2 cytokine production ex vivo and CD69 expression in vivo. In essence, the T-lymphocyte phenotype in the old CO/FR and FO/FR groups was identical to that in the young disease-free mice. Taken together, the data suggest that both CO/FR and FO/FR increase life span, in part, by maintaining a youthful immune phenotype in autoimmune-prone mice. However, FO/FR appears to represent a more potent dietary strategy in delaying disease-associated immune dysregulation than CO/FR.

GvHD risk assessment in hematopoietic stem cell transplantation: role of cytokine gene polymorphisms and an in vitro human skin explant model

This present review concentrates on the recent results investigating the role of certain cytokine gene polymorphisms, including tumor necrosis factor alpha, interferon gamma, interleukin-6 (IL-6), IL-10, and IL-1 receptor antagonist, in allogeneic stem cell transplantation. The review discusses their potential role in predicting outcome and the development of a genetic risk index for graft-versus-host disease in human leukocyte antigen matched sibling transplants. By the comparative use of an in vitro human skin explant model, initial results suggest that certain polymorphisms may be associated with more severe disease.

Interleukin-10 and the interleukin-10 receptor

Interleukin-10 (IL-10), first recognized for its ability to inhibit activation and effector function of T cells, monocytes, and macrophages, is a multifunctional cytokine with diverse effects on most hemopoietic cell types. The principal routine function of IL-10 appears to be to limit and ultimately terminate inflammatory responses. In addition to these activities, IL-10 regulates growth and/or differentiation of B cells, NK cells, cytotoxic and helper T cells, mast cells, granulocytes, dendritic cells, keratinocytes, and endothelial cells. IL-10 plays a key role in differentiation and function of a newly appreciated type of T cell, the T regulatory cell, which may figure prominently in control of immune responses and tolerance in vivo. Uniquely among hemopoietic cytokines, IL-10 has closely related homologs in several virus genomes, which testify to its crucial role in regulating immune and inflammatory responses. This review highlights findings that have advanced our understanding of IL-10 and its receptor, as well as its in vivo function in health and disease.

Lupus in the family--analysis of a cohort followed from 1978 to 1999

Familial lupus is recognised but rarely described in mother-daughter case pairs. We describe the prevalence of lupus occurring in the first degree relatives of a cohort of 300 lupus patients under long-term follow-up at a specialised lupus clinic. Three instances of mothers and their daughters who both developed the disease are described in detail to try and ascertain whether there are any particular clinical/serological/genetic factors in common which might explain the phenomenon.