Interleukin-10 and interleukin-6 in lupus erythematosus and rheumatoid arthritis, correlations with acute phase proteins

IL-10-induced STAT3/NF-κB crosstalk modulates pineal and extra-pineal melatonin synthesis

Immune-pineal axis activation is part of the assembly of immune responses. Proinflammatory cytokines inhibit the pineal synthesis of melatonin while inducing it in macrophages by mechanisms dependent on nuclear factor-κB (NF-κB) activation. Cytokines activating the Janus kinase/signal transducer and activator of transcription (STAT) pathways, such as interferon-gamma (IFN-γ) and interleukin-10 (IL-10), modulate melatonin synthesis in the pineal, bone marrow (BM), and spleen. The stimulatory effect of IFN-γ upon the pineal gland depends on STAT1/NF-κB interaction, but the mechanisms controlling IL-10 effects on melatonin synthesis remain unclear. Here, we evaluated the role of STAT3 and NF-κB activation by IL-10 upon the melatonin synthesis of rats' pineal gland, BM, spleen, and peritoneal cells. The results show that IL-10-induced interaction of (p)STAT3 with specific NF-κB dimmers leads to different cell effects. IL-10 increases the pineal's acetylserotonin O-methyltransferase (ASMT), N-acetylserotonin, and melatonin content via nuclear translocation of NF-κB/STAT3. In BM, the nuclear translocation of STAT3/p65-NF-κB complexes increases ASMT expression and melatonin content. Increased pSTAT3/p65-NF-κB nuclear translocation in the spleen enhances phosphorylated serotonin N-acetyltransferase ((p)SNAT) expression and melatonin content. Conversely, in peritoneal cells, IL-10 leads to NF-κB p50/p50 inhibitory dimmer nuclear translocation, decreasing (p)SNAT expression and melatonin content. In conclusion, IL-10's effects on melatonin production depend on the NF-κB subunits interacting with (p)STAT3. Thus, variations of IL-10 levels and downstream pathways during immune responses might be critical regulatory factors adjusting pineal and extra-pineal synthesis of melatonin.

CD39 and CD73 activity are protective in a mouse model of antiphospholipid antibody-induced miscarriages

OBJECTIVE

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder of young adults associated with devastating pregnancy complications (recurrent miscarriages, preeclampsia and low birth weight) and vascular complications including thrombosis. The key components implicated in pathogenesis of APS are the complement cascade and tissue factor (TF) activity causing inflammation and coagulation. Purinergic signalling involving catabolism of ATP to adenosine by cell-surface enzymes CD39 and CD73 has anti-inflammatory and anti-thrombotic effects. We studied whether activities of CD39 and CD73 are important in preventing the development of miscarriages in APS.

METHODS

We studied frequency of miscarriages and decidual pathology following passive transfer of human aPL-ab to pregnant wildtype mice, and mice deficient in CD39 and CD73, and also transgenic mice exhibiting 2-3X higher CD39 activity.

RESULTS

aPL-ab infusion in pregnant CD39-or CD73-knockout mice triggers an increase in miscarriages, associated with increased TF expression and complement deposition as well as elevated oxidative stress and pro-inflammatory TNF-α and IL-10 expression within the placental decidua. In contrast, aPL-ab induced miscarriages are prevented in mice over-expressing CD39, with reduced decidual TF expression and C3d deposition, diminished lipid peroxidation (4-hydroxynonenal or 4-HNE positive lipid adducts), and reduced TNF-α expression.

CONCLUSION

We demonstrate a protective role for CD39 in APS and provide rationale for both the development of endothelial cell-targeted soluble CD39 as a novel therapeutic for APS and analysis of perturbations in the purinergic pathway to explain human disease.

Development of a plug and play ImmunoPCR technique for the analysis of biomolecules

Aim: ImmunoPCR technology combines the advantages of specificity and robustness of a ligand binding assay with the amplification potential of PCR. We describe through three case studies a plug-and-play immuno polymerase chain reaction (iPCR) technique to measure biomolecules. Results: Case Study 1 demonstrated feasibility of measurement of IgG1 in cerebrospinal fluid at the desired level of sensitivity with minimal cost and timelines of clinical assay implementation. Case Study 2 translated the iPCR protocol to measure multiple IgG1 analytes in cerebrospinal fluid. Case Study 3 demonstrated broad applicability of the technique to yet another analyte IL-6. Conclusion: The advantages of our iPCR approach were: lack of reliance on a single vendor for technology platform/software, minimal reliance on proprietary reagents and reduced method development times and cost.

Studies of drug interactions with alpha1-acid glycoprotein by using on-line immunoextraction and high-performance affinity chromatography

A method that combined on-line immunoextraction with high-performance affinity chromatography was developed to examine the binding of drugs with α₁-acid glycoprotein (AGP). Affinity microcolumns containing immobilized polyclonal anti-AGP antibodies were developed that had a capture efficiency of up to 98.4% for AGP and a binding capacity of 0.72nmol AGP when using a 20mm×2.1mm i.d. microcolumn. These microcolumns were employed in various formats to examine the binding of drugs to normal AGP and AGP that had been adsorbed from serum samples for patients with systemic lupus erythematosus (SLE). Drugs that were screened in zonal elution experiments for their overall binding to these types of AGP included chlorpromazine, disopyramide, imipramine, propranolol, and warfarin. Most of these drugs showed an increase in their binding to the AGP from SLE serum when compared to normal AGP (i.e., an increase of 13-76%); however, disopyramide gave a 21-25% decrease in retention when the same AGP samples were compared. Frontal analysis was used to further evaluate the binding of disopyramide and imipramine to these forms of AGP. Both drugs gave a good fit to a model that involved a combination of saturable and non-saturable interactions with AGP. Changes in the non-saturable interactions accounted for most of variations seen in the binding of disopyramide and imipramine with the AGP samples. The methods used in this study could be adapted for use in personalized medicine and the study of other proteins or drugs using aqueous mixtures or clinical samples.

Reno-protective effect and mechanism study of Huang Lian Jie Du Decoction on lupus nephritis MRL/lpr mice

BACKGROUND

Huang Lian Jie Du Decoction (HLJDD), a very famous traditional Chinese medicinal prescription, has been used for heat dissipation and detoxification in China. This study was aimed to evaluate the reno-protective effects of HLJDD against lupus nephritis (LN) in vivo in MRL/lpr mice.

METHODS

Animals were administered orally every day for eight consecutive weeks except the mice of normal group and model group. Organ indexes, serum interleukin-6 (IL-6), interleukin-10 (IL-10), interferon-gamma (IFN-γ) and the anti-double stranded DNA (anti-dsDNA) antibody were tested, respectively. Creatinine (Cr), blood urea nitrogen (BUN) and urine protein were measured for renal function evaluation. The expression of phosphorylated signal transducer and activator of transcription 3 (p-STAT 3) in kidney tissue was observed by western blot (WB) and immunohistochemical (IHC) method. Meanwhile, histopathological changes in the renal were studied by hematoxylin-eosin (H&E) staining.

RESULTS

The mice of HLJDD-treated group exhibited a significant reduced mortality (p < 0.05), serum anti-dsDNA level (p < 0.05) and renal immune complex deposition (p < 0.05), compared with the untreated MRL/lpr mice. In addition, HLJDD treatment remarkably reduced the levels of BUN, Cr, proteinuria (p < 0.01) and the levels of inflammatory cytokines such as IL-6, IL-10 and IFN-γ (p < 0.01). Moreover, HLJDD significantly suppressed the phosphorylations of STAT 3 (p < 0.05) and the renal pathological changes.

CONCLUSIONS

The study implied that HLJDD may be a potential agent for the therapy of LN, and the down-regulated p-STAT 3 expression suggesting that it may be one of the LN therapy targets for HLJDD.

Clinical associations of IL-10 and IL-37 in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by the development of autoantibodies to nuclear antigens and inflammatory responses mediated by multiple cytokines. Although previous studies have determined clinical associations between SLE and the anti-inflammatory cytokines IL-10 and IL-37, their role in the disease, or their potential as biomarkers, remains unclear. We examined serum levels of IL-10 and IL-37 in a large cohort of SLE patients, with detailed longitudinal clinical data. We demonstrate a statistically significant association of serum IL-10 with disease activity, with higher levels in active compared to inactive disease. High first visit IL-10 was predictive of high subsequent disease activity; patients with IL-10 in highest quartile at first visit were 3.6 times more likely to have active disease in subsequent visits. Serum IL-37 was also higher in SLE patients compared to control, and was strongly associated with Asian ethnicity. However, IL-37 was not statistically significantly associated with disease activity. IL-37 was significantly reduced in patients with organ damage but this association was attenuated in multivariable analysis. The data suggest that IL-10, but not IL-37, may have potential as a biomarker predictive for disease activity in SLE.

Association between polymorphisms of interleukin 10 with inflammatory biomarkers in East Chinese Han patients with rheumatoid arthritis

OBJECTIVES

The aim of the present study was to examine the association between polymorphisms of IL-10 with inflammatory biomarkers in East Chinese Han patients with rheumatoid arthritis (RA).

METHODS

We examined IL-10 rs1800872 A/C polymorphisms in 615 RA patients, and 839 controls, in an East Chinese Han population. Genotyping was performed using a custom-by-design 48-Plex SNP scan TM Kit. The blood plasma concentration of IL-10 was measured using an Iodine [(125)I] IL-10 Radioimmunoassay Kit, in 90 RA patients and 90 controls.

RESULTS

IL-10 rs1800872 A/C polymorphisms were associated with risk of RA. Following stratified analysis, an increased risk of RA was associated with the CC genotype among male, older, C-reactive protein-positive, anti-cyclic citrullinated peptide antibody-positive, and rheumatoid factor-positive-patients, and among patients with a DAS28 of≥3.20 or an erythrocyte sedimentation rate of≥25, and in functional class I and II patients. The average plasma concentration of IL-10 was significantly higher in RA patients compared with controls. RA patients positive for the homozygote CC were characterized by significantly higher levels of IL-10 compared with patients with the heterozygote AC. We also found that there were significant relationships between the single nucleotide polymorphisms in the human IL-10 rs1800872 A/C and production of IL-10.

CONCLUSIONS

Our results suggest that the IL-10 rs1800872 A/C allele might increase the risk of RA. The IL-10 rs1800872 A/C allele might also impact the inflammatory reaction of IL-10 in patients with RA.

[Impact of interleukin-10 and interleukin-28 gene polymorphisms on the development and course of lupus nephritis]

AIM

To assess the relationship of the carriage of IL-10-1080 G/A and IL-28 rs8099917 C/T polymorphisms to the course of lupus nephritis (LN).

SUBJECTS AND METHODS

Ninety-nine patients with systemic lupus erythematosus (SLE), including 68 with LN, were examined. Gene polymorphisms were analyzed using standard molecular genetic techniques. The frequency of the clinical manifestations of LN was analyzed; renal survival (RS) was estimated by the Kaplan-Meier method.

RESULTS

Ten-year RS rates were 80 and 86% of the patients with and without the mutant IL-10 allele, respectively (p = 0.78). The 10-year RS was lower (75%) in carriers of the mutant IL-28 rsl2979860 allele than in patients without this mutant allele (83%; p = 0.049) and in those of the mutant IL28 rs8099917 allele than in patients without the above mutant allele (67 and 88%, respectively; p = 0.047). LN patients, carriers of the mutant IL-10-1028 G/A allele, were observed to have higher-grade proteinuria in the presence of nephritic syndrome (mean 6.1 g/l) than those without the mutant allele of this gene (mean 2.9 g/l; p = 0.034). However, the mutant allele carriers responded to treatment better (p = 0.050). The mutant IL-10 and IL-28 alleles were unassociated with the development of rapidly progressive nephritis, the activity of a renal lupus process, and the rate of onset of SLE and LN.

CONCLUSION

In the LN patients, the carriage of the mutant IL-10 allele A is associated with a better response to treatment and that of the mutant IL-28 allele is linked to the severe course of the disease.

Association of serum C-reactive protein levels with lupus disease activity in the absence of measurable interferon-α and a C-reactive protein gene variant

OBJECTIVE

The type I interferon (IFN) system is important in the pathogenesis of systemic lupus erythematosus (SLE). We previously demonstrated an inhibitory effect of IFNα on interleukin-6 (IL-6)-induced C-reactive protein (CRP) in vitro, hypothetically explaining the poor correlation between disease activity and CRP levels in SLE. This study was undertaken to investigate disease activity, IL-6 levels, and CRP levels in relation to a CRP gene polymorphism and IFNα.

METHODS

Sera from 155 SLE patients and 100 controls were analyzed for CRP. Patients were genotyped for a CRP single-nucleotide polymorphism (rs1205) associated with low CRP levels. Serum IFNα and IL-6 levels were quantified by immunoassays. Clinical disease activity was assessed using the SLE Disease Activity Index 2000 (SLEDAI-2K).

RESULTS

CRP levels were increased in SLE patients compared to controls, but were not associated with SLEDAI-2K or IL-6 levels. However, exclusion of patients carrying at least one rs1205 minor allele revealed an association between disease activity and CRP levels (P = 0.005). We found a strong association between disease activity and CRP levels (P < 0.0005) when patients with measurable IFNα levels as well as the minor allele of rs1205 were excluded from the analysis. Similarly, when patients with elevated IFNα levels and/or the rs1205 polymorphism were excluded, IL-6 levels were associated with CRP levels.

CONCLUSION

The present study demonstrates that the serum IFNα level as well as the CRP genotype affect the CRP response in SLE patients. Lack of correlation between serum levels of CRP and disease activity could therefore be explained by activation of the type I IFN system and polymorphisms in the CRP gene.

Naja naja atra Venom Protects against Manifestations of Systemic Lupus Erythematosus in MRL/lpr Mice

Systemic lupus erythematosus (SLE) is an autoimmune disease and effective therapy for this pathology is currently unavailable. We previously reported that oral administration of Naja naja atra venom (NNAV) had anti-inflammatory and immune regulatory actions. We speculated that NNAV may have therapeutic effects in MRL/lpr SLE mice. Twelve-week-old MRL/lpr mice received oral administration of NNAV (20, 40, and 80 μg/kg) or Tripterygium wilfordii polyglycosidium (10 mg/kg) daily for 16 weeks. The effects of NNAV on SLE manifestations, including skin erythema, proteinuria, and anxiety-like behaviors, were assessed with visual inspection and Multistix 8 SG strips and open field test, respectively. The pathology of spleen and kidney was examined with H&E staining. The changes in autoimmune antibodies and cytokines were determined with ELISA kits. The results showed that NNAV protected against the manifestation of SLE, including skin erythema and proteinuria. In addition, although no apparent histological change was found in liver and heart in MRL/lpr SLE mice, NNAV reduced the levels of glutamate pyruvate transaminase and creatine kinase. Furthermore, NNAV increased serum C3 and reduced concentrations of circulating globulin, anti-dsDNA antibody, and inflammatory cytokines IL-6 and TNF-α. NNAV also reduced lymphadenopathy and renal injury. These results suggest that NNAV may have therapeutic values in the treatment of SLE by inhibiting autoimmune responses.

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.

IFNα serum levels are associated with endothelial progenitor cells imbalance and disease features in rheumatoid arthritis patients

Introduction

IFNα has been largely implicated in the ethiopathogenesis of autoimmune diseases but only recently it has been linked to endothelial damage and accelerated atherosclerosis in autoimmunity. In addition, proinflammatory conditions are supposed to be implicated in the cardiovascular status of these patients. Since a role for IFNα in endothelial damage and impaired Endothelial Progenitor Cell (EPC) number and function has been reported in other diseases, we aimed to evaluate the potential associations of IFNα serum levels on EPC populations and cytokine profiles in Rheumatoid Arthritis (RA) patients.

Methods

pre-EPC, EPC and mature EPC (mEPC) populations were quantified by flow cytometry analyzing their differential CD34, CD133 and VEGFR2 expression in blood samples from 120 RA patients, 52 healthy controls (HC), and 83 systemic lupus erythematosus (SLE) patients as disease control. Cytokine serum levels were measured by immunoassays and clinical and immunological data, including cardiovascular (CV) events and CV risk factors, were retrospectively obtained by reviewing clinical records.

Results

Long-standing, but not recent onset RA patients displayed a significant depletion of all endothelial progenitor populations, unless high IFNα levels were present. In fact, the IFN^high RA patient group (n = 40, 33%), showed increased EPC levels, comparable to SLE patients. In addition, high IFNα serum levels were associated with higher disease activity (DAS28), presence of autoantibodies, higher levels of IL-1β, IL-6, IL-10 and MIP-1α, lower amounts of TGF-β, and increased mEPC/EPC ratio, thus suggesting higher rates of endothelial damage and an endothelial repair failure. Finally, the relationship between high IFNα levels and occurrence of CV events observed in RA patients seems to support this hypothesis.

Conclusions

IFNα serum marker could be used to identify a group of RA patients with increased disease activity, EPC imbalance, enhanced proinflammatory profile and higher cardiovascular risk, probably due, at least in part, to an impaired endothelial repair.

IL-10 gene polymorphisms and susceptibility to systemic lupus erythematosus: a meta-analysis

Background

A number of observational studies have been conducted to investigate the association of the IL-10 gene polymorphisms with systemic lupus erythematosus (SLE) susceptibility. However, their results are conflicting.

Method

We searched published case-control studies on the IL-10 polymorphisms and SLE in PubMed, EMBASE and Chinese Biomedical Literature Database. A meta-analysis was conducted using a fixed-effect or random-effect model based on between-study heterogeneity.

Results

A total of 42 studies with 7948 cases and 11866 controls were included in this meta-analysis. Among Caucasians, the CA27 allele of the IL10.G microsatellites (OR 2.38, 95% CI 1.01–5.62), the G allele of the IL-10 -1082G/A polymorphism (G vs. A: OR 1.21, 95% CI 1.02–1.44; GG vs. AA: OR 1.45, 95% CI 1.16–1.82; GG+GA vs. AA: OR 1.16, 95% CI 1.03–1.29) and its associated haplotype -1082G/−819C/−592C (OR 1.25, 95% CI 1.10–1.42) were associated with increased SLE susceptibility without or with unimportant between-study heterogeneity. Removing studies deviating from Hardy-Weinberg equilibrium (HWE) hardly changed these results. Among Asians, the CA21 allele of the IL-10.G microsatellites (OR 1.28, 95% CI 1.02–1.60) and the -1082G/−819C/−592C haplotype (OR 1.24, 95% CI 1.00–1.53) were associated with increased SLE susceptibility, but with substantial between-study heterogeneity or sensitive to HWE status. Removing studies deviating from HWE also produced statistically significant associations of the IL-10 -1082G/A (GG vs. AA: OR 3.21, 95% CI 1.24–8.28; GG vs. AA+GA: OR 2.85, 95% CI 1.19–6.79) and -592C/A polymorphisms (CC+CA vs. AA: OR 0.69, 95% CI 0.51–0.94) with SLE among Asians.

Conclusion

This meta-analysis showed that the IL10.G microsatellites, the IL-10 -1082G/A and -592C/A polymorphisms and the haplotype -1082G/−819C/−592C are associated with SLE susceptibility. Besides, this is the first time to report an association between the CA27 allele of the IL-10.G microsatellites and SLE among Caucasians. Further studies are needed to confirm these findings.

Role of interleukin-10 and interleukin-10 receptor in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by excessive production of a variety of autoantibodies, accumulation of immune complexes, and multiple organ systems involvement. Interleukin-10 (IL-10) has an important role in the growth, survival, differentiation, and function of B cells. Abnormally increased IL-10 synthesis seems contributing to the spontaneous hyperactivity of the B cell compartment, so that it can directly result in autoantibody production by committed plasma cells, circulating immune complexes formation, and eventually in tissue and organ damage, suggesting it might associate with the development of SLE. A better understanding of the regulation of IL-10 and its receptors (IL-10R) can likely provide more valuable clues to the pathogenic mechanisms underlying specific forms of SLE, so as to pave the way toward more effective therapeutics.

The function of hematopoietic stem cells is altered by both genetic and inflammatory factors in lupus mice

Hematopoietic stem cells (HSCs) are protected in a metabolically dormant state within the bone marrow stem cell niche. Inflammation has been shown to disrupt HSC dormancy and cause multiple functional changes. Here, we investigated whether HSC functions were altered in systemic lupus erythematosus (SLE)-prone mice and whether this contributed to clinical manifestations of SLE. We found that HSCs were significantly expanded in lupus mice. The increase in HSC cellularity was caused by both genetic lupus risk factors and inflammatory cytokines in lupus mice. In addition, the inflammatory conditions of lupus led to HSC mobilization and lineage-biased hematopoiesis. Strikingly, these functionally altered HSCs possessed robust self-renewal capacity and exhibited repopulating advantages over wild-type HSCs. A single-nucleotide polymorphism in the cdkn2c gene encoding p18(INK4c) within a SLE susceptibility locus was found to account for reduced p18(INK4c) expression and the increase in HSC self-renewal capacity in lupus mice. Lupus HSCs with enhanced self-renewal capacity and resistance to stress may compete out transplanted healthy HSCs, thereby leading to relapses after HSC transplantation.

B cell-activating factor enhances interleukin-6 and interleukin-10 production by ODN-activated human B cells

We aim to investigate the additive value of B cell-activating factor (BAFF) when added to oligodeoxynucleotides (ODN)-activated B cells with respect to TLR-9, CD69, MHC-II expression, IL-6 and IL-10 secretion and B cell cycling. Therefore, B cells from healthy individuals were incubated under the following conditions: (1) B cells with medium, (2) B cells with ODN 0.5 μm, (3) B cells with BAFF 20 μm and (4) B cells with both ODN 0.5 μm and BAFF 20 μm. We found that addition of BAFF did not enhance the expression of TLR-9, CD69 and MHC-II in ODN-activated B cells. Incubation of B cells with BAFF and ODN together leads to a marked elevation of IL-6 and IL-10 levels compared to ODN alone. Synthesis and mitosis were higher in B cells stimulated by BAFF than in B cells stimulated by ODN. These findings suggest that both BAFF and TLR-9 contribute independently to B cell function.

Effects of glucocorticoid treatment on CD25⁻FOXP3⁺ population and cytokine-producing cells in rheumatoid arthritis

OBJECTIVES

To investigate CD25(-)FOXP3(+) cells in RA patients and their possible relationship with disease features and response to glucocorticoids (GCs).

METHODS

Peripheral blood mononuclear cells were collected from 147 RA patients, 29 healthy controls and 75 SLE patients as disease controls. The proportion of CD4(+)FOXP3(+) cells with negative, low or high CD25 expression and the levels of IL-10-, TNF-α-, IL-17- and IFNγ-producing cells were assessed by flow cytometry. The presence of the high IL-10 genotype (-1082GG), associated with good response to GC, was determined by PCR amplification and hybridization with allele-specific fluorescently labelled probes. Data were related to treatment and clinical parameters.

RESULTS

The CD25(-)FOXP3(+) population was significantly increased in RA patients and negatively correlated with DAS-28 and other disease parameters. The IL-10 genotype did not influence the frequency of these cells in controls or the entire RA group; however, GC-treated patient carriers of the high IL-10 genotype presented significantly higher levels of this population in addition to an increased percentage of IL-10-secreting cells and relatively low amounts of TNF-α-, IFN-γ- and IL-17-positive cells. Finally, a prospective study confirmed that genetically high IL-10 producers significantly increase CD25(-)FOXP3(+) cells after 6 months of GC treatment.

CONCLUSION

The present study provides the first evidence of increased CD25(-)FOXP3(+) cells in RA patients, which were associated with disease activity and with GC treatment in carriers of the high IL-10 genotype, suggesting that this population plays a role in the clinical response to prednisone in RA.

Effect of pregnancy on serum cytokines in SLE patients

Introduction

The aim of this study was to evaluate an extensive panel of cytokines involved in immune regulation during pregnancy in patients with systemic lupus erythematosus (SLE) and in healthy women.

Methods

A total of 47 consecutive successful pregnancies in 46 SLE patients and 56 pregnancies in 56 matched healthy subjects, as controls, were prospectively studied. Serum interleukin (IL)-1-α, IL-1-β, IL-2, IL-6, IL-8, IL-10, IL-12p70, interferon (INF)-γ and tumor necrosis factor (TNF)-α were detected in sera obtained at the first and third trimester of pregnancy by a highly sensitive, multiplexed sandwich ELISA.

Results

Medians (pg/ml) of serum levels of most helper T (Th)1-type cytokines were significantly lower in the third trimester compared with those observed in the first trimester of pregnancy in healthy women: INF-γ 2.0 vs 3.4, TNF-α 10.2 vs 11.5, IL-1-α 0.9 vs 1.1, IL-1-β 0.6 vs 1.0, IL-2 3.0 vs 3.5, and IL-12p70 4.9 vs 5.6 (P-values < 0.02 for all). By contrast, only the IL-1-α serum levels were lower in the third trimester compared with the first trimester in SLE patients (P = 0.006). IFN-γ/IL-6 and IFN-γ/IL-10 ratios were higher in controls than in SLE (P = 0.002, and P = 0.001, respectively); moreover, they were significantly reduced in the third compared to the first trimester of pregnancy in healthy women, but not in SLE.

Conclusions

In SLE patients, Th1/Th2 cytokine serum level ratio does not decrease during pregnancy progression as much as in healthy pregnant women. This could account for the observation of a low frequency of disease flares in the third trimester of gestation.

Autoantibodies against the catalytic domain of BRAF are not specific serum markers for rheumatoid arthritis

BACKGROUND

Autoantibodies to the catalytic domain of v-raf murine sarcoma viral oncogene homologue B1 (BRAF) have been recently identified as a new family of autoantibodies involved in rheumatoid arthritis (RA). The objective of this study was to determine antibody responses to the catalytic domain of BRAF in RA and other autoimmune diseases. The association between RA-related clinical indices and these antibodies was also assessed.

METHODOLOGY/PRINCIPAL FINDINGS

The presence of autoantibodies to the catalytic domain of BRAF (anti-BRAF) or to peptide P25 (amino acids 656-675 of the catalytic domain of BRAF; anti-P25) was determined in serum samples from patients with RA, primary Sjögren's syndrome (pSS), systemic lupus erythematosus (SLE), and healthy controls by using indirect enzyme-linked immunosorbent assays (ELISAs) based on the recombinant catalytic domain of BRAF or a synthesized peptide, respectively. Associations of anti-BRAF or anti-P25 with disease variables of RA patients were also evaluated. Our results show that the BRAF-specific antibodies anti-BRAF and anti-P25 are equally present in RA, pSS, and SLE patients. However, the erythrocyte sedimentation rate (ESR) used to detect inflammation was significantly different between patients with and without BRAF-specific antibodies. The anti-BRAF-positive patients were found to have prolonged disease, and active disease occurred more frequently in anti-P25-positive patients than in anti-P25-negative patients. A weak but significant correlation between anti-P25 levels and ESRs was observed (r = 0.319, p = 0.004).

CONCLUSIONS/SIGNIFICANCE

The antibody response against the catalytic domain of BRAF is not specific for RA, but the higher titers of BRAF-specific antibodies may be associated with increased inflammation in RA.

Down-regulated NOD2 by immunosuppressants in peripheral blood cells in patients with SLE reduces the muramyl dipeptide-induced IL-10 production

BACKGROUND

Pattern recognition receptors (PRRs) such as Toll-like receptors are aberrantly expressed of peripheral blood mononuclear cells (PBMCs) in systemic lupus erythematosus (SLE) patients, for playing immunopathological roles.

METHODOLOGY/PRINCIPAL FINDINGS

We investigated the expression and function of the PRR nucleotide-binding oligomerization domain (NOD2) in SLE. NOD2 expression in T, B lymphocytes, monocytes, myeloid dendritic cells (mDCs) and plasmacytoid dendritic cells (pDCs) was assessed in SLE patients and healthy controls (HCs) using flow cytometric analysis. Ex vivo production of cytokines from PBMCs upon NOD2 agonist muramyl dipeptide (MDP) stimulation was assessed using Cytometric Bead Array. Over-expression of NOD2 in monocytes was observed in immunosuppressant naïve SLE patients, and was positively associated with longer disease duration. Immunosuppressive therapy was an independent explanatory variable for downregulating NOD2 expression in CD8+ T, monocytes, mDCs and pDCs. Ex vivo basal productions of cytokines (IL-6, IL-8 and IL-10) were significantly increased in immunosuppressant naïve patients and patients with active disease despite immunosuppressants compared with HCs. Upon MDP stimulaiton, relative induction (%) of cytokines (IL-1β) from PBMC was significantly increased in immunosuppressant naïve patients with inactive disease, and patients with active disease despite immunosuppressant treatment compared with HCs. Immunosuppressant usage was associated with a decreased basal production and MDP induced relative induction (%) of IL-10 in patients with inactive disease compared with immunosuppressant naïve patients and HCs.

CONCLUSIONS/SIGNIFICANCE

Bacterial exposure may increase the NOD2 expression in monocytes in immunosuppressant naïve SLE patients which can subsequently lead to aberrant activation of PBMCs to produce proinflammatory cytokines, implicating the innate immune response for extracellular pathogens in the immunopathological mechanisms in SLE. Immunosuppressant therapy may downregulate NOD2 expression in CD8+ T lymphocytes, monocytes, and DCs in SLE patients which subsequently IL-10 reduction, contributing towards the regulation of immunopathological mechanisms of SLE, at the expense of increasing risk of bacterial infection.

High-sensitivity C-reactive protein and erythrocyte sedimentation rate in systemic lupus erythematosus

Levels of C-reactive protein (CRP) have been shown to rise in acute illnesses such as infections and some autoimmune diseases, but not in flares of systemic lupus erythematosus (SLE). Our goal was to investigate the high-sensitivity CRP (hsCRP) response to infection versus disease flare in patients with SLE, and to compare this with the erythrocyte sedimentation rate (ESR) response in these patients. We aimed to determine the hsCRP level that distinguishes between infection and flare in SLE, and investigated the correlation between hsCRP and organ involvement in SLE. We reviewed electronic medical records of all patients with SLE admitted to Cedars Sinai Medical Center between 28 August 2001 and 27 April 2008. Patients were divided into three groups based on the reason for hospitalization: 1) lupus flare; 2) active infection; and 3) both lupus flare and active infection. Data were collected on patient demographics, medication use, microbial culture results, organ involvement in lupus flare, ESR and CRP levels. Data were collected on 85 eligible patients, of whom 54 had a lupus flare, 22 had active infection and eight had both. While the ESR levels did not differ significantly between patients with disease flare and active infection, the hsCRP level was significantly lower in the lupus flare group than in the infection group. Most patients in the lupus flare group who had a significantly high hsCRP level had serositis. We found that at a cut-off of above 5 mg/dl, hsCRP level was correlated with infection with a specificity of 80%. At a cut-off of above 6 mg/dl, hsCRP correlated with infection with a specificity of 84%. hsCRP level was found to be significantly higher in patients with pulmonary involvement than without. hsCRP levels are significantly lower in SLE patients with disease flare than in those with active infection. Elevated hsCRP levels can be used as a predictor of active infection in SLE patients with a high specificity. We review the relationship between IL-6 and hsCRP production in lupus patients.

Cytokines and Regulatory T Cells in Rheumatoid Arthritis and Their Relationship with Response to Corticosteroids

Objective.

To analyze circulating cytokines and regulatory T cells (Treg) in patients with rheumatoid arthritis (RA) of different durations, and their association with functional interleukin 10 (IL-10) and tumor necrosis factor-α (TNF-α) genotypes in patients treated with corticosteroids.

Methods.

Serum levels of IL-6, IL-10, IL-17, IL-18, TNF-α, and transforming growth factor-ß (TGF-ß) were quantified in 196 patients and 61 healthy controls. Percentage of CD4+CD25high cells was determined by flow cytometry and Foxp3 expression by real-time reverse-transcription polymerase chain reaction. Data were related to clinical measurements and presence of the genotype −1082GG IL-10/−308GG TNF-α, previously associated with good response to corticosteroids.

Results.

Levels of TNF-α, IL-6, and IL-18 were significantly higher in patients compared to controls, while TGF-ß and IL-10 were lower. Serum samples of patients at disease onset (n = 32) had increased IL-6 and decreased TGF-ß, but there were no differences in other cytokines. These patients also presented a higher percentage of CD4+CD25high cells than those with established disease, although no significant differences were detected in Foxp3. Patients under corticosteroid treatment who were carriers of the good responder genotype had higher levels of TGF-ß, Foxp3, and Treg compared to patients with other genotypes, while relatively lower levels of TNF-α and IL-17 were observed.

Conclusion.

Patients at onset of RA present fewer alterations in cytokine levels and Treg than those with longer disease duration, supporting the role of disease progression in subsequent changes. The antiinflammatory balance observed in high IL-10/low TNF-α patients treated with prednisone supports the use of these genetic polymorphisms as predictors of response to corticosteroid therapy.

IVIg attenuates TLR-9 activation in B cells from SLE patients

INTRODUCTION

Toll-like receptor-9 (TLR-9) plays an important role in the pathogenesis of systemic lupus erythematosus (SLE). The aim of this study was to evaluate the influence of intravenous immunoglobulin (IVIg) on CpG oligodeoxynucleotides (ODN-CpG) activated B cells from SLE patients.

METHODS

Peripheral blood B cells were isolated from 16 SLE patients and 21 healthy age-matched controls. B cells were cultured with ODN-CpG 1μM alone or IVIg (10mg/ml) together with ODN-CpG. After 24-h incubation, B cells and supernatants were collected and analyzed for interleukin (IL)-10, IL-6 secretion, and TLR-9 expression.

RESULTS

IVIg decreased the secretion of IL-10 from ODN-CpG-activated B cells isolated from both SLE patients and healthy controls (194 ± 46.2 to 103.2 ± 27.13 pg/ml, p < 0.016, 153.2 ± 19 vs 84.6 ± 7.5, p < 0.0001, respectively). Similarly, IVIg decreased the secretion of IL-6 from ODN-CpG-activated B cell isolated from both SLE patients and healthy controls (431.2 ± 83 to 307.6 ± 94.3 pg/ml, p < 0.0008, 319.5 ± 31 vs 193.3 ± 22.8, p < 0.0001, respectively). The decrement of IL-10 and IL-6 secretion was associated with a significant decrease in TLR-9 expression in memory B cells from SLE patients and healthy controls (11.47 ± 1.2 vs 13.29 ± 1.2, p = 0.005, 11 ± 0.8 vs 12.8 ± 0.98, p = 0.0016, respectively).

CONCLUSIONS

IVIg attenuates the activation of TLR-9 in B cells from SLE patients, suggesting a novel additional mechanism of IVIg mode of action in these patients.

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.

B-cell-directed therapies in systemic lupus erythematosus

OBJECTIVE

Owing to their ability to promote the onset and flares of systemic lupus erythematosus (SLE), B-cells are now established as key players in the pathogenesis of the disease, and, therefore, have become a major therapeutic focus in SLE. In this article, we review the literature on B-cell-directed therapies for SLE focusing on B-cell depletion, B-cell tolerance, costimulatory signals, and cytokines that affect B-cell survival and activation.

METHODS

The clinical trials reviewed in this article were accessed from the PubMed database (www.pubmed.gov) and Clinical Trials database (www.clinicaltrials.gov) through an English language search of the literature published between January 2002 and March 2007. Keywords included the following terms: B-cells, SLE, and therapy.

RESULTS

Seventeen completed clinical trials enrolling 973 patients and 5 ongoing studies with anticipated enrollment of 785 patients were reviewed. Novel SLE therapies that target B-cells directly or indirectly were included. B-cell-depleting therapies with the monoclonal antibodies rituximab and epratuzumab have shown good therapeutic results. On the contrary, the well-studied B-cell tolerogen LJP 394 has not demonstrated much clinical benefit. Studies targeting costimulatory pathways have shown variable results; clinical trials with anti-CD40L antibody were terminated because of thromboembolic events, whereas studies targeting the B7-CD28 pathway seem promising. Anticytokine agents against B-lymphocyte stimulator (BLyS), interleukin (IL)-10, IL-6, and interferon alpha (IFN-alpha) are the newcomers that need further evaluation in the treatment of SLE.

CONCLUSIONS

Progress in technology has led to the variety of B-cell-directed therapies. In contrast to general immunosuppressants, novel treatments that interfere with specific aspects of B-cell functions create the possibility of developing targeted therapeutic approaches for specific subpopulations of lupus patients.

Selected acute phase proteins and interleukin-6 in systemic lupus erythematosus patients treated with low doses of quinagolide

The relationship between endocrine regulation and immune system has recently become the subject of intense investigations. The objective of this study was to determine the extent of selected serum acute phase proteins (APP), IL-6 and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) involvement in systemic lupus erythematosus (SLE) patients during quinagolide therapy. A further aim of this study was to evaluate the relationships between the above mentioned parameters. In 25 SLE patients treated with a low dose of quinagolide (12.5-50 microg per day) and in 25 healthy persons who constituted the control group, serum concentration of C-creative protein (CRP), alpha-1-antitripsin (AAT), ceruloplasmin (CER), IL-6 and prolactin (PRL) were estimated at entry and in patients after 3 months of treatment. Moreover, SLEDAI score was calculated at entry and after 3 months of therapy with quinagolide. IL-6 and PRL levels were significantly higher in SLE group whereas the concentrations of CRP, AAT and CER were higher than in the controls, but without statistical significance. After 3 month therapy statistically significant decrease of serum level of IL-6 and PRL was revealed. Statistically significant lower serum concentration of CER was also obtained after 3 months of therapy whereas serum CRP and AAT concentration was lower compared with the mean pretreatment level but the results did not reach statistical significance. A raised SLEDAI score at entry was significantly reduced after 3 month therapy and positive correlation with PRL level in examined group of patients with SLE was noted at entry. The decreased serum concentration of IL-6, APP and SLEDAI score observed during applied therapy with small dose of quinagolide confirms the hypothesis that quinagolide may become a valuable and safe drug in the therapy of patients with mild SLE.

Correlation between levels of TNF-alpha and IL-6 and hematological involvement in SLE Egyptian patients with lupus nephritis

BACKGROUND

Systemic lupus Erythematosus (SLE) is a rheumatic autoimmune disease characterized by multisystem organ involvement and by high titers of auto antibodies against several nuclear and cytoplasmic antigens. Numerous abnormalities of the cytokine network have been described in patients suffering from SLE. However the role of cytokines in different organ involvement is not yet well defined.

OBJECTIVE

To determine if levels of Interlukin-6 (IL-6) and Tumor necrosis factor (TNF-alpha) correlate with SLE disease activity in Egyptian SLE patients and more specifically with hematological involvement.

METHODS

Levels of TNF-alpha and IL-6 in serum samples from sixty individuals (40 with Systemic lupus Erythmatosus and 20 healthy controls) were determined and renal biopsies were obtained from SLE patients.

RESULTS

Levels of TNF-alpha and IL-6 were higher in SLE patients with active compared with inactive hematological disease. Further analysis showed that this association was dependent on inverse correlation (P=0.017, r=-0.49) for IL-6 and (P=0.76, r=-.243) for TNF-alpha. The mean level of TNF-alpha and Il-6 was (766.95+/-357.82 pg/ml) and (135.4+/-54.23 pg/ml) respectively for patients with active disease while it was (314.01+/-100.87 pg/ml) and (47.33+/-18.61 pg/ml) for those with inactive disease and (172.7+/-39.19 pg/ml) and (21.15+/-10.99 pg/ml) for the healthy control group respectively. The difference was statistically significant (P=0.002). We found significant positive correlations between TNF-alpha and IL-6 and the SLE Disease Activity Index (SLEDAI) score. (r=+0.743 and +0.772 respectively).

CONCLUSION

Raised level of Il-6 and TNF-alpha may influence the development of anemia in Egyptian patients with Lupus Nephritis.

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

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

Sle1ab Mediates the Aberrant Activation of STAT3 and Ras-ERK Signaling Pathways in B Lymphocytes

The Sle1ab genomic interval on murine chromosome 1 mediates the loss of immune tolerance to chromatin resulting in antinuclear Abs (ANA) production in the lupus-prone NZM2410 mouse. Global gene expression analysis was used to identify the molecular pathways that are dysregulated at the initiation of B lymphocyte autoimmunity in B6.Sle1ab mice. This analysis identified that STAT3 and ras-ERK signaling pathways are aberrantly activated in Sle1ab B lymphocytes, consistent with increased production of IL-6 by splenic B lymphocytes and monocytes in B6.Sle1ab mice. In vitro treatment of splenic mononuclear cells isolated from ANA-positive Sle1ab mice with anti-IL-6 Ab or AG490, an inhibitor of STAT3 signaling pathway, suppressed ANA production in short-term culture, indicating that this pathway was essential to the production of autoantibodies. In vivo treatment of ANA-positive B6.Sle1ab mice with the ras pathway inhibitor, perillyl alcohol, suppressed the increase of ANA. These findings identify IL-6 as a early key cytokine in Sle1ab-mediated disease development and indicate that the STAT3 and ras-ERK signaling pathways are potential therapeutic targets for treating systemic lupus erythematosus.

Increased CCR4 expression on circulating CD4(+) T cells in ankylosing spondylitis, rheumatoid arthritis and systemic lupus erythematosus

Previous studies have suggested that CCR4 is particularly important in the selective recruitment of various subsets of leucocytes in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). In this study, we examined the percentage of CD4(+)/CCR4(+) T cells within circulating lymphocytes in active ankylosing spondylitis (AS), RA and SLE patients. The clinical significance of CCR4 expression as well as possible associations between the expression and serum levels of tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma and interleukin (IL)-10 were also examined. Our results showed that the percentage of CD4(+)/CCR4(+) T cells was significantly elevated in AS and RA patients as compared with normal controls. The percentage was also significantly higher in SLE patients who had received no treatment with glucocorticoids or cytotoxic drugs (untreated SLE) than that in controls. In addition, the percentage of CD4(+)/CCR4(+) T cells showed significant positive correlations with the Bath ankylosing spondylitis disease activity index (BASDAI) in AS and with the SLE disease activity index (SLEDAI) in untreated SLE. Of all the cytokines examined, the elevated serum IL-10 level was closely correlated with the percentage of CD4(+)/CCR4(+) T cells in AS, RA and untreated SLE. These results suggest that CCR4 may be crucial in the pathogenesis of AS, RA and SLE. The percentage of CD4(+)/CCR4(+) T cells can serve as a useful marker for the activity of AS and untreated SLE.

Immune complex-stimulated production of interleukin-12 in peripheral blood mononuclear cells is regulated by the complement system

Immune complexes (IC) can induce cytokine production in vitro. While immune aggregates (IA) consisting of heat-aggregated gamma globulin (HAGG) as model IC increased interleukin (IL)-10 levels in cell cultures with native human serum, IL-12p40/p70 production was inhibited. Three series of experiments suggested that the effects of IA on IL-12 production depended on a functionally intact complement system: (1) heat-inactivation of serum inverted the inhibitory effect of IA on IL-12p40/p70 production; (2) IA-induced IL-12p40 production in a C4 deficient serum was lowered by addition of C4; and (3) addition of the peptide compstatin, which blocks C3 activation, mimicked the effects of heat inactivation on IL-12p40 levels. Neutralization of IL-12 resulted in modestly increased IL-10 levels, while neutralization of IL-10 had no effects on IL-12p40 production. IA-induced production of IL-10 was partially blocked by anti-Fcgamma RII antibodies, whereas Fcgamma R or CR blockade had no effect on IL-12p40 production. IC and local or systemic complement activation characterize rheumatoid arthritis, systemic lupus erythematosus and many malignancies. Different and complement-dependent effects on the production of IL-10 and IL-12 can be of importance in these diseases, where control of the complement system might be a way to direct IC-induced cytokine production in either a type 1 or type 2 direction.

Immunopathology and the gene therapy of lupus

Lupus is a chronic autoimmune inflammatory disease with complex clinical manifestations. In humans, lupus, also known as systemic lupus erythematosus (SLE), affects between 40 and 250 individuals, mostly females, in each 100 000 of the population. There are also a number of murine models of lupus widely used in studies of the genetics, immunopathology, and treatment of lupus. Human patients and murine models of lupus manifest a wide range of immunological abnormalities. The most pervasive of these are: (1) the ability to produce pathogenic autoantibodies; (2) lack of T- and B-lymphocyte regulation; and (3) defective clearance of autoantigens and immune complexes. This article briefly reviews immunological abnormalities and disease mechanisms characteristic of lupus autoimmunity and highlight recent studies on the use of gene therapy to target these abnormalities.

Immune complexes from SLE sera induce IL10 production from normal peripheral blood mononuclear cells by an FcgammaRII dependent mechanism: implications for a possible vicious cycle maintaining B cell hyperactivity in SLE

BACKGROUND

Raised interleukin (IL)6 and IL10 levels are thought to contribute to the pathogenesis of systemic lupus erythematosus (SLE) by enhancing autoantibody production and immune complex (IC) formation. These immune complexes can then stimulate cellular reactions through Fc and complement receptors.

OBJECTIVE

To investigate whether circulating SLE ICs stimulate type 2 cytokine production.

METHODS

Twenty serum samples from patients with active SLE were compared with sera from 18 healthy controls. Sera and polyethylene glycol (PEG) precipitates from sera were added to peripheral blood mononuclear cell (PBMC) cultures, and the production of IL10 and IL6 was investigated by enzyme linked immunospot assay (ELISPOT) and enzyme linked immunosorbent assay (ELISA). Fc gamma receptor (FcgammaR) antibodies were used in blocking experiments, and flow cytometry was used to assess the correlation between monocyte FcgammaR expression and IC-induced cytokine production.

RESULTS

Ten per cent dilutions of the SLE sera induced a significantly increased number of IL10-producing cells in comparison with control sera (median, 11.75 v 1.25 spot forming cells/50 000 PBMC; p<0.0001). PEG precipitates from SLE sera also induced significantly increased levels of IL10 (p=0.016) and IL6 (p=0.042) in comparison with control PEG precipitates. IL10 production induced by SLE PEG precipitates or by artificial ICs could be blocked by anti-FcgammaRII antibodies, and the FcgammaRII expression on CD14+ monocytes correlated with the IC-induced production of IL10 and IL6.

CONCLUSIONS

SLE sera stimulate IL10 and IL6 production from PBMC, and this effect is at least partly explained by precipitable ICs acting through FcgammaRII. This effect provides a possible mechanism for the enhanced production of IL10 in SLE, whereby B cell activation, antibody production, IC stimulated monocytes/macrophages, and type 2 cytokines create a vicious cycle that may help to maintain B cell hyperactivity in 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.

Corticotropin-releasing factor modulates cardiovascular and pupillary autonomic reflexes in man: is there a link to inflammation-induced autonomic nervous hyperreflexia?

In two recent studies, we found autonomic nervous hyperreflexia in subjects with chronic inflammatory diseases, particularly, in those subjects with higher degrees of systemic inflammation. Since corticotropin-releasing factor (CRF) is induced by inflammatory stimuli and acts within the brain to change neuroendocrine and autonomic activity, we investigated CRF modulation of standard autonomic nervous reflexes. Fifteen healthy subjects were administered 100 microg CRF i.v., which led to a short-term increase of heart rate (p < 0.001) and a decrease in systolic and diastolic blood pressure (p < 0.050). These changes were accompanied by a reduction in heart rate variation at rest (p = 0.010) and during the respiratory sinus arrhythmia test (p = 0.019), and a reduction of pupillary latency time (p = 0.038). In further 21 normal subjects we studied the effect of prednisolone treatment on autonomic nervous function (100 mg/d during three days --> CRF reduction), which resulted in an increase of heart rate (p < 0.001), increase of heart rate variation during the respiratory sinus arrhythmia test (p < 0.001), increase in pupillary latency time (p = 0.012), a increase in maximal pupillary area (p = 0.002), and a decrease in diastolic blood pressure (p = 0.002). In conclusion, induction of a low central CRF content by prednisolone leads to a marked hyperreflexia in respiratory sinus arrhythmia and hyporeflexia in the latency time test. It is obvious that CRF can regulate autonomic reflexes. Possibly, central CRF status may also influence autonomic reflexes during chronic inflammation due to chronically changed central CRF concentration.

AVEMAR (a new benzoquinone-containing natural product) administration interferes with the Th2 response in experimental SLE and promotes amelioration of the disease

The potential of oral treatment with AVEMAR (AVEMAR), a new benzoquinone-containing fermentation product of wheat germ, on features of experimental systemic lupus erythematosus (SLE) in naive mice, induced by idiotypic manipulation, was studied. We assessed the effect of AVEMAR on the profile of autoantibody production and the response of Th1/Th2 related cytokines as well as the clinical picture of experimental SLE in the SLE-induced mice. When the product was given in the pre-immunization period, down-regulation of autoantibody production (anti-dsDNA, mouse 16/6 Id, and anti-histones) following treatment with AVEMAR was noted (eg anti-dsDNA decreased from 0.898+/-0.097 OD at 405 nm to 0.519+/-0.103 OD following treatment). This effect was sustained for at least 4 weeks after discontinuation of the therapy. Serological manifestations associated with a delay in Th2 response (IL-4 and IL-10) were recorded (eg IL-4 decreased from 91.7+/-8.11 to 59.55+/-7.78 ng/ml in splenocyte condition media). The mice showed normal ESR, WBC and less than 100 mg/dl of protein in the urine in comparison to > 300 mg/dl protein in the SLE non-treated mice. In conclusion, oral intake of AVEMAR can ameliorate the clinical manifestations of experimental SLE, via affecting the Th1/Th2 network inhibiting Th2 response.

Levels of mast-cell growth factors in plasma and in suction skin blister fluid in adults with mastocytosis: correlation with dermal mast-cell numbers and mast-cell tryptase

BACKGROUND

Mast-cell accumulation has been observed in the skin and other organs of patients with systemic indolent mastocytosis (SM). The basis for this pathologic increase is not fully understood.

OBJECTIVE

We sought to determine levels of mast-cell growth factors in the skin and plasma of patients with SM, patients with atopic dermatitis (AD), and healthy individuals and to correlate these levels to dermal mast-cell numbers and levels of mast-cell tryptase.

METHODS

Skin suction blister fluid and plasma levels of stem-cell factor, IL-3, IL-4, IL-6, vascular endothelial growth factor, and total mast-cell tryptase were analyzed by means of ELISA. The number of mast cells was determined in a biopsy section taken from adjacent skin.

RESULTS

Mast-cell numbers in the dermis were higher in patients with SM compared with numbers in patients with AD (P <.001) or in healthy control subjects (P <.0001) and correlated with tryptase levels in both skin blister fluid (P <.0001) and plasma (P <.0001). Stem-cell factor and vascular endothelial growth factor levels in the skin blister fluid and plasma of patients with SM were not significantly different from those in patients with AD or healthy control subjects. IL-3 and IL-4 levels were below the limit of detection. IL-6 levels were significantly increased in the plasma of patients with SM compared with in plasma of patients with AD (P <.002) and healthy control subjects (P <.0001) and correlated with plasma tryptase levels (P <.05) and dermal mast-cell numbers (P <.02).

CONCLUSION

Because elevated levels of IL-6 could contribute to the fever, fatigue, and osteoporosis observed in patients with SM and because IL-6 is antiapoptotic for mast cells, IL-6 could potentiate the biologic consequences of this disease.

Signal transduction in rheumatoid arthritis

Extracellular signals are transduced intracellularly by multiple pathways, resulting in alterations in the transcription and translation of specific proteins. The end result of some of these signalling pathways is the production of proteins, including cytokines and matrix metalloproteinases, that are implicated in the pathogenesis of rheumatoid arthritis. This chapter includes a discussion of these signal transduction pathways, including tumour necrosis factor receptor signalling, interleukin-1, -4, and -6 receptor signalling, stress- and mitogen-activated protein kinase pathways, CD14 and Toll-like receptor signalling, and T cell signal transduction. The known effects of currently available rheumatoid arthritis (RA) therapeutics on these signalling pathways are also reviewed. In addition, potential future targets for therapeutic intervention in RA are discussed.

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.

Human alpha-1-glycoprotein and its interactions with drugs

For about half a century, the binding of drugs to plasma albumin, the "silent receptor," has been recognized as one of the major determinants of drug action, distribution, and disposition. In the last decade, the binding of drugs, especially but not exclusively basic entities, to another plasma protein, alpha 1-acid glycoprotein (AAG), has increasingly become important in this regard. The present review points out that hundreds of drugs with diverse structures bind to this glycoprotein. Although plasma concentration of AAG is much lower than that of albumin, AAG can become the major drug binding macromolecule in plasma with significant clinical implications. Also, briefly reviewed are the physiological, pathological, and genetic factors that influence binding, the role of AAG in drug-drug interactions, especially the displacement of drugs and endogenous substances from AAG binding sites, and pharmacokinetic and clinical consequences of such interactions. It can be predicted that in the future, rapid automatic methods to measure binding to albumin and/or AAG will routinely be used in drug development and in clinical practice to predict and/or guide therapy.

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.

Increased levels of proinflammatory cytokines and nitric oxide metabolites in neuropsychiatric lupus erythematosus

OBJECTIVE

To investigate systemic and intrathecal production of proinflammatory cytokines in relation to cerebrospinal fluid (CSF) nitric oxide (NO) release in patients with neuropsychiatric lupus erythematosus (NPLE).

METHODS

Thirty patients with NPLE rated as mild, moderate, or severe were studied and CSF was obtained from 21 of these. Cytokine mRNA expressing cells were detected by in situ hybridisation. Soluble cytokines were assessed by enzyme linked immunosorbent assay (ELISA). Nitrite and nitrate were determined by capillary electrophoresis.

RESULTS

Patients with NPLE had high numbers of lymphocytes expressing mRNA for tumour necrosis factor alpha (TNFalpha), interferon gamma, and interleukin 10 in blood. The number of peripheral blood TNFalpha mRNA positive cells correlated strongly with the level of NO metabolites in the CSF (r(2)=0.69). Both the number of peripheral blood mononuclear cells expressing mRNA for TNFalpha as well as the CSF level of NO metabolites correlated with NPLE disease severity.

CONCLUSION

These data suggest that increased peripheral production of proinflammatory cytokines such as TNFalpha may contribute both to an increased production of NO in the central nervous system and to generation of clinical NPLE. The data also support the possibility that measurements of NO metabolites in CSF may be of value in the diagnosis of neurological symptoms related to SLE.

Novel single nucleotide polymorphisms in the distal IL-10 promoter affect IL-10 production and enhance the risk of systemic lupus erythematosus

Family studies of first-degree relatives and analysis of twins indicate that as much as 75% of the differences in quantitative IL-10 production in man derive from heritable genetic factors. Studies of single nucleotide polymorphisms (SNP) in the proximal 1.0 kb of the IL-10 promoter have yielded inconsistent association with IL-10 production and variable results in promoter-reporter studies. However, in normal donors, an association of quantitative production with certain alleles of the IL-10.R short tandem repeat polymorphism at -4.0 kb suggested that SNPs in the more distal promoter might be informative. We have identified seven novel SNP sites in the genomic sequence of the first 4 kb of the IL-10 promoter region 5' to the ATG start site from Caucasian individuals with either a high or a low IL-10 production phenotype. We have also identified eight SNP haplotypes in the distal promoter that segregate with significant differences in quantitative IL-10 production in normal donors. These SNPs are significantly associated with systemic lupus erythematosus in African-Americans and may define one component of the genetic susceptibility to systemic lupus erythematosus in this group.