Evidence for chronic, peripheral activation of neutrophils in polyarticular juvenile rheumatoid arthritis

Although strong epidemiologic evidence suggests an important role for adaptive immunity in the pathogenesis of polyarticular juvenile rheumatoid arthritis (JRA), there remain many aspects of the disease that suggest equally important contributions of the innate immune system. We used gene expression arrays and computer modeling to examine the function in neutrophils of 25 children with polyarticular JRA. Computer analysis identified 712 genes that were differentially expressed between patients and healthy controls. Computer-assisted analysis of the differentially expressed genes demonstrated functional connections linked to both interleukin (IL)-8- and interferon-gamma (IFN-gamma)-regulated processes. Of special note is that the gene expression fingerprint of children with active JRA remained essentially unchanged even after they had responded to therapy. This result differed markedly from our previously reported work, in which gene expression profiles in buffy coats of children with polyarticular JRA reverted to normal after disease control was achieved pharmacologically. These findings suggest that JRA neutrophils remain in an activated state even during disease quiescence. Computer modeling of array data further demonstrated disruption of gene regulatory networks in clusters of genes modulated by IFN-gamma and IL-8. These cytokines have previously been shown to independently regulate the frequency (IFN-gamma) and amplitude (IL-8) of the oscillations of key metabolites in neutrophils, including nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) and superoxide ion. Using real-time, high-speed, single-cell photoimaging, we observed that 6/6 JRA patients displayed a characteristic defect in 12% to 23% of the neutrophils tested. Reagents known to induce only frequency fluctuations of NAD(P)H and superoxide ion induced both frequency and amplitude fluctuations in JRA neutrophils. This is a novel finding that was observed in children with both active (n = 4) and inactive (n = 2) JRA. A subpopulation of polyarticular JRA neutrophils are in a chronic, activated state, a state that persists when the disease is well controlled pharmacologically. Furthermore, polyarticular JRA neutrophils exhibit an intrinsic defect in the regulation of metabolic oscillations and superoxide ion production. Our data are consistent with the hypothesis that neutrophils play an essential role in the pathogenesis of polyarticular JRA.     

Quantitative analysis of cytokine gene expression in rheumatoid arthritis

Previous studies of the cytokine profile of rheumatoid arthritis (RA) have been primarily limited to the assessment of the levels of these mediators in synovial fluid (SF) or synovial tissues (ST) by biologic or immunologic assays. We have studied cytokine gene expression in RA by in situ hybridization of SF cells, enzymatically dispersed ST cells, and frozen sections of ST. RA ST cells (n = 7) were studied and a high percentage of cells hybridized to the following anti-sense probes: IL-6 = 19 +/- 3.3%; IL-1 beta = 9.9 +/- 1.7%; TNF-alpha = 5.8 +/- 1.4%; granulocyte-macrophage-CSF = 2.2 +/- 0.8%; transforming growth factor-beta 1 = 1.3 +/- 0.2% (p less than 0.05 for each compared to sense probes). Similar results were found using osteoarthritis ST cells, although the percentage of cells expressing the IL-6 gene (7.1 +/- 2.5%) was significantly less in osteoarthritis compared to RA. RA ST cells did not significantly bind the IFN-gamma probe (0.2 +/- 0.1% positive), although they were capable of expressing the IFN-gamma gene if stimulated with PHA. The OKM1+ population of ST cells (i.e., macrophage lineage cells) was greatly enriched for IL-1 beta and TNF-alpha, whereas the OKM1- population (lymphocytes, fibroblasts, and type B synoviocytes) was enriched for IL-6. The vast majority of cells expressing the IL-6 gene were non-T cells. Furthermore, hybridization to RA ST frozen sections localized IL-6 mRNA to the synovial lining layer, which is comprised of type A and type B synoviocytes. In contrast to the high level of cytokine gene expression observed in ST, SF cells did not hybridize significantly to any of the cytokine probes. If stimulated with LPS or PHA, SF cells expressed IL-1 beta or IFN-gamma genes, respectively.     

Mannose-binding lectin deficiency is associated with early onset of polyarticular juvenile rheumatoid arthritis: a cohort study

Background  

Mannose-binding lectin (MBL) is an innate immune protein. The aim of our study was to determine whether genetically determined MBL deficiency is associated with susceptibility to juvenile rheumatoid arthritis (JRA) and whether MBL2 genotypes are associated with JRA severity.     

Fungal arthritis simulating juvenile rheumatoid arthritis.

Petriellidium boydii is often isolated from maduromycosis but has recently been associated with arthritis. A previously healthy 6-year-old boy developed chronic purulent arthritis of the knee after a bicycle accident. Culture of aspirate grew no pathogens and antibiotic treatment had no effect. Culture of synovial fluid grew P boydii, which responded initially to amphotericin but reappeared after six months. Subsequent treatment with miconazole was stopped after development of haematuria. The fungus was sensitive to ketoconazole, and treatment with this drug cured the infection. With the introduction of ketoconazole it is of practical importance to recognise fungal infections.     

Facial deformity of juvenile rheumatoid arthritis

Arthritis of the temporomandibular joint and resulting deficient mandibular growth are seen in as many as 25 percent of patients with juvenile rheumatoid arthritis. The magnitude of joint involvement and resulting growth deficiency varies significantly. These patients typically develop a "birdface" deformity with retruding mandible, alteration of the cervicofacial angle, and class II occlusion with limitation of the bite opening. A multidisciplinary approach, including the surgeon, a dentist, an orthodontist, and a rheumatologist, is necessary to ensure a safe and successful surgical outcome. The side effects of pharmacologic agents used to control the disease on coagulation, healing, and bone density should be considered seriously.     

Cerebral complications in juvenile rheumatoid arthritis

A study of 170 patients with juvenile rheumatoid arthritis and a review of the literature indicate that this disease can significantly affect the central nervous system. Signs of CNS dysfunction were observed in 13 children. During the acute toxic stages the EEG is abnormal in many cases. Other manifestations of toxic encephalopathy such as irritability, drowsiness, stupor, convulsions and marked meningismus may be evident in severe cases. Meningitis is often suspected but ruled out by the finding of normal CSF. Steroids can rapidly improve the condition of these children. If `unexplained'' seizures occur during the chronic stage, the diagnosis of cerebral vasculitis should be entertained.     

Novel IL10 gene family associations with systemic juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is the most common cause of chronic childhood disability and encompasses a number of disease subgroups. In this study we have focused on systemic JIA (sJIA), which accounts for approximately 11% of UK JIA cases. This study reports the investigation of three members of the IL10 gene family as candidate susceptibility loci in children with sJIA. DNA from 473 unaffected controls and 172 patients with sJIA was genotyped for a single nucleotide polymorphism (SNP) in IL19 and IL20 and two SNPs in IL10. We examined evidence for association of the four SNPs by single marker and haplotype analysis. Significant differences in allele frequency were observed between cases and controls, for both IL10-1082 (p = 0.031) and IL20-468 (p = 0.028). Furthermore, examination of the haplotypes of IL10-1082 and IL20-468 revealed greater evidence for association (global p = 0.0006). This study demonstrates a significant increased prevalence of the low expressing IL10-1082 genotype in patients with sJIA. In addition, we show a separate association with an IL20 polymorphism, and the IL10-1082A/IL20-468T haplotype. The two marker 'A-T' haplotype confers an odds ratio of 2.24 for sJIA. This positive association suggests an important role for these cytokines in sJIA pathogenesis.     

HDAC inhibition in rheumatoid arthritis and juvenile idiopathic arthritis

Rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) are heterogeneous autoimmune diseases characterized by chronic joint inflammation. Methotrexate is used as the gold standard to treat rheumatoid arthritis, yet there are many patients in whom the disease cannot be controlled or who experience unacceptable intolerance. Most of the biologics currently used are effective, but mostly if combined with methotrexate. Long-term possible side effects, such as impaired host defense mechanisms against infection and lymphoma, are distinct disadvantages and a major concern of anticytokine therapies. Parenteral administration is a problem, particularly in children. Thus, there is a need to explore new treatment options. Here we review the properties of histone deacetylase inhibitors (HDACi) as they apply to rheumatoid arthritis by looking at effects on cytokine production, T-cell differentiation and the function of macrophages, dendritic cells, osteoblasts, osteoclasts and synovial fibroblasts. We also review the safety and efficacy of givinostat (ITF 2357) in the treatment of systemic onset juvenile idiopathic arthritis (SOJIA) and its influence on the cytokine networks in SOJIA. Givinostat is an orally active HDACi which was given to children with SOJIA. After 12 wk of treatment, there were significant benefits, particularly in reducing the pain and arthritic component of the disease and decreasing the neutrophilia. CD40L, IL-1α and IFNγ in whole blood lysates decreased at wks 2 and 4 compared with baseline levels. The clinical data are consistent with those from animal models of rheumatoid arthritis and suggest that trials with HDACi are promising as a safe oral alternative to anticytokines and methotrexate.     

Novel approaches to monitor bacterial gene expression in infected tissue and host

Elucidating the complex and dynamic host-microbe interactions during infection requires, among other things, detailed knowledge of microbial gene expression in vivo. Recently, advances in fluorescence and bioluminescence detection techniques, as well as recombinase-based in vivo expression technology, have rendered monitoring virulence gene expression in vivo a feasible task. These techniques have been adapted by several laboratories to study the spatial and temporal patterns of virulence gene expression by organisms such as Salmonella typhimurium, Listeria monocytogenes, Yersinia entercolitica and Vibrio cholerae during infection of tissue culture or animal models of infection.     

Cerebral complications in juvenile rheumatoid arthritis.

The antecedents of myocardial infarction have been reviewed in 102 patients (117 episodes) undergoing a program of rehabilitation. The year prior to the first attack was characterized by business and social problems, with some weight gain; in the week before the attach there was added tiredness, poor general health and, in some cases, increasing anginal pain. Heavy lifting and/or unusual exercise were common immediately before or during an attack; five attacks were related to the shovelling of wet snow.Both bed and the normal place of work were uncommon sites for an attack. More than 50% of patients had 30 minutes'' warning of infarction. The relevance of these findings to a safe program of therapeutic exercise is discussed.     

Treatment of juvenile rheumatoid arthritis with growth hormone

Severe growth retardation and profoundly altered body composition are observed in children with juvenile chronic arthritis receiving glucocorticoids. This study assessed the effects of growth hormone (GH) on height velocity, body composition and bone density. Fourteen patients were treated with GH (1.4 U/kg/week) for 1 year and then studied for a 2nd year off GH. The treatment increased insulin-like growth factor 1 and insulin-like growth factor binding protein 3 plasma levels. All patients showed an increase in height velocity. Lean body mass increased by 12%. After the cessation of GH therapy, height velocity fell to pretreatment values, and weight and fat mass increased markedly. Bone formation and resorption markers significantly increased during treatment and returned to pretreatment values after discontinuation of GH treatment. These results suggest that GH may partially counteract the adverse effects of glucocorticoids on growth and metabolism in patients with chronic inflammatory disease.     

Inhibition of IL6 in rheumatoid arthritis and juvenile idiopathic arthritis

A number of clinical trials have been done to investigate the role of interleukin-6 (IL-6) as a potential therapeutic target in rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA). Most of the data testing this comes from trials of the humanized anti Il-6 receptor antibody tocilizumab. Results from clinical trials worldwide have been promising so far. Additional study will define the ultimate role of tocilizumab and Il6 inhibitors in the treatment paradigms for RA and JIA.     

Polymorphism in a T-cell receptor variable gene is associated with susceptibility to a juvenile rheumatoid arthritis subset

This report demonstrates a T-cell receptor (Tcr) restriction fragment length polymorphism, defined by a Tcrb-V6.1 gene probe and Bgl II restriction enzyme, to be absolutely correlated with allelic variation in the coding sequence of a Tcrb-V6.1 gene. A pair of non-conservative amino acid substitutions distinguish the Tcrb-V6.1 allelic variants. An association of this Tcrb-V6.1 gene allelic variant with one form of juvenile rheumatoid arthritis (JRA) was established in a cohort of 126 patients. The association was observed in patients possessing the HLA-DQA1*0101 gene. Among HLA-DQA*0101 individuals, 19 of 26 patients (73.1%) carried one particular Tcrb-V6.1 gene allele as opposed to 11 of 33 controls (33%; p<0.005). Haplotypes carrying this HLA gene have previously been shown to confer increased risk for progression of arthritis in JRA. This demonstration of a disease-associated Tcrb-V gene allelic variant has not, to our knowledge, been previously reported and supports the contribution of polymorphism in the Tcr variable region genomic repertoire to human autoimmune disease.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession numbers M67511 for V6.1A and M67512 for V6.1B.     

Current and future management approaches for rheumatoid arthritis

With the introduction of new disease-modifying antirheumatic drugs (DMARDs) and other therapeutic agents, the management of rheumatoid arthritis (RA) has shifted toward earlier, more aggressive therapy. The ultimate goal is to prevent structural joint damage that leads to pain and functional disability. Early diagnosis of RA is therefore essential, and early DMARD treatment combined with nonsteroidal anti-inflammatory drugs is recommended. Combination DMARD regimens and new biologic agents (anti-tumor necrosis factor [TNF] therapies [infliximab, etanercept] and the interleukin [IL]-1 antagonist [anakinra]) have emerged as viable options for early treatment of RA patients. These new biologic agents and future nonbiologic agents that target proteins in signaling cascades are likely to change the landscape of RA treatments.     

Synovial histopathology of psoriatic arthritis,both oligo- and polyarticular,resembles spondyloarthropathy more than it does rheumatoid arthritis

At present only few biological data are available to indicate whether psoriatic arthritis (PsA) is part of the spondyloarthropathy (SpA) concept, whether it is a separate disease entity or a heterogeneous disease group with oligoarticular/axial forms belonging to SpA and polyarticular forms resembling rheumatoid arthritis (RA). To address this issue with regard to peripheral synovitis, we compared the synovial characteristics of PsA with those of ankylosing spondylitis (AS)/undifferentiated SpA (USpA) and RA, and compared the synovium of oligoarticular versus polyarticular PsA. Synovial biopsies were obtained from patients with RA, nonpsoriatic SpA (AS + USpA), and oligoarticular and polyarticular PsA. The histological analysis included examination(s) of the lining layer thickness, vascularity, cellular infiltration, lymphoid aggregates, plasma cells and neutrophils. Also, we performed immunohistochemical assessments of CD3, CD4, CD8, CD20, CD38, CD138, CD68, CD163, CD83, CD1a, CD146, α_Vβ₃, E-selectin, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, S100A12, intracellular citrullinated proteins and major histocompatibility complex (MHC)–human cartilage (HC) gp39 peptide complexes. Comparing SpA (PsA + AS + USpA) with RA, vascularity, and neutrophil and CD163⁺ macrophage counts were greater in SpA (P < 0.05), whereas lining layer thickness and the number of CD83⁺ dendritic cells were greater in RA (P < 0.05). In RA, 44% of samples exhibited positive staining for intracellular citrullinated proteins and 46% for MHC–HC gp39 peptide complexes, whereas no staining for these markers was observed in SpA samples. We excluded influences of disease-modifying antirheumatic drug and/or corticosteroid treatment by conducting systematic analyses of treated and untreated subgroups. Focusing on PsA, no significant differences were observed between PsA and nonpsoriatic SpA. In contrast, vascularity (P < 0.001) and neutrophils were increased in PsA as compared with RA (P = 0.010), whereas staining for intracellular citrullinated proteins and MHC–HC gp39 peptide complexes was exclusively observed in RA (both P = 0.001), indicating that the same discriminating features are found in PsA and other SpA subtypes compared with RA. Exploring synovial histopathology between oligoarticular and polyarticular PsA, no significant differences were noted. Moreover, intracellular citrullinated proteins and MHC–HC gp39 peptide complexes, which are specific markers for RA, were observed in neither oligoarticular nor polyarticular PsA. Taken together, these data indicate that the synovial histopathology of PsA, either oligoarticular or polyarticular, resembles that of other SpA subtypes, whereas both groups can be differentiated from RA on the basis of these same synovial features, suggesting that peripheral synovitis in PsA belongs to the SpA concept.     

New experimental and computational approaches to the analysis of gene expression.

Public and private EST (Expressed Sequence Tag) programs provide access to a large number of ESTs from a number of plant species, including Arabidopsis, corn, soybean, rice, wheat. In addition to the homology of each EST to genes in GenBank, information about homology to all other ESTs in the data base can be obtained. To estimate expression levels of genes represented in the DuPont EST data base we count the number of times each gene has been seen in different cDNA libraries, from different tissues, developmental stages or induction conditions. This quantitation of message levels is quite accurate for highly expressed messages and, unlike conventional Northern blots, allows comparison of expression levels between different genes. Lists of most highly expresses genes in different libraries can be compiled. Also, if EST data is available for cDNA libraries derived from different developmental stages, gene expression profiles across development can be assembled. We present an example of such a profile for soybean seed development. Gene expression data obtained from Electronic Northern analysis can be confirmed and extended beyond the realm of highly expressed genes by using high density DNA arrays. The ESTs identified as interesting can be arrayed on nylon or glass and probed with total labeled cDNA first strand from the tissue of interest. Two-color fluorescent labeling allows accurate mRNA ratio measurements. We are currently using the DNA array technology to study chemical induction of gene expression and the biosynthesis of oil, carbohydrate and protein in developing seeds.