IL-18 as a biomarker linking systemic juvenile idiopathic arthritis and macrophage activation syndrome.

OBJECTIVES: Systemic juvenile idiopathic arthritis (sJIA) is a childhood arthritis with features of autoinflammation and high risk of macrophage activation syndrome (MAS). IL-18 has been shown to have key roles in sJIA and MAS. We aimed to examine IL-18 levels in sJIA in relation to disease activity and history of MAS and other disease biomarkers namely S100 proteins and CXCL9. METHODS: Total IL-18, CXCL9 and S100 proteins levels were determined in 40 sJIA patients, and IL-18 levels were compared between patients with regards to disease activity, history of MAS, and other biomarkers. RESULTS: Total IL-18 levels were significantly higher in patients with active sJIA (median 16 499 pg/ml; interquartile range (IQR) 4816-61 839), and remained persistently elevated even in the majority of patients with inactive disease (1164 pg/ml; IQR 587-3444). Patients with history of MAS had significantly higher IL-18 levels (13 380 pg/ml; IQR 4212-62 628) as compared with those without MAS history (956.5 pg/ml; IQR 276.3-4262.5). Total IL-18 performed well with area under the curve of 0.8145 and 0.84 in predicting disease activity and history of MAS, respectively. We observed moderate correlation between IL-18 and CXCL9 (R = 0.56), S100A8/A9 (R = 0.47) and S100A12 (R = 0.46). The correlation was stronger for ferritin (R = 0.74) and overall for those with active disease. CONCLUSION: Total IL-18 levels were elevated in the majority of sJIA patients regardless of clinical features, but were higher in patients with active disease and history of MAS. Change in IL-18 may reflect increased disease activity or development of MAS.

Reintroduction of immunosuppressive medications in pediatric rheumatology patients with histoplasmosis: a case series.

BACKGROUND: Children with rheumatic diseases (cRD) receiving immunosuppressive medications (IM) are at a higher risk for acquiring potentially lethal pathogens, including Histoplasma capsulatum (histoplasmosis), a fungal infection that can lead to prolonged hospitalization, organ damage, and death. Withholding IM during serious infections is recommended yet poses risk of rheumatic disease flares. Conversely, reinitiating IM increases risk for infection recurrence. Tumor necrosis factor alpha inhibitor (TNFai) biologic therapy carries the highest risk for histoplasmosis infection after epidemiological exposure, so other IM are preferred during active histoplasmosis infection. There is limited guidance as to when and how IM can be reinitiated in cRD with histoplasmosis. This case series chronicles resumption of IM, including non-TNFai biologics, disease-modifying anti-rheumatic drugs (DMARDs), and corticosteroids, following histoplasmosis among cRD. CASE PRESENTATION: We examine clinical characteristics and outcomes of 9 patients with disseminated or pulmonary histoplasmosis and underlying rheumatic disease [juvenile idiopathic arthritis (JIA), childhood-onset systemic lupus erythematosus (cSLE), and mixed connective tissue disease (MCTD)] after reintroduction of IM. All DMARDs and biologics were halted at histoplasmosis diagnosis, except hydroxychloroquine (HCQ), and patients began antifungals. Following IM discontinuation, all patients required systemic or intra-articular steroids during histoplasmosis treatment, with 4/9 showing Cushingoid features. Four patients began new IM regimens [2 abatacept (ABA), 1 HCQ, and 1 methotrexate (MTX)] while still positive for histoplasmosis, with 3/4 (ABA, MTX, HCQ) later clearing their histoplasmosis and 1 (ABA) showing decreasing antigenemia. Collectively, 8/9 patients initiated or continued DMARDs and/or non-TNFai biologic use (5 ABA, 1 tocilizumab, 1 ustekinumab, 3 MTX, 4 HCQ, 1 leflunomide). No fatalities, exacerbations, or recurrences of histoplasmosis occurred during follow-up (median 33 months). CONCLUSIONS: In our cohort of cRD, histoplasmosis course following reintroduction of non-TNFai IM was favorable, but additional studies are needed to evaluate optimal IM management during acute histoplasmosis and recovery. In this case series, non-TNFai biologic, DMARD, and steroid treatments did not appear to cause histoplasmosis recurrence. Adverse events from corticosteroid use were common. Further research is needed to implement guidelines for optimal use of non-TNFai (like ABA), DMARDs, and corticosteroids in cRD following histoplasmosis presentation.

Neutrophils From Children With Systemic Juvenile Idiopathic Arthritis Exhibit Persistent Proinflammatory Activation Despite Long-Standing Clinically Inactive Disease.

Background: Systemic juvenile idiopathic arthritis (SJIA) is a chronic childhood arthropathy with features of autoinflammation. Early inflammatory SJIA is associated with expansion and activation of neutrophils with a sepsis-like phenotype, but neutrophil phenotypes present in longstanding and clinically inactive disease (CID) are unknown. The objective of this study was to examine activated neutrophil subsets, S100 alarmin release, and gene expression signatures in children with a spectrum of SJIA disease activity. Methods: Highly-purified neutrophils were isolated using a two-step procedure of density-gradient centrifugation followed by magnetic-bead based negative selection prior to flow cytometry or cell culture to quantify S100 protein release. Whole transcriptome gene expression profiles were compared in neutrophils from children with both active SJIA and CID. Results: Patients with SJIA and active systemic features demonstrated a higher proportion of CD16+CD62Llo neutrophil population compared to controls. This neutrophil subset was not seen in patients with CID or patients with active arthritis not exhibiting systemic features. Using imaging flow cytometry, CD16+CD62Llo neutrophils from patients with active SJIA and features of macrophage activation syndrome (MAS) had increased nuclear hypersegmentation compared to CD16+CD62L+ neutrophils. Serum levels of S100A8/A9 and S100A12 were strongly correlated with peripheral blood neutrophil counts. Neutrophils from active SJIA patients did not show enhanced resting S100 protein release; however, regardless of disease activity, neutrophils from SJIA patients did show enhanced S100A8/A9 release upon PMA stimulation compared to control neutrophils. Furthermore, whole transcriptome analysis of highly purified neutrophils from children with active SJIA identified 214 differentially expressed genes (DEG) compared to neutrophils from healthy controls. The most significantly upregulated gene pathway was Immune System Process, including AIM2, IL18RAP, and NLRC4. Interestingly, this gene set showed intermediate levels of expression in neutrophils from patients with long-standing CID yet persistent serum IL-18 elevation. Indeed, all patient samples regardless of disease activity demonstrated elevated inflammatory gene expression, including inflammasome components and S100A8. Conclusion: We identify features of neutrophil activation in SJIA patients with both active disease and CID, including a proinflammatory gene expression signature, reflecting persistent innate immune activation. Taken together, these studies expand understanding of neutrophil function in chronic autoinflammatory disorders such as SJIA.

Effects of heparin and related molecules upon neutrophil aggregation and elastase release in vitro.

1 Neutrophil-derived elastase is an enzyme implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). Heparin inhibits the enzymatic activity of elastase and here we provide evidence for the first time that heparin can inhibit the release of elastase from human neutrophils. 2 Unfractionated and low molecular weight heparins (UH and LMWH, 0.01-1000 U ml(-1)) and corresponding concentrations (0.06-6000 micro g ml(-1)) of nonanticoagulant O-desulphated heparin (ODH), dextran sulphate (DS) and nonsulphated poly-L-glutamic acid (PGA) were compared for their effects on both elastase release from and aggregation of neutrophils. 3 UH, ODH and LMWH inhibited (P<0.05) the homotypic aggregation of neutrophils, in response to both N-formyl-methionyl-leucyl-phenylalanine (fMLP, 10(-6) M) and platelet-activating factor (PAF, 10(-6) M), as well as elastase release in response to these stimuli, in the absence and presence of the priming agent tumour necrosis factor-alpha (TNF-alpha, 100 U ml(-1)). 4 DS inhibited elastase release under all the conditions of cellular activation tested (P<0.05) but had no effect on aggregation. PGA lacked efficacy in either assay, suggesting general sulphation to be important in both effects of heparin on neutrophil function and specific patterns of sulphation to be required for inhibition of aggregation. 5 Further investigation of the structural requirements for inhibition of elastase release confirmed the nonsulphated GAG hyaluronic acid and neutral dextran, respectively, to be without effect, whereas the IP(3) receptor antagonist 2-aminoethoxydiphenylborate (2-APB) mimicked the effects of heparin, itself an established IP(3) receptor antagonist, suggesting this to be a possible mechanism of action.

Cutaneous sarcoidosis presenting as leonine facies.

Cutaneous sarcoidosis often masquerades as many other disease entities. We describe the case of a 56-year-old African American man with a 1-year history of progressively enlarging nodules and plaques of the face resulting in a leonine appearance and madarosis. The diagnosis of cutaneous sarcoidosis was made after skin biopsy results revealed noncaseating granulomas without evidence of foreign body, mycobacteria, or deep fungal infection. A thorough systemic workup was void of other comorbidities. The reports of tumoral sarcoidosis or sarcoidosis presenting with leonine facies are rare, and those cases that have been reported have been linked to other systemic findings.

Long-term effects of anti-tumour necrosis factor therapy on weight in patients with rheumatoid arthritis.

In patients with rheumatoid arthritis (RA), weight is an important prognostic factor. Preliminary evidence has indicated that treatment with anti-tumour necrosis factor (TNF) therapy can affect the weight of patients with RA, but the relationship between improved prognosis and weight changes remains to be clarified. Our aim was to investigate the effects of anti-TNF therapy on the weight of patients with RA following 24 months of treatment. Patients (n = 168) were selected for this retrospective analysis on the basis of having received anti-TNF therapy for the first time. Change in body weight after 12 and 24 months of treatment was calculated and analysed by multiple regression analysis using age, sex, baseline body mass index (BMI), baseline DAS28 score, disease-modifying antirheumatic drug use, steroid use and specific anti-TNF drug as explanatory variables. The mean weight change of the patient group after 12 months of treatment was +1.58 kg (95% CI 0.71 to 2.46 kg) and after 24 months was +1.80 kg (95% CI 0.69 to 2.67 kg). After 24 months, 64.3% of patients had gained weight. There was no statistically significant association between weight gain at 12 or 24 months and age, sex, steroid use at baseline, anti-TNF drug or baseline DAS28 score. Baseline BMI had a statistically significant negative association with weight gain at 12 and 24 months. RA patients with lower BMIs tend to gain weight with anti-TNF therapy. Further studies are required to determine if the weight gained is fat and/or muscle and the effects upon general health outcomes.

Binding specificity of Toll-like receptor cytoplasmic domains.

MyD88 participates in signal transduction by binding to the cytoplasmic Toll/IL-1 receptor (TIR) domains of activated Toll-like receptors (TLR). Yeast two-hybrid experiments reveal that the TIR domains of human TLR differ in their ability to associate with MyD88: The TIR of TLR2 binds to MyD88 but the TIR of the closely related TLR1, 6, or 10 do not. Using chimeric TIR domains, we define the critical region responsible for differential MyD88 binding, and use a computational analysis of the critical region to reveal the amino acids that differ between MyD88 binders and non-binders. Remarkably, a single missense mutation created in TLR1 (N672D) confers on it the ability to bind MyD88, without affecting its association with other proteins. Mutations identified as critical for MyD88 binding also affect signaling of TLR pairs in mammalian cells. To investigate the difference between MyD88 binders and non-binders, we identify novel interacting proteins for each cytoplasmic domain of TLR1, 2, 6, and 10. For example, heat shock protein (HSP)60 binds to TLR1 but not to TLR2, and HSP60 and MyD88 appear to bind the same region of the TIR domain. In summary, interactions between the TLR, MyD88, and novel associated proteins have been characterized.

Additional clinical benefit of enoxaparin in COPD patients receiving salmeterol and fluticasone propionate in combination.

It is now well recognised that heparin possesses numerous anti-inflammatory properties in addition to its anticoagulant properties. Thus, the aim of this study was to investigate the effects of the low molecular weight heparin, enoxaparin (ENX), as an add-on therapy for a period of 12 weeks, to inhaled salmeterol/fluticasone propionate (SLM/FP) combination in patients with stable chronic obstructive pulmonary disease (COPD). Forty-six patients were randomised to receive 12 weeks of treatment in one of two treatment groups: (1) fixed combination of SLM 50 microg and FP 500 microg Diskus, one inhalation twice daily; or (2) as group 1 plus 20 mg ENX administered subcutaneously once daily for 12 weeks. Patients attended the clinic before and after 4, 8 and 12 weeks of treatment for evaluations of lung function, blood gas tensions, dyspnoea and supplemental salbutamol use. Thirty-six patients completed the 12-week treatment period, 20 from group 1 and 16 from group 2. A significant increase in forced expiratory volume in 1 s (FEV1) over baseline was observed after 12 weeks of treatment in group 1 (0.145 L, 95% CI: 0.994-1.406, p<0.01), whilst significant increases in FEV1 over baseline were observed in group 2 after 4, 8 and 12 weeks of treatment with a maximum increase at 12 weeks of 0.244 L (95% CI: 1.175-1.596, p<0.01). Both treatment groups experienced similar improvements in blood gas tensions, dyspnoea and supplemental salbutamol use. Our results suggest that addition of ENX to conventional therapy of COPD may provide additional clinical benefit and must be further investigated as a treatment for COPD.

Comparison of three different leptospiral vaccines for induction of a type 1 immune response to Leptospira borgpetersenii serovar Hardjo.

Leptospira serovar Hardjo are bacterial pathogens of cattle that cause zoonotic infections of humans. Monovalent serovar Hardjo vaccines protect cattle from serovar Hardjo while pentavalent vaccines do not even though they contain serovar Hardjo organisms. Here, cattle vaccinated with either of two monovalent vaccines had lymphocytes that made interferon-gamma (IFN-gamma) and IgG(1) and IgG(2) antibodies to Hardjo antigen while those from cattle vaccinated with a pentavalent Leptospira vaccine did not. IFN-gamma-producing cells were mainly CD4(+), but included CD8(+) and gamma delta TCR(+) cells. Despite their monovalent composition, those vaccines also induced IFN-gamma responses to serovar Grippotyphosa antigens. Thus, induction of a type 1 immune response is consistent with protective immunity to serovar Hardjo infections.

Chymase-like angiotensin II-generating activity in end-stage human autosomal dominant polycystic kidney disease.

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by exuberant inflammation and fibrosis, a process believed to contribute to progressive loss of normal renal function. Despite early-onset hypertension and intrarenal renin/angiotensin II (AngII) activation, angiotensin-converting enzyme (ACE) inhibition does not consistently confer renal protection in ADPKD. The hypothesis was that mast cells within the inflammatory interstitium release chymase, an enzyme capable of efficient conversion of AngI to AngII, providing an ACE-independent route of AngII generation. End-stage ADPKD renal tissue extracts and cyst fluids were assayed for time-dependent, chymostatin-inhibitable conversion of (125)I-AngI to (125)I-AngII under conditions of ACE and aminopeptidase inhibition by means of HPLC. Thirteen of 14 ADPKD kidney extracts exhibited chymase-like AngII-generating capacity; calculated initial reaction rates averaged 3.9 +/- 2.9 fmol AngII/min/ micro g protein with a mean maximal conversion of 55% +/- 30% of added substrate. AngII-generating activity was both protein and substrate dependent. All five cyst fluid samples were negative. Chymase-like activity was detectable in only three of six non-ADPKD kidney extracts. Immunoreactive chymase protein was present in/around mast cells within the fibrotic renal interstitium in all samples. Findings demonstrate for the first time the presence of mast cells, mast cell-associated immunoreactive chymase protein, and chymase-like AngII generating capacity in ADPKD cystic kidneys. Results support the potential for ACE-independent AngII generation and for mast cell-initiated inflammatory processes in ADPKD, each with therapeutic implications for ADPKD renal progression.