Expression of myeloid-related protein-8 and -14 in patients with acute Kawasaki disease

Illuminating the enigmatic pathogenesis of Kawasaki disease: Unveiling novel therapeutic avenues by targeting FCGR3B-S100A12 pathway

Kawasaki disease (KD) primarily affects the pediatric population and exhibits a notable incidence of drug resistance, resulting in coronary artery damage and thrombosis. This study aimed to identify innovative therapeutic targets for KD treatment. By harnessing single-cell data derived from peripheral blood mononuclear cells, we identified differentially expressed genes. Through the integration of eQTL data and Mendelian randomization analysis, we identified FCGR3B and S100A12 were causally linked to KD. The DrugBank database showed their potential as drug target candidates. GSEA further elucidated their roles on coronary artery damage and thrombosis. Furthermore, we have confirmed that the ligand-FCGR3B complex enhances the intracellular calcium concentration (Ca2+) within the cytoplasm, which in turn accelerates the secretion of S100A12, a pro-inflammatory cytokine that targets endothelial cells, from neutrophils. By integrating existing research, we proposed a synergistic effect that FCGR3B-S100A12 pathway positively modulates the development of coronary artery damage and thrombus formation, suggesting their perspectives in clinical treatment.

The Future of Kawasaki Disease Diagnosis: Liquid Biopsy May Hold the Key

Kawasaki disease (KD) is a febrile illness characterised by systemic inflammation of small- and medium-sized blood vessels, which commonly occurs in young children. Although self-limiting, there is a risk of developing coronary artery lesions as the disease progresses, with delay in diagnosis and treatment. Unfortunately, the diagnosis of KD continues to remain a clinical dilemma. Thus, this article not only summarises the key research gaps associated with KD, but also evaluates the possibility of using circulating endothelial injury biomarkers, such as circulating endothelial cells, endothelial microparticles and vascular endothelial cell-free DNA, as diagnostic and prognostic tools for KD: a "liquid biopsy" approach. The challenges of translating liquid biopsies to use in KD and the opportunities for improvement in its diagnosis and management that such translation may provide are discussed. The use of endothelial damage markers, which are easily obtained via blood collection, as diagnostic tools is promising, and we hope this will be translated to clinical applications in the near future.

Serum Levels of S100A8/A9 as a Biomarker of Disease Activity in Patients with IgA Vasculitis

S100A8/A9 protein is a well-known marker of disease activity or severity in many autoimmune and autoinflammatory diseases, but there have not been many studies about the role of S100A8/A9 in IgA vasculitis (IgAV). The aim of our study was to evaluate S100A8/A9 as a possible biomarker of activity in IgAV. We measured the serum levels of S100A8/A9 in pediatric patients with IgA vasculitis at the onset of the disease, after three months, and after six months. We compared these levels between patients with active disease, remission, and a control group, and assessed their correlation with disease activity and other markers of inflammation. Patients with active disease had significantly higher levels of serum S100A8/A9 (median ± SD) than those in the control group at the beginning of the disease (5740 ± 3157 ng/mL vs. 1447 ± 858.3 ng/mL; p < 0.0001), but also three months and six months after disease onset (p < 0.001). There was a positive correlation between S100A8/A9 serum levels and disease activity (p = 0.0003). Patients with active disease had significantly higher levels of S100A8/A9 than those in remission three months after disease onset (p = 0.0260). There was a correlation between S100A8/A9 and C-reactive protein, the C3 component of complement, ferritin, and fibrinogen. Serum levels of S100A8/A9 were also higher in patients with greater skin areas covered with rash. We demonstrated that serum levels of S100A8/A9 correlated well with disease activity and other biomarkers of inflammation in children with IgAV. According to our results, serum S100A8/A9 may be a good indicator of active disease in IgAV.

The functions and regulatory pathways of S100A8/A9 and its receptors in cancers

Inflammation primarily influences the initiation, progression, and deterioration of many human diseases, and immune cells are the principal forces that modulate the balance of inflammation by generating cytokines and chemokines to maintain physiological homeostasis or accelerate disease development. S100A8/A9, a heterodimer protein mainly generated by neutrophils, triggers many signal transduction pathways to mediate microtubule constitution and pathogen defense, as well as intricate procedures of cancer growth, metastasis, drug resistance, and prognosis. Its paired receptors, such as receptor for advanced glycation ends (RAGEs) and toll-like receptor 4 (TLR4), also have roles and effects within tumor cells, mainly involved with mitogen-activated protein kinases (MAPKs), NF-κB, phosphoinositide 3-kinase (PI3K)/Akt, mammalian target of rapamycin (mTOR) and protein kinase C (PKC) activation. In the clinical setting, S100A8/A9 and its receptors can be used complementarily as efficient biomarkers for cancer diagnosis and treatment. This review comprehensively summarizes the biological functions of S100A8/A9 and its various receptors in tumor cells, in order to provide new insights and strategies targeting S100A8/A9 to promote novel diagnostic and therapeutic methods in cancers.

Platelets exacerbate cardiovascular inflammation in a murine model of Kawasaki disease vasculitis

Kawasaki disease (KD) is the leading cause of acquired heart disease among children. Increased platelet counts and activation are observed during the course of KD, and elevated platelet counts are associated with higher risks of developing intravenous immunoglobulin resistance and coronary artery aneurysms. However, the role of platelets in KD pathogenesis remains unclear. Here, we analyzed transcriptomics data generated from the whole blood of patients with KD and discovered changes in the expression of platelet-related genes during acute KD. In the Lactobacillus casei cell wall extract (LCWE) murine model of KD vasculitis, LCWE injection increased platelet counts and the formation of monocyte-platelet aggregates (MPAs), upregulated the concentration of soluble P-selectin, and increased circulating thrombopoietin and interleukin 6 (IL-6). Furthermore, platelet counts correlated with the severity of cardiovascular inflammation. Genetic depletion of platelets (Mpl-/- mice) or treatment with an anti-CD42b antibody significantly reduced LCWE-induced cardiovascular lesions. Furthermore, in the mouse model, platelets promoted vascular inflammation via the formation of MPAs, which likely amplified IL-1B production. Altogether, our results indicate that platelet activation exacerbates the development of cardiovascular lesions in a murine model of KD vasculitis. These findings enhance our understanding of KD vasculitis pathogenesis and highlight MPAs, which are known to enhance IL-1B production, as a potential therapeutic target for this disorder.

S100A8 and S100A9 in Cancer

S100A8 and S100A9 are Ca²⁺ binding proteins that belong to the S100 family. Primarily expressed in neutrophils and monocytes, S100A8 and S100A9 play critical roles in modulating various inflammatory responses and inflammation-associated diseases. Forming a common heterodimer structure S100A8/A9, S100A8 and S100A9 are widely reported to participate in multiple signaling pathways in tumor cells. Meanwhile, S100A8/A9, S100A8, and S100A9, mainly as promoters, contribute to tumor development, growth and metastasis by interfering with tumor metabolism and the microenvironment. In recent years, the potential of S100A8/A9, S100A9, and S100A8 as tumor diagnostic or prognostic biomarkers has also been demonstrated. In addition, an increasing number of potential therapies targeting S100A8/A9 and related signaling pathways have emerged. In this review, we will first expound on the characteristics of S100A8/A9, S100A9, and S100A8 in-depth, focus on their interactions with tumor cells and microenvironments, and then discuss their clinical applications as biomarkers and therapeutic targets. We also highlight current limitations and look into the future of S100A8/A9 targeted anti-cancer therapy.

Platelet Indices as Diagnostic Marker for Kawasaki Disease

Various candidate biomarkers have been investigated for the early and accurate diagnosis of Kawasaki disease (KD). We aimed to evaluate platelet activity using platelet indices (PI) in patients with KD or simple febrile illness to determine whether these indices might support a diagnosis of KD. Another objective of the study was to delineate the changes in PI from the acute to convalescent phases of KD. A total of 225 patients with complete KD (cKD), 110 with incomplete KD (iKD), and 71 with simple febrile illness (control) were enrolled. PI included mean platelet volume (MPV), platelet distribution width (PDW), and plateletcrit (PCT). We serially measured the serum PI four times for each patient with KD from the acute to convalescent phases: on D0 (day of intravenous immunoglobulin (IVIG) treatment) and repeated on days 2 (D2), 14 (D14), and 56 (D56) after IVIG therapy. Data from the control group were collected during the acute stage of the disease (D0). The platelet counts in the cKD (341±103×10³/mm³) and iKD (374±135×10³/mm³) at diagnosis were higher than the control group (290±128×10³/mm³). The PCT in the cKD (0.284±0.085%) and iKD (0.313±0.109%) groups at diagnosis were also higher than the control group (0.246±0.108%). However, the MPV and PDW levels in the KD group were not statistically significant. Therefore, platelet count and PCT are adjuvant parameters for the differential diagnosis of KD from a simple febrile illness.

Molecular mechanisms of endothelial dysfunction in Kawasaki-disease-associated vasculitis

Kawasaki disease (KD) is an acute, inflammation mediated vasculitis, mainly affecting in children under five, which is consider as the most common coronary artery disease in children. The injuries of coronary arteries would result in dilation or thrombus formation, bringing great threaten to patients. Endothelium, located in the inner surface of coronary artery, serves as the interface between the circulating inflammatory cells and vascular media or adventitia, which is the first target of inflammatory attacks during early stage of KD. A series of studies have determined vascular endothelial cells damages and dysfunction in KD patients. However, current therapeutic strategy is still challenging. So that it is critical to underline the mechanisms of endothelium injuries. In this review, the role of endothelial cells in the pathogenesis of KD and the therapeutic methods for endothelial cells were systematically described.

Combination of fecal calprotectin and initial coronary dimensions to predict coronary artery lesions persistence in Kawasaki disease

Kawasaki Disease (KD) is systemic vasculitis involving medium-sized vessels in children. The aim of our study is to determine if fecal calprotectin (FC) could be useful in predicting the development or persistence of coronary artery lesions (CALs) in KD. We conducted a prospective monocentric study including all consecutive diagnoses of. Clinical, laboratory, echocardiographic data were recorded during the acute and subacute phase, including FC. Correlations among laboratory values, FC, clinical manifestations, IVIG-responsiveness and CALs development were investigated. We enrolled 26 children (76.9% boys; median age 34.5 months). The combination of FC > 250 microg/g and z-score > 2 during the acute phase was associated with the persistence of CALs (p = 0.022). A z-score > 2 alone during the acute phase was not related to CALs during the subacute stage (p > 0.05). A neutrophil percentage > 70% and WBC > 15,000/mmc during the acute phase significantly correlated with the presence of CALs during the subacute phase (p = 0.008). C-reactive protein (CRP) > 13 mg/dL at KD onset was significantly associated with the presence of CALs during the acute (p = 0.017) and subacute phase (p = 0.001). The combination of FC > 250 microg/g and a z-score > 2 during the acute phase of KD may be used as a predictor of CALs persistence. It can be useful especially in children with an initial CRP < 13 mg/dl.

S100A8/A9 Is a Marker for the Release of Neutrophil Extracellular Traps and Induces Neutrophil Activation

Neutrophils are the most abundant innate immune cells in the circulation and they are the first cells recruited to sites of infection or inflammation. Almost half of the intracellular protein content in neutrophils consists of S100A8 and S100A9, though there has been controversy about their actual localization. Once released extracellularly, these proteins are thought to act as damage-associated molecular patterns (DAMPs), though their mechanism of action is not well understood. These S100 proteins mainly form heterodimers (S100A8/A9, also known as calprotectin) and this heterocomplex is recognized as a useful biomarker for several inflammatory diseases. We observed that S100A8/A9 is highly present in the cytoplasmic fraction of neutrophils and is not part of the granule content. Furthermore, we found that S100A8/A9 was not released in parallel with granular content but upon the formation of neutrophil extracellular traps (NETs). Accordingly, neutrophils of patients with chronic granulomatous disease, who are deficient in phorbol 12-myristate 13-acetate (PMA)-induced NETosis, did not release S100A8/A9 upon PMA stimulation. Moreover, we purified S100A8/A9 from the cytoplasmic fraction of neutrophils and found that S100A8/A9 could induce neutrophil activation, including adhesion and CD11b upregulation, indicating that this DAMP might amplify neutrophil activation.

Evaluation of Serum Calprotectin Levels in Patients with Inflammatory Bowel Disease

BACKGROUND

Fecal calprotectin has been proposed as a useful biomarker of disease activity in inflammatory bowel disease (IBD). However, the role of calprotectin in systemic circulation is not well established. Thus, this study aimed to quantify serum calprotectin levels to identify a potential inflammatory marker for IBD.

METHODS

Ninety-eight patients with ulcerative colitis (UC) and 105 patients with Crohn's disease (CD) were prospectively enrolled and clinically scored. Ninety-two healthy, age-matched subjects served as controls. Blood samples from UC and CD patients and controls were analyzed for serum calprotectin levels and routine laboratory parameters. Disease activity was assessed by partial Mayo score and Harvey-Bradshaw index for UC and CD, respectively.

RESULTS

Serum calprotectin levels were higher in CD and UC patients than in controls and were higher during active disease than during inactive disease in CD but not in UC. In UC, serum calprotectin levels were correlated with C-reactive protein (CRP) but not with other laboratory parameters or disease activity. In CD, serum calprotectin levels were positively correlated with disease activity, serum CRP, and platelet count. In UC and CD, serum calprotectin and CRP levels increased during the acute phase and decreased towards remission.

CONCLUSIONS

Serum calprotectin is an inflammatory marker in IBD but might be more effective in evaluating patients with CD than those with UC. Further studies are needed to confirm these findings and to better determine the specific uses of serum calprotectin in routine practice.

Single-cell RNA sequencing of peripheral blood mononuclear cells from acute Kawasaki disease patients

Kawasaki disease (KD) is the most common cause of acquired heart disease in children in developed countries. Although functional and phenotypic changes of immune cells have been reported, a global understanding of immune responses underlying acute KD is unclear. Here, using single-cell RNA sequencing, we profile peripheral blood mononuclear cells from seven patients with acute KD before and after intravenous immunoglobulin therapy and from three age-matched healthy controls. The most differentially expressed genes are identified in monocytes, with high expression of pro-inflammatory mediators, immunoglobulin receptors and low expression of MHC class II genes in acute KD. Single-cell RNA sequencing and flow cytometry analyses, of cells from an additional 16 KD patients, show that although the percentage of total B cells is substantially decreased after therapy, the percentage of plasma cells among the B cells is significantly increased. The percentage of CD8+ T cells is decreased in acute KD, notably effector memory CD8+ T cells compared with healthy controls. Oligoclonal expansions of both B cell receptors and T cell receptors are observed after therapy. We identify biological processes potentially underlying the changes of each cell type. The single-cell landscape of both innate and adaptive immune responses provides insights into pathogenesis and therapy of KD.

S100A8 and S100A9 Are Important for Postnatal Development of Gut Microbiota and Immune System in Mice and Infants

BACKGROUND & AIMS

After birth, the immune system matures via interactions with microbes in the gut. The S100 calcium binding proteins S100A8 and S100A9, and their extracellular complex form, S100A8-A9, are found in high amounts in human breast milk. We studied levels of S100A8-A9 in fecal samples (also called fecal calprotectin) from newborns and during infancy, and their effects on development of the intestinal microbiota and mucosal immune system.

METHODS

We collected stool samples (n = 517) from full-term (n = 72) and preterm infants (n = 49) at different timepoints over the first year of life (days 1, 3, 10, 30, 90, 180, and 360). We measured levels of S100A8-A9 by enzyme-linked immunosorbent assay and analyzed fecal microbiomes by 16S sRNA gene sequencing. We also obtained small and large intestine biopsies from 8 adults and 10 newborn infants without inflammatory bowel diseases (controls) and 8 infants with necrotizing enterocolitis and measured levels of S100A8 by immunofluorescence microscopy. Children were followed for 2.5 years and anthropometric data and medical information on infections were collected. We performed studies with newborn C57BL/6J wild-type and S100a9^-/- mice (which also lack S100A8). Some mice were fed or given intraperitoneal injections of S100A8 or subcutaneous injections of Staphylococcus aureus. Blood and intestine, mesenterial and celiac lymph nodes were collected; cells and cytokines were measured by flow cytometry and studied in cell culture assays. Colon contents from mice were analyzed by culture-based microbiology assays.

RESULTS

Loss of S100A8 and S100A9 in mice altered the phenotypes of colonic lamina propria macrophages, compared with wild-type mice. Intestinal tissues from neonatal S100-knockout mice had reduced levels of CX3CR1 protein, and Il10 and Tgfb1 mRNAs, compared with wild-type mice, and fewer T-regulatory cells. S100-knockout mice weighed 21% more than wild-type mice at age 8 weeks and a higher proportion developed fatal sepsis during the neonatal period. S100-knockout mice had alterations in their fecal microbiomes, with higher abundance of Enterobacteriaceae. Feeding mice S100 at birth prevented the expansion of Enterobacteriaceae, increased numbers of T-regulatory cells and levels of CX3CR1 protein and Il10 mRNA in intestine tissues, and reduced body weight and death from neonatal sepsis. Fecal samples from term infants, but not preterm infants, had significantly higher levels of S100A8-A9 during the first 3 months of life than fecal samples from adults; levels decreased to adult levels after weaning. Fecal samples from infants born by cesarean delivery had lower levels of S100A8-A9 than from infants born by vaginal delivery. S100 proteins were expressed by lamina propria macrophages in intestinal tissues from infants, at higher levels than in intestinal tissues from adults. High fecal levels of S100 proteins, from 30 days to 1 year of age, were associated with higher abundance of Actinobacteria and Bifidobacteriaceae, and lower abundance of Gammaproteobacteria-particularly opportunistic Enterobacteriaceae. A low level of S100 proteins in infants' fecal samples associated with development of sepsis and obesity by age 2 years.

CONCLUSION

S100A8 and S100A9 regulate development of the intestinal microbiota and immune system in neonates. Nutritional supplementation with these proteins might aide in development of preterm infants and prevent microbiota-associated disorders in later years.

Role of mechanical stress and neutrophils in the pathogenesis of plaque erosion

Mechanical stress is a well-recognized driver of plaque rupture. Likewise, investigating the role of mechanical forces in plaque erosion has recently begun to provide some important insights, yet the knowledge is by far less advanced. The most significant example is that of shear stress, which has early been proposed as a possible driver for focal endothelial death and denudation. Recent findings using optical coherence tomography, computational sciences and mechanical models show that plaque erosion occurs most likely around atheromatous plaque throats with specific stress pattern. In parallel, we have recently shown that neutrophil-dependent inflammation promotes plaque erosion, possibly through a noxious action on ECs. Most importantly, spontaneous thrombosis - associated or not with EC denudation - can be impacted by hemodynamics, and it is now established that neutrophils promote thrombosis and platelet activation, highlighting a potential relationship between, mechanical stress, inflammation, and EC loss in the setting of coronary plaque erosion. Here, we review our current knowledge regarding the implication of both mechanical stress and neutrophils, and we discuss their implication in the promotion of plaque erosion via EC loss and thrombosis.

Biomarkers of Inflammation and Fibrosis in Kawasaki Disease Patients Years After Initial Presentation With Low Ejection Fraction

Background Coronary artery aneurysms and myocarditis are well-recognized complications of Kawasaki disease (KD) but no systematic evaluation of the consequences of myocarditis has been performed in the subset presenting with low ejection fraction (EF). We postulated that more severe myocardial inflammation as evidenced by low EF during the acute phase could lead to late myocardial fibrosis. Methods and Results We measured the carboxyterminal propeptide of procollagen type I (PIPC), soluble suppressor of tumorigenicity 2, galectin-3 (Gal-3), growth-differentiation factor-15, and calprotectin by ELISA in late convalescent blood samples from 16 KD patients who had an EF ≤55% on their initial echocardiogram. Results were compared with samples from sex- and age-matched KD patients with initial EF >60%. In the univariate analysis, the median Gal-3 and PIPC levels in the low EF group were significantly higher than those in the normal EF group (Gal-3: low EF 6.216 versus normal EF 4.976 mg/dL P=0.038, PIPC: low EF 427.4 versus normal EF 265.2 mg/dL, P=0.01). In a multivariable analysis, there were significant differences for Gal-3 and PIPC levels between the low and normal EF groups, adjusting for age, sex, and worst z score. Conclusions Convalescent KD patients with a history of low EF during the acute illness had significantly elevated levels of Gal-3 and PIPC when compared with matched-control KD patients with normal EF. These findings raise concern for myocardial fibrosis as a potential late sequela of the more severe myocarditis experienced by a subset of KD patients during the acute phase.

Biomarkers for the Discrimination of Acute Kawasaki Disease From Infections in Childhood

Background: Kawasaki disease (KD) is a vasculitis of early childhood mimicking several infectious diseases. Differentiation between KD and infectious diseases is essential as KD's most important complication-the development of coronary artery aneurysms (CAA)-can be largely avoided by timely treatment with intravenous immunoglobulins (IVIG). Currently, KD diagnosis is only based on clinical criteria. The aim of this study was to evaluate whether routine C-reactive protein (CRP) and additional inflammatory parameters myeloid-related protein 8/14 (MRP8/14 or S100A8/9) and human neutrophil-derived elastase (HNE) could distinguish KD from infectious diseases. Methods and Results: The cross-sectional study included KD patients and children with proven infections as well as febrile controls. Patients were recruited between July 2006 and December 2018 in Europe and USA. MRP8/14, CRP, and HNE were assessed for their discriminatory ability by multiple logistic regression analysis with backward selection and receiver operator characteristic (ROC) curves. In the discovery cohort, the combination of MRP8/14+CRP discriminated KD patients (n = 48) from patients with infection (n = 105), with area under the ROC curve (AUC) of 0.88. The HNE values did not improve discrimination. The first validation cohort confirmed the predictive value of MRP8/14+CRP to discriminate acute KD patients (n = 26) from those with infections (n = 150), with an AUC of 0.78. The second validation cohort of acute KD patients (n = 25) and febrile controls (n = 50) showed an AUC of 0.72, which improved to 0.84 when HNE was included. Conclusion: When used in combination, the plasma markers MRP8/14, CRP, and HNE may assist in the discrimination of KD from both proven and suspected infection.

Circulating Markers of Inflammation Persist in Children and Adults With Giant Aneurysms After Kawasaki Disease

Background:

The sequelae of Kawasaki disease (KD) vary widely with the greatest risk for future cardiovascular events among those who develop giant coronary artery aneurysms (CAA). We sought to define the molecular signature associated with different outcomes in pediatric and adult KD patients.

Methods:

Molecular profiling was conducted using mass spectrometry–based shotgun proteomics, transcriptomics, and glycomics methods on 8 pediatric KD patients at the acute, subacute, and convalescent time points. Shotgun proteomics was performed on 9 KD adults with giant CAA and matched healthy controls. Plasma calprotectin was measured by ELISA in 28 pediatric KD patients 1 year post-KD, 70 adult KD patients, and 86 healthy adult volunteers.

Results:

A characteristic molecular profile was seen in pediatric patients during the acute disease, which resolved at the subacute and convalescent periods in patients with no coronary artery sequelae but persisted in 2 patients who developed giant CAA. We, therefore, investigated persistence of inflammation in KD adults with giant CAA by shotgun proteomics that revealed a signature of active inflammation, immune regulation, and cell trafficking. Correlating results obtained using shotgun proteomics in the pediatric and adult KD cohorts identified elevated calprotectin levels in the plasma of patients with CAA. Investigation of expanded pediatric and adult KD cohorts revealed elevated levels of calprotectin in pediatric patients with giant CAA 1 year post-KD and in adult KD patients who developed giant CAA in childhood.

Conclusions:

Complex patterns of biomarkers of inflammation and cell trafficking can persist long after the acute phase of KD in patients with giant CAA. Elevated levels of plasma calprotectin months to decades after acute KD and infiltration of cells expressing S100A8 and A9 in vascular tissues suggest ongoing, subclinical inflammation. Calprotectin may serve as a biomarker to inform the management of KD patients following the acute illness.

Monocyte-Derived Interleukin-1β As the Driver of S100A12-Induced Sterile Inflammatory Activation of Human Coronary Artery Endothelial Cells: Implications for the Pathogenesis of Kawasaki Disease

OBJECTIVE

Kawasaki disease (KD) is an acute vasculitis of childhood, predominantly affecting the coronary arteries. S100A12, a granulocyte-derived agonist of both the receptor for advanced glycation end products (RAGE) and Toll-like receptor 4 (TLR-4), is strongly up-regulated in KD. This study was undertaken to investigate the potential contributions of S100A12 to the pathogenesis of KD.

METHODS

Serum samples from patients with KD (n = 30) at different stages pre- and post-intravenous immunoglobulin (IVIG) treatment were analyzed for the expression of S100A12, cytokines, chemokines, and soluble markers of endothelial cell activation. Primary human coronary artery endothelial cells (HCAECs) were analyzed for responsiveness to direct stimulation with S100A12 or lipopolysaccharide (LPS), as assessed by real-time quantitative reverse transcription-polymerase chain reaction analysis of cytokine and endothelial cell adhesion molecule messenger RNA expression. Alternatively, HCAECs were cultured in conditioned medium obtained from primary human monocytes that were stimulated with LPS or S100A12 in the absence or presence of IVIG or cytokine antagonists.

RESULTS

In the serum of patients with KD, pretreatment S100A12 levels were associated with soluble vascular cell adhesion molecule 1 titers in the course of IVIG therapy (r_s = -0.6, P = 0.0003). Yet, HCAECs were not responsive to direct S100A12 stimulation, despite the presence of appropriate receptors (RAGE, TLR-4). HCAECs did, however, respond to supernatants obtained from S100A12-stimulated primary human monocytes, as evidenced by the gene expression of inflammatory cytokines and adhesion molecules. This response was strictly dependent on interleukin-1β (IL-1β) signaling (P < 0.001).

CONCLUSION

In its role as a highly expressed mediator of sterile inflammation in KD, S100A12 appears to activate HCAECs in an IL-1β-dependent manner. These data provide new mechanistic insights into the contributions of S100A12 and IL-1β to disease pathogenesis, and may therefore support current IL-1-targeting studies in the treatment of patients with KD.

Serum calprotectin and ischemia modified albumin levels as markers of disease activity in Behçet's disease

Introduction

Behçet’s disease (BD) is a complex multisystemic inflammatory disorder which is characterized by recurrent attacks of acute inflammation. As there is no universally recognized pathognomonic laboratory marker of BD, its diagnosis is still based on clinical findings.

Aim

To evaluate the role of calprotectin and ischemia modified albumin (IMA) as biomarkers in the assessment of disease activity of BD.

Material and methods

A total of 93 patients with BD and 62 age- and gender-matched healthy controls were included in the study. Disease activity was assessed with the BD Current Activity Form (BDCAF) score. Serum levels of calprotectin, high-sensitivity C-reactive protein (hsCRP) and IMA were measured in the patient and control groups.

Results

Serum levels of calprotectin, IMA and hsCRP in patients with BD were higher than those of the healthy control group (p < 0.001 for all). No correlations between calprotectin and IMA, hsCRP, erythrocyte sedimentation rate, CRP, or BDCAF score were found.

Conclusions

As the calprotectin level are increased in BD patients, it could be a candidate biomarker which plays a role in BD pathogenesis.

High expression of S100 calgranulin genes in peripheral blood mononuclear cells from patients with Takayasu arteritis

BACKGROUND

Toll-like receptors (TLR) 1 to 4 are highly expressed in aorta. Activation of TLR4 causes transmural arteritis in Human temporal artery-SCID chimera model. Neither TLR-4 nor its ligands have been studied in TA patients as yet. Aim of this study was to examine the expression of TLR4 and its endogenous ligands in peripheral blood mononuclear cells (PBMCs) of patients with Takayasu arteritis (TA).

METHODS

mRNA expression of TLR4, RAGE and various endogenous TLR4 ligands were quantified in PBMCs of 24 TA patients and 19 sex and age matched healthy controls by real time PCR using specific primers and SYBR Green qPCR master mix. S100A8/A9 and S100A12 were measured in cell culture supernatant of PBMCs from TA patients and healthy controls, both in un-stimulated state as well as, after lipopolysaccharides (LPS) stimulated cultures for 4 h. Expression of S100A8/A9 in aortic tissues was assessed by immunohistochemistry.

RESULTS

The mRNA expression of S100A8, S100A9, S100A12 and TLR4 were higher, while expression of RAGE and HSP70 were lower in TA as compared to healthy controls. Induction with LPS led to increase in secretion of both S100A8/A9 and S100A12 levels in TA as well as healthy controls. The fold of induction, measured by LPS stimulated/unstimulated control was higher in healthy controls [2.88 (1.7-3.53) fold] as compared to TA [1.345 (1-1.82) fold]; p < 0.05. Numerically, S100A8/A9 was also higher in healthy controls [2.04 (1.7-5.6) fold] as compared to TA [1.38 (1.09-3.6) fold], but it didn't reach statistical significance; p = 0.129. Mild to moderate intensity expression of S100A8/A9 protein was noted in aortic tissues from patients with TA.

CONCLUSION

mRNA expression of TLR4 and its ligand S100A8, S100A9, and S100A12 in PBMCs of TA patients was higher as compared to healthy controls. LPS stimulation led to higher induction of S100A12 secretion in healthy controls as compared to TA. Expression of S100A8/A9 was detected in inflamed aortic tissues from patients with TA.

Pleiotropic Anti-Infective Effects of Defensin-Derived Antimicrobial Compounds

We identified low-molecular weight compounds derived from the antimicrobial peptide human neutrophil peptide-1 that bind to Lipid II, an essential precursor of bacterial cell wall biosynthesis. These compounds act as antibacterials on multiple biosynthesis pathways with specificity against gram-positive organisms. Here, we have tested a small subset of our most promising leads against the bacterium Clostridium perfringens and sporozoites of Eimeria tenella, an intracellular protozoan parasite that causes intestinal disease in poultry. We found one compound, 1611-0203 (2-{2,3,5,6-tetrafluoro-4-[2,3,5,6-tetrafluoro-4-(2-hydroxyphenoxy)phenyl]phenoxy}phenol), specifically to inhibit growth of both agents out of all compounds tested. Additionally, compound 1611-0203 inhibits Staphylococcus aureus and Enterococcus spp. Mechanism-of-action studies further reveal that 1611-0203 affects cell wall biosynthesis and inhibits additional biosynthetic pathways. Combined, our results indicate that compounds such as 1611-0203 have therapeutic potential to act as anti-infectives against various organisms simultaneously.

Therapeutic potential of targeting S100A11 in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive tumor with an unfavorable prognosis. The standard therapeutic approaches are limited to surgery, chemotherapy, and radiotherapy. Because the consequent clinical outcome is often unsatisfactory, a different approach in MPM treatment is required. S100A11, a Ca²⁺-binding small protein with two EF-hands, is frequently upregulated in various human cancers. Interestingly, it has been found that intracellular and extracellular S100A11 have different functions in cell viability. In this study, we focused on the impact of extracellular S100A11 in MPM and explored the therapeutic potential of an S100A11-targeting strategy. We examined the secretion level of S100A11 in various kinds of cell lines by enzyme-linked immunosorbent assay. Among them, six out of seven MPM cell lines actively secreted S100A11, whereas normal mesothelial cell lines did not secrete it. To investigate the role of secreted S100A11 in MPM, we inhibited its function by neutralizing S100A11 with an anti-S100A11 antibody. Interestingly, the antibody significantly inhibited the proliferation of S100A11-secreting MPM cells in vitro and in vivo. Microarray analysis revealed that several pathways including genes involved in cell proliferation were negatively enriched in the antibody-treated cell lines. In addition, we examined the secretion level of S100A11 in various types of pleural effusions. We found that the secretion of S100A11 was significantly higher in MPM pleural effusions, compared to others, suggesting the possibility for the use of S100A11 as a biomarker. In conclusion, our results indicate that extracellular S100A11 plays important roles in MPM and may be a therapeutic target in S100A11-secreting MPM.

MicroRNA-145-5p and microRNA-320a encapsulated in endothelial microparticles contribute to the progression of vasculitis in acute Kawasaki Disease

Kawasaki Disease (KD) is an acute inflammatory disease that takes the form of systemic vasculitis. Endothelial microparticles (EMPs) have been recognized as an important transcellular delivery system. We hypothesized whether EMPs are involved in vasculitis in acute KD. Fifty patients with acute KD were enrolled, divided into two subgroups: those with coronary artery lesions (CAL) (n = 5) and those without CAL (NCAL) (n = 45). EMPs were measured using flow cytometry, and microRNA (miR) expression profiling was performed by microRNA array. The percentage of EMPs in acute KD was significantly higher than in controls (P < 0.0001). EMPs in patients with CAL rapidly increased after the initial treatment, and was significantly higher than those in NCAL (P < 0.001). In patients with CAL, we identified 2 specific miRs encapsulated in EMPs, hsa-miR-145-5p and hsa-miR-320a, which are predicted to affect monocyte function using in silico analysis, and were demonstrated to upregulate inflammatory cytokine mRNAs in THP-1 monocytes. In situ hybridization confirmed that hsa-miR-145-5p was preferentially expressed in CAL. EMPs may serve as a sensitive marker for the severity of vasculitis in acute KD. Moreover, these 2 specific miRs encapsulated in EMPs might be involved in inflammatory cytokine regulation and the pathogenesis of vasculitis in acute KD.

Detection of calprotectin in inflammatory bowel disease: Fecal and serum levels and immunohistochemical localization

The aim of the present study was to quantify calprotectin levels using an enzyme-linked immunosorbent assay (ELISA) and a point-of-care test (POCT) in patients with inflammatory bowel disease. Overall, 113 patients with ulcerative colitis (UC; 51 men and 62 women) and 42 patients with Crohn's disease (CD; 29 men and 13 women), who were scheduled to undergo a colonoscopy, were prospectively enrolled and scored endoscopically and clinically. An additional 96 healthy, age-matched subjects served as the normal controls. Feces and blood samples from the patients with UC and CD, and the normal controls were analyzed. These patients had received adequate medical treatment. The tissue distribution of calprotectin was investigated using immunohistochemistry. The fecal calprotectin levels, as measured using an ELISA, were correlated with the endoscopic and clinical disease activities and laboratory parameters, including serum levels of hemoglobin (Hb), albumin and C-reactive protein, and erythrocyte sedimentation rate, particularly among the patients with UC. The fecal Hb level was close to that of the fecal calprotectin level (r=0.57; P<0.0001). The fecal calprotectin level measured using an ELISA was well-correlated with the fecal calprotectin level measured using the POCT (r=0.81; P<0.0001), but was not correlated with the serum calprotectin level (r=0.1013; P=0.47). An immunohistochemical investigation revealed that patients with both UC and CD had higher neutrophil and monocyte/macrophage calprotectin-positive cell expression levels, compared with those in the normal controls. Fecal calprotectin was considered a reliable marker for disease activity, and the assessment of fecal calprotectin via POCT showed potential as a rapid and simple measurement in clinical settings.

Association of Serum Calprotectin (S100A8/A9) Level With Disease Relapse in Proteinase 3-Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

OBJECTIVE

S100A8/A9 (calprotectin) has shown promise as a biomarker for predicting relapse in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This study was undertaken to investigate serum S100A8/A9 level as a biomarker for predicting future relapse in a large cohort of patients with severe AAV.

METHODS

Serum levels of S100A8/A9 were measured at baseline and months 1, 2, and 6 following treatment initiation in 144 patients in the Rituximab in ANCA-Associated Vasculitis trial (cyclophosphamide/azathioprine versus rituximab [RTX] for induction of remission) in whom complete remission was attained.

RESULTS

Patients were divided into 4 groups: proteinase 3 (PR3)-ANCA with relapse (n = 37), PR3-ANCA without relapse (n = 56), myeloperoxidase (MPO)-ANCA with relapse (n = 6), and MPO-ANCA without relapse (n = 45). Serum S100A8/A9 level decreased in all groups during the first 6 months of treatment. The percentage reduction from baseline to month 2 was significantly different between patients who experienced a relapse and those who did not in the PR3-ANCA group (P = 0.046). A significantly higher risk of relapse was associated with an increase in S100A8/A9 level between baseline and month 2 (P = 0.0043) and baseline and month 6 (P = 0.0029). Subgroup analysis demonstrated that patients treated with RTX who had increased levels of S100A8/A9 were at greatest risk of future relapse (P = 0.028).

CONCLUSION

An increase in serum S100A8/A9 level by month 2 or 6 compared to baseline identifies a subgroup of PR3-ANCA patients treated with RTX who are at higher risk of relapse by 18 months. Since RTX is increasingly used for remission induction in PR3-ANCA-positive patients experiencing a relapse, S100A8/A9 level may assist in identifying those patients requiring more intensive or prolonged treatment.

Calprotectin in rheumatic diseases: a review

Calprotectin also known as MRP8/14 or S100A8/A9 is a heterodimeric complex of two S100 calcium-binding proteins: myeloid-related protein 8 (MRP-8 or S100A8) and MRP-14 (or S100A9). At present, according to many authors, it is considered that calprotectin MRP8/14 is a potentially more sensitive biomarker of disease activity in rheumatoid disease than conventional inflammatory indices such as the erythrocyte sedimentation rate, C-reactive protein and others. A review of the literature on concentration of calprotectin in patients with some rheumatic diseases (rheumatoid arthritis, juvenile idiopathic arthritis, adult-onset Still's disease, systemic vasculitis, polymyalgia rheumatica, ankylosis spondylitis, systemic lupus erythematosus, and primary Sjögren's syndrome) is presented.

Serum myeloid-related protein 8/14 in minimal change- and glomerulonephritis-related nephrotic syndrome

BACKGROUND

Myeloid-related protein 8/14 (MRP8/14) forms stable heterodimers and is the major calcium-binding protein secreted by activated granulocytes and monocytes. We evaluated whether serum MRP8/14 level is a useful indicator for a differential diagnosis of glomerulonephritis (GN)- and minimal change disease (MC)- related nephrotic syndrome (NS).

METHODS

Serum MRP8/14 complex was evaluated in 37 NS patients with MC or GN. These patients were divided into two groups. Group 1 consisted of 13 NS patients with MC, and group 2 consisted of 24 NS patients with GN. Group 2 was further divided into four subgroups: IgA nephropathy (IgAN; n = 5), Henoch-Schönlein purpura nephritis (HSPN; n = 6), focal segmental glomerulosclerosis (FSGS; n = 12), and acute GN Poststreptococcal acute glomeruloNephritis (PSAGN; n = 1).

RESULTS

The clinical manifestations, laboratory findings, serum MRP8/14 level, and renal accumulation of MRP8 were investigated for each group. No significant inter-group differences were observed for serum total protein, serum albumin, or blood urea nitrogen and urinary protein excretions. Mean serum MRP8/14 in the IgAN, HSPN, FSGS, and PSAGN groups was higher than in group 1. Further, the mean glomerular and interstitial MRP8 staining scores in the IgAN, HSPN, and PSAGN groups were higher than in group 1.

CONCLUSIONS

Serum MRP8/14 level may be a useful indicator for differential diagnosis between GN- and MC- related NS.

MicroRNA-93 may control vascular endothelial growth factor A in circulating peripheral blood mononuclear cells in acute Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is the most common systemic vasculitis syndrome primarily affecting medium-sized arteries, particularly the coronary arteries. Though KD may be associated with immunological problems, the involvement of microRNAs (miRs) has not been fully described.

METHODS

We enrolled 23 KD patients and 12 controls. We performed miR and mRNA microarray analysis of peripheral blood mononuclear cells (PBMCs) isolated from acute KD patients and controls. Continuously, we measured specific miRs, mRNA and the expression of proteins by using reverse-transcriptase PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA).

RESULTS

We identified strikingly high levels of miR-182 and miR-296-5p during the acute febrile phase, and of miR-93, miR-145-5p, miR-145-3p, and miR-150-3p in the defervescence stage, especially in refractory KD patients. The expression of vascular endothelial growth factor A (VEGFA) mRNA, previously reported to be controlled by miR-93, was significantly elevated during the febrile phase and normalized upon treatment, negatively correlating with the expression of miR-93. Further, plasma levels of VEGF-A correlated with PBMC VEGFA mRNA expression.

CONCLUSION

Several miRs are highly specific to the acute phase of KD, and may participate in regulating the expression of genes in pathways associated with KD. In particular, miR-93 may participate in regulating expression of VEGF-A and contribute to the pathogenesis of arteritis in acute KD.

Calprotectin: Clinical Applications in Pediatrics

As seen over the past 20 years, calprotectin has evolved as a novel, non-invasive biomarker of gastrointestinal (GI) inflammation. We present this review of calprotectin in pediatrics. This article will focus on studies using calprotectin concentrations from different body fluids to monitor inflammation in different disease states and conditions. The ultimate goal of our group is to lay down a foundation as we consider using calprotectin prospectively as a marker of intestinal inflammation that could lead to further testing and possibly a marker of preparedness for feeding. We surveyed all published studies in English of calprotectin in neonates, infants, children, and adolescents through February 2014. We will discuss calprotectin's basic properties and analysis such as characteristics, identification, presence in body fluids, and maturational development. In addition, calprotectin's use in inflammatory diseases exploring both GI and non-GI conditions will be evaluated and compared with other serum markers presently available. Finally, a summary of our findings and discussion of future work that could be undertaken in order to render calprotectin as a more useful monitoring tool to the medical research community will complete the review.

Current and novel biomarkers in anti-neutrophil cytoplasm-associated vasculitis

Anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) is characterized by a variable disease course, with up to 50% of patients having one relapse within 5 years and many progressing to end-stage organ damage despite modern treatment strategies. Moreover, complications arising from treatment dominate the causes of mortality and morbidity both early and late during disease, especially in the elderly and those with severe renal involvement, and there is additional uncertainty as to how long treatment should be continued. There is, therefore, an urgent clinical need to identify robust biomarkers to better predict treatment responses, risk of disease relapse and eventual complete clinical and immunological quiescence. To date, no such biomarkers exist, but better understanding of disease pathogenesis and the underlying immune dysfunction has provided some potential candidates linked to the discovery of new antibodies, different leukocyte activation states, the role of the alternative complement pathway and markers of vascular activation. With all promising new biomarkers, there is the need to rapidly replicate and validate early findings using large biobanks of samples that could be brought together by leaders in the field.

Cardiovascular status after Kawasaki disease in the UK

OBJECTIVE

Kawasaki disease (KD) is an acute vasculitis that causes coronary artery aneurysms (CAA) in young children. Previous studies have emphasised poor long-term outcomes for those with severe CAA. Little is known about the fate of those without CAA or patients with regressed CAA. We aimed to study long-term cardiovascular status after KD by examining the relationship between coronary artery (CA) status, endothelial injury, systemic inflammatory markers, cardiovascular risk factors (CRF), pulse-wave velocity (PWV) and carotid intima media thickness (cIMT) after KD.

METHODS

Circulating endothelial cells (CECs), endothelial microparticles (EMPs), soluble cell-adhesion molecules cytokines, CRF, PWV and cIMT were compared between patients with KD and healthy controls (HC). CA status of the patients with KD was classified as CAA present (CAA+) or absent (CAA-) according to their worst-ever CA status. Data are median (range).

RESULTS

Ninety-two KD subjects were studied, aged 11.9 years (4.3-32.2), 8.3 years (1.0-30.7) from KD diagnosis. 54 (59%) were CAA-, and 38 (41%) were CAA+. There were 51 demographically similar HC. Patients with KD had higher CECs than HC (p=0.00003), most evident in the CAA+ group (p=0.00009), but also higher in the CAA- group than HC (p=0.0010). Patients with persistent CAA had the highest CECs, but even those with regressed CAA had higher CECs than HC (p=0.011). CD105 EMPs were also higher in the KD group versus HC (p=0.04), particularly in the CAA+ group (p=0.02), with similar findings for soluble vascular cell adhesion molecule 1 and soluble intercellular adhesion molecule 1. There was no difference in PWV, cIMT, CRF or in markers of systemic inflammation in the patients with KD (CAA+ or CAA-) compared with HC.

CONCLUSIONS

Markers of endothelial injury persist for years after KD, including in a subset of patients without CAA.

Elevated serum levels of calprotectin (MRP8/MRP14) in patients with Behçet's disease and its association with disease activity and quality of life

BACKGROUND

Behçet's disease (BD) is an inflammatory disease with multisystem chronic vasculitis. The disease is characterized by attacks of oral and genital ulcerations, skin lesions, arthritis, uveitis and deep vein thrombosis. The main histopathological feature is known to be vascular inflammatory change. Calprotectin (MRP8/MRP14) has been identified as an important alarmin that is expressed by activated phagocytes, granulocytes, monocytes and vascular endothelial cells, recognized by toll-like receptors, and induces a thrombogenic and inflammatory response in human microvascular endothelial cells.

AIM

We aimed to investigate the serum levels of calprotectin in patients with BD and its association with disease activity and quality of life.

MATERIALS AND METHODS

Forty-eight patients (25 males and 23 females) and 47 healthy controls (29 males and 18 females) were included to study. BD Current Activity Form (BDCAF) was used to assess the disease activity of patients with BD. Quality of life was assessed by using the Nottingham Health Profile (NHP). Depression and anxiety symptoms were assessed by using the Hospital Anxiety and Depression Scale (HADS). Serum level of calprotectin was determined using an ELISA kit. Results. Serum levels of calprotectin was significantly higher in patients with BD compared to healthy controls (p = 0.001). Serum levels of calprotectin did not correlate with the sores of BDCAF, NHP and HADS.

CONCLUSION

Calprotectin may play a significant role in the pathogenetic mechanisms of BD. Further insight into this area of research might provide opportunities to develop novel treatment strategies.

S100A1 is released from ischemic cardiomyocytes and signals myocardial damage via Toll-like receptor 4

Members of the S100 protein family have been reported to function as endogenous danger signals (alarmins) playing an active role in tissue inflammation and repair when released from necrotic cells. Here, we investigated the role of S100A1, the S100 isoform with highest abundance in cardiomyocytes, when released from damaged cardiomyocytes during myocardial infarction (MI). Patients with acute MI showed significantly increased S100A1 serum levels. Experimental MI in mice induced comparable S100A1 release. S100A1 internalization was observed in cardiac fibroblasts (CFs) adjacent to damaged cardiomyocytes. In vitro analyses revealed exclusive S100A1 endocytosis by CFs, followed by Toll-like receptor 4 (TLR4)-dependent activation of MAP kinases and NF-κB. CFs exposed to S100A1 assumed an immunomodulatory and anti-fibrotic phenotype characterized i.e. by enhanced intercellular adhesion molecule-1 (ICAM1) and decreased collagen levels. In mice, intracardiac S100A1 injection recapitulated these transcriptional changes. Moreover, antibody-mediated neutralization of S100A1 enlarged infarct size and worsened left ventricular functional performance post-MI. Our study demonstrates alarmin properties for S100A1 from necrotic cardiomyocytes. However, the potentially beneficial role of extracellular S100A1 in MI-related inflammation and repair warrants further investigation.

The role of calprotectin in pediatric disease

Calprotectin (CP) is a calcium- and zinc-binding protein of the S100 family expressed mainly by neutrophils with important extracellular activity. The aim of the current review is to summarize the latest findings concerning the role of CP in a diverse range of inflammatory and noninflammatory conditions among children. Increasing evidence suggests the implication of CP in the diagnosis, followup, assessment of relapses, and response to treatment in pediatric pathological conditions, such as inflammatory bowel disease, necrotizing enterocolitis, celiac disease, intestinal cystic fibrosis, acute appendicitis, juvenile idiopathic arthritis, Kawasaki disease, polymyositis-dermatomyositis, glomerulonephritis, IgA nephropathy, malaria, HIV infection, hyperzincemia and hypercalprotectinemia, and cancer. Further studies are required to provide insights into the actual role of CP in these pathological processes in pediatrics.

Myeloid related protein induces muscle derived inflammatory mediators in juvenile dermatomyositis

Introduction

The aetiopathogenesis of juvenile dermatomyositis (JDM) remains poorly understood. In particular the contribution of monocytes or macrophages, which are frequently observed to be an infiltrate within muscle tissue very early in the disease process, is unknown. We hypothesised that these cells secrete the pro-inflammatory myeloid related protein (MRP) 8/14 which may then contribute to muscle pathology in JDM.

Methods

In this study of 56 JDM patients, serum MRP8/14 levels were compared with clinical measures of disease activity. Muscle biopsies taken early in disease were assessed by immunohistochemistry to determine the frequency and identity of MRP-expressing cells. The effects of MRP stimulation and endoplasmic reticulum (ER) stress on muscle were tested in vitro. Serum or supernatant levels of cytokines were analyzed by multiplex immunoassay.

Results

Serum MRP8/14 correlated with physician’s global assessment of disease activity in JDM (R = 0.65, p = 0.0003) and muscle strength/endurance, childhood myositis assessment score (CMAS, R = −0.55, p = 0.004). MRP8/14 was widely expressed by CD68+ macrophages in JDM muscle tissue. When cultured with human myoblasts, MRP8 led to the secretion of MCP-1 and IL-6, which was enhanced by ER stress. Both inflammatory mediators were detected in significantly higher levels in the serum of JDM patients compared to healthy controls.

Conclusions

This study is the first to identify serum MRP8/14 as a potential biomarker for disease activity in JDM. We propose that tissue infiltrating macrophages secreting MRP8/14 may contribute to myositis, by driving the local production of cytokines directly from muscle.

HLA class III genes involvement in Kawasaki disease: a case-control study in Caucasian population

Kawasaki disease (KD) is an acute, multisystemic, febrile vasculitis of unknown aetiology, which affects young children mainly under 5 years of age. The clinical variability has until now prevented to decrypt KD aetiological factors. Recently, the importance of genetics and the pivotal role of the immune system have emerged. To investigate in this direction, genomic DNA from 74 Caucasian KD cases and 440 healthy controls has been analysed to characterize functional polymorphisms of relevant HLA class III genes: AGER -429 and -374, TNF -857, -308 and -238, HSPA1A +190, HSPA1B +1267 and HSPA1L +2437. Allele, genotype and haplotype frequencies were therefore compared with the chi-squared test and Fisher's exact test. Our data showed significant deviations between patients with Kawasaki disease and controls concerning the TNF -308 polymorphism genotype (GG: P = 0.0449) and allele (G,A: P = 0.0433) and -238 polymorphism genotype frequencies (AA: P = 0.0351). Moreover, we found differences concerning the HSPA1A +190 polymorphism (GC: P = 0.0317) and the HSPA1L +2437 polymorphism (TT: P = 0.0072; TC: P = 0.0250; T: P = 0.0037; C: P = 0.0037). The calculation of TNF -238 and HSPA1L haplotype frequencies also pointed out a statistically significant decrease in patients of CG haplotype (P = 0.0001), which could have a role in protecting from the inflammatory processes that characterize the disease progression. The results obtained point to a possible involvement of the entire HLA class III region in KD susceptibility.

Leukocyte and serum S100A8/S100A9 expression reflects disease activity in ANCA-associated vasculitis and glomerulonephritis

Antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) commonly results in glomerulonephritis, in which neutrophils and monocytes have important roles. The heterodimer calprotectin (S100A8/S100A9, mrp8/14) is a Toll-like receptor-4 ligand found in neutrophils and monocytes and is elevated in inflammatory conditions. By immunohistochemistry of renal biopsies, patients with focal or crescentic glomerular lesions were found to have the highest expression of calprotectin and those with sclerotic the least. Serum levels of calprotectin as measured by ELISA were elevated in patients with active AAV and the levels decreased but did not normalize during remission, suggesting subclinical inflammation. Calprotectin levels in patients with limited systemic disease increased following treatment withdrawal and were significantly elevated in patients who relapsed compared with those who did not. As assessed by flow cytometry, patients with AAV had higher monocyte and neutrophil cell surface calprotectin expression than healthy controls, but this was not associated with augmented mRNA expression in CD14(+) monocytes or CD16(+) neutrophils. Thus, serum calprotectin is a potential disease biomarker in patients with AAV, and may have a role in disease pathogenesis.

Management of acute and refractory Kawasaki disease

Acute Kawasaki disease (KD) is treated with high-dose intravenous immunoglobulin (IVIG), which is proven to decrease the incidence of coronary artery aneurysms from 25% to less than 5%. Aspirin is also given, although the evidence base is less secure. There is increasing evidence for steroid therapy as adjunctive primary therapy with IVIG, especially in Asian children. Approximately 10-30% of patients fail to respond to the initial IVIG and are at increased risk of coronary artery aneurysms. The optimal treatment for IVIG-nonresponsive KD remains controversial. Management options include further dose(s) of IVIG, corticosteroids, TNF-α blockade, cyclosporin A, anti-IL-1 and anti-CD20 therapy. In this article, the authors review the current evidence for treatment of acute KD and discuss options for IVIG nonresponders.

Primary and secondary central nervous system vasculitis

Central nervous system vasculitis is an increasingly recognized inflammatory brain disease causing devastating neurological deficits and psychiatric manifestations in previously healthy children. Primary central nervous system vasculitis represents an isolated inflammatory attack targeting the cerebral vessels. In contrast, in children with secondary central nervous system vasculitis, an underlying condition can be identified. The spectrum of childhood primary and secondary central nervous system vasculitis is rapidly expanding, as is the differential diagnosis including nonvasculitic inflammatory brain diseases and noninflammatory vasculopathies. Early recognition, rapid diagnostic evaluation, and initiation of treatment have led to improved morbidity and mortality. This review focuses on clinical, laboratory, and neuroimaging characteristics of the distinct subtypes of primary childhood central nervous system vasculitis, reports the etiology of secondary central nervous system vasculitis, provides an overview of the differential diagnosis, and reviews the current approaches in treatment.

Increased percentages of tumor necrosis factor-alpha+/interferon-gamma+ T [corrected] lymphocytes and calprotectin+/tumor necrosis factor-alpha+ monocytes in patients with acute Kawasaki disease

In vivo exposure to microorganisms resident in the oral cavity is considered as a possible cause of Kawasaki disease (KD), and some epitopes derived from streptococci display homology with Factor H of Complement. Additionally, calprotectin, a major calcium binding protein released by neutrophils and activated monocytes, could be directly involved in endothelial damage occurring in KD. The aim of our study is to evaluate the percentages of IFN-gamma+ and/or TNF-alpha+ lymphocytes and double positive calprotectin/TNF-alpha monocytes (CD14+) after in vitro stimulation with streptococcal- and/or Factor H-derived peptides, in patients with acute KD. Peripheral Blood Mononuclear Cells (PBMCs) obtained from KD patients and febrile controls were stimulated in vitro with peptides. After culture, cells were collected, stained with fluorochrome-labelled monoclonal antibodies against CD3, CD14, calprotectin, IFN-gamma and TNF-alpha, and cytofluorimetric analyses were performed. Our results showed increased percentages of TNF-alpha+/IFN-gamma+ lymphocytes in KD patients in respect to controls when PBMCs were stimulated with streptococcal or Factor H-derived epitopes. In addition, also calprotectin+/TNF-alpha+ monocytes from KD patients were activated after PBMC in vitro stimulation. These findings lead us to speculate that some peptides, derived from oral streptococci and cross-reactive with the human Factor H of Complement, could induce lymphocyte and monocyte activation potentially involved in the pathogenesis of KD. Our results should be confirmed by further studies enrolling more patients and controls than those analyzed in our study.

In vivo targeting of inflammation-associated myeloid-related protein 8/14 via gadolinium immunonanoparticles

OBJECTIVE

Myeloid-related protein (Mrp) 8/14 complex (is a highly expressed extracellularly secreted protein, implicated in atherosclerosis. In this study, we evaluated the feasibility of targeting Mrp in vivo through synthetic immuno-nanoprobes.

METHODS AND RESULTS

Anti-Mrp-14 and nonspecific IgG-conjugated gadolinium nanoprobes (aMrp-) were synthesized and characterized. Pharmacokinetics and vascular targeting via MRI of the formulations were assessed in vivo in high fat-fed apolipoprotein E deficient (ApoE(-/-)), ApoE(-/-)/Mrp14(-/-) (double knockout) and chow-fed wild-type (C57BL/6) mice. Bone marrow-derived myeloid progenitor cells were isolated from both ApoE(-/-) and double knockout mice, differentiated to macrophages, and were treated with LPS, with or without Mrp8, Mrp14, or Mrp8/14; conditioned media was used for in vitro studies. Mrp-activated cells secreted significant amounts of proinflammatory cytokines, which was abolished by pretreatment with aMrp-NP. We show in vitro that aMrp-NP binds endothelial cells previously treated with conditioned media containing Mrp8/14. MRI following intravenous delivery of aMrp-NP revealed prolonged and substantial delineation of plaque in ApoE(-/-) but not double knockout or wild-type animals. Nonspecific IgG-conjugated gadolinium nanoprobe-injected animals in all groups did not show vessel wall enhancement. Flow-cytometric analysis of aortic digesta revealed that aMrp-NP present in Ly-6G(+), CD11b(+), CD11c(+), and CD31(+) cells in ApoE(-/-) but not in double knockout animals.

CONCLUSIONS

Targeted imaging with aMrp-NP demonstrates enhancement of plaque with binding to inflammatory cells and reduction in inflammation. This strategy has promise as a theranostic approach for atherosclerosis.

The role of serum myeloid-related protein 8/14 complex in Henoch-Schönlein purpura nephritis

Myeloid-related protein (MRP) 8/14 complex is a marker of monocyte and neutrophil activation. We evaluated whether serum MRP8/14 complex is associated with clinical manifestations and pathological findings of Henoch-Schönlein purpura nephritis (HSPN). Patients were divided into two groups based on serum MRP8/14 complex levels at renal biopsy. Group 1 consisted of 18 HSPN patients with less than median (670 ng/ml) MRP8/14 complex levels, and Group 2 of 12 HSPN patients with greater than median levels. Clinical manifestations, laboratory findings and serum E-selectin levels, as a marker of vascular endothelial cell dysfunction, as well as histological and immunohistochemical findings were investigated for both groups. We also measured MRP8/14 complex levels in disease control and healthy control children. Urinary protein excretions, serum MRP8/14 complex levels, and serum E-selectin levels were all higher in Group 2 than in Group 1 patients. Serum MRP8/14 complex levels were higher in HSPN patients than in controls. Serum MRP8/14 complex levels were strongly associated with serum E-selectin levels. Pathological findings revealed that the proportions of patients with ISKDC grades III, IV and V in Group 2 were higher than in Group 1. Our findings suggest that serum MRP8/14 complex levels might be associated with the severity of renal injury and endothelial cell dysfunction in HSPN patients.

Human eosinophils express RAGE, produce RAGE ligands, exhibit PKC-delta phosphorylation and enhanced viability in response to the RAGE ligand, S100B

This study tested the hypothesis that human eosinophils produce ligands for the receptor for advanced glycation end-products (RAGE), express RAGE and exhibit RAGE-mediated responses. In examining our microarray data, we identified the presence of RAGE and RAGE ligand (S100A4, S100A6, S100A8, S100A9, S100A11, S100P, HMGB1) transcripts. Expression of eosinophil RAGE mRNA was also compared with a known positive control and further assessed via bioinformatics and sequence analysis of RAGE cDNA. Positive and negative controls were used to identify RAGE, S100A8 and S100A9 protein in human primary eosinophils. Immunoblot assessment of eosinophils treated with cytokines (IL-5 or granulocyte macrophage colony-stimulating factor) indicated an up-regulation of S100A8 and S100A9 production, whereas co-treatment of eosinophils with a RAGE ligand and cytokines displayed a down-regulation in the levels of RAGE. Analysis of eosinophil-conditioned media revealed that eosinophils are capable of releasing RAGE, S100A8 and S100A9. To test the eosinophil response to RAGE activation, the most well-characterized RAGE ligand, S100B, was examined. Treatment of eosinophils with S100B resulted in RAGE-mediated PKC-delta phosphorylation, a 3-fold dose-dependent increase in cell survival and an increase in the level of cellular RAGE. Combined, these studies reveal eosinophil expression of RAGE, RAGE ligands and RAGE-mediated responses. The expression of eosinophil RAGE, soluble RAGE and RAGE ligands may be pivotal to the functions of eosinophils in various human diseases involving RAGE and S100 ligands.

Transcript abundance patterns in Kawasaki disease patients with intravenous immunoglobulin resistance

Intravenous immunoglobulin (IVIG)-resistant Kawasaki disease (KD) patients comprise at least 20% of treated patients and are at high risk for coronary artery abnormalities. If identified early in the course of the disease, such patients may benefit from additional anti-inflammatory therapy. The aim of this study was to compare the transcript abundance between IVIG resistant and -responsive KD patients, to identify biomarkers that might differentiate between these two groups and to generate new targets for therapies in IVIG resistant KD patients. We compared the transcript abundance profiles of whole-blood RNA on Agilent arrays from acute and convalescent KD subjects and age-similar, healthy controls. KD subjects were stratified as IVIG resistant or -responsive based on response to initial IVIG therapy. Transcript abundance was higher for IL-1 pathway genes (IL-1 receptor, interleukin receptor associated kinase, p38 mitogen-activated protein kinase), and MMP-8. These findings point to candidate biomarkers that may predict IVIG resistance in acute KD patients. The results also underscore the importance of the IL-1 pathway as a mediator of inflammation in KD and suggest that IL-1 or its receptor may be reasonable targets for therapy, particularly for IVIG resistant patients.

A systematic review and meta-analysis of tumor necrosis factor α-308 polymorphism and Kawasaki disease

BACKGROUND

There have been genetic studies assessing the association between tumor necrosis factor (TNF)-α-308 and Kawasaki disease (KD) but the results have been conflicting due to lack of power. Therefore, a systematic review and meta-analysis was conducted to increase the power for identifying the association between the TNF-α-308 polymorphism and KD.

METHOD

Studies were identified from MEDLINE and EMBASE databases and were included if the subjects were children and the frequencies between TNF-α-308 and KD were reported. Data were pooled using a random effect model if heterogeneity between studies was present.

RESULTS

Thirteen studies were identified however only six studies were included. The pooled prevalence of minor A allele was 5.2% (95% confidence interval [CI]: 0.1%-9.5%). Gene effect was assessed using per-allele and per-genotype approaches. The pooled odds ratio of G versus A with the random effect model was 1.13 (95%CI: 0.34-3.27). The genotype effects for GG versus GA+AA was estimated and the pooled odds ratio was 1.08 (95%CI: 0.42-2.92).

CONCLUSION

This review suggests a trend of association between the TNF-α-308 G-allele and KD. However, the gene effects are heterogeneous and assessing sources of heterogeneity are limited. An updated meta-analysis is needed if more studies are published.