Sustained activation of neutrophils in the course of Kawasaki disease: an association with matrix metalloproteinases

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.

Novel predictors of intravenous immunoglobulin resistance in patients with Kawasaki disease: a retrospective study

Objective

The aim of this study was to investigate the predictive value of systemic immune inflammation index (SII), systemic inflammatory response index (SIRI), and pan-immune inflammation value (PIV) in predicting intravenous immunoglobulin (IVIG) resistance in children diagnosed with Kawasaki disease (KD).

Methods

The clinical data of pediatric patients diagnosed with Kawasaki disease and admitted to our hospital between January 2006 and December 2022 were retrospectively analyzed.

Results

In total, 771 children diagnosed with KD were included in this study, 86 (11.2%) of whom were diagnosed with IVIG resistance. The correlation between SII, SIRI, PIV and IVIG resistance was evaluated using univariate testing, binary logistic regression analysis, and receiver operating characteristic (ROC) curve analysis. Our study found that the SII, SIRI, and PIV were independent risk factors (p=0.001, p<0.001, and p=0.02, respectively). The area under the ROC curve (AUC) values of the SII, SIRI, and PIV were 0.626 (95% confidence interval (CI): 0.553-0.698, p<0.001), 0.571 (95% CI: 0.500-0.642, p=0.032), and 0.568 (95% CI: 0.495-0.641, p=0.040), respectively, and the cutoff values were 2209.66, 3.77, and 1387.825, respectively.

Conclusion

The SII, SIRI, and PIV have potential value in predicting IVIG resistance in patients with KD.

Long-term cardiovascular inflammation and fibrosis in a murine model of vasculitis induced by Lactobacillus casei cell wall extract

Background

Kawasaki disease (KD), an acute febrile illness and systemic vasculitis, is the leading cause of acquired heart disease in children in industrialized countries. KD leads to the development of coronary artery aneurysms (CAA) in affected children, which may persist for months and even years after the acute phase of the disease. There is an unmet need to characterize the immune and pathological mechanisms of the long-term complications of KD.

Methods

We examined cardiovascular complications in the Lactobacillus casei cell wall extract (LCWE) mouse model of KD-like vasculitis over 4 months. The long-term immune, pathological, and functional changes occurring in cardiovascular lesions were characterized by histological examination, flow cytometric analysis, immunofluorescent staining of cardiovascular tissues, and transthoracic echocardiogram.

Results

CAA and abdominal aorta dilations were detected up to 16 weeks following LCWE injection and initiation of acute vasculitis. We observed alterations in the composition of circulating immune cell profiles, such as increased monocyte frequencies in the acute phase of the disease and higher counts of neutrophils. We determined a positive correlation between circulating neutrophil and inflammatory monocyte counts and the severity of cardiovascular lesions early after LCWE injection. LCWE-induced KD-like vasculitis was associated with myocarditis and myocardial dysfunction, characterized by diminished ejection fraction and left ventricular remodeling, which worsened over time. We observed extensive fibrosis within the inflamed cardiac tissue early in the disease and myocardial fibrosis in later stages.

Conclusion

Our findings indicate that increased circulating neutrophil counts in the acute phase are a reliable predictor of cardiovascular inflammation severity in LCWE-injected mice. Furthermore, long-term cardiac complications stemming from inflammatory cell infiltrations in the aortic root and coronary arteries, myocardial dysfunction, and myocardial fibrosis persist over long periods and are still detected up to 16 weeks after LCWE injection.

The Systemic Immune-Inflammation Index (SII) and coronary artery lesions in Kawasaki disease

Coronary artery lesions (CALs) are the most common complications of Kawasaki disease (KD) and play a crucial role in determining the prognosis of the disease. Consequently, the early identification of children with KD who are at risk of developing coronary artery damage is vitally important. We sought to investigate the relationship between the Systemic Immune-Inflammation Index (SII) and CALs in patients with KD and to assess its predictive value. We carried out a retrospective review and analysis of medical records for KD patients treated at the First Affiliated Hospital of Anhui Medical University between January 2017 and January 2023. We utilized single-variable tests, binary logistic regression analysis, ROC curve analysis, restricted cubic spline tests, and curve fitting to evaluate the association between SII and CALs. In our study, 364 patients were included, with 63 (17.3%) presenting with CALs at the time of admission. The binary logistic regression analysis indicated that SII was a significant risk factor for CALs at admission, evident in both unadjusted and models adjusted for confounders. The ROC curve analysis revealed an AUC (Area Under the Curve) value of 0.789 (95%CI 0.723-0.855, P < 0.001) for SII's predictive ability regarding CALs at admission. A consistent positive linear relationship between SII and the risk of CALs at admission was observed in both the raw and adjusted models. Our research findings suggest that SII serves as a risk factor for CALs and can be used as an auxiliary laboratory biomarker for predicting CALs.

Predicting immunoglobulin resistance in Kawasaki disease: an assessment of neutrophil to lymphocyte platelet ratio

BACKGROUND

Kawasaki disease (KD) is an acute febrile illness of unknown etiology and predictors for intravenous immunoglobulin (IVIG) resistance have been widely explored in recent decades. Neutrophil to lymphocyte platelet ratio (NLPR) was reported to be associated with the outcomes in many diseases. However, its relationship with IVIG resistance has not be explored.

METHODS

The medical data of patients diagnosed with KD in Children's Hospital of Soochow University between January 2019 and December 2020 were retrospectively reviewed and analyzed. Patients were trisected into three groups based on NLPR. Logistics regression was used to analyze the association between NLPR and IVIG resistance. Restricted cubic spine was used to exhibit the relationship. Sensitivity analysis and subgroup analysis were also carried out.

RESULTS

A total of 803 patients were included in the present study (61.8% males; median age: 24 months). IVIG resistance occurred in 74 (9.2%) patients. Multivariable-adjusted analyses revealed higher NLPR (odds ratio [95% confidence interval]: 1.12 [1.00-1.24]) was an independent predictor of IVIG resistance, which was strengthened by sensitivity analyses. The association of NLPR and IVIG resistance was not modified by age, sex, CALs, or days of IVIG initiation ≤ 4.

CONCLUSION

NLPR may be a valuable prognostic marker in KD patients with IVIG resistance.

The neutrophil: A key resourceful agent in immune‐mediated vasculitis

The term "vasculitis" refers to a group of rare immune-mediated diseases characterized by the dysregulated immune system attacking blood vessels located in any organ of the body, including the skin, lungs, and kidneys. Vasculitides are classified according to the size of the vessel that is affected. Although this observation is not specific to small-, medium-, or large-vessel vasculitides, patients show a high circulating neutrophil-to-lymphocyte ratio, suggesting the direct or indirect involvement of neutrophils in these diseases. As first responders to infection or inflammation, neutrophils release cytotoxic mediators, including reactive oxygen species, proteases, and neutrophil extracellular traps. If not controlled, this dangerous arsenal can injure the vascular system, which acts as the main transport route for neutrophils, thereby amplifying the initial inflammatory stimulus and the recruitment of immune cells. This review highlights the ability of neutrophils to "set the tone" for immune cells and other cells in the vessel wall. Considering both their long-established and newly described roles, we extend their functions far beyond their direct host-damaging potential. We also review the roles of neutrophils in various types of primary vasculitis, including immune complex vasculitis, anti-neutrophil cytoplasmic antibody-associated vasculitis, polyarteritis nodosa, Kawasaki disease, giant cell arteritis, Takayasu arteritis, and Behçet's disease.

Severe COVID-19 Shares a Common Neutrophil Activation Signature with Other Acute Inflammatory States

Severe COVID-19 patients present a clinical and laboratory overlap with other hyperinflammatory conditions such as hemophagocytic lymphohistiocytosis (HLH). However, the underlying mechanisms of these conditions remain to be explored. Here, we investigated the transcriptome of 1596 individuals, including patients with COVID-19 in comparison to healthy controls, other acute inflammatory states (HLH, multisystem inflammatory syndrome in children [MIS-C], Kawasaki disease [KD]), and different respiratory infections (seasonal coronavirus, influenza, bacterial pneumonia). We observed that COVID-19 and HLH share immunological pathways (cytokine/chemokine signaling and neutrophil-mediated immune responses), including gene signatures that stratify COVID-19 patients admitted to the intensive care unit (ICU) and COVID-19_nonICU patients. Of note, among the common differentially expressed genes (DEG), there is a cluster of neutrophil-associated genes that reflects a generalized hyperinflammatory state since it is also dysregulated in patients with KD and bacterial pneumonia. These genes are dysregulated at the protein level across several COVID-19 studies and form an interconnected network with differentially expressed plasma proteins that point to neutrophil hyperactivation in COVID-19 patients admitted to the intensive care unit. scRNAseq analysis indicated that these genes are specifically upregulated across different leukocyte populations, including lymphocyte subsets and immature neutrophils. Artificial intelligence modeling confirmed the strong association of these genes with COVID-19 severity. Thus, our work indicates putative therapeutic pathways for intervention.

Blood routine risk factors for coronary artery aneurysm in infants younger than 8 months with Kawasaki disease

Objective

The aims of this study were to characterize the evolution of routine blood values within the first 10 days of illness and coronary artery outcome in infants < 8 months with Kawasaki disease (KD) and to identify risk factors for coronary artery aneurysm (CAA).

Methods

Laboratory data, clinical features and coronary artery outcomes from 78 infants < 8 months old and 86 patients between 8 months and 7 years old were retrospectively analyzed. Logistic regression analysis was conducted to evaluate the potential risk factors for CAA.

Results

Infants < 8 months old were more likely to present with incomplete KD (37.2% vs 4.7%, P < 0.001), erythema and induration at the BCG inoculation site (24.4% vs 3.5%, P < 0.001) and CAA (47.4% vs 15.1%, P < 0.001) even with timely diagnosis and treatment with intravenous immunoglobulin (IVIG) compared with patients ≥8 months old. Clinical feature related to diagnostic criteria for KD including bilateral conjunctival injection, oral changes, unilateral cervical lymphadenopathy and extremity changes were less common in the younger group. During the acute phase, the percentage neutrophils and neutrophil to lymphocyte ratio [NLR] peaked on median illness day 3, followed by white blood cell (WBC) and CRP on median illness day 4, hemoglobin on median illness day 7 and platelet count on median illness day 9. CAA occurred on median illness day 6 and regressed on median illness day 28. Multivariate logistic regression analysis revealed that the peak percentage neutrophils (odds ratio [OR] per 0.1: 1.597, 95% confidence interval [CI]: 1.041–2.452, P = 0.032) and the peak platelet count (OR per 10 × 10⁹/L: 1.029, 95% CI: 1.004–1.055, P = 0.024) were independent risk factors for CAA. Hemoglobin on the 5th day was associated with persistent CAA at 1 year after KD onset.

Conclusion

Factors associated with CAA include a high peak percentage neutrophils, increased peak platelet count, and reduced hemoglobin within 4–6 days during the acute phase of KD. Therefore, this population should receive primary therapy with IVIG and adjunctive anti-inflammatory medications.

The autoimmune signature of hyperinflammatory multisystem inflammatory syndrome in children

Multisystem inflammatory syndrome in children (MIS-C) manifests as a severe and uncontrolled inflammatory response with multiorgan involvement, occurring weeks after SARS-CoV-2 infection. Here, we utilized proteomics, RNA sequencing, autoantibody arrays, and B cell receptor (BCR) repertoire analysis to characterize MIS-C immunopathogenesis and identify factors contributing to severe manifestations and intensive care unit admission. Inflammation markers, humoral immune responses, neutrophil activation, and complement and coagulation pathways were highly enriched in MIS-C patient serum, with a more hyperinflammatory profile in severe than in mild MIS-C cases. We identified a strong autoimmune signature in MIS-C, with autoantibodies targeted to both ubiquitously expressed and tissue-specific antigens, suggesting autoantigen release and excessive antigenic drive may result from systemic tissue damage. We further identified a cluster of patients with enhanced neutrophil responses as well as high anti-Spike IgG and autoantibody titers. BCR sequencing of these patients identified a strong imprint of antigenic drive with substantial BCR sequence connectivity and usage of autoimmunity-associated immunoglobulin heavy chain variable region (IGHV) genes. This cluster was linked to a TRBV11-2 expanded T cell receptor (TCR) repertoire, consistent with previous studies indicating a superantigen-driven pathogenic process. Overall, we identify a combination of pathogenic pathways that culminate in MIS-C and may inform treatment.

Is there any association between asthma and Kawasaki disease? A systematic review and meta-analysis

OBJECTIVE

Shared immune factors are involved in the pathogenesis of asthma and Kawasaki disease (KD). Consequently, several observational studies have explored an association between KD and asthma. This systematic review and meta-analysis aimed to explore the association between KD and asthma.

METHODS

PubMed and Embase databases were searched for cross-sectional, case-control and cohort studies that investigated the association between KD and asthma. The first author, publication year, study type, sample size, and participant demographics were retrieved. The association between KD and asthma was expressed by the odds ratio (OR) and 95% confidence interval (CI).

RESULTS

Eleven studies were eligible in the systematic review. The crude ORs (cORs) were extracted from 11 studies, and seven of them also provided adjusted ORs (aORs). The cORs between KD and asthma was 1.53 (95% CI, 1.29-1.81). After adjustment for some confounding factors (age, sex, region), asthma also had an association with KD (aOR, 1.08; 95% CI, 1.00-1.17). The subgroup analyses showed the study design and study location to influence between-study heterogeneity. Analyses of aOR values revealed that asthma onset before KD onset does not appear to increase KD prevalence, whereas people suffering from KD could increase the prevalence of developing asthma.

CONCLUSION

Our meta-analysis suggested a possible association between preceding KD and asthma onset, but care must be taken when interpreting this result. Prospective cohort studies are needed to assess a causal relationship between these two diseases.

Kawasaki Disease Patient Stratification and Pathway Analysis Based on Host Transcriptomic and Proteomic Profiles

The aetiology of Kawasaki disease (KD), an acute inflammatory disorder of childhood, remains unknown despite various triggers of KD having been proposed. Host 'omic profiles offer insights into the host response to infection and inflammation, with the interrogation of multiple 'omic levels in parallel providing a more comprehensive picture. We used differential abundance analysis, pathway analysis, clustering, and classification techniques to explore whether the host response in KD is more similar to the response to bacterial or viral infections at the transcriptomic and proteomic levels through comparison of 'omic profiles from children with KD to those with bacterial and viral infections. Pathways activated in patients with KD included those involved in anti-viral and anti-bacterial responses. Unsupervised clustering showed that the majority of KD patients clustered with bacterial patients on both 'omic levels, whilst application of diagnostic signatures specific for bacterial and viral infections revealed that many transcriptomic KD samples had low probabilities of having bacterial or viral infections, suggesting that KD may be triggered by a different process not typical of either common bacterial or viral infections. Clustering based on the transcriptomic and proteomic responses during KD revealed three clusters of KD patients on both 'omic levels, suggesting heterogeneity within the inflammatory response during KD. The observed heterogeneity may reflect differences in the host response to a common trigger, or variation dependent on different triggers of the condition.

The up-to-date pathophysiology of Kawasaki disease

Kawasaki disease (KD) is an acute systemic vasculitis of an unknown aetiology. A small proportion of children exposed to severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) or infected by Yersinia reproducibly develop principal symptoms of KD in various ethnic areas, but not in all studies. These microbes provoke a rapid cell‐damaging process, called ‘pyroptosis’, which is characterised by a subsequent release of proinflammatory cellular components from damaged endothelial and innate immune cells. In agreement with these molecular events, patients with KD show elevated levels of damage‐associated molecular patterns derived from cell death. In addition, an overwhelming amount of oxidative stress‐associated molecules, including oxidised phospholipids or low‐density lipoproteins, are generated as by‐products of inflammation during the acute phase of the disease. These molecules induce abnormalities in the acquired immune system and activate innate immune and vascular cells to produce a range of proinflammatory molecules such as cytokines, chemokines, proteases and reactive oxygen species. These responses further recruit immune cells to the arterial wall, wherein inflammation and oxidative stress closely interact and mutually amplify each other. The inflammasome, a key component of the innate immune system, plays an essential role in the development of vasculitis in KD. Thus, innate immune memory, or ‘trained immunity’, may promote vasculitis in KD. Hence, this review will be helpful in understanding the pathophysiologic pathways leading to the development of principal KD symptoms and coronary artery lesions in patients with KD, as well as in subsets of patients with SARS‐CoV‐2 and Yersinia infections.

A Molecular network approach reveals shared cellular and molecular signatures between chronic fatigue syndrome and other fatiguing illnesses

The molecular mechanisms of chronic fatigue syndrome (CFS, or Myalgic encephalomyelitis), a disease defined by extreme, long-term fatigue, remain largely uncharacterized, and presently no molecular diagnostic test and no specific treatments exist to diagnose and treat CFS patients. While CFS has historically had an estimated prevalence of 0.1-0.5% [1], concerns of a “long hauler” version of Coronavirus disease 2019 (COVID-19) that symptomatically overlaps CFS to a significant degree(Supplemental Table-1)and appears to occur in 10% of COVID-19 patients[2], has raised concerns of a larger spike in CFS [3]. Here, we established molecular signatures of CFS and a corresponding network-based disease context from RNA-sequencing data generated on whole blood and FACs sorted specific peripheral blood mononuclear cells (PBMCs) isolated from CFS cases and non-CFS controls. The immune cell type specific molecular signatures of CFS we identified, overlapped molecular signatures from other fatiguing illnesses, demonstrating a common molecular etiology. Further, after constructing a probabilistic causal model of the CFS gene expression data, we identified master regulator genes modulating network states associated with CFS, suggesting potential therapeutic targets for CFS.

Identifying Downregulation of Autophagy Markers in Kawasaki Disease

Kawasaki disease (KD) is the most common cause of heart disease acquired in childhood. Even if treated with high-dose intravenous immunoglobulin G (IVIG) at the early stage; children are still at risk of developing coronary artery lesions. Accumulating evidence suggests that autophagy is enhanced in various heart diseases. Evaluating the pathogenic role of autophagy in KD and coronary artery lesions (CAL) may aid in identifying a potential therapeutic target for the treatment or prevention of the disease. Blood samples were obtained from 20 children with KD at the onset of disease and 21 days after IVIG therapy. Twenty children with other causes of febrile disease and 20 healthy children were included as controls. Total RNA was extracted from white blood cells; and autophagy-related gene mRNA expression levels were measured using real-time polymerase chain reaction. The patients with KD had downregulated levels of LC3B mRNA (0.50 ± 0.06 vs. 1.67 ± 0.15; p < 0.001), BECN1 mRNA (0.70 ± 0.08 vs. 1.43 ± 0.23; p < 0.05), and ATG16L1 mRNA (0.28 ± 0.04 vs. 0.96 ± 0.16; p < 0.01) compared to the febrile control group. The values of these parameters all increased significantly 21 days after the IVIG therapy as follows: LC3B mRNA (1.77 ± 0.29 vs. 0.50 ± 0.06; p < 0.001), BECN1 mRNA (1.67 ± 0.36 vs. 0.70 ± 0.08; p < 0.05), and ATG16L1 mRNA (2.96 ± 0.43 vs. 0.28 ± 0.04; p < 0.001), while the level of ATG16L1 mRNA persists low in KD patients with CAL. Our results showed the autophagy-related genes expressions in KD and their change after IVIG administration. This suggests that autophagy may have a protective effect on KD.

Prenatal Endotoxin Exposure Induces Fetal and Neonatal Renal Inflammation via Innate and Th1 Immune Activation in Preterm Pigs

Chorioamnionitis (CA) predisposes to preterm birth and affects the fetal mucosal surfaces (i.e., gut, lungs, and skin) via intra-amniotic (IA) inflammation, thereby accentuating the proinflammatory status in newborn preterm infants. It is not known if CA may affect more distant organs, such as the kidneys, before and after preterm birth. Using preterm pigs as a model for preterm infants, we investigated the impact of CA on fetal and neonatal renal status and underlying mechanisms. Fetal pigs received an IA dose of lipopolysaccharide (LPS), were delivered preterm by cesarean section 3 days later (90% gestation), and compared with controls (CON) at birth and at postnatal day 5. Plasma proteome and inflammatory targets in kidney tissues were evaluated. IA LPS-exposed pigs showed inflammation of fetal membranes, higher fetal plasma creatinine, and neonatal urinary microalbumin levels, indicating renal dysfunction. At birth, plasma proteomics revealed LPS effects on proteins associated with renal inflammation (up-regulated LRG1, down-regulated ICA, and ACE). Kidney tissues of LPS pigs at birth also showed increased levels of kidney injury markers (LRG1, KIM1, NGLA, HIF1A, and CASP3), elevated molecular traits related to innate immune activation (infiltrated MPO⁺ cells, complement molecules, oxidative stress, TLR2, TLR4, S100A9, LTF, and LYZ), and Th1 responses (CD3⁺ cells, ratios of IFNG/IL4, and TBET/GATA3). Unlike in plasma, innate and adaptive immune responses in kidney tissues of LPS pigs persisted to postnatal day 5. We conclude that prenatal endotoxin exposure induces fetal and postnatal renal inflammation in preterm pigs with both innate and adaptive immune activation, partly explaining the potential increased risks of kidney injury in preterm infants born with CA.

Non-coronary cardiac events, younger age, and IVIG unresponsiveness increase the risk for coronary aneurysms in Italian children with Kawasaki disease

OBJECTIVES

Kawasaki disease (KD) is the most frequent cause of acquired heart disease in children in high-income countries because of coronary artery involvement. Risk factors for coronary lesions can vary in consideration of different genetic background and environmental factors.

METHODS

Multicenter retrospective and prospective study including 372 consecutive children (58% boys; mean age 34.3 ± 30.3 months, Caucasian 85%) was diagnosed with KD. We divided the cohort into 2 groups according to the presence of coronary anomalies (CAA) and aneurysms. We compared the groups and studied the risk factors for CAA and for aneurysms, the most severe lesions.

RESULTS

Children with CAA were 91/372 (24.46%, aneurysms 20/372, 5.37%). Children with CAA were more likely to have a longer duration of fever (p < 0.001), later day of treatment (p < 0.001), to be IVIG non-responders and late treated (p < 0.001), while age, clinical presentation, and seasonality were not different. They also had significantly higher WBC and neutrophils, lower lymphocytes, Hb and Na during the acute stage, and slower resolution of inflammation. Age, IVIG unresponsiveness, and presence of non-coronary cardiac findings were independent risk factors for CAA and for aneurysms, while neutrophils just for CAA. Age under 6 months was a risk factor for the aneurysm. Aneurysms occurred more frequently in the first quartile of the age of KD onset (under 14 months).

CONCLUSION

Very young children with non-coronary cardiac findings are at increased risk for a more severe form of KD with aneurysms. These children could benefit from adjunctive therapy beside IVIG, especially if they have higher markers of inflammation, particularly neutrophils. Key points • Risk factors for coronary lesions can vary in consideration of different genetic background and environmental factors. • Risk factors for coronary involvement have been extensively studied in the Asian population, and others have been validated in cohorts with mixed ethnicities. • In our predominantly Caucasian population, non-coronary cardiac findings, age younger than 6 months, and IVIG unresponsiveness are independent risk factors for a more severe form of KD with aneurysms.

Lipocalin-2-induced proliferative endoplasmic reticulum stress participates in Kawasaki disease-related pulmonary arterial abnormalities

Clinical cases have reported pulmonary arterial structural and functional abnormalities in patients with Kawasaki disease (KD); however, the underlying mechanisms are unclear. In this study, a KD rat model was established via the intraperitoneal injection of Lactobacillus casei cell wall extract (LCWE). The results showed that pulmonary arterial functional and structural abnormalities were observed in KD rats. Furthermore, proliferative endoplasmic reticulum stress (ER stress) was observed in the pulmonary arteries of KD rats. Notably, the level of lipocalin-2 (Lcn 2), a trigger factor of inflammation, was remarkably elevated in the plasma and lung tissues of KD rats; increased Lcn 2 levels following LCWE stimulation may result from polymorphonuclear neutrophils (PMNs). Correspondingly, in cultured pulmonary artery smooth muscle cells (PASMCs), Lcn 2 markedly augmented the cleavage and nuclear localization of activating transcription factor-6 (ATF6), upregulated the transcription of glucose regulated protein 78 (GRP78) and neurite outgrowth inhibitor (NOGO), and promoted PASMCs proliferation. However, proapoptotic C/EBP homologous protein (CHOP) and caspase 12 levels were not elevated. Treatment with 4-phenyl butyric acid (4-PBA, a specific inhibitor of ER stress) inhibited PASMCs proliferation induced by Lcn 2 and attenuated pulmonary arterial abnormalities and right ventricular hypertrophy and reduced right ventricular systolic pressure in KD rats. In conclusion, Lcn 2 remarkably facilitates proliferative ER stress in PASMCs, which probably accounts for KD-related pulmonary arterial abnormalities.

A neutrophil activation signature predicts critical illness and mortality in COVID-19

Pathologic immune hyperactivation is emerging as a key feature of critical illness in COVID-19, but the mechanisms involved remain poorly understood. We carried out proteomic profiling of plasma from cross-sectional and longitudinal cohorts of hospitalized patients with COVID-19 and analyzed clinical data from our health system database of over 3,300 patients. Using a machine learning algorithm, we identified a prominent signature of neutrophil activation, including resistin, lipocalin-2, HGF, IL-8, and G-CSF, as the strongest predictors of critical illness. Neutrophil activation was present on the first day of hospitalization in patients who would only later require transfer to the intensive care unit, thus preceding the onset of critical illness and predicting increased mortality. In the health system database, early elevations in developing and mature neutrophil counts also predicted higher mortality rates. Altogether, we define an essential role for neutrophil activation in the pathogenesis of severe COVID-19 and identify molecular neutrophil markers that distinguish patients at risk of future clinical decompensation.

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.

Defining the Boundary Between Myelodysplastic Syndromes and Myeloproliferative Neoplasms

In this article we provide a practical and comprehensive review of myeloid neoplasms with overlapping myelodysplastic (MDS) and myeloproliferative (MPN) features, with emphasis on recent updates in classification, particularly the utility of morphologic, cytogenetic, and molecular findings in better defining and classifying these disease entities. We provide the reader with a summary of the most recent developments and updates that have helped further our understanding of the genomic landscape, clinicopathologic features, and prognostic elements of myeloid neoplasms with MDS/MPN features.

Neutrophil Heterogeneity as Therapeutic Opportunity in Immune-Mediated Disease

Neutrophils are versatile innate effector cells essential for immune defense but also responsible for pathologic inflammation. This dual role complicates therapeutic targeting. However, neither neutrophils themselves nor the mechanisms they employ in different forms of immune responses are homogeneous, offering possibilities for selective intervention. Here we review heterogeneity within the neutrophil population as well as in the pathways mediating neutrophil recruitment to inflamed tissues with a view to outlining opportunities for therapeutic manipulation in inflammatory disease.

Neutrophil gelatinase-associated lipocalin reflects inflammation and is not a reliable renal biomarker in neonates and infants after cardiopulmonary bypass: a prospective case-control study

Introduction Acute kidney injury is a frequent complication after cardiac surgery with cardiopulmonary bypass in infants. Neutrophil gelatinase-associated lipocalin has been suggested to be a promising early biomarker of impending acute kidney injury. On the other hand, neutrophil gelatinase-associated lipocalin has been shown to be elevated in systemic inflammatory diseases without renal impairment. In this secondary analysis of data from our previous study on acute kidney injury after infant cardiac surgery, our hypothesis was that neutrophil gelatinase-associated lipocalin may be associated with surgery-related inflammation.

METHODS

We prospectively enrolled 59 neonates and infants undergoing cardiopulmonary bypass surgery for CHD and measured neutrophil gelatinase-associated lipocalin in plasma and urine and interleukin-6 in the plasma. Values were correlated with postoperative acute kidney injury according to the paediatric Renal-Injury-Failure-Loss-Endstage classification.

RESULTS

Overall, 48% (28/59) of patients developed acute kidney injury. Of these, 50% (14/28) were classified as injury and 11% (3/28) received renal replacement therapy. Both plasma and urinary neutrophil gelatinase-associated lipocalin values were not correlated with acute kidney injury occurrence. Plasma neutrophil gelatinase-associated lipocalin showed a strong correlation with interleukin-6. Urinary neutrophil gelatinase-associated lipocalin values correlated with cardiopulmonary bypass time.

CONCLUSION

Our results suggest that plasma and urinary neutrophil gelatinase-associated lipocalin values are not reliable indicators of impending acute kidney injury in neonates and infants after cardiac surgery with cardiopulmonary bypass. Inflammation may have a major impact on plasma neutrophil gelatinase-associated lipocalin values in infant cardiac surgery. Urinary neutrophil gelatinase-associated lipocalin may add little prognostic value over cardiopulmonary bypass time.

Unique Molecular Patterns Uncovered in Kawasaki Disease Patients with Elevated Serum Gamma Glutamyl Transferase Levels: Implications for Intravenous Immunoglobulin Responsiveness

Background

Resistance to intravenous immunoglobulin (IVIG) occurs in 10–20% of patients with Kawasaki disease (KD). The risk of resistance is about two-fold higher in patients with elevated gamma glutamyl transferase (GGT) levels. We sought to understand the biological mechanisms underlying IVIG resistance in patients with elevated GGT levels.

Method

We explored the association between elevated GGT levels and IVIG-resistance with a cohort of 686 KD patients (Cohort I). Gene expression data from 130 children with acute KD (Cohort II) were analyzed using the R square statistic and false discovery analysis to identify genes that were differentially represented in patients with elevated GGT levels with regard to IVIG responsiveness. Two additional KD cohorts (Cohort III and IV) were used to test the hypothesis that sialylation and GGT may be involved in IVIG resistance through neutrophil apoptosis.

Results

Thirty-six genes were identified that significantly explained the variations of both GGT levels and IVIG responsiveness in KD patients. After Bonferroni correction, significant associations with IVIG resistance persisted for 12 out of 36 genes among patients with elevated GGT levels and none among patients with normal GGT levels. With the discovery of ST6GALNAC3, a sialyltransferase, as the most differentially expressed gene, we hypothesized that sialylation and GGT are involved in IVIG resistance through neutrophil apoptosis. We then confirmed that in Cohort III and IV there was significantly less reduction in neutrophil count in IVIG non-responders.

Conclusions

Gene expression analyses combining molecular and clinical datasets support the hypotheses that: (1) neutrophil apoptosis induced by IVIG may be a mechanism of action of IVIG in KD; (2) changes in sialylation and GGT level in KD patients may contribute synergistically to IVIG resistance through blocking IVIG-induced neutrophil apoptosis. These findings have implications for understanding the mechanism of action in IVIG resistance, and possibly for development of novel therapeutics.

GM-CSF primes cardiac inflammation in a mouse model of Kawasaki disease

Using a mouse model of Kawasaki disease, Stock and collaborators have discovered an essential role for GM-CSF as an instigator of cardiac inflammation.

Kawasaki disease (KD) is the leading cause of pediatric heart disease in developed countries. KD patients develop cardiac inflammation, characterized by an early infiltrate of neutrophils and monocytes that precipitates coronary arteritis. Although the early inflammatory processes are linked to cardiac pathology, the factors that regulate cardiac inflammation and immune cell recruitment to the heart remain obscure. In this study, using a mouse model of KD (induced by a cell wall Candida albicans water-soluble fraction [CAWS]), we identify an essential role for granulocyte/macrophage colony-stimulating factor (GM-CSF) in orchestrating these events. GM-CSF is rapidly produced by cardiac fibroblasts after CAWS challenge, precipitating cardiac inflammation. Mechanistically, GM-CSF acts upon the local macrophage compartment, driving the expression of inflammatory cytokines and chemokines, whereas therapeutically, GM-CSF blockade markedly reduces cardiac disease. Our findings describe a novel role for GM-CSF as an essential initiating cytokine in cardiac inflammation and implicate GM-CSF as a potential target for therapeutic intervention in KD.

Atopic Predilection among Kawasaki Disease Patients: A Cross-Sectional Study of 1,187,757 Teenagers

BACKGROUND

Kawasaki disease (KD) is an acute, systemic vasculitis in children, with an etiology that is not completely understood. It is assumed that the development of KD is mediated by an immunologic response. Several reports from East Asia have found a higher prevalence of atopic diseases among patients with KD, but a large-scale study of a non-Asian population regarding this correlation is still lacking. The purpose of this article was to achieve this goal.

METHODS

We conducted a cross-sectional, large-scale study to estimate the correlation of KD with allergic diseases. The medical history of 1,187,757 Israeli teenagers (aged 16-20 years during the years 1998-2013) was retrieved. The study population was divided into 3 groups according to a past history of noncomplicated and complicated KD and a control group. The prevalence of allergic diseases among these groups was further investigated.

RESULTS

The prevalence of atopic diseases in the 3 study groups was presented (asthma in 11.4, 8.1 and 3.5%, respectively; angioedema/urticaria in 7.1, 0 and 0.46%, respectively; allergic rhinitis in 20, 12.1 and 6.7%, respectively). In noncomplicated KD, a statistically significant link to asthma [odds ratio (OR) 2.4; p = 0.048] and a borderline significant link to allergic rhinitis (OR 1.9; p = 0.06) were found. In KD complicated with cardiac disease, statistically significant links were found for all the allergic conditions, asthma (OR 3.5; p = 0.003), allergic rhinitis (OR 3.5; p < 0.001) and angioedema/urticaria (OR 16.48; p < 0.001).

CONCLUSION

KD is associated with allergic diseases. This association increases with the severity of the disease.

Remission of autoimmune neutropenia after development of Kawasaki disease

We report the second case of the association of Kawasaki disease (KD) and autoimmune neutropenia (AIN). A 21-month-old female diagnosed as having AIN of infancy developed a complete KD when severe neutropenia continued. The patient suffered from no coronary artery lesions, and well responded to a single high-dose gamma-globulin therapy. The cytokine profile of the neutropenic infant was representative of the typical KD. Neutrophil counts notably increased during the convalescent phase of KD, and were then normalized forthwith. The prompt resolutions of KD and AIN paralleled the increase of circulating transforming growth factor (TGF)-β1 levels. The clinical course of the patient was contrasted to that of the first reported case of a patient who developed severe and refractory KD after the high dose granulocyte-colony stimulating factor (G-CSF) therapy.

Global gene expression profiling identifies new therapeutic targets in acute Kawasaki disease

Background

Global gene expression profiling can provide insight into the underlying pathophysiology of disease processes. Kawasaki disease (KD) is an acute, self-limited vasculitis whose etiology remains unknown. Although the clinical illness shares certain features with other pediatric infectious diseases, the occurrence of coronary artery aneurysms in 25% of untreated patients is unique to KD.

Methods

To gain further insight into the molecular mechanisms underlying KD, we investigated the acute and convalescent whole blood transcriptional profiles of 146 KD subjects and compared them with the transcriptional profiles of pediatric patients with confirmed bacterial or viral infection, and with healthy control children. We also investigated the transcript abundance in patients with different intravenous immunoglobulin treatment responses and different coronary artery outcomes.

Results

The overwhelming signature for acute KD involved signaling pathways of the innate immune system. Comparison with other acute pediatric infections highlighted the importance of pathways involved in cell motility including paxillin, relaxin, actin, integrins, and matrix metalloproteinases. Most importantly, the IL1β pathway was identified as a potential therapeutic target.

Conclusion

Our study revealed the importance of the IL-1 signaling pathway and a prominent signature of innate immunity and cell migration in the acute phase of the illness.

Electronic supplementary material

The online version of this article (doi:10.1186/s13073-014-0102-6) contains supplementary material, which is available to authorized users.

Feasibility of Optical Coherence Tomography in Children With Kawasaki Disease and Pediatric Heart Transplant Recipients

Background—

Optical coherence tomography (OCT) is a high-resolution intravascular imaging technique used in adults. We tested the hypothesis that OCT could identify coronary abnormalities not seen by angiography in children with a history of Kawasaki disease (KD) and pediatric heart transplant (TX) recipients.

Methods and Results—

Patients with KD and TX recipients were evaluated between December 2012 and October 2013 with angiography and OCT (Ilumien System, LightLabs, St Jude Medical, Westford, MA). Modifications were made to the adult OCT protocol to adapt this technique for children. Serial cross-sectional area measurements of the lumen, intima, and media were made. Entire imaging data were analyzed for the presence of qualitative changes. Seventeen children were evaluated (5 patients with KD; 12 TX recipients). In patients with KD, angiography was normal. However, OCT imaging revealed that significant vessel wall abnormalities were present in all children including intimal thickening (intima/lumen cross-sectional area ratio>0.4), loss of the normal layered structure of the vessel wall, white thrombus, calcification, and neovascularization. There was extensive destruction of the internal elastic lamina. In TX recipients, angiography was normal; however, intimal thickening (intima/media cross-sectional area ratio>1) was seen in 9 of 12 patients. The median intima/media cross-sectional area ratio was 1.18.

Conclusions—

In this initial experience with OCT in children, we have identified significant coronary abnormalities with OCT that are angiographically silent in children with a history of coronary aneurysms because of KD and in pediatric TX recipients.

Plasma CD147 reflects histological features in patients with lupus nephritis

OBJECTIVE

A glycosylated transmembrane protein, CD147, has been implicated in regulating lymphocyte responsiveness and leukocyte recruitment. As lupus nephritis (LN) often follows a relapsing-remitting disease course, accurate understanding of the disease activity would be extremely helpful in improving prognosis. Unfortunately, neither clinical nor serological data can accurately reflect the histological features of LN. The present study investigated whether CD147 can accurately predict pathological features of LN.

METHODS

Plasma and spot urine samples were collected from 64 patients who underwent renal biopsy between 2008 and 2011. Disease activity for LN tissues was evaluated using the biopsy activity index, and compared to levels of biomarkers including CD147.

RESULTS

In LN tissues, CD147 induction was striking in injured glomeruli and infiltrating inflammatory cells, but not in damaged tubules representing atrophy. Plasma CD147 levels accurately reflected the histological disease activity. However, prediction using a single molecule would be quite difficult because of the complex pathogenesis of LN. The diagnostic accuracy of multiplex parameters indicated that the combination including plasma CD147 might yield excellent diagnostic abilities for guiding ideal LN therapy.

CONCLUSION

Plasma CD147 levels might offer useful insights into disease activity as a crucial biomarker in patients with LN.

Serum and urinary NGAL in septic newborns

Neutrophil gelatinase-associated lipocalin (NGAL) is postulated to be a potentially new and highly specific/sensitive marker of acute kidney injury (AKI). The aim of this study was to assess the impact of inflammation on serum and urine NGAL in newborns that were treated due to infection. We determined serum and urine NGAL concentrations in 73 infants (51 with sepsis; 22 with severe sepsis) admitted to the Intensive Care Unit in the first month of life, for three consecutive days during the course of treatment for infection. 29 neonates without infection served as the control group. Septic patients, in particular, severe sepsis patients, had increased serum and urinary NGAL levels in the three subsequent days of observation. Five septic patients who developed AKI had elevated serum and urinary NGAL values to a similar extent as septic neonates without AKI. A strong correlation was found between the concentration of serum and urinary NGAL and inflammatory markers, such as CRP and procalcitonin. Serum and urinary NGAL levels were also significantly associated with NTISS (neonatal therapeutic intervention scoring system) values. We conclude that increased serum and urinary NGAL values are not solely a marker of AKI, and more accurately reflect the severity of inflammatory status.

Update on Kawasaki disease: epidemiology, aetiology and pathogenesis

Kawasaki disease is an acute systemic vasculitis predominantly affecting young children. It is due to an abnormal host response to as yet unidentified infectious trigger(s). Kawasaki disease may cause coronary artery damage, long-term cardiovascular morbidity and occasionally mortality, especially if the diagnosis is missed or timely treatment is not given. This is the first of two updates on Kawasaki disease. Here we review recent advances in epidemiology, possible aetiologies, host susceptibility and pathogenesis of this fascinating condition.

Differential role of lipocalin 2 during immune complex-mediated acute and chronic inflammation in mice

OBJECTIVE

Lipocalin 2 (LCN-2) is an innate immune protein that is expressed by a variety of cells and is highly up-regulated during several pathologic conditions, including immune complex (IC)-mediated inflammatory/autoimmune disorders. However, the function of LCN-2 during IC-mediated inflammation is largely unknown. Therefore, this study was undertaken to investigate the role of LCN-2 in IC-mediated diseases.

METHODS

The up-regulation of LCN-2 was determined by enzyme-linked immunosorbent assay in 3 different mouse models of IC-mediated autoimmune disease: systemic lupus erythematosus, collagen-induced arthritis, and serum-transfer arthritis. The in vivo role of LCN-2 during IC-mediated inflammation was investigated using LCN-2-knockout mice and their wild-type littermates.

RESULTS

LCN-2 levels were significantly elevated in all 3 of the autoimmune disease models. Further, in an acute skin inflammation model, LCN-2-knockout mice exhibited a 50% reduction in inflammation, with histopathologic analysis revealing notably reduced immune cell infiltration as compared to wild-type mice. Administration of recombinant LCN-2 to LCN-2-knockout mice restored inflammation to levels observed in wild-type mice. Neutralization of LCN-2 using a monoclonal antibody significantly reduced inflammation in wild-type mice. In contrast, LCN-2-knockout mice developed more severe serum-induced arthritis compared to wild-type mice. Histologic analysis revealed extensive tissue and bone destruction, with significantly reduced neutrophil infiltration but considerably more macrophage migration, in LCN-2-knockout mice compared to wild-type mice.

CONCLUSION

These results demonstrate that LCN-2 may regulate immune cell recruitment to the site of inflammation, a process essential for the controlled initiation, perpetuation, and resolution of inflammatory processes. Thus, LCN-2 may present a promising target in the treatment of IC-mediated inflammatory/autoimmune diseases.

Kawasaki disease and subsequent risk of allergic diseases: a population-based matched cohort study

Background

The risk of allergic diseases among Kawasaki disease (KD) patients relative to the general population is not known. The aim of this study was to perform a population-based cohort study to investigate the risk of allergic diseases among children after KD in Taiwan- a country with the third highest incidence of KD in the world.

Methods

Data were obtained from the Taiwan National Health Insurance Research Database. In total, 253 patients who were 5 years of age or younger and had a first-time hospitalization with a diagnosis of KD between 1997 and 2005 were included as the study cohort and 1,012 non-KD patients matched for age and sex were included as comparison cohort. Multivariate Cox proportional hazard regression model was used to adjust for confounding and to compare the 6-year allergic-free survival rate between these two cohorts.

Results

The incidence rate of allergic diseases (184.66 per 1000 person-year) was significantly higher in the KD cohort than in the control cohort (124.99 per 1000 person-years). After adjusting for potential confounders, the adjusted hazard ratios of asthma and allergic rhinitis were 1.51 (95% confidence interval = 1.17-1.95) and 1.30 (95% confidence interval = 1.04-1.62), respectively.

Conclusion

We conclude that KD patients were at an increased risk for allergic diseases compared with the comparison cohort.

Urinary vascular cell adhesion molecule, but not neutrophil gelatinase-associated lipocalin, is associated with lupus nephritis

OBJECTIVE

Vascular cell adhesion molecule-1 (VCAM-1), an adhesion molecule, is involved in the progression of glomerular and tubulointerstitial injury. Neutrophil gelatinase-associated lipocalin (NGAL), a member of the lipocalin superfamily, has been shown to rise in both acute and chronic kidney damage. Both VCAM-1 and NGAL have been found at high levels in the urine of patients with active lupus nephritis. We investigated both as potential biomarkers for lupus nephritis.

METHODS

VCAM-1 and NGAL were measured by ELISA during 1 to 8 clinic visits in 107 patients with systemic lupus erythematosus (SLE; 91% women, 51% black, 36% white, 4% Asian, 4% Hispanic, and 5% others) for a total of 190 visits. Patients' mean age was 41 years. We analyzed the relationship between these potential urine biomarkers and the urine protein/creatinine ratio (urine Pr/Cr), the Systemic Lupus International Collaborating Clinics (SLICC) renal activity score, SLE Disease Activity Index renal descriptors, and other clinical variables.

RESULTS

VCAM-1 levels were strongly associated with the physician's global estimate of disease activity (p = 0.0002), the renal visual analog scale (p < 0.0001), the urine Pr/Cr (p < 0.0001), and SLICC renal activity score (p < 0.0001). VCAM-1 levels were also associated with a urine Pr/Cr ≥ 0.5 (p < 0.0001). NGAL was not associated with any measure of disease activity or with lupus serologies.

CONCLUSION

Urine VCAM-1 had a strong association with measures of disease activity, including multiple renal activity descriptors. In contrast to previous SLE studies, NGAL failed to show any association with lupus nephritis.

Role of activating FcγR gene polymorphisms in Kawasaki disease susceptibility and intravenous immunoglobulin response

BACKGROUND

A functional polymorphism in the inhibitory IgG-Fc receptor gene FcγRIIB influences intravenous immunoglobulin (IVIG) response in Kawasaki disease (KD), a vasculitis preferentially affecting the coronary arteries in children. We tested the hypothesis that the polymorphisms in the activating receptors (FcγRIIA, FcγRIIIA, and FcγRIIIB) also influence susceptibility, IVIG treatment response, and coronary artery disease in patients with KD.

METHODS AND RESULTS

We genotyped polymorphisms in the activating FcγRIIA, FcγRIIIA, and FcγRIIIB using pyrosequencing in 443 patients with KD, including 266 trios and 150 single parent-child pairs, in northwest United States and genetically determined race with 155 ancestry informative markers. We used family-based association to test for transmission disequilibrium and further generated pseudosibling controls for comparisons with the cases. The FcγRIIA-131H variant showed an association with KD (P=0.001) with an additive odds ratio (OR) of 1.51 (95% CI, 1.16-1.96; P=0.002) for the primary combined population, which persisted in both white (P=0.04) and Asian (P=0.01) subgroups and is consistent with the recent genome-wide association study. We also identified overtransmission of the FcγRIIIB neutrophil antigen 1 (NA1) variant among IVIG nonresponders (P=0.0002) and specifically to white IVIG nonresponders (P=0.007). ORs for overall and white nonresponders were 3.67 (95% CI, 1.75-7.66; P=0.0006) and 3.60 (95% CI, 1.34-9.70; P=0.01), respectively. Excess NA1 transmission also occurred in patients with KD with coronary artery disease (OR(additive), 2.13; 95% CI, 1.11-4.0; P=0.02).

CONCLUSIONS

A common variation in FcγRIIA is associated with increased KD susceptibility. The FcγRIIIB-NA1 variant, which confers higher affinity for IgG than the NA2 variant, is a determining factor for treatment response. These activating FcγRs play an important role in KD pathogenesis and the IVIG antiinflammatory mechanism.

Association of the resistin gene promoter region polymorphism with Kawasaki disease in Chinese children

Objectives. The −420 C > G polymorphism located in the resistin gene (RETN) promoter has recently been suggested to play a potential role in proinflammatory conditions and cardiovascular disease. This study investigated the association of the RETN promoter polymorphism with Kawasaki disease (KD) and its clinical parameters in Chinese children. Methods. We compared patients with complete KD to incomplete KD children. Genotyping of the RETN promoter polymorphism was performed using MassARRAY system, and serum resistin levels were estimated using the sandwich enzyme immunoassay method. Results. There was no significant difference in RETN (−420 C > G) genotypes between KD and control groups. However, the frequency of the G allele was higher in iKD patients than in cKD children due to a significantly increased frequency of the GG genotypes. Serum levels of resistin were significantly higher in KD patients than in controls regardless of the presence of coronary artery lesions (CALs). Conclusion. The present findings suggest that while resistin may play a role in the pathogenesis of KD, there is no apparent association between CAL and the RETN (−420 C > G) gene polymorphism in KD children. However, the diagnosis of iKD is challenging but can be supported by the presence of the G allele and the GG genotypes.

A diagnostic algorithm combining clinical and molecular data distinguishes Kawasaki disease from other febrile illnesses

BACKGROUND

Kawasaki disease is an acute vasculitis of infants and young children that is recognized through a constellation of clinical signs that can mimic other benign conditions of childhood. The etiology remains unknown and there is no specific laboratory-based test to identify patients with Kawasaki disease. Treatment to prevent the complication of coronary artery aneurysms is most effective if administered early in the course of the illness. We sought to develop a diagnostic algorithm to help clinicians distinguish Kawasaki disease patients from febrile controls to allow timely initiation of treatment.

METHODS

Urine peptidome profiling and whole blood cell type-specific gene expression analyses were integrated with clinical multivariate analysis to improve differentiation of Kawasaki disease subjects from febrile controls.

RESULTS

Comparative analyses of multidimensional protein identification using 23 pooled Kawasaki disease and 23 pooled febrile control urine peptide samples revealed 139 candidate markers, of which 13 were confirmed (area under the receiver operating characteristic curve (ROC AUC 0.919)) in an independent cohort of 30 Kawasaki disease and 30 febrile control urine peptidomes. Cell type-specific analysis of microarrays (csSAM) on 26 Kawasaki disease and 13 febrile control whole blood samples revealed a 32-lymphocyte-specific-gene panel (ROC AUC 0.969). The integration of the urine/blood based biomarker panels and a multivariate analysis of 7 clinical parameters (ROC AUC 0.803) effectively stratified 441 Kawasaki disease and 342 febrile control subjects to diagnose Kawasaki disease.

CONCLUSIONS

A hybrid approach using a multi-step diagnostic algorithm integrating both clinical and molecular findings was successful in differentiating children with acute Kawasaki disease from febrile controls.

Hospitalisation with infection, asthma and allergy in Kawasaki disease patients and their families: genealogical analysis using linked population data

BACKGROUND

Kawasaki disease results from an abnormal immunological response to one or more infectious triggers. We hypothesised that heritable differences in immune responses in Kawasaki disease-affected children and their families would result in different epidemiological patterns of other immune-related conditions. We investigated whether hospitalisation for infection and asthma/allergy were different in Kawasaki disease-affected children and their relatives.

METHODS/MAJOR FINDINGS

We used Western Australian population-linked health data from live births (1970-2006) to compare patterns of hospital admissions in Kawasaki disease cases, age- and sex-matched controls, and their relatives. There were 295 Kawasaki disease cases and 598 age- and sex-matched controls, with 1,636 and 3,780 relatives, respectively. Compared to controls, cases were more likely to have been admitted at least once with an infection (cases, 150 admissions (50.8%) vs controls, 210 admissions (35.1%); odds ratio (OR) = 1.9, 95% confidence interval (CI) 1.4-2.6, P = 7.2×10⁻⁶), and with asthma/allergy (cases, 49 admissions (16.6%) vs controls, 42 admissions (7.0%); OR = 2.6, 95% CI 1.7-4.2, P = 1.3×10⁻⁵). Cases also had more admissions per person with infection (cases, median 2 admissions, 95% CI 1-5, vs controls, median 1 admission, 95% CI 1-4, P = 1.09×10⁻⁵). The risk of admission with infection was higher in the first degree relatives of Kawasaki disease cases compared to those of controls, but the differences were not significant.

CONCLUSION

Differences in the immune phenotype of children who develop Kawasaki disease may influence the severity of other immune-related conditions, with some similar patterns observed in relatives. These data suggest the influence of shared heritable factors in these families.

Matrix metalloproteinase haplotypes associated with coronary artery aneurysm formation in patients with Kawasaki disease

Aneurysms of the vascular wall represent a final common pathway for a number of inflammatory processes including atherosclerosis and idiopathic vasculitis syndromes. Kawasaki disease is an acute, self-limited vasculitis in children and the leading cause of acquired coronary artery aneurysms. We sought to identify shared molecular mechanisms of aneurysm formation by genotyping 8 polymorphisms in MMP-1, 3, 7, 12 and 13 in the gene cluster on Chr.11q22 whose gene products have been implicated in aneurysm formation or are known to have elastase activity. We genotyped 482 US-UK Kawasaki disease patients (aneurysm+: n=111, aneurysm−: n=371) and tested our findings in an independent cohort of 200 Japanese Kawasaki disease patients (aneurysm+: n=58, aneurysm−: n=142). Analysis of the five MMP genes identified modest trends in allele and genotype frequencies for MMP-3 rs3025058 (−/T) and haplotypes containing MMP-3 rs3025058 (−/T) and MMP-12 rs2276109 (A/G) (nominal p= 2-4 × 10⁻⁵) that conferred increased risk of aneurysm formation in US-UK subjects. This finding was validated in Japanese subjects and suggests the importance of this locus in aneurysm formation in children with Kawasaki disease. The region encompassing these risk haplotypes is a prime candidate for re-sequencing to look for rare genetic variation that may influence aneurysm formation.

Unique activation status of peripheral blood mononuclear cells at acute phase of Kawasaki disease

Although Kawasaki disease (KD) is characterized by a marked activation of the immune system with elevations of serum proinflammatory cytokines and chemokines at acute phase, the major sources for these chemical mediators remain controversial. We analysed the activation status of peripheral blood mononuclear cells (PBMCs) by flow cytometry, DNA microarray and quantitative reverse transcription-polymerase chain reaction. The proportions of CD69+ cells in both natural killer cells and gammadeltaT cells at acute-phase KD were significantly higher than those at convalescent-phase KD. Microarray analysis revealed that five genes such as NAIP, IPAF, S100A9, FCGR1A and GCA up-regulated in acute-phase KD and the pathways involved in acute phase KD were related closely to the innate immune system. The relative expression levels of damage-associated molecular pattern molecule (DAMP) (S100A9 and S100A12) genes in PBMCs at acute-phase KD were significantly higher than those at convalescent-phase KD, while those of TNFA, IL1B and IL6 genes were not significantly different between KD patients and healthy controls. Intracellular production of tumour necrosis factor-alpha, interleukin-10 and interferon-gamma in PBMCs was not observed in KD patients. The present data have indicated that PBMCs showed a unique activation status with high expression of DAMP genes but low expression of proinflammatory cytokine genes, and that the innate immune system appears to play a role in the pathogenesis and pathophysiology of KD.

Doxycycline therapy for abdominal aneurysm: Improved proteolytic balance through reduced neutrophil content

BACKGROUND

Matrix metalloproteinase-9 (MMP-9) is thought to play a central role in abdominal aortic aneurysm (AAA) initiation. Doxycycline, a tetracycline analogue, has direct MMP-9-inhibiting properties in vitro, and it effectively suppresses AAA development in rodents. Observed inhibition of AAA progression, and contradictory findings in human studies evaluating the effect of doxycycline therapy on aortic wall MMP-9, suggest that the effects of doxycycline extend beyond MMP-9 inhibition and that the effect may be dose-dependent.

METHODS

This clinical trial evaluated the effect of 2 weeks of low- (50 mg/d), medium- (100 mg/d), or high-dose (300 mg/d) doxycycline vs no medication in four groups of 15 patients undergoing elective AAA repair. The effect of doxycycline treatment on MMP and cysteine proteases, and their respective inhibitors, was evaluated by quantitative polymerase chain reaction, Western blot analysis, immunocapture protease activity assays, and immunohistochemistry.

RESULTS

Doxycycline was well tolerated and no participants dropped out. Doxycycline treatment reduced aortic wall MMP-3 and MMP-25 messenger RNA expression (P < .045 and P < .014, respectively), selectively suppressed neutrophil collagenase and gelatinase (MMP-8 and MMP-9) protein levels (P < .013 and <.004, respectively), and increased protein levels of the protease inhibitors tissue inhibitor of metalloproteinase 1 and cystatin C (P < .029). As for the apparent selective effect on neutrophil-associated proteases, we sought for a reducing effect on aortic wall neutrophil content that was indeed confirmed by immunohistochemical analysis that revealed a 75% reduction in aneurysm wall neutrophil content (P < .001).

CONCLUSIONS

Independent of its dose, short-term preoperative doxycycline therapy improves the proteolytic balance in AAA, presumably through an effect on aortic wall neutrophil content. This study provides a rationale for doxycycline treatment in patients with an AAA as well as in other (vascular) conditions involving neutrophil influx such as Kawasaki disease and Behçet disease.

Inflammatory markers neopterin and alanine aminotransferase in HCV patients treated with HCV NS3.4A protease inhibitor telaprevir (VX-950) and/or peginterferon alfa-2a

OBJECTIVE

Neopterin is a marker of monocyte/macrophage activity. Alanine aminotransferase (ALAT) is a marker of hepatocyte injury. The aim of this study was to determine changes in neopterin and ALAT levels, as markers of inflammation, in two ancillary studies during two-phase 1b trials of hepatitis C virus (HCV) NS3.4A protease inhibitor telaprevir (VX-950), with or without peginterferon alfa-2a (Peg-IFN).

MATERIAL AND METHODS

Fifty-four chronic hepatitis C patients (genotype 1) received placebo or telaprevir, with or without Peg-IFN, for 14 days in two multiple-dose studies.

RESULTS

During administration of telaprevir, every patient demonstrated a >2-log decrease in HCV RNA. Mean neopterin and ALAT levels decreased in all four groups receiving telaprevir alone. In contrast, mean neopterin levels increased and ALAT levels decreased in the Peg-IFN plus telaprevir and Peg-IFN plus placebo groups.

CONCLUSIONS

These data suggest that treatment of chronic hepatitis C patients with an HCV NS3.4A protease inhibitor ameliorates inflammation. The increase in neopterin levels and the decrease in ALAT levels during administration of Peg-IFN with or without telaprevir are in accordance with earlier observations showing that IFN reduces hepatocyte injury but increases monocyte/macrophage activity. The IFN-mediated immunomodulatory effects appear to remain intact when IFN is combined with telaprevir.

Association of the matrix metalloproteinase-3 (-439C/G) promoter polymorphism with Kawasaki disease in Korean children

Kawasaki disease (KD) is a multisystemic vasculitis that often includes coronary artery involvement. The serum levels of matrix metalloproteinase (MMP)-3 and -9 are significantly elevated in KD patients, and polymorphisms in the genes encoding MMP-3 and MMP-9 have been associated with the susceptibility, severity, and progression of atherosclerosis and aneurysm. However, the association between MMP-3 gene polymorphisms and development of aneurysm is somewhat controversial in a number of diseases. Ninety-seven children with KD and 194 children with congenital heart disease (CHD) were included in this study. Echocardiography was used to examine all children in the KD group for coronary artery aneurysm. Genotyping of the MMP-3 (-439C/G) promoter polymorphism was performed using the single-base extension method, and serum MMP-3 levels were estimated using the sandwich enzyme immunoassay method. There was no significant difference in MMP-3 (-439C/G) genotypes between KD and control groups. There was no association between this MMP-3 polymorphism and development of coronary aneurysm in KD. Serum MMP-3 levels were significantly higher in KD patients compared to control subjects. Among the KD patients, serum MMP-3 levels were higher in children with genotypes CG+GG compared to the CC group, but this difference was not significant. Although further large-scale studies will be required to fully examine the relationship between MMP-3 gene polymorphisms and coronary artery lesions (CAL) in KD, the present findings suggest that while MMP-3 may play a role in the pathogenesis of KD, there is no apparent association between CAL and the MMP-3 (-439C/G) gene polymorphism in Korean children with KD.