Delayed apoptosis of circulating neutrophils in Kawasaki disease

Bioinformatics analysis and identification of hub genes of neutrophils in Kawasaki disease: a pivotal study

BACKGROUND

Kawasaki disease (KD) is considered the main contributor to acquired heart diseases in developed countries. However, the precise pathogenesis of KD remains unclear. Neutrophils play roles in KD. This study aimed to select hub genes in neutrophils in acute KD.

METHODS

mRNA microarray of neutrophils from four acute KD patients and three healthy controls was performed to screen differentially expressed mRNAs (DE-mRNAs). DE-mRNAs were analyzed and predicted by Gene Ontology (GO), Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathways, and protein-protein interaction networks. Real time-PCR was finally conducted to confirm the reliability and validity of the expression level of DE-mRNAs from blood samples of healthy controls and KD patients in both acute and convalescent stage.

RESULTS

A total of 1950 DE-mRNAs including 1287 upregulated and 663 downregulated mRNAs were identified. GO and KEGG analyses revealed the DE-mRNAs were mainly enriched in the regulation of transcription from RNA polymerase II promoter, apoptotic process, intracellular signal transduction, protein phosphorylation, protein transport, metabolic pathways, carbon metabolism, lysosome, apoptosis, pyrimidine metabolism, alzheimer disease, prion disease, sphingolipid metabolism, huntington disease, glucagon signaling pathway, non-alcoholic fatty liver disease, pyruvate metabolism, sphingolipid signaling pathway, and peroxisome. Twenty hub DE-mRNAs were selected including GAPDH, GNB2L1, PTPRC, GART, HIST2H2AC, ACTG1, H2AFX, CREB1, ATP5A1, ENO1, RAC2, PKM, BCL2L1, ATP5B, MRPL13, SDHA, TLR4, RUVBL2, TXNRD1, and ITGAM. The real-time PCR results showed that BCL2L1 and ITGAM mRNA were upregulated in acute KD and were normalized in the convalescent stage.

CONCLUSIONS

These findings may improve our understanding of neutrophils in KD. Key Points • Neutrophilic BCL2L1 and ITGAM mRNA were first reported to be correlated with the pathogenic mechanism of KD.

The activation of CaN/NFAT signaling pathway in macrophages aggravated Lactobacillus casei cell wall extract-induced Kawasaki disease vasculitis

OBJECTIVES

By using GWAS(genome-wide association studies) and linkage disequilibrium analysis to investigate the susceptibility genes of KD(Kawasaki disease), previous studies have identified that the CaN(calcineurin)-NFAT(the nuclear factor of activated T cell) signal pathway were significantly associated with susceptibility to KD. However, little is known about the molecular basis of the CaN/NFAT pathway involved in KD. Therefore, in our study we investigate the role of Ca2+/CaN/NFAT signaling pathway in macrophages in vitro and in vivo on coronary artery lesions induced by LCWE (Lactobacillus casei cell wall extract).

METHODS AND RESULTS

We observed that LCWE could increase the expression of NFAT1 and NFAT2 in macrophages in vitro, and also enhance the transcriptional activity of NFAT by promoting the nucleus translocation. Similarly, in LCWE-induced mice model, the expression of NFAT1 and NFAT2 and associated proinflammatory factors were increased significantly. In addition, by knocking down or overexpressing NFAT1 or NFAT2 in macrophages, the results indicated that NFAT signaling pathway mediated LCWE-induced immune responses in macrophages and regulated the synthesis of IL(interleukin)-6, IL-1β and TNF(tumor necrosis factor)-α in LCWE-induced macrophage activation. As well, we found that this process could be suppressed by CaN inhibitor CsA(cyclosporinA).

CONCLUSIONS

Therefore, the CaN/NFAT signaling pathway mediated LCWE-induced immune responses in macrophages, and also participated in the LCWE-induced CALs(coronary artery lesions). And also the inhibitory effect of CsA in LCWE-induced cell model towards a strategy to modulate the CaN/NFAT pathway during the acute course of KD might be helpful in alleviate KD-induced CALs.

Intravenous Immunoglobulin in Kawasaki Disease-Evolution and Pathogenic Mechanisms

Kawasaki disease (KD) is an acute vasculitis of childhood that affects the medium vessels with a special predilection to the involvement of coronary arteries. The major morbidity of this disease is due to coronary artery aneurysm, which occurs in about 25-30% of untreated cases. For decades now, intravenous immunoglobulin (IVIg) has consistently been shown to reduce the risk of CAAs to less than 5%. However, the mechanism of immunomodulation remains unclear. Several studies on the role of IVIg in the modulation of toll-like receptor pathways, autophagy, and apoptosis of the mononuclear phagocytic system, neutrophil extracellular trap, and dendritic cell modulation suggest a modulatory effect on the innate immune system. Similarly, certain studies have shown its effect on T-cell differentiation, cytokine release, and regulatory T-cell function. In this review, we discuss the potential mechanisms underlying the immunomodulatory actions of IVIg in patients with Kawasaki disease. Furthermore, we provide a summary of the evidence regarding various infusion protocols and dosages utilized in the treatment of KD patients.

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.

Co-culture of peripheral blood mononuclear cell (PBMC) and human coronary artery endothelial cell (HCAEC) reveals the important role of autophagy implicated in Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is a systemic vasculitis syndrome that commonly occurs in children. Autophagy has been increasingly shown to be involved in various cardiovascular diseases, including endothelial dysfunction and vascular endothelial injury. However, whether autophagy is implicated in the pathogenesis of KD remains poorly understood, and particularly, how the dysfunction of human coronary artery endothelial cells (HCAECs) is associated with autophagy in peripheral blood mononuclear cells (PBMCs) from KD patients awaits further investigation.

METHODS

Peripheral blood samples were collected from KD patients, common fever patients, and healthy controls. The PBMC samples were isolated from KD blood samples collected at three different phases: the acute phase before therapy (acute-KD), 1 week (subacute-KD), and 4 weeks (convalescent-KD) after drug administration.

RESULTS

The autophagy flux was significantly increased in the PBMCs of KD patients at acute phase. The PBMCs of acute KD patients could induce autophagy in HCAECs and promote the secretion of chemokines and pro-inflammatory factors after cocultured with HCAECs whereas 3-methyladenine (3-MA) drug could partly reverse this process.

CONCLUSIONS

Autophagy is involved in the inflammatory injury of vascular endothelial cells associated with PBMCs in KD patients, and may play a crucial role in regulating inflammation. Hence, we identify a novel regulatory mechanism of vascular injury in this disease.

Immune response to intravenous immunoglobulin in patients with Kawasaki disease and MIS-C

BACKGROUNDMultisystem inflammatory syndrome in children (MIS-C) is a rare but potentially severe illness that follows exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Kawasaki disease (KD) shares several clinical features with MIS-C, which prompted the use of intravenous immunoglobulin (IVIG), a mainstay therapy for KD. Both diseases share a robust activation of the innate immune system, including the IL-1 signaling pathway, and IL-1 blockade has been used for the treatment of both MIS-C and KD. The mechanism of action of IVIG in these 2 diseases and the cellular source of IL-1β have not been defined.METHODSThe effects of IVIG on peripheral blood leukocyte populations from patients with MIS-C and KD were examined using flow cytometry and mass cytometry (CyTOF) and live-cell imaging.RESULTSCirculating neutrophils were highly activated in patients with KD and MIS-C and were a major source of IL-1β. Following IVIG treatment, activated IL-1β+ neutrophils were reduced in the circulation. In vitro, IVIG was a potent activator of neutrophil cell death via PI3K and NADPH oxidase, but independently of caspase activation.CONCLUSIONSActivated neutrophils expressing IL-1β can be targeted by IVIG, supporting its use in both KD and MIS-C to ameliorate inflammation.FUNDINGPatient Centered Outcomes Research Institute; NIH; American Asthma Foundation; American Heart Association; Novo Nordisk Foundation; NIGMS; American Academy of Allergy, Asthma and Immunology Foundation.

Bioinformatics identification of hub genes and signaling pathways regulated by intravenous immunoglobulin treatment in acute Kawasaki disease

Kawasaki disease (KD) is an acute, self-limiting form of vasculitis commonly encountered in infants and young children. Intravenous immunoglobulin (IVIG) is the primary drug used for the treatment of KD, which may significantly reduce the occurrence of coronary artery lesions. However, the specific molecular profile changes of KD caused by IVIG treatment have remained elusive and require further research. The present study was designed to identify key genes, pathways and immune cells affected by IVIG treatment using multiple bioinformatics analysis methods. The results suggested that myeloid cells and neutrophils were affected by IVIG treatment. Kyoto Encyclopedia of Genes and Genomes pathway analysis identified that hematopoietic cell lineages and osteoclast differentiation may have an important role in the mechanism of action of IVIG treatment. Immune cell analysis indicated that the levels of monocytes, M1 macrophages, neutrophils and platelets were markedly changed in patients with KD after vs. prior to IVIG treatment. The key upregulated genes, including ZW10 interacting kinetochore protein, GINS complex subunit 1 and microRNA-30b-3p in whole blood cells of patients with KD following treatment with IVIG indicated that these IVIG-targeted molecules may have important roles in KD. In addition, these genes were further examined by literature review and indicated to be involved in cell proliferation, apoptosis and virus-related immune response in patients with KD. Therefore, the present results may provide novel insight into the mechanisms of action of IVIG treatment for KD.

The Blood Gene Expression Signature for Kawasaki Disease in Children Identified with Advanced Feature Selection Methods

Kawasaki disease (KD) is an acute vasculitis, accompanied by coronary artery aneurysm, coronary artery dilatation, arrhythmia, and other serious cardiovascular diseases. So far, the etiology of KD is unclear; it is necessary to study the molecular mechanism and related factors of KD. In this study, we analyzed the expression profiles of 75 DB (identifying bacteria), 122 DV (identifying virus), 71 HC (healthy control), and 311 KD (Kawasaki disease) samples. 332 key genes related to KD and pathogen infections were identified using a combination of advanced feature selection methods: (1) Boruta, (2) Monte-Carlo Feature Selection (MCFS), and (3) Incremental Feature Selection (IFS). The number of signature genes was narrowed down step by step. Subsequently, their functions were revealed by KEGG and GO enrichment analyses. Our results provided clues of potential molecular mechanisms of KD and were helpful for KD detection and treatment.

In silico Identification of 10 Hub Genes and an miRNA-mRNA Regulatory Network in Acute Kawasaki Disease

Kawasaki disease (KD) causes acute systemic vasculitis and has unknown etiology. Since the acute stage of KD is the most relevant, the aim of the present study was to identify hub genes in acute KD by bioinformatics analysis. We also aimed at constructing microRNA (miRNA)–messenger RNA (mRNA) regulatory networks associated with acute KD based on previously identified differentially expressed miRNAs (DE-miRNAs). DE-mRNAs in acute KD patients were screened using the mRNA expression profile data of GSE18606 from the Gene Expression Omnibus. The functional and pathway enrichment analysis of DE-mRNAs were performed with the DAVID database. Target genes of DE-miRNAs were predicted using the miRWalk database and their intersection with DE-mRNAs was obtained. From a protein–protein interaction (PPI) network established by the STRING database, Cytoscape software identified hub genes with the two topological analysis methods maximal clique centrality and Degree algorithm to construct a miRNA-hub gene network. A total of 1,063 DE-mRNAs were identified between acute KD and healthy individuals, 472 upregulated and 591 downregulated. The constructed PPI network with these DE-mRNAs identified 38 hub genes mostly enriched in pathways related to systemic lupus erythematosus, alcoholism, viral carcinogenesis, osteoclast differentiation, adipocytokine signaling pathway and tumor necrosis factor signaling pathway. Target genes were predicted for the up-regulated and down-regulated DE-miRNAs, 10,203, and 5,310, respectively. Subsequently, 355, and 130 overlapping target DE-mRNAs were obtained for upregulated and downregulated DE-miRNAs, respectively. PPI networks with these target DE-mRNAs produced 15 hub genes, six down-regulated and nine upregulated hub genes. Among these, ten genes (ATM, MDC1, CD59, CD177, TRPM2, FCAR, TSPAN14, LILRB2, SIRPA, and STAT3) were identified as hub genes in the PPI network of DE-mRNAs. Finally, we constructed the regulatory network of DE-miRNAs and hub genes, which suggested potential modulation of most hub genes by hsa-miR-4443 and hsa-miR-6510-5p. SP1 was predicted to potentially regulate most of DE-miRNAs. In conclusion, several hub genes are associated with acute KD. An miRNA–mRNA regulatory network potentially relevant for acute KD pathogenesis provides new insights into the underlying molecular mechanisms of acute KD. The latter may contribute to the diagnosis and treatment of acute KD.

SARS-CoV-2 spike protein binds to bacterial lipopolysaccharide and boosts proinflammatory activity

There is a link between high lipopolysaccharide (LPS) levels in the blood and the metabolic syndrome, and metabolic syndrome predisposes patients to severe COVID-19. Here, we define an interaction between SARS-CoV-2 spike (S) protein and LPS, leading to aggravated inflammation in vitro and in vivo. Native gel electrophoresis demonstrated that SARS-CoV-2 S protein binds to LPS. Microscale thermophoresis yielded a KD of ∼47 nM for the interaction. Computational modeling and all-atom molecular dynamics simulations further substantiated the experimental results, identifying a main LPS-binding site in SARS-CoV-2 S protein. S protein, when combined with low levels of LPS, boosted nuclear factor-kappa B (NF-κB) activation in monocytic THP-1 cells and cytokine responses in human blood and peripheral blood mononuclear cells, respectively. The in vitro inflammatory response was further validated by employing NF-κB reporter mice and in vivo bioimaging. Dynamic light scattering, transmission electron microscopy, and LPS-FITC analyses demonstrated that S protein modulated the aggregation state of LPS, providing a molecular explanation for the observed boosting effect. Taken together, our results provide an interesting molecular link between excessive inflammation during infection with SARS-CoV-2 and comorbidities involving increased levels of bacterial endotoxins.

Neutropenia Is Not Associated With the Outcomes in Patients With Kawasaki Disease

Objective: To investigate the outcomes of coronary artery lesions (CALs) and intravenous immunoglobulin (IVIG) resistance in patients with and without neutropenia during the disease course and to explore the relationships between Δ absolute neutrophils count (ΔANC) and the outcomes. Methods: We retrospectively reviewed the medical records of patients hospitalized in Children's Hospital of Soochow University with a main diagnosis of KD during January 2019 and December 2019. 1:4 propensity score matching was carried out to adjust the baseline characteristics. Smoothed plots and threshold effect analyses were performed to reveal the relationships between ΔANC and the outcomes. Results: Of the 438 patients enrolled, 75 (17.1%) were neutropenia cases and 363 (82.9%) were non-neutropenia cases. Patients with neutropenia were younger, had lower levels of initial ANC, white blood cell (WBC) count and C-reactive protein (CRP). Propensity score matching included 75 neutropenia and 247 non-neutropenia patients. No significant difference was found between neutropenia and non-neutropenia groups regarding CALs, coronary artery aneurysms, irregular coronary lumen, IVIG resistance and days of fever duration. There was a non-linear relationship between ΔANC and IVIG resistance. However, threshold effect analysis showed the incidence of IVIG resistance decreased with increasing ΔANC before the turning point (ΔANC = 1.6) (OR = 0.65, 95% CI = 0.50-0.8.4 P = 0.001). On the other hand, there was a linear relationship between ΔANC and CALs, even after adjusting the confounders (OR = 1.06, 95% CI = 1.02-1.11, P = 0.008). Conclusions: Neutropenia after IVIG was not exactly associated with the outcomes. However, ΔANC was in relation to CALs and IVIG resistance.

Molecular Mechanisms for Regulation of Neutrophil Apoptosis under Normal and Pathological Conditions

Neutrophils are one of the main cells of innate immunity that perform a key effector and regulatory function in the development of the human inflammatory response. Apoptotic forms of neutrophils are important for regulating the intensity of inflammation and restoring tissue homeostasis. This review summarizes current data on the molecular mechanisms of modulation of neutrophil apoptosis by the main regulatory factors of the inflammatory response-cytokines, integrins, and structural components of bacteria. Disturbances in neutrophil apoptosis under stress are also considered, molecular markers of changes in neutrophil lifespan associated with various diseases and pathological conditions are presented, and data on pharmacological agents for modulating apoptosis as potential therapeutics are also discussed.

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.

Enhanced Pro-apoptotic Effects of Fe(II)-Modified IVIG on Human Neutrophils

Mild modification of intravenous immunoglobulin (IVIG) has been reported to result in enhanced polyspecificity and leveraged therapeutic effects in animal models of inflammation. Here, we observed that IVIG modification by ferrous ions, heme or low pH exposure, shifted the repertoires of specificities in different directions. Ferrous ions exposed Fe(II)-IVIG, but not heme or low pH exposed IVIG, showed increased pro-apoptotic effects on neutrophil granulocytes that relied on a FAS-dependent mechanism. These effects were also observed in human neutrophils primed by inflammatory mediators or rheumatoid arthritis joint fluid in vitro, or patient neutrophils ex vivo from acute Crohn's disease. These observations indicate that IVIG-mediated effects on cells can be enhanced by IVIG modification, yet specific modification conditions may be required to target specific molecular pathways and eventually to enhance the therapeutic potential.

Enhanced formation of neutrophil extracellular traps in Kawasaki disease

BACKGROUND

Neutrophils contribute to the clearance of pathogens through the formation of neutrophil extracellular traps (NETs) in a process known as NETosis, but the excessive release of NETs has been reported to be involved in the pathogenesis of various diseases, including vasculitis, by inducing tissue injury. The aim of the present study was to investigate whether or not NETosis is enhanced in the acute phase of Kawasaki disease (KD).

METHODS

After neutrophils isolated from the peripheral blood of patients with KD and healthy control (HC) were cultured in vitro, the degree of spontaneous NETosis was evaluated by measuring the number of NETs formed and the titers of cell-free DNA (cfDNA) and neutrophil elastase (NE)-DNA complex.

RESULTS

Spontaneous NET formation in vitro was observed in neutrophils isolated from KD patients, and the number of NET formations was significantly higher in acute KD than in convalescent KD and HC. The increased levels of cfDNA and NE-DNA complexes in the acute phase of KD tended to decrease in the convalescent phase.

CONCLUSIONS

Spontaneous NET formation was enhanced in neutrophils from patients with acute KD, suggesting that circulating neutrophils may be primed to undergo NETosis in KD vasculitis.

The elevated serum levels of calcineurin and nuclear factor of activated T-cells 1 in children with Kawasaki disease

BACKGROUND

The calcineurin and nuclear factor of activated T-cells (CaN-NFAT) signaling pathway had been found to be associated with Kawasaki disease (KD) susceptibility and coronary artery aneurysm formation as a contributor. To evaluate serum calcineurin (CaN) and nuclear factor of activated T-cells 1(NFAT1) levels in patients with Kawasaki disease (KD).

METHODS

Serum levels of CaN and NFAT1 were measured by enzyme-linked immunosorbent assay method in 66 healthy children and 74 KD patients at acute, afebrile and subacute stage.

RESULTS

The serum levels of CaN and NFAT1 increased significantly in the acute stage, and decreased progressively in the afebrile and subacute stage, along with the reduction of C-reactive protein, white blood cells and neutrophil counts. And in the acute stage, the afebrile stage and the subacute stage, the expression of CaN and NFAT1 was upregulated significantly in KD patients compared to that in the healthy control. After the IVIG treatment, the serum levels of CaN and NFAT1 declined significantly in IVIG responders. However, the CaN and NTAT1 levels in the IVIG non-responders declined slowly. And in the afebrile stage, the NFAT1 levels were lower in KD patients with coronary artery lesions (CALs) (268.82 ± 11.96 ng/ml) than those without CALs (285.84 ± 25.13 ng/ml). However, the serum levels of CaN in KD patients with CALs had no significant difference with those in KD patients without CALs.

CONCLUSIONS

The specific regulation of CaN and NFAT1 serum levels in the course of KD was suggested that both of them were related in the development of KD.

Increased Neutrophil Respiratory Burst Predicts the Risk of Coronary Artery Lesion in Kawasaki Disease

Background: Kawasaki diseases (KD) is a febrile systemic vasculitis in infants associated with coronary aneurysm. The etiology of KD remains unclear. Human neutrophils have great capacity to cause tissue damage in inflammatory diseases via their inappropriate activation to release reactive oxygen species (ROS). Brain natriuretic peptide (BNP) is a substantial modulator of neutrophil activation to regulate ROS production. It is increasingly released from the myocardium in heart failure and myocardial inflammatory states. Objective: The purpose of this study was to explore the potential role of neutrophil respiratory burst in the pathogenesis of coronary artery lesions (CAL) in KD. Materials and Methods: A total of 78 children were enrolled. Of all the cases, 20 cases are healthy control (HC), 20 are with coronary artery lesion (CAL), and 38 are with non-coronary artery lesion (NCAL). The activation ratio of neutrophils was evaluated by flow cytometry. In addition, plasma levels of BNP were detected. Results: Our results showed that the activation ratio of neutrophils in KD with CAL is significantly higher than the other two groups (HC and NCAL). Besides, the plasma levels of BNP in KD (with or without CAL) were higher than that in HC. Conclusions: These findings suggested that neutrophil respiratory burst may play a significant role in the pathogenesis of CAL, and predicts the risk of CAL in Kawasaki disease.

Lower CMV and EBV Exposure in Children With Kawasaki Disease Suggests an Under-Challenged Immune System

Background: Kawasaki Disease (KD) is a pediatric vasculitis of which the pathogenesis is unclear. The hypothesis is that genetically pre-disposed children develop KD when they encounter a pathogen which remains most often unidentified or pathogen derived factors. Since age is a dominant factor, prior immune status in children could influence their reactivity and hence the acquisition of KD. We hypothesized that systemic immune responses early in life could protect against developing KD. With this study we tested whether the incidence of previous systemic cytomegalovirus (CMV) or Epstein-Barr virus (EBV) infection is lower in children with KD compared to healthy age-matched controls. Methods and Results: We compared 86 KD patients with an age-matched control group regarding CMV and EBV VCA IgG measurements (taken before or 9 months after IVIG treatment). We found that both CMV and EBV had an almost 2-fold lower seroprevalence in the KD population than in the control group. Conclusions: We suggest that an under-challenged immune system causes an altered immune reactivity which may affect the response to a pathological trigger causing KD in susceptible children.

A comparison of efficacy of six prediction models for intravenous immunoglobulin resistance in Kawasaki disease

Background

Kawasaki disease (KD) is the most common pediatric vasculitis. Several models have been established to predict intravenous immunoglobulin (IVIG) resistance. The present study was aimed to evaluate the efficacy of prediction models using the medical data of KD patients.

Methods

We collected the medical records of patients hospitalized in the Department of Cardiology in Children’s Hospital of Soochow University with a diagnosis of KD from Jan 2015 to Dec 2016. IVIG resistance was defined as recrudescent or persistent fever ≥36 h after the end of their IVIG infusion.

Results

Patients with IVIG resistance tended to be younger, have higher occurrence of rash and changes of extremities. They had higher levels of c-reactive protein, aspartate aminotransferase, neutrophils proportion (N%), total bilirubin and lower level of albumin. Our prediction model had a sensitivity of 0.72 and a specificity of 0.75. Sensitivity of Kobayashi, Egami, Kawamura, Sano and Formosa were 0.72, 0.44, 0.48, 0.20, and 0.68, respectively. Specificity of these models were 0.62, 0.82, 0.66, 0.91, and 0.48, respectively.

Conclusions

Our prediction model had a powerful predictive value in this area, followed by Kobayashi model while all the other prediction models had less excellent performances than ours.

A critical appraisal of the role of intracellular Ca2+-signaling pathways in Kawasaki disease

Kawasaki disease is a multi-systemic vasculitis that generally occurs in children and that can lead to coronary artery lesions. Recent studies showed that Kawasaki disease has an important genetic component. In this review, we discuss the single-nucleotide polymorphisms in the genes encoding proteins with a role in intracellular Ca²⁺ signaling: inositol 1,4,5-trisphosphate 3-kinase C, caspase-3, the store-operated Ca²⁺-entry channel ORAI1, the type-3 inositol 1,4,5-trisphosphate receptor, the Na⁺/Ca²⁺ exchanger 1, and phospholipase Cß4 and Cß1. An increase of the free cytosolic Ca²⁺ concentration is proposed to be a major factor in susceptibility to Kawasaki disease and disease outcome, but only for polymorphisms in the genes encoding the inositol 1,4,5-trisphosphate 3-kinase C and the Na⁺/Ca²⁺ exchanger 1, the free cytosolic Ca²⁺ concentration was actually measured and shown to be increased. Excessive cytosolic Ca²⁺ signaling can result in hyperactive calcineurin in T cells with an overstimulated nuclear factor of activated T cells pathway, in hypersecretion of interleukin-1ß and tumor necrosis factor-α by monocytes/macrophages, in increased urotensin-2 signaling, and in an overactivation of vascular endothelial cells.

Inhibition of neutrophil activity in cardiac surgery with cardiopulmonary bypass: a novel strategy with the leukocyte inhibition module

Recently, we showed that the arterial in-line application of the leukocyte inhibition module (LIM) within the heart-lung machine limits overshooting leukocyte activity and cardiac tissue damage. Moreover, significantly better cardiac function was found in an experimental animal model when LIM was used. In the meantime, the first promising clinical data exist. LIM has to be regarded as an essential tool in extracorporeal circulation, in the future, to improve postoperative clinical outcome and to reduce costs. This review summarizes the biological background of LIM and the current experience obtained in experimental models and clinical studies.

Transient Deformation of Neutrophils in Kawasaki Disease

In the treatment of Kawasaki disease, resistance to high-dose immunoglobulin intravenous (IGIV) can occur. The neutrophil morphology analyses in 17 patients revealed that transient pseudo-Pelger-Huët anomaly was more frequently detected in the IGIV-resistant group. This finding may aid the prediction of IGIV resistance.

Oocytes lacking O-glycans alter follicle development and increase fertility by increasing follicle FSH sensitivity, decreasing apoptosis, and modifying GDF9:BMP15 expression

The number of eggs ovulated varies within and between species and is influenced by many variables. However, the regulatory mechanisms remain poorly understood. We previously demonstrated a key role for the oocyte because mice generating oocytes deficient in core 1-derived O-glycans ovulate ∼40-50% more eggs than Controls. Here we analyze the basis of this phenotype using Mutant [core 1 β1,3-galactosyltransferase 1 (C1galt1)(FF):zona pellucida glycoprotein 3 Cre (ZP3Cre)] and Control (C1galt1(FF)) female mice. In culture, Mutant follicles exhibited delayed antrum formation [indicative of follicle stimulant hormone (FSH) dependence] and increased sensitivity to FSH. Although the Mutant estrous cycle was extended, comprehensive endocrine changes were not observed; rather FSH, LH, inhibin B, and anti-Mullerian hormone were temporally altered, revealing estrous cycle stage-specific modifications to the hypothalamic-pituitary-gonadal axis. At proestrus, when FSH levels were decreased in Mutants, ovaries contained more, smaller, preantral follicles. Mutant follicles exhibited reduced levels of apoptosis, and both B-cell lymphoma 2 (Bcl-2) and BCL-2-associated X protein (Bax) were altered compared with Controls. Mutant ovaries also had an increase in the expression ratio of growth differentiation factor 9 (GDF9):bone morphogenetic protein 15 (BMP15) at diestrus. On the basis of these data, we propose that modified oocyte glycoproteins alter GDF9:BMP15 expression modifying follicle development resulting in the generation of more follicles. Thus, the oocyte is a key regulator of follicle development and has a crucial role in determining ovulation rate.

Triptolide as an Alternative to IVIG Therapy for Kawasaki Disease in a Mouse Model

BACKGROUND

Kawasaki disease is treated by immunoglobulin therapy, which has adverse side effects like renal damage.

AIMS

The aim of the present study was to explore the effectiveness of triptolide, a compound derived from threewingnut that has anti-inflammatory effects, on the treatment of Kawasaki disease in a mouse model.

STUDY DESIGN

Animal experiment.

METHODS

A mouse model of Kawasaki disease was established through exposure to Candida albicans by intraperitoneal injection. Exposed mice were then randomly divided into several groups (each n=15): model group (saline-treated), low- or high-dose triptolide groups (0.2 mg/kg or 0.4 mg/kg, respectively), and IVIG (high-dose immunoglobulin) group (1 g/kg body weight). Unexposed mice served as an additional control group. Nine weeks from the initial exposure, mice were euthanised and coronary tissues and blood samples were harvested. The rate of apoptosis was detected by TUNEL, and ICAM-1 expression was detected by immunohistochemistry in coronary endothelial cells. Serum TNF-α levels were detected by ELISA.

RESULTS

Compared to mice in the (unexposed) control group, apoptosis of endothelial cells, ICAM-1 expression, and serum TNF-α levels were significantly increased in all exposed mice (p<0.05), confirming the presence of disease. However, treatment with triptolide or IVIG significantly lowered these measures compared to untreated exposed mice (model group; p<0.05).

CONCLUSIONS

Triptolide treatment reduces markers of coronary endothelial inflammation in a mouse model of Kawasaki disease, similar to IVIG treatment, and therefore may be a useful alternative therapy for this disease.

Understanding the pathogenesis of Kawasaki disease by network and pathway analysis

Kawasaki disease (KD) is a complex disease, leading to the damage of multisystems. The pathogen that triggers this sophisticated disease is still unknown since it was first reported in 1967. To increase our knowledge on the effects of genes in KD, we extracted statistically significant genes so far associated with this mysterious illness from candidate gene studies and genome-wide association studies. These genes contributed to susceptibility to KD, coronary artery lesions, resistance to initial IVIG treatment, incomplete KD, and so on. Gene ontology category and pathways were analyzed for relationships among these statistically significant genes. These genes were represented in a variety of functional categories, including immune response, inflammatory response, and cellular calcium ion homeostasis. They were mainly enriched in the pathway of immune response. We further highlighted the compelling immune pathway of NF-AT signal and leukocyte interactions combined with another transcription factor NF- κ B in the pathogenesis of KD. STRING analysis, a network analysis focusing on protein interactions, validated close contact between these genes and implied the importance of this pathway. This data will contribute to understanding pathogenesis of KD.

A novel anti-peroxiredoxin autoantibody in patients with Kawasaki disease

Antibodies to the anti-oxidative peroxiredoxin (Prx) enzymes occur in both systemic autoimmune disease and vasculitis in adulthood. Because increased oxidative stress induces vasculitis in Kawasaki disease (KD), autoimmunity to Prxs in patients with KD was investigated. The presence of antibodies to Prx 1, 2 and 4 was analyzed by ELISA and Western blot. Of 30 patients with KD, 13 (43.3%) possessed antibodies to Prx 2, whereas these antibodies were present in only 1 of 10 patients (10.0%) with sepsis (4 with purulent meningitis and 6 with septicemia). In contrast, antibodies to Prx 1 and 4 were not detected in either group. There was no significant correlation among the titers of the three antibodies. Clinical parameters were compared between anti-Prx 2-positive and -negative patients. The presence of anti-Prx 2 antibodies correlated with a longer period of fever and poor response to high-dose γ-globulin therapy in patients with KD. Anti-Prx 2-positive patients had significantly greater excretion of urinary 8-isoprostaglandin than did anti-Prx 2-negative patients. These results provide the first evidence for an antibody to Prx 2 in patients with KD. They also suggest that this antibody might serve as a marker of disease severity and be involved in the pathophysiology of vasculitis in some patients with KD.

Decreased neutrophil apoptosis in quiescent ANCA-associated systemic vasculitis

Background

ANCA-Associated Systemic Vasculitis (AASV) is characterized by leukocytoclasis, accumulation of unscavenged apoptotic and necrotic neutrophils in perivascular tissues. Dysregulation of neutrophil cell death may contribute directly to the pathogenesis of AASV.

Methods

Neutrophils from Healthy Blood Donors (HBD), patients with AASV most in complete remission, Polycythemia Vera (PV), Systemic Lupus Erythematosus (SLE), Rheumatoid Arthritis (RA) and renal transplant recipients (TP) were incubated in vitro, and the rate of spontaneous apoptosis was measured by FACS. Plasma levels of cytokines and sFAS were measured with cytometric bead array and ELISA. Expression of pro/anti-apoptotic factors, transcription factors C/EBP-α, C/EBP-β and PU.1 and inhibitors of survival/JAK2-pathway were measured by real-time-PCR.

Results

AASV, PV and RA neutrophils had a significantly lower rate of apoptosis compared to HBD neutrophils (AASV 50±14% vs. HBD 64±11%, p<0.0001). In RA but not in AASV and PV, low apoptosis rate correlated with increased plasma levels of GM-CSF and high mRNA levels of anti-apoptotic factors Bcl-2A1 and Mcl-1. AASV patients had normal levels of G-CSF, GM-CSF and IL-3. Both C/EBP-α, C/EBP-β were significantly higher in neutrophils from AASV patients than HBD. Levels of sFAS were significantly higher in AASV compared to HBD.

Conclusion

Neutrophil apoptosis rates in vitro are decreased in AASV, RA and PV but mechanisms seem to differ. Increased mRNA levels of granulopoiesis-associated transcription factors and increased levels of sFAS in plasma were observed in AASV. Additional studies are required to define the mechanisms behind the decreased apoptosis rates, and possible connections with accumulation of dying neutrophils in regions of vascular lesions in AASV patients.

Ulinastatin, a urinary trypsin inhibitor, for the initial treatment of patients with Kawasaki disease: a retrospective study

BACKGROUND

Markedly activated neutrophils or higher plasma levels of neutrophil elastase are involved in the poor response to intravenous immunoglobulin (IVIG) and the formation of coronary artery lesions (CAL) in patients with acute Kawasaki disease. We hypothesized that ulinastatin (UTI), by both direct and indirect suppression of neutrophils, would reduce the occurrence of CAL.

METHODS AND RESULTS

We retrospectively analyzed the clinical records of patients with Kawasaki disease between 1998 and 2009. Three hundred sixty-nine patients were treated with a combination of UTI, aspirin, and IVIG as an initial treatment (UTI group), and 1178 were treated with a conventional initial treatment, and IVIG with aspirin (control group). The baseline characteristics did not demonstrate notable differences between the two groups. The occurrence of CAL was significantly lower in the UTI group than in the control group (3% versus 7%; crude odds ratio [OR], 0.46; 95% confidence interval [CI], 0.25-0.86; P=0.01). The OR adjusted for sex, Gunma score (the predictive score for IVIG unresponsiveness), and dosage of initial IVIG (1 or 2 g/kg) was 0.32 (95% CI, 0.17-0.60; P<0.001). In addition, most CAL occurred in patients requiring additional rescue treatment and the proportion of those patients was significantly lower in the UTI group than in the control group (13% versus 22%; crude OR, 0.52; 95% CI, 0.38-0.73; P<0.001). The adjusted OR was 0.30 (95% CI, 0.20-0.44; P<0.001).

CONCLUSIONS

UTI was associated with fewer patients requiring additional rescue treatment and reduction of CAL in this retrospective study.

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.

Common variants in CASP3 confer susceptibility to Kawasaki disease

Kawasaki disease (KD; OMIM 611775) is an acute vasculitis syndrome which predominantly affects small- and medium-sized arteries of infants and children. Epidemiological data suggest that host genetics underlie the disease pathogenesis. Here we report that multiple variants in the caspase-3 gene (CASP3) that are in linkage disequilibrium confer susceptibility to KD in both Japanese and US subjects of European ancestry. We found that a G to A substitution of one commonly associated SNP located in the 5' untranslated region of CASP3 (rs72689236; P = 4.2 x 10(-8) in the Japanese and P = 3.7 x 10(-3) in the European Americans) abolished binding of nuclear factor of activated T cells to the DNA sequence surrounding the SNP. Our findings suggest that altered CASP3 expression in immune effecter cells influences susceptibility to KD.

Neonatal neutrophils with prolonged survival secrete mediators associated with chronic inflammation

BACKGROUND

The resolution of inflammation involves the efficient removal of apoptotic neutrophils (PMN). However, a subpopulation of PMN that are resistant to apoptosis may contribute to PMN persistence in tissues, an early hallmark of chronic inflammation. We previously made observations that neonatal PMN with prolonged survival had augmented expression of CD18/CD11b, an adhesion molecule critical to inflammation.

OBJECTIVES

The objectives of this study were to test the hypothesis that surviving neonatal PMN retain the capacity to secrete key mediators associated with chronic inflammation.

METHODS

We profiled cytokine and chemokine secretion patterns of lipopolysaccharide (LPS)-stimulated neonatal and adult PMN using multicytokine array and ELISA.

RESULTS

We observed that surviving 24-hour neonatal PMN stimulated with LPS had enhanced secretion of interleukin (IL)-8, a chemokine involved in PMN activation and recruitment. In addition, 24-hour neonatal PMN secreted levels of monocyte inhibitory protein (MIP)-1β that were higher than those secreted by 0-hour PMN, but amounts of IL-1 receptor antagonist (IL-1Ra) were lower.

CONCLUSIONS

The results of the present study extend previous observations of augmented function in surviving neonatal neutrophils, and further suggest their potential contribution to the pathogenesis of inflammatory disorders in neonates.

A unique plasma proteomic profiling with imbalanced fibrinogen cascade in patients with Kawasaki disease

Kawasaki disease (KD) is the leading cause of acquired heart disease during childhood in the developed countries. The mechanism and biomarkers of KD remain to be determined. In this study, we sought to elucidate potential plasma proteomic markers in KD patients in comparison to that in febrile controls. Plasma samples from KD patients and febrile controls were subjected to two-dimensional polyacrylamide gel electrophoresis analysis. Differential protein displays between KD patients and febrile controls were determined. Fibrinogen beta and gamma chains, alpha-1-antitrypsin (A1AT), CD5 antigen-like precursor (CD5L), and clusterin were increased in KD patients, whereas immunoglobulin free light chains were decreased, as compared with controls. The differential protein displays were validated with enzyme-linked immunosorbent assay tests. We found higher fibrinogen-related proteins (fibrinogen, A1AT, clusterin, and CD5L), along with a lower level of the immunoglobulin free light chains that involve fibrin degradation in KD. Results from this study showing a unique proteomic profiling with abnormal fibrinogen cascade may afford a good biomarker of KD and a better strategy to prevent cardiovascular complications of KD by correcting abnormal fibrin deposition or degradation.

Neutropenia in the acute phase of Kawasaki disease and prevention of coronary artery aneurysm

BACKGROUND

The significance of neutropenia in Kawasaki disease (KD) has not been fully elucidated as yet.

METHODS

Subjects were retrospectively sampled from two clinical trials. These patients treated with aspirin alone (ASA) and PolyglobinN-Bayel (PolyN) given as i.v. immunoglobulin were categorized as ASA-early (n = 0), ASA-late (n = 8), PolyN-early (n = 18), or PolyN-late (n = 27) based on the therapy administered and the incidence of neutropenia before the 10th day of illness (DI) and after 11 DI. Data regarding the time of onset of neutropenia, and incidence of coronary artery lesion (CAL) formation were obtained. P < 0.05 was considered statistically significant.

RESULTS

No patients in the ASA group exhibited neutropenia within 10 DI. The time of onset of neutropenia in the PolyN-early group was 8 +/- 1.3 DI. That in the PolyN-late group (19.8 +/- 8 DI) was earlier than in the ASA-late group (26.6 +/- 14 DI; P < 0.025). PolyN-early patients had a lower incidence of CAL formation than ASA-non patients (patients without neutropenia in the ASA group; P = 0.00019) and ASA-late patients (P = 0.04). That in the PolyN-early group tended to be lower than in the PolyN-late group (P < 0.1).

CONCLUSION

Early neutropenia indicated that circulating neutrophils within 10 DI may play an indispensable role in the following sequence to CAL formation in KD.

Delayed neutrophil apoptosis in patients with unstable angina: relation to C-reactive protein and recurrence of instability

AIMS

To investigate spontaneous polymorphonuclear neutrophils (PMNs) apoptosis in unstable angina (UA) and its association with recurrence of instability.

METHODS AND RESULTS

We compared PMNs apoptotic rate at 4 and 24 h in patients with UA, stable angina (SA), and controls (H) with two different protocols by flow cytometry. We measured apoptotic rate of isolated PMNs (Protocol 1) in 30 UA patients, 13 SA patients, and 34 H; and apoptosis of PMNs in whole blood culture (Protocol 2) in further 10 UA patients, 7 SA patients, and 6 H. Serum high-sensitivity C-reactive protein was also measured. Polymorphonuclear neutrophils of UA patients showed a decreased apoptotic rate compared with SA patients and H at 4 h in Protocol 1 (both P < 0.01), and at 24 h in Protocol 2 (P < 0.05 and <0.01, respectively). In overall population, a negative correlation was found between apoptotic rate at 4 h and high-sensitivity C-reactive protein levels (P < 0.01). Six among 40 patients with UA had early recurrence of symptoms and their apoptotic rate was significantly reduced compared with UA patients without recurrence of symptoms (P = 0.024).

CONCLUSIONS

Our study demonstrates delayed PMN apoptosis in UA. This alteration might be involved in the persistence of inflammatory activation and affects recurrence of instability.

Neutrophil survival factors (TNF-alpha, GM-CSF, and G-CSF) produced by macrophages in cats infected with feline infectious peritonitis virus contribute to the pathogenesis of granulomatous lesions

Feline infectious peritonitis (FIP) is a feline coronavirus (FCoV)-induced fatal disease of domestic and wild cats. The infiltration of neutrophils into granulomatous lesions is unusual for a viral disease, but it is a typical finding of FIP. This study aimed to investigate the reason for the lesions containing neutrophils in cats with FIP. Neutrophils of cats with FIP were cultured, and changes in the cell survival rate were assessed. In addition, the presence or absence of neutrophil survival factors was investigated in specimens collected from cats with FIP. Furthermore, it was investigated whether macrophages, one of the target cells of FIPV infection, produce neutrophil survival factors (TNF-alpha, GM-CSF, and G-CSF). We showed that virus-infected macrophages overproduce neutrophil survival factors, and these factors act on neutrophils and up-regulate their survival. These observations suggest that sustained production of neutrophil survival factors by macrophages during FCoV infection is sufficient for neutrophil survival and contributes to development of granulomatous lesions.

A genome-wide association study identifies novel and functionally related susceptibility Loci for Kawasaki disease

Kawasaki disease (KD) is a pediatric vasculitis that damages the coronary arteries in 25% of untreated and approximately 5% of treated children. Epidemiologic data suggest that KD is triggered by unidentified infection(s) in genetically susceptible children. To investigate genetic determinants of KD susceptibility, we performed a genome-wide association study (GWAS) in 119 Caucasian KD cases and 135 matched controls with stringent correction for possible admixture, followed by replication in an independent cohort and subsequent fine-mapping, for a total of 893 KD cases plus population and family controls. Significant associations of 40 SNPs and six haplotypes, identifying 31 genes, were replicated in an independent cohort of 583 predominantly Caucasian KD families, with NAALADL2 (rs17531088, p(combined) = 1.13 x 10(-6)) and ZFHX3 (rs7199343, p(combined) = 2.37 x 10(-6)) most significantly associated. Sixteen associated variants with a minor allele frequency of >0.05 that lay within or close to known genes were fine-mapped with HapMap tagging SNPs in 781 KD cases, including 590 from the discovery and replication stages. Original or tagging SNPs in eight of these genes replicated the original findings, with seven genes having further significant markers in adjacent regions. In four genes (ZFHX3, NAALADL2, PPP1R14C, and TCP1), the neighboring markers were more significantly associated than the originally associated variants. Investigation of functional relationships between the eight fine-mapped genes using Ingenuity Pathway Analysis identified a single functional network (p = 10(-13)) containing five fine-mapped genes-LNX1, CAMK2D, ZFHX3, CSMD1, and TCP1-with functional relationships potentially related to inflammation, apoptosis, and cardiovascular pathology. Pair-wise blood transcript levels were measured during acute and convalescent KD for all fine-mapped genes, revealing a consistent trend of significantly reduced transcript levels prior to treatment. This is one of the first GWAS in an infectious disease. We have identified novel, plausible, and functionally related variants associated with KD susceptibility that may also be relevant to other cardiovascular diseases.

Fas/FasL interaction: a novel immune therapy approach with immobilized biologicals

Systemically applied agents to modulate the Fas/FasL system, e.g., by stimulation of Fas on activated leukocytes or tumor cells failed as strategies in immune therapy due to severe toxic effects in the host. Recently, a novel strategy has been developed by using immobilized immune active biologicals in a medical device that may allow immune management without expensive systemic therapy. This review reports on the potential role of Fas/FasL in immune therapy and summarizes current experimental and clinical data with the leukocyte inhibition module (LIM), an immobilized anti-Fas antibody containing device yet used in extracorporeal blood circulation. This proof of principal may stimulate the development of other devices based on the regulation of Fas/FasL or other targets relevant for immune disorders.

gamma-Globulin-induced modulation with necrotic-like morphology of peripheral blood neutrophils

To determine the effect of intravenous immunoglobulin-administration on neutrophil function, we obtained neutrophils from patients with an acute phase of Kawasaki disease. In vitro IgG-induced modulation of neutrophils into Annexin-V-positive and propidium iodide-negative cells was observed in 20 of 28 patients in the presence of more than 300 microg/ml IgG and showed necrosis-like changes in morphologic features. However, we could not find any patients showing promotion of the sub-G1 cell fraction on DNA content analysis. The modulatory effect of in vitro IgG was not observed in neutrophils from healthy volunteers and was significantly correlated with the antifebrile effect of in vivo IgG.

Neonatal neutrophils with prolonged survival exhibit enhanced inflammatory and cytotoxic responsiveness

Apoptosis is critical to the resolution of inflammation, as it promotes the removal of neutrophils (PMN) by the reticuloendothelial system. In contrast, PMN persistence characterizes the early stages of chronic inflammation. Adult PMN with delayed senescence retain some functionality, although this has not been described for neonatal PMN. We hypothesized that neonatal PMN with prolonged survival retain cytotoxic and inflammatory function. To test one aspect of inflammatory function, we determined surface CD11b expression on 0-h and 24-h PMN after chemotactic formyl-methionine-leucine-phenylalanine (fMLP) stimulation. Although fMLP induced a greater percentage up-regulation of CD11b on 0-h adult PMN, this was similar between nonapoptotic cord blood and adult PMN at 24 h. Furthermore, percentage up-regulation of CD11b was more robust for 24-h than for 0-h cord blood PMN. In contrast, there was no difference in responsiveness between 0-h and 24-h adult PMN. In studies of cytotoxic potential, we determined the expression of reactive oxygen intermediates (ROI) in phorbol 12-myristate 13-acetate-stimulated cord blood and adult PMN at 0 h and in 24-h nonapoptotic PMN, using the dihydrorhodamine 123 assay. Stimulated cord blood PMN generated more ROI than did adult PMN at both 0 h and 24 h; in addition, ROI levels in 24-h cord blood PMN were similar to those of 0-h adult PMN. We conclude that PMN with prolonged survival retain specific cytotoxic and inflammatory functions, and these are enhanced in cord blood PMN. We speculate that neonatal PMN with prolonged survival have the functional capacity to contribute to the pathogenesis of inflammatory disorders.

Suppressive effect of intravenous immunoglobulin on peripheral blood neutrophil count in patients with idiopathic thrombocytopenic purpura

PURPOSE

To determine the effect of intravenous immunoglobulin (IVIG) on neutrophil count, the authors studied patients with idiopathic thrombocytopenic purpura (ITP).

PATIENTS AND METHODS

Thirty-one of 40 patients with ITP were treated with an IVIG regimen (400 mg/kg/daily for 5 days), while the other 9 were observed without any medications. Peripheral samples were examined during the clinical course.

RESULTS

The absolute neutrophil count in 22 patients with no fever as a side effect decreased significantly by day 2 after the start of IVIG, but in most patients it began to increase soon after the last IVIG. There was also a significant difference between the decreased level of the absolute neutrophil count in patients with and without IVIG. However, re-administration of IVIG within 2 weeks did not significantly suppress the neutrophil count. In contrast, the neutrophil count increased in every patient with a fever as a side effect of IVIG.

CONCLUSIONS

IVIG induced a decrease in peripheral blood neutrophil count in patients with ITP.

In vivo inhibition of neutrophil activity by a FAS (CD95) stimulating module: arterial in-line application in a porcine cardiac surgery model

OBJECTIVE

Cardiac surgery with cardiopulmonary bypass is associated with aberrant neutrophil activation and potentially severe pathogenic sequelae. This experimental study was done to evaluate a leukocyte inhibition module that rapidly inactivates neutrophils through CD95 stimulation.

METHODS

German landrace pigs (4 groups, each n = 5) underwent cardiac surgery without cardiopulmonary bypass (group I), with cardiopulmonary bypass (group II), with cardiopulmonary bypass plus a leukocyte filter (group III), and with cardiopulmonary bypass plus a leukocyte inhibition module (group IV). The leukocyte filter or leukocyte inhibition module was introduced into the arterial line of the heart-lung machine.

RESULTS

Leukocyte counts were decreased by up to 43% in group IV compared with values in group II (P =.023). In group IV, but not in groups I to III, no delay in spontaneous neutrophil apoptosis was observed after annexin V-propidium iodide staining. Late apoptotic (11.7%) or necrotic neutrophils (9.3%) were detected in 2 animals (group IV). Tumor necrosis factor alpha serum levels increased over time in groups I to III (>2-fold) but remained at baseline levels in group IV (P <.05). Interleukin 8-mediated chemotactic neutrophil transmigration activity increased over time in groups I to III but was totally abrogated in group IV at any time point. The perioperative increase of creatine kinase and creatine kinase MB levels was lower in groups III (1.5-fold and 1.3-fold, respectively) and IV (1.2-fold and 1.5-fold, respectively) compared with values in group II (both 1.9-fold).

CONCLUSIONS

The leukocyte inhibition module downregulated cardiopulmonary bypass-related neutrophil activity and thus might be beneficial in cardiac surgery and other clinical settings with unappreciated neutrophil activation.

The role of anti-endothelial cell antibodies in Kawasaki disease - in vitro and in vivo studies

Kawasaki disease (KD) is a systemic vasculitis with cardiac and noncardiac complications. Anti--endothelial cell antibodies (AECA) are found among many patients with KD. The aim of this study was to investigate the pathogenic role of AECA in KD using in vitro and in vivo experimental models. F(ab)2 fragments of IgG-AECA and IgM-AECA were affinity purified from a patient with active KD. Their endothelial binding and ability to induce a pro-adhesive and a pro-inflammatory phenotype were evaluated in vitro. Twenty Balb/C mice were immunized with KD-AECA or with control Ig (N-Ig) to induce AECA in a murine model by the idiotypic manipulation method. Both KD-AECA isotypes bind significantly to human umbilical vein endothelial cell (HUVEC) compared to N-Ig. The in vitro activity was demonstrated by the antibodies ability to activate endothelial cells resulting in increased IL-6 secretion, adhesion molecule expression and monocytic cell line (U937) adherence to HUVEC. Five of the mice that received KD-AECA developed murine AECA after 3 months. None of the mice that received N-Ig produced AECA. The murine AECA increased monocyte adhesion to EC in vitro, similarly to the AECA used for immunization. Furthermore, all the mice that developed AECA had proteinuria and IgG deposition in the renal mesangium. No histological or immunofluorescence evidence of cardiac vasculitis could be detected. AECA might play a role in the emergence of some of KD manifestations.

Intravenous immunoglobulin therapy induces neutrophil apoptosis in Kawasaki disease

To investigate the effect of high-dose intravenous immunoglobulin (IVIg) on neutrophil apoptosis in Kawasaki disease (KD), we studied the in vitro spontaneous and IVIg-induced apoptosis of neutrophils by analyzing a proportion of annexin V-positive cells and cells with fragmented DNA. The mean number of peripheral neutrophils in the post-IVIg phase decreased significantly (P < 0.01) compared with that in the pre-IVIg phase. The mean proportion of spontaneous apoptotic neutrophils in the post-IVIg phase was significantly higher (P < 0.01) than that in the pre-IVIg phase, and there was a significantly positive correlation (P < 0.01) with the reduction ratio of the circulating neutrophil counts from the pre-IVIg through the post-IVIg phases. IVIg induced a dose-dependent increase in the proportion of apoptotic neutrophils in the pre-IVIg phase. As a result, the present study demonstrated a novel action in which high-dose IVIg therapy decreased the number of circulating neutrophils by accelerating their apoptosis in KD.