Increased CD11b expression on polymorphonuclear leucocytes and cytokine profiles in patients with 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.

Innate immune dysregulation in multisystem inflammatory syndrome in children (MIS-C)

MIS-C is a systemic inflammation disorder with poorly characterised immunopathological mechanisms. We compared changes in the systemic immune response in children with MIS-C (n = 12, 5-13 years) to healthy controls (n = 14, 5-15 years). Analysis was done in whole blood treated with LPS. Expression of CD11b and Toll-like receptor-4 (TLR4) in neutrophils and monocytes were analysed by flow cytometry. Serum cytokines (IL-1β, IL-2, IL-6, IL-8, IL-10, IL-Ira, TNF-α, TNF-β, IFN-Υ, VEGF, EPO and GM-CSF) and mRNA levels of inflammasome molecules (NLRP3, ASC and IL-1β) were evaluated. Subpopulations of lymphocytes (CD3+, CD19+, CD56+, CD4+, CD8+, TCR Vδ1+, TCR Vδ2+) were assessed at basal levels. Absolute counts of neutrophils and NLR were high in children with MIS-C while absolute counts of lymphocytes were low. Children with MIS-C had increased levels of IL-6, IL-10, TNF-β and VEGF serum cytokines at the basal level, and significantly increased TNF-β post-LPS, compared to controls. IL-1RA and EPO decreased at baseline and post-LPS in MIS-C patients compared to controls. The percentage of CD3+ cells, NK cells and Vδ1 was lower while B cells were higher in children with MIS-C than in controls. Dysregulated immune response in children with MIS-C was evident and may be amenable to immunomodulation.

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.

Expression of Eosinophilic Subtype Markers in Patients with Kawasaki Disease

PURPOSE

Eosinophils may rise to a higher level in the acute phase of Kawasaki disease (KD) both before and after intravenous immunoglobulin (IVIG) therapy. A substantial body of research was carried out on the association between KD and allergic diseases. Eosinophils play an important role in type 2 inflammation. Recent studies have shown that there are two distinct subtypes of eosinophils. In addition to their role in inflammation, lung-resident eosinophils (rEOS) also regulate homeostasis. Inflammatory eosinophils (iEOS) reflect type 2 inflammation in tissues. iEOS were considered the primary eosinophils in non-severe allergic asthma, while rEOS were thought to be the primary eosinophils in severe non-allergic eosinophilic asthma. This case-control study aimed to investigate the marker expression of eosinophilic subtypes in KD patients.

MATERIALS AND METHODS

The marker expressions of eosinophilic subtypes in the leukocytes of patients with KD were evaluated by the recently established KDmarkers online tool, a web server including gene expression data. Finally, the results were validated with a quantitative reverse transcriptase polymerase chain reaction (RT-PCR). We analyzed the mRNA expression levels of SELL and IL10RA in leukocytes from KD patients and febrile children.

RESULTS

Included in our screening tools were transcriptome arrays, which provided clues showing the importance of rEOS, whose role was identified by three genes (lower IL10RA, higher SELL, and SERPINB1 than controls). In contrast, the iEOS representative gene CD101 was not elevated in KD. It was found that the gene IL10RA, a marker of inflammatory eosinophilic leukocytes, was more highly expressed in the leukocytes of KD patients (n = 43) than febrile controls (n = 32), especially those without coronary artery lesions (CAL) (n = 26). Before treatment, SELL expression was higher in leukocytes of CAL patients (CAL, 1.33 ± 0.18, n = 39; non-CAL, 0.87 ± 0.12, n = 55; p = 0.012). SELL was significantly higher after half a year compared to febrile controls.

CONCLUSIONS

To our knowledge, this is the first study to demonstrate that KD patients have increased SELL than febrile controls after 6 months of treatment. We present evidence here that dynamically different eosinophilic involvement exists between KD patients with and without CAL. The role of eosinophilic subtypes in KD patients warrants further investigation.

Macrophage activation syndrome in children with Kawasaki disease: diagnostic and therapeutic approaches

BACKGROUND

Macrophage activation syndrome (MAS) is a rare, life-threatening complication of Kawasaki disease (KD). Early recognition and treatment of MAS are very important, but sometimes it is difficult to distinguish MAS from a severe form of KD.

DATA SOURCES

A PubMed search was performed in Clinical Queries using the key terms "macrophage activation syndrome or secondary hemophagocytic lymphohistiocytosis (HLH)" and "Kawasaki disease".

RESULTS

KD patients with MAS show high intravenous immunoglobulin (IVIG) resistance and coronary complications. Mortality is also as high as MAS in other diseases. Persistent fever greater than 10 days is highly associated with development of MAS in KD. Splenomegaly is observed in more than two-thirds of KD patients with MAS. Thrombocytopenia is often the earliest laboratory finding of MAS. Hyperferritinemia is highly specific and sensitive for detecting MAS in KD; so, ferritin levels should be checked if there are unexplained clinical exacerbations in KD patients. Given the under-recognition of MAS in KD, it is prudent to consider resistant KD as occult/subclinical MAS. Many KD patients with MAS have good outcomes on immune modulators. However, if KD patients fulfill the HLH-2004 diagnostic criteria, they may undergo longer and more intensive treatment than needed.

CONCLUSIONS

The possible existence of MAS should be taken into account when a KD patient shows persistent fever, splenomegaly, thrombocytopenia, hyperferritinemia, or IVIG resistance. The under-diagnosis of MAS in patients with KD is an important issue to be addressed. Therapeutically, however, there is a possibility of over-treatment of MAS in patients with KD.

A Case of Hemophagocytic Lymphohistiocytosis and Kawasaki Disease: Concurrent or Overlapping Diagnoses?

Hemophagocytic lymphohistiocytosis (HLH) is not always suspected at the time of presentation. It is often mistaken for other diagnoses; complicated by the fact that it is often associated with an inciting event that has significant overlap. Kawasaki disease, along with other disorders, such as Ebstein Barr Virus infection, are conditions that may lead HLH. Our patient had a presentation that was consistent with Kawasaki disease on initial presentation, however subsequently met the diagnostic criteria of HLH. It provided an interesting discussion about diagnoses with clinical criteria and how the overlap can sometimes delay or complicate initial diagnosis.

Innate immune cells in the pathogenesis of primary systemic vasculitis

Innate immune system forms the first line of defense against foreign substances. Neutrophils, eosinophils, erythrocytes, platelets, monocytes, macrophages, dendritic cells, γδ T cells, natural killer and natural killer T cells comprise the innate immune system. Genetic polymorphisms influencing the activation of innate immune cells predispose to development of vasculitis and influence its severity. Abnormally activated innate immune cells cross-talk with other cells of the innate immune system, present antigens more efficiently and activate T and B lymphocytes and cause tissue destruction via cell-mediated cytotoxicity and release of pro-inflammatory cytokines. These secreted cytokines further recruit other cells to the sites of vascular injury. They are involved in both the initiation as well as the perpetuation of vasculitis. Evidences suggest reversal of aberrant activation of immune cells in response to therapy. Understanding the role of innate immune cells in vasculitis helps understand the potential of therapeutic modulation of their activation to treat vasculitis.

Circulating platelet-neutrophil aggregates play a significant role in Kawasaki disease

BACKGROUND

Circulating platelet-neutrophil aggregates play a crucial role in amplifying acute inflammation and could promote adverse effects involving vascular injury. The aim of this study was to evaluate the role of platelet-neutrophil aggregates in Kawasaki disease (KD).

METHODS AND RESULTS

Forty patients with KD (30 intravenous immunoglobulin [IVIG] responders and 10 IVIG non-responders), 7 febrile patients with bacterial infections, and 9 normal volunteers were analyzed. Thirty-three patients with KD were treated with IVIG, and 7 were treated with IVIG plus prednisolone. We evaluated the rate of platelet-neutrophil aggregates and measured the platelet factor 4 (PF4) and β-thromboglobulin (β-TG) levels. The rate of platelet-neutrophil aggregates was significantly higher in patients with KD than those with bacterial infection and normal volunteers. The rate of platelet-neutrophil aggregates was significantly higher in patients with coronary artery abnormalities (CAA) than in those without CAA, and was correlated with PF4 and β-TG levels in patients with KD. Comparing time-course analysis, the rate of platelet-neutrophil aggregates was significantly decreased in patients treated with IVIG plus prednisolone than in those treated with IVIG alone.

CONCLUSIONS

The findings demonstrate that platelet-neutrophil aggregates are significantly present in higher rates and are closely related to pathological developments of CAA in KD. Additional prednisolone treatment for patients in the acute phase of KD could suppress platelet-neutrophil aggregates, indicating that platelet-neutrophil aggregates would inhibit amplified reciprocal vascular inflammatory activation.

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.

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.

CD40 Gene polymorphisms associated with susceptibility and coronary artery lesions of Kawasaki disease in the Taiwanese population

BACKGROUND

Kawasaki disease (KD) is characterized by systemic vasculitis of unknown etiology. Our previous studies showed expression of CD40 ligand on CD4+ T cells correlated to the coronary artery lesion (CAL) and disease progress in KD. Other studies from Japan suggested the role of CD40L in the pathogenesis of CAL, and this might help explain the excessive number of males affected with KD but cannot be reproduced by Taiwanese population. This study was conducted to investigate the CD40 polymorphism in KD and CAL formation.

METHODS

A total of 950 subjects (381 KD patients and 569 controls) were investigated to identify 2 tagging single-nucleotide polymorphisms (tSNPs) of CD40 (rs4810485 and rs1535045) by using the TaqMan allelic discrimination assay.

RESULTS

A significant association was noted with regards to CD40 tSNPs (rs1535045) between controls and KD patients (P = 0.0405, dominant model). In KD patients, polymorphisms of CD40 (rs4810485) showed significant association with CAL formation (P = 0.0436, recessive model). Haplotype analysis did not yield more significant results between polymorphisms of CD40 and susceptibility/disease activity of KD.

CONCLUSIONS

This study showed for the first time that polymorphisms of CD40 are associated with susceptibility to KD and CAL formation, in the Taiwanese population.

Hemophagocytic lymphohistiocytosis at initiation of kawasaki disease and their differential diagnosis

The authors report a case of hemophagocytic lymphohistiocytosis that became apparent and was confirmed by a specific Th1/Th2 cytokine pattern at the initiation of Kawasaki disease in an 18-month-old child. His condition deteriorated fast and produced no response to intravenous immunoglobulin and dexamethasone. A standard HLH-2004 regimen was started. But he developed respiratory failure, seizure, and cardiac arrest, and died. This case is unique for developing hemophagocytic lymphohistiocytosis at the initiation of Kawasaki disease, with fatal outcome. This case may indicate a yet unknown mechanism triggers these 2 diseases; a specific Th1/Th2 cytokine pattern helps rapid differential diagnosis between these 2 diseases.

Kawasaki disease: aetiopathogenesis and therapeutic utility of intravenous immunoglobulin

Kawasaki disease (KD) is an acute febrile childhood vasculitis, associated with the development of coronary artery abnormalities in 25–30% of untreated patients. The aetiopathogenesis is not well known but it is accepted that an undefined infectious trigger in genetically predisposed individuals results in the disease. KD is characterized by an endothelial cell injury, which could be due to abnormal cytokine production and to generation of cytotoxic antibodies against the endothelial cells. Intravenous immunoglobulin IVIG is an effective treatment in preventing the occurrence of coronary artery abnormalities in KD. Several mechanisms may explain the anti-inflammatory effects of IVIG in this disease. They include modification of the cytokine balance, and alteration on both the differentiation and the function of monocytes/macrophages, neutrophils and lymphocytes.

Hemophagocytic lymphohistiocytosis and Kawasaki disease: combined manifestation and differential diagnosis

Both hemophagocytic lymphohistiocytosis (HLH) and Kawasaki disease (KD) are diagnosed in patients with prolonged resistant fever by using a scoring system. Concurrent manifestation of both conditions has been reported previously. We describe an infant of 7 weeks whose condition fulfilled the criteria of HLH, but who, after clinical response to treatment, suddenly died from a myocardial infarction at 11 weeks. Post-mortem examination revealed a previously unknown coronary arteritis typical for KD. Since it is difficult to distinguish between KD and HLH, both diseases should be considered in young children with overlapping symptoms. Repeated echocardiograms may be helpful in these cases.

Modulation of the cellular immune system by intravenous immunoglobulin

Intravenous immunoglobulin (IVIg) is therapeutically used in a variety of immune-mediated diseases. The beneficial effects of IVIg in auto-antibody-mediated diseases can be explained by neutralization, accelerated clearance and prevention of Fcgamma-receptor binding of auto-antibodies. However, the means by which IVIg exerts therapeutic effects in disorders mediated by cellular immunity have remained enigmatic. Clinical improvements, followed by IVIg treatment, often extend beyond the half-life of infused IgG, thereby indicating that IVIg modifies the cellular immune compartment for a prolonged period. Here, we discuss recent advances in the understanding of different, mutually non-exclusive mechanisms of action of IVIg on cells of the innate and adaptive immune system. These mechanisms might explain the beneficial effects of IVIg in certain autoimmune and inflammatory diseases.