Identifying genetic hypomethylation and upregulation of Toll-like receptors in Kawasaki disease

NLRC4 methylation and its response to intravenous immunoglobulin therapy in Kawasaki disease: a case control study

BACKGROUND

Kawasaki disease (KD) is a systemic vasculitis accompanied by many systemic physiological and biochemical changes. Elucidating its molecular mechanisms is crucial for diagnosing and developing effective treatments. NLR Family CARD Domain Containing 4 (NLRC4) encodes the key components of inflammasomes that function as pattern recognition receptors. The purpose of this study was to investigate the potential of NLRC4 methylation as a biomarker for KD.

METHODS

In this study, pyrosequencing was utilized to analyze NLRC4 promoter methylation in blood samples from 44 children with initial complete KD and 51 matched healthy controls. Methylation at five CpG sites within the NLRC4 promoter region was evaluated.

RESULTS

Compared to controls, NLRC4 methylation significantly decreased in KD patients (CpG1: p = 2.93E-06; CpG2: p = 2.35E-05; CpG3: p = 6.46E-06; CpG4: p = 2.47E-06; CpG5: p = 1.26E-05; average methylation: p = 5.42E-06). These changes were significantly reversed after intravenous immunoglobulin (IVIG) treatment. ROC curve analysis demonstrated remarkable diagnostic capability of mean NLRC4 gene methylation for KD (areas under ROC curve = 0.844, sensitivity = 0.75, p = 9.61E-06, 95% confidence intervals were 0.762-0.926 for mean NLRC4 methylation). In addition, NLRC4 promoter methylation was shown to be significantly negatively correlated with the levels of central granulocyte percentage, age, mean haemoglobin quantity and mean erythrocyte volume. Besides, NLRC4 promoter methylation was positively correlated with lymphocyte percentage, lymphocyte absolute value.

CONCLUSIONS

Our work revealed the role of peripheral NLRC4 hypomethylation in KD pathogenesis and IVIG treatment response, could potentially serve as a treatment monitoring biomarker, although its precise functions remain to be elucidated.

Clinical indicators combined with S100A12/TLR2 signaling molecules to establish a new scoring model for coronary artery lesions in Kawasaki disease

Coronary artery lesions (CALs) are the most common and serious complication of Kawasaki disease (KD), and the pathogenesis is unknown. Exploring KD-specific biomarkers and related risk factors is significant for clinical diagnosis and treatment. This study aimed to explore the feasibility of combining clinical indicators with S100A12/TLR2-associated signaling molecules for the predictive modeling of CALs in KD. A total of 346 patients (224 males and 122 females) with KD who visited the rheumatology department of Wuhan Children's Hospital between April 2022 and March 2025 were enrolled and divided into two groups according to the presence or absence of CALS (292 patients had CALs and 54 patients did not). Forty-one variables were collected from the two groups, including demographic characteristics, clinical manifestations, and laboratory data. Single nucleated cells from each patient were extracted, and the expression of the S100A12/TLR2 signal transduction-related molecules S100A12, TLR2, MYD88, and NF-κB were detected by real-time fluorescent quantitative polymerase chain reaction. Statistically significant variables were subjected to logistic regression analysis to determine the independent risk factors for KD with CALs, and a new risk score model was established to assess the predictive efficacy based on receiver operating characteristic curves. Sixteen variables significantly differed between the no-CALs and CALs groups: gender, fever duration, white blood cells (WBC), hemoglobin (HGB), Ce reactive protein (CRP), procalcitonin, serum ferritin (SF), erythrocyte sedimentation rate (ESR), fibrinogen (FIB), aspartate aminotransferase-to-alanine aminotransferase ratio (AST/ALT), serum albumin (ALB), sodium (Na), Interleukin (IL-10), tumor necrosis factor (TNF-α), S100 calcium binding protein A12 (S100A12), and Myeloid Differentiation Factor 88 (MYD88) (p < 0.05). After performing a univariate analysis, 12 variables (gender, fever duration, WBC, HGB, CRP, SF, ESR, FIB, AST/ALT, ALB, Na, and S100A12) were included in the multifactorial binary logistic regression, which showed that fever duration ≥ 6.5 days, ESR ≥ 46.5 mm/h, AST/ALT ≤ 1.51, and S100A12 ≥ 10.02 were independent risk factors for KD with CALs and were assigned scores of 3, 2, 1, and 2, respectively, according to the odds ratio (OR). The total score of each patient was counted, and a new prediction model for KD combined with CALs was established, where < 3.5 was considered low risk and ≥ 3.5 was regarded as high risk; the sensitivity, specificity, Jorden index, and area under the curve of this scoring system were 0.667, 0.836, 0.502, and 0.838, respectively. This new scoring model has good efficacy for predicting the occurrence of KD with CALs. The expression of S100A12 was significantly increased in the CALs group and was an independent risk factor for the occurrence of CALs, and has the potential as a biomarker for predicting KD with CALs.

Preliminary Evidence of the Differential Expression of Human Endogenous Retroviruses in Kawasaki Disease and SARS-CoV-2-Associated Multisystem Inflammatory Syndrome in Children

Multisystem inflammatory syndrome in children (MIS-C) is a postinfectious sequela of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with some clinical features overlapping with Kawasaki disease (KD). Our research group and others have highlighted that the spike protein of SARS-CoV-2 can trigger the activation of human endogenous retroviruses (HERVs), which in turn induces inflammatory and immune reactions, suggesting HERVs as contributing factors in COVID-19 immunopathology. With the aim to identify new factors involved in the processes underlying KD and MIS-C, we analysed the transcriptional levels of HERVs, HERV-related genes, and immune mediators in children during the acute and subacute phases compared with COVID-19 paediatric patients and healthy controls. The results showed higher levels of HERV-W, HERV-K, Syn-1, and ASCT-1/2 in KD, MIS-C, and COV patients, while higher levels of Syn-2 and MFSD2A were found only in MIS-C patients. Moreover, KD and MIS-C shared the dysregulation of several inflammatory and regulatory cytokines. Interestingly, in MIS-C patients, negative correlations have been found between HERV-W and IL-10 and between Syn-2 and IL-10, while positive correlations have been found between HERV-K and IL-10. In addition, HERV-W expression positively correlated with the C-reactive protein. This pilot study supports the role of HERVs in inflammatory diseases, suggesting their interplay with the immune system in this setting. The elevated expression of Syn-2 and MFSD2A seems to be a distinctive trait of MIS-C patients, allowing to distinguish them from KD ones. The understanding of pathological mechanisms can lead to the best available treatment for these two diseases, limiting complications and serious outcomes.

From Co-Infections to Autoimmune Disease via Hyperactivated Innate Immunity: COVID-19 Autoimmune Coagulopathies, Autoimmune Myocarditis and Multisystem Inflammatory Syndrome in Children

Neutrophilia and the production of neutrophil extracellular traps (NETs) are two of many measures of increased inflammation in severe COVID-19 that also accompany its autoimmune complications, including coagulopathies, myocarditis and multisystem inflammatory syndrome in children (MIS-C). This paper integrates currently disparate measures of innate hyperactivation in severe COVID-19 and its autoimmune complications, and relates these to SARS-CoV-2 activation of innate immunity. Aggregated data include activation of Toll-like receptors (TLRs), nucleotide-binding oligomerization domain (NOD) receptors, NOD leucine-rich repeat and pyrin-domain-containing receptors (NLRPs), retinoic acid-inducible gene I (RIG-I) and melanoma-differentiation-associated gene 5 (MDA-5). SARS-CoV-2 mainly activates the virus-associated innate receptors TLR3, TLR7, TLR8, NLRP3, RIG-1 and MDA-5. Severe COVID-19, however, is characterized by additional activation of TLR1, TLR2, TLR4, TLR5, TLR6, NOD1 and NOD2, which are primarily responsive to bacterial antigens. The innate activation patterns in autoimmune coagulopathies, myocarditis and Kawasaki disease, or MIS-C, mimic those of severe COVID-19 rather than SARS-CoV-2 alone suggesting that autoimmunity follows combined SARS-CoV-2-bacterial infections. Viral and bacterial receptors are known to synergize to produce the increased inflammation required to support autoimmune disease pathology. Additional studies demonstrate that anti-bacterial antibodies are also required to account for known autoantigen targets in COVID-19 autoimmune complications.

Comparable bidirectional neutrophil immune dysregulation between Kawasaki disease and severe COVID-19

Kawasaki disease (KD), a multisystem inflammatory syndrome that occurs in children, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or COVID-19) may share some overlapping mechanisms. The purpose of this study was to analyze the differences in single-cell RNA sequencing between KD and COVID-19. We performed single-cell RNA sequencing in KD patients (within 24 hours before IVIG treatment) and age-matched fever controls. The single-cell RNA sequencing data of COVID-19, influenza, and health controls were downloaded from the Sequence Read Archive (GSE149689/PRJNA629752). In total, 22 single-cell RNA sequencing data with 102,355 nuclei were enrolled in this study. After performing hierarchical and functional clustering analyses, two enriched gene clusters demonstrated similar patterns in severe COVID-19 and KD, heightened neutrophil activation, and decreased MHC class II expression. Furthermore, comparable dysregulation of neutrophilic granulopoiesis representing two pronounced hyperinflammatory states was demonstrated, which play a critical role in the overactivated and defective aging program of granulocytes, in patients with KD as well as those with severe COVID-19. In conclusion, both neutrophil activation and MHC class II reduction play a crucial role and thus may provide potential treatment targets for KD and severe COVID-19.

The Role of E3 Ligase Pirh2 in Disease

The p53-dependent ubiquitin ligase Pirh2 regulates a number of proteins involved in different cancer-associated processes. Targeting the p53 family proteins, Chk2, p27Kip1, Twist1 and others, Pirh2 participates in such cellular processes as proliferation, cell cycle regulation, apoptosis and cellular migration. Thus, it is not surprising that Pirh2 takes part in the initiation and progression of different diseases and pathologies including but not limited to cancer. In this review, we aimed to summarize the available data on Pirh2 regulation, its protein targets and its role in various diseases and pathological processes, thus making the Pirh2 protein a promising therapeutic target.

Effect of TLR9 methylation on its transcription in apical inflammation

AIM

to explore the methylation pattern, its role on transcriptional regulation and potential modifiers of methylation of theTLR9 gene in chronic periapical inflammation.

METHODOLOGY

In this cross-sectional study, apical lesions of endodontic origin (ALEO, n=61) and healthy periodontal ligaments (HPL, n=15) were included. Products from bisulfited and PCR-amplified DNA were analyzed for their methylation profiles in the promoter region and at each CpG island. Additionally, TLR9 mRNA levels were quantified by qPCR and bivariate and multiple modelling were performed to better understand the influence of methylations on gene transcription.

RESULTS

TLR9 mRNA levels were upregulated in ALEO compared to HPL (p<0.001). TLR9 promoter CpG sites and CpG +2086 in the intragenic island 1 were demethylated in ALEO compared to HPL (p<0.05). Multivariate analysis, adjusted by smoking and gender, revealed that demethylation of TLR9 promoter sites enhanced transcriptional activity, specifically demethylated CpGs at positions -736 and -683, (p=0.02), which are close to CRE binding. Whereas ALEO reduced the global methylation of the gene-promoter and intragenic-island 2 (p<0.05) by -42.5 and -9.5 percentage points, respectively, age reduced the global methylation of intragenic-island 3 within the exon 2.

CONCLUSIONS

Demethylations of TLR9 promoter CpG sites, along with the intragenic DNA methylation status, were involved in higher transcription in ALEO. Hence, chronic periapical inflammation and aging modify the methylation status both in the gene promoter and in intragenic CpG islands.

CD36 is Associated With the Development of Coronary Artery Lesions in Patients With Kawasaki Disease

Kawasaki disease (KD) is an autoimmune-like vasculitis of childhood involving the coronary arteries. Macrophages require scavenger receptors such as CD36 to effectively clear cellular debris and induce self-tolerance. In this study, we hypothesized that CD36 plays an important role in the immunopathogenesis of KD, by aiding in the clearance of plasma mitochondrial DNA, and by amplifying the immune response by activating the inflammasome pathway via AIM2. Fifty-two healthy controls, 52 febrile controls, and 102 KD patients were recruited for RT-PCR of target mRNA expression and plasma mitochondrial DNA. Blood samples were obtained 24 hours prior and 21 days after the administration of intravenous immunoglobulin (IVIG) therapy. Patients with acute KD had higher plasma levels of cell-free mitochondrial DNA (ND1, ND4, and COX1), and higher mRNA expressions of CD36 and AIM2 when compared to both healthy and febrile controls. A greater decrease in both CD36 and AIM2 mRNA expression after IVIG therapy was associated with the development of coronary artery lesions. Coronary artery lesions were associated with a larger decrease of CD36 expression following IVIG therapy, which may indicate that prolonged expression of the scavenger receptor may have a protective effect against the development of coronary artery lesions in KD.

KDmarkers: A biomarker database for investigating epigenetic methylation and gene expression levels in Kawasaki disease

Kawasaki disease (KD) is a form of acute systemic vasculitis that primarily affects children and has become the most common cause of acquired heart disease. While the etiopathogenesis of KD remains unknown, the diagnostic criteria of KD have been well established. Nevertheless, the diagnosis of KD is currently based on subjective clinical symptoms, and no molecular biomarker is yet available. We have previously performed and combined methylation array (Illumina HumanMethylation450 BeadChip) and transcriptome array (Affymetrix GeneChip Human Transcriptome Array 2.0) to identify genes that are differentially methylated/expressed in KD patients compared with control subjects. We have found that decreased methylation levels combined with elevated gene expression can indicate genes (e.g., toll-like receptors and CD177) involved in the disease mechanisms of KD. In this study, we constructed a database called KDmarkers to allow researchers to access these valuable potential KD biomarkers identified via methylation array and transcriptome array. KDmarkers provides three search modes. First, users can search genes differentially methylated and/or differentially expressed in KD patients compared with control subjects. Second, users can check the KD patient groups in which a given gene is differentially methylated and/or differentially expressed. Third, users can explore the DNA methylation levels and gene expression levels in all samples (KD patients and controls) for a particular gene of interest. We further demonstrated that the results in KDmarkers are strongly associated with KD immune responses. All analysis results can be downloaded for downstream experimental designs. KDmarkers is available online at https://cosbi.ee.ncku.edu.tw/KDmarkers/.

Human Transcriptome Array Analysis Identifies CDR2 as a Novel Suppressed Gene for Kawasaki Disease

Kawasaki disease (KD) is a febrile childhood vasculitis that involves the coronary arteries. Most previous studies have focused on the genes activated in the acute phase of KD. However, in this study, we focused on suppressed genes in the acute stage of KD and identified novel targets with clinical significance and potential prognostic value for KD patients. We enrolled 18 patients with KD, 18 healthy controls (HC), and 18 febrile controls (FC) for human transcriptome array analysis. Another 19 healthy controls, 20 febrile controls, and 31 patients with KD were recruited for RT-PCR validation of target mRNA expressions. The results of Human Transcriptome Array (HTA) 2.0 showed 461 genes that were significantly higher in KD and then normalized after IVIG, as well as 99 suppressed genes in KD. Furthermore, we identified the four genes in KD with the most downregulation, including BCL11B, DUSP2, DDX24, and CDR2, as well as the upregulation of their expression following IVIG administration. The mRNA expression of CDR2 by qRT-PCR was the most compatible with the pattern of the HTA2.0 results. Furthermore, we found higher DDX24 mRNA expression in KD patients with CAL when compared to those without CAL 3 weeks after IVIG administration. In summary, activated gene expression represented a majority in the immune response of KD. In this study, we identified CDR2 as a novel suppressed gene for Kawasaki disease via human transcriptome array analysis and DDX24 associated with CAL formation, which may contribute to further understanding of CAL pathogenesis in KD.

G0S2 regulates innate immunity in Kawasaki disease via lncRNA HSD11B1-AS1

BACKGROUND

Kawasaki disease (KD) is a systemic vasculitis that is currently the most common cause of acquired heart disease in children. However, its etiology remains unknown. Long non-coding RNAs (lncRNAs) contribute to the pathophysiology of various diseases. Few studies have reported the role of lncRNAs in KD inflammation; thus, we investigated the role of lncRNA in KD inflammation.

METHODS

A total of 50 patients with KD (median age, 19 months; 29 males and 21 females) were enrolled. We conducted cap analysis gene expression sequencing to determine differentially expressed genes in monocytes of the peripheral blood of the subjects.

RESULTS

About 21 candidate lncRNA transcripts were identified. The analyses of transcriptome and gene ontology revealed that the immune system was involved in KD. Among these genes, G0/G1 switch gene 2 (G0S2) and its antisense lncRNA, HSD11B1-AS1, were upregulated during the acute phase of KD (P < 0.0001 and <0.0001, respectively). Moreover, G0S2 increased when lipopolysaccharides induced inflammation in THP-1 monocytes, and silencing of G0S2 suppressed the expression of HSD11B1-AS1 and tumor necrosis factor-α.

CONCLUSIONS

This study uncovered the crucial role of lncRNAs in innate immunity in acute KD. LncRNA may be a novel target for the diagnosis of KD.

IMPACT

This study revealed the whole aspect of the gene expression profile of monocytes of patients with Kawasaki disease (KD) using cap analysis gene expression sequencing and identified KD-specific molecules: G0/G1 switch gene 2 (G0S2) and long non-coding RNA (lncRNA) HSD11B1-AS1. We demonstrated that G0S2 and its antisense HSD11B1-AS1 were associated with inflammation of innate immunity in KD. lncRNA may be a novel key target for the diagnosis of patients with KD.

Epigenetic regulation of pediatric and neonatal immune responses

Epigenetic regulation of transcription is a collective term that refers to mechanisms known to regulate gene transcription without changing the underlying DNA sequence. These mechanisms include DNA methylation and histone tail modifications which influence chromatin accessibility, and microRNAs that act through post-transcriptional gene silencing. Epigenetics is known to regulate a variety of biological processes, and the role of epigtenetics in immunity and immune-mediated diseases is becoming increasingly recognized. While DNA methylation is the most widely studied, each of these systems play an important role in the development and maintenance of appropriate immune responses. There is clear evidence that epigenetic mechanisms contribute to developmental stage-specific immune responses in a cell-specific manner. There is also mounting evidence that prenatal exposures alter epigenetic profiles and subsequent immune function in exposed offspring. Early life exposures that are associated with poor long-term health outcomes also appear to impact immune specific epigenetic patterning. Finally, each of these epigenetic mechanisms contribute to the pathogenesis of a wide variety of diseases that manifest during childhood. This review will discuss each of these areas in detail. IMPACT: Epigenetics, including DNA methylation, histone tail modifications, and microRNA expression, dictate immune cell phenotypes. Epigenetics influence immune development and subsequent immune health. Prenatal, perinatal, and postnatal exposures alter immune cell epigenetic profiles and subsequent immune function. Numerous pediatric-onset diseases have an epigenetic component. Several successful strategies for childhood diseases target epigenetic mechanisms.

Increased Expression of Pyroptosis in Leukocytes of Patients with Kawasaki Disease

Background: Kawasaki disease (KD) is a form of febrile vasculitis that primarily occurs in children. It can cause inflammation of the coronary arteries, which leads to aneurysms. The pathogenesis of coronary arteries may be associated with apoptosis or pyroptosis mediated by caspases activity, but this idea has not been discussed much in KD. Materials and Methods: We enrolled 236 participants in this study. In the Affymetrix GeneChip^® Human Transcriptome Array 2.0 study, there were 18 KD patients analyzed prior to receiving intravenous immunoglobulin (IVIG) treatment, at least 3 weeks after IVIG treatment, and 36 non-KD control subjects. We also recruited 24 KD patients prior to receiving IVIG treatment, at least 3 weeks after IVIG treatment, and 24 non-KD control subjects for Illumina HumanMethylation450 BeadChip study. A separate cohort of 134 subjects was analyzed to validate real-time quantitative PCR. Results: The mRNA levels of caspase-1, -3, -4, and -5 were significantly increased in KD patients compared with control subjects (p < 0.05). After administration of IVIG, the expression of these genes decreased considerably. Of particular note, the methylation status of the CpG sites of the caspase-4 and -5 genes demonstrated significant opposite tendencies between the KD patients and controls. Furthermore, compared with patients who responded to IVIG, refractory KD patients had a lower expression of the caspase-3 gene prior to IVIG treatment. Conclusion: Our study is the first to report the upregulation of pyroptotic caspase-1, -4, and -5 in peripheral leukocytes of KD patients. Moreover, the expression of caspase-3 may be associated with IVIG resistance in KD.

Prognostic Impact of Genetic Variants of MECP2 and TIRAP on Clinical Outcomes of Systemic Lupus Erythematosus with and without Nephritis

Systemic lupus erythematosus (SLE) is a chronic autoimmune illness with a growing prevalence in many populations. Few studies have examined genetic predisposition to SLE, so we aimed to examine the clinical impact of the genetic polymorphisms MECP2 rs2734647and TIRAP rs8177374 on the outcomes and therapeutic precision of SLE with and without nephritis. This study included 110 SLE patients-divided into 63 with lupus nephritis (LN), and 47 without nephritis-and 100 controls. Laboratory measurements including CRP, ESR, ACR, CBC, anti-ds-DNA, vitamin A, C3, and C4 were carried out, along with genotyping of MECP2 rs2734647and TIRAP rs8177374 by real-time PCR and sequencing. Treg %, vitamin A, C3, and C4 were lower, whereas Th17 % was higher, in patients vs. controls (p < 0.001). The T allele of MECP2 rs2734647 was higher in LN than in non-nephritis and control subjects. Moreover, the T allele of TIRAP rs8177374 was higher in LN than in non-nephritis and control subjects. The MECP2 and TIRAP genes could play a role in predisposition to SLE, and can also predict disease progress to nephritis, helping to personalize medicine.

Public Health Interventions for COVID-19 Reduce Kawasaki Disease in Taiwan

Background: Kawasaki disease (KD) is a syndrome of unknown cause that results in high fever and coronary vasculitis in children. The incidence of KD increased in Taiwan over the past few decades. Taiwanese government executed domains of early screening, effective methods for isolation or quarantine, and digital technologies for identifying potential cases for the early elimination strategy for coronavirus disease 2019 (COVID-19) and public health interventions for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or COVID-19 pandemic, leading to an effective reduction of the risk of airway infections in children. The purpose of this study is to analyze whether those public health interventions reduce the incidence of KD in 2020. Methods: Patients with KD who visited Chang Gung Memorial Hospital (CGMH) between 1 January, 2018, and 31 December, 2020 were included for trend analysis. This is a retrospective case series study conducted at the CGMH, which consists of a network of seven hospital branches equipped with more than 10,000 beds in different areas of Taiwan. Results: Compared with the 2018 and 2019 databases, the incidence of KD decreased significantly by 30% and 31%, respectively (p < 0.05) in 2020, when public health interventions were comprehensively implemented in Taiwan. This result shows that the incidence of KD decreased during the COVID-19 pandemic in Taiwan without change of the presentation KD (typical or incomplete) and percentage of IVIG resistance in 2020. Conclusion: As public health interventions were carried out for the SARS-CoV-2 pandemic, the incidence of KD was significantly reduced in Taiwan. Is KD a preventable disease?

Identification of Key Genes and Underlying Mechanisms in Acute Kawasaki Disease Based on Bioinformatics Analysis

Background

Kawasaki disease (KD) is a systemic vasculitis that predominantly occurs in children, but the pathogenesis of KD remains unclear. Here, we explored key genes and underlying mechanisms potentially involved in KD using bioinformatic analyses.

Material/Methods

The shared differentially expressed genes (DEGs) in KD compared to control samples were identified using the microarray data from the Gene Expression Omnibus Series (GSE) 18606, GSE68004, and GSE73461. Analyses of the functional annotation, protein-protein interaction (PPI) network, microRNA-target DEGs regulatory network, and immune cell infiltration were performed. The expression of hub genes before and after intravenous immunoglobulin (IVIG) treatment in KD was further verified using GSE16797.

Results

A total of 195 shared DEGs (164 upregulated and 31 downregulated genes) were identified between KD and healthy controls. These shared DEGs were mainly enriched in immune and inflammatory responses. Ten upregulated hub genes (ITGAX, SPI1, LILRB2, MMP9, S100A12, C3AR1, RETN, MAPK14, TLR5, MYD88) and the most significant module were identified in the PPI network. There were 309 regulatory relationships detected within 70 predicted microRNAs and 193 target DEGs. The immune cell infiltration analysis showed that monocytes, neutrophils, activated mast cells, and activated natural killer cells had relatively high proportions and were significantly more infiltrated in KD samples. Six hub genes of ITGAX, LILRB2, C3AR1, MAPK14, TLR5, and MYD88 were markedly downregulated after IVIG treatment for KD.

Conclusions

Our study identified the candidate genes and associated molecules that may be related to the KD process, and provided new insights into potential mechanisms and therapeutic targets for KD.

Phenotype, Susceptibility, Autoimmunity, and Immunotherapy Between Kawasaki Disease and Coronavirus Disease-19 Associated Multisystem Inflammatory Syndrome in Children

Coronavirus disease-19 (COVID-19) in children is usually mild but some are susceptible to a Kawasaki disease (KD)-like multisystem inflammatory syndrome in children (MIS-C) in the convalescent stage, posing a need to differentiate the phenotype, susceptibility, autoimmunity, and immunotherapy between KD and MIS-C, particularly in the upcoming mass vaccination of COVID-19. Patients with MIS-C are prone to gastrointestinal symptoms, coagulopathy, and shock in addition to atypical KD syndrome with fever, mucocutaneous lesions, lymphadenopathy, and/or cardiovascular events. MIS-C manifests KD-like symptoms that alert physicians to early recognize and adopt the KD treatment regimen for patients with MIS-C. MIS-C linked to COVID-19 teaches us infection-associated autoimmune vasculitis and vice versa. Studies on genetic susceptibility have identified certain human leukocyte antigen (HLA) locus and toll-like receptor (TLR) associated with KD and/or COVID-19. Certain HLA subtypes, such as HLA-DRB1 and HLA-MICA A4 are associated with KD. HLA-B*46:01 is proposed to be the risk allele of severe COVID-19 infection, and blood group O type is a protective factor of COVID-19. The autoimmune vasculitis of KD, KD shock syndrome (KDSS), or MIS-C is mediated by a genetic variant of HLA, FcγR, and/or antibody-dependent enhancement (ADE) resulting in hyperinflammation with T helper 17 (Th17)/Treg imbalance with augmented Th17/Th1 mediators: interleukin-6 (IL-6), IL-10, inducible protein-10 (IP-10), Interferon (IFNγ), and IL-17A, and lower expression of Treg-signaling molecules, FoxP3, and transforming growth factor (TGF-β). There are certain similarities and differences in phenotypes, susceptibility, and pathogenesis of KD, KDSS, and MIS-C, by which a physician can make early protection, prevention, and precision treatment of the diseases. The evolution of immunotherapies for the diseases has shown that intravenous immunoglobulin (IVIG) alone or combined with corticosteroids is the standard treatment for KD, KDSS, and MIS-C. However, a certain portion of patients who revealed a treatment resistance to IVIG or IVIG plus corticosteroids, posing a need to early identify the immunopathogenesis, to protect hosts with genetic susceptibility, and to combat Th17/Treg imbalance by anti-cytokine or pro-Treg for reversal of the hyperinflammation and IVIG resistance. Based on physiological and pathological immunity of the diseases under genetic susceptibility and host milieu conditions, a series of sequential regimens are provided to develop a so-called "Know thyself, enemy (pathogen), and ever-victorious" strategy for the prevention and immunotherapy of KD and/or MIS-C.

Epigenetics in Kawasaki Disease

Kawasaki disease (KD) is a common febrile multisystemic inflammatory illness in children that preferentially affects coronary arteries. Children with KD who develop coronary artery aneurysms have a life-long risk of premature coronary artery disease. Hypothesis of inherent predisposition to KD is supported by epidemiological evidence that suggests increased risk of development of disease in certain ethnicities and in children with a previous history of KD in siblings or parents. However, occurrence of cases in clusters, seasonal variation, and very low risk of recurrence suggests an acquired trigger (such as infections) for the development of illness. Epigenetic mechanisms that modulate gene expression can plausibly explain the link between genetic and acquired predisposing factors in KD. Analysis of epigenetic factors can also be used to derive biomarkers for diagnosis and prognostication in KD. Moreover, epigenetic mechanisms can also help in pharmacogenomics with the development of targeted therapies. In this review, we analysed the available literature on epigenetic factors such as methylation, micro-RNAs, and long non-coding RNAs in KD and discuss how these mechanisms can help us better understand the disease pathogenesis and advance the development of new biomarkers in KD.

Identification of increased expression of activating Fc receptors and novel findings regarding distinct IgE and IgM receptors in Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is associated with expression and methylation of Fc gamma receptor genes. We characterized immunoglobulin A (IgA), IgE, IgG, and IgM receptor expression levels in KD.

METHODS

Fc receptor expression levels were characterized using GeneChip Human Transcriptome Array 2.0 (HTA 2.0) with 18 KD patients, 18 non-febrile controls, and 18 febrile controls. Another 48 control individuals and 46 patients with KD were measured using pyrosequencing for the methylation levels.

RESULTS

The mRNA expression levels of FCER1A and FCER2 were significantly lower in KD patients than in non-febrile controls and then rose following treatments with intravenous immunoglobulin (IVIG). Expression levels of FCER1G increased compared to the non-febrile subjects and then subsided after IVIG. FCER1A methylation was significantly lower among KD patients and even lower in KD patients with IVIG resistance. HTA analysis revealed higher mRNA levels of FCAR, FCGR1C, and FCGR2A in KD patients. FCMR mRNA expression levels were significantly lower in KD patients. FCMR expression levels rose after IVIG treatment. After IVIG, FCGR1A, B, and C decreased even lower than the febrile controls.

CONCLUSION

This is the first study indicating that IgA, IgE, IgG, and IgM receptors are associated with KD. We highlighted potential biomarkers related to Fc receptors and their regulation.

Perspective of Immunopathogenesis and Immunotherapies for Kawasaki Disease

Kawasaki Disease (KD) is an acute inflammatory illness that mostly occurs in children below 5 years of age, with intractable fever, mucocutaneous lesions, lymphadenopathy, and lesions of the coronary artery (CAL). KD is sharing clinical symptoms with systemic inflammatory syndrome in children (MIS-C) which is related to COVID-19. Certain genes are identified to be associated with KD, but the findings usually differ between countries and races. Human Leukocyte Antigen (HLA) allele types and toll-like receptor (TLR) expression are also correlated to KD. The acute hyperinflammation in KD is mediated by an imbalance between augmented T helper 17 (Th17)/Th1 responses with high levels of interleukin (IL)-6, IL-10, IL-17A, IFN-γ, and IP-10, in contrast to reduced Th2/Treg responses with lower IL-4, IL-5, FoxP3, and TGF-β expression. KD has varying phenotypic variations regarding age, gender, intravenous immunoglobulin (IVIG) resistance, macrophage activation and shock syndrome. The signs of macrophage activation syndrome (MAS) can be interpreted as hyperferritinemia and thrombocytopenia contradictory to thrombocytosis in typical KD; the signs of KD with shock syndrome (KDSS) can be interpreted as overproduction of nitric oxide (NO) and coagulopathy. For over five decades, IVIG and aspirin are the standard treatment for KD. However, some KD patients are refractory to IVIG required additional medications against inflammation. Further studies are proposed to delineate the immunopathogenesis of IVIG-resistance and KDSS, to identify high risk patients with genetic susceptibility, and to develop an ideal treatment regimen, such as by providing idiotypic immunoglobulins to curb cytokine storms, NO overproduction, and the epigenetic induction of Treg function.

Low FCMR mRNA expression in leukocytes of patients with Kawasaki disease six months after disease onset

BACKGROUND

Immunoglobulin (Ig) M plays an important role in immune regulation. FCMR-encoded FcμR is a receptor of IgM. Previous research has suggested that IgM levels may be involved in the coronary artery lesions of Kawasaki syndrome or Kawasaki disease (KD). In this study, we aimed to explore the roles of mRNA expressions of IgM receptors, particularly FCMR, in KD patients. FCMR encodes the Fc fragment of immunoglobulin M receptor.

METHODS

We enrolled 60 KD patients and 55 non-KD controls. Whole-blood leukocytes were isolated, and the mRNA expression for FCMR was determined. Each mRNA consisted of a sample taken before intravenous immunoglobulin (IVIG) was administered (acute, KD1) and those taken at three weeks, six months, and one year later (KD3, KD4, KD5). Paired KD subjects were analyzed from both the acute and convalescent phases (n = 28).

RESULTS

After six months and one year of treatment, KD patients still apparently have lower FCMR compared with controls (P = .004). FCMR expressions were downregulated in male patients with KD prior to IVIG administration (P = .044). The FCMR of paired KD patients who received IVIG treatments after six months was significantly lower than before undergoing IVIG treatment (P = .044). Expressions in the polymorphonuclear leukocytes were similar to those in the peripheral blood mononuclear cells.

CONCLUSION

The unique data supported that FCMR is expressed by granulocytes at RNA levels in humans and demonstrated lower FCMR six months after the onset of KD. The findings remind us of the need to track the health of children with KD over the long term, even if we think patients have fully recovered.

Epigenetic Regulation of Macrophage Marker Expression Profiles in Kawasaki Disease

Kawasaki disease (KD) is a common systemic vasculitides in children younger than 5 years of age. Activated macrophages are key drivers of vascular inflammation in KD. The aim of this study was to examine differences in M1 and M2 macrophage marker expression in patients with KD. Blood samples were obtained from 18 healthy controls and 18 patients with KD at 24 h prior and 21 days after to intravenous immunoglobulin therapy. GeneChip Human Transcriptome Array 2.0 and Illumina HumanMethylation450 BeadChip were used to examined the mRNA expression and corresponding CpG site methylation ratios of 10 M1 surface markers and 15 M2 surface markers. Of the markers examined 2 M1 markers (TLR2, IL2RA) and 8 M2 markers (ARG1, CCR2, TLR1, TLR8, TLR5, MS4A6A, CD36, and MS4A4A) showed increased mRNA expression in the acute phase of KD which decreased after IVIG therapy (P < 0.05). Corresponding CpG sites in the promoter regions these markers were hypomethylated in the acute phase of KD and significantly increased after IVIG therapy. In conclusion, both M1 and M2 markers showed increased mRNA expression in the acute phase of KD. CpG site methylation may be one of the mechanisms governing macrophage polarization in KD.

The Expression of Glycoprotein Genes in the Inflammatory Process of Kawasaki Disease

Background: Kawasaki disease (KD) is the most common form of febrile coronary vasculitis disease to occur in children. Early diagnosis and proper therapy can prevent the complication of coronary artery lesions (CAL). The main pathogenesis of KD is an inflammatory process related to the host's genetic characteristics. In innate human immunity, the interaction of leukocytes and glycoprotein plays an important role against microbes. The purpose of our study was to understand the role of leukocytes' glycoprotein genes during the acute phase of KD. Materials and Methods: We enrolled a total of 97 subjects from a medical center. Of those, 24 subjects were healthy controls, and 24 subjects were fever controls; the other 49 subjects were KD patients who had had blood samples taken both before and after IVIG treatment. We collected the total RNA from leukocytes and performed a quantitative polymerase chain reaction for the HP, GRP84, and CLEC4D genes in real time. Results: Compared with both the healthy and fever controls, the upregulation of HP, GRP84, and CLEC4D genes was significant in peripheral leukocytes during acute-phase KD. The transcriptional level of these respective genes not only demonstrated a positive correlation with each other, but were also effective predictors for KD (all auROC >0.87) according to the ROC curve analysis. The hyper-expression of these three genes was significantly associated with IVIG resistance, but not CAL formation. Conclusions: Our study demonstrates that the expression of HP, GRP84, and CLEC4D genes of leukocytes play an important role in the pathogenesis and primary IVIG response during the acute inflammatory process of KD.

Current State of Precision Medicine in Primary Systemic Vasculitides

Precision medicine (PM) is an emerging data-driven health care approach that integrates phenotypic, genomic, epigenetic, and environmental factors unique to an individual. The goal of PM is to facilitate diagnosis, predict effective therapy, and avoid adverse reactions specific for each patient. The forefront of PM is in oncology; nonetheless, it is developing in other fields of medicine, including rheumatology. Recent studies on elucidating the genetic architecture of polygenic and monogenic rheumatological diseases have made PM possible by enabling physicians to customize medical treatment through the incorporation of clinical features and genetic data. For complex inflammatory disorders, the prevailing paradigm is that disease susceptibility is due to additive effects of common reduced-penetrance gene variants and environmental factors. Efforts have been made to calculate cumulative genetic risk score (GRS) and to relate specific susceptibility alleles for use of target therapies. The discovery of rare patients with single-gene high-penetrance mutations informed our understanding of pathways driving systemic inflammation. Here, we review the advances in practicing PM in patients with primary systemic vasculitides (PSVs). We summarize recent genetic studies and discuss current knowledge on the contribution of epigenetic factors and extracellular vesicles (EVs) in disease progression and treatment response. Implementation of PM in PSVs is a developing field that will require analysis of a large cohort of patients to validate data from genomics, transcriptomics, metabolomics, proteomics, and epigenomics studies for accurate disease profiling. This multi-omics approach to study disease pathogeneses should ultimately provide a powerful tool for stratification of patients to receive tailored optimal therapies and for monitoring their disease activity.

Immunomics in Pediatric Rheumatic Diseases

The inherent complexity in the immune landscape of pediatric rheumatic disease necessitates a holistic system approach. Uncertainty in the mechanistic workings and etiological driving forces presents difficulty in personalized treatments. The development and progression of immunomics are well suited to deal with this complexity. Immunomics encompasses a spectrum of biological processes that entail genomics, transcriptomics, epigenomics, proteomics, and cytomics. In this review, we will discuss how various high dimensional technologies in immunomics have helped to grow a wealth of data that provide salient clues and biological insights into the pathogenesis of autoimmunity. Interfaced with critical unresolved clinical questions and unmet medical needs, these platforms have helped to identify candidate immune targets, refine patient stratification, and understand treatment response or resistance. Yet the unprecedented growth in data has presented both opportunities and challenges. Researchers are now facing huge heterogeneous data sets from different origins that need to be integrated and exploited for further data mining. We believe that the utilization and integration of these platforms will help unravel the complexities and expedite both discovery and validation of clinical targets.

Increase expression of CD177 in Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is the most common acute coronary vasculitis disease to occur in children. Its incidence has been attributed to the combined effects of infection, genetics, and immunity. Although the etiopathogenesis of KD remains unknown, we have performed a survey of global genetic DNA methylation status and transcripts expression in KD patients in order to determine their contribution to the pathogenesis of KD.

METHODS

We recruited 148 participants for this case-control study. The chip studies consisted of 18 KD patients that were analyzed both before undergoing intravenous immunoglobulin (IVIG) treatment and at least 3 weeks afterward, as well as 36 non-KD control subjects, using Illumina HumanMethylation450 BeadChip and Affymetrix GeneChip® Human Transcriptome Array 2.0. We then carried out real-time quantitative PCR on a separate cohort of 94 subjects for validation.

RESULTS

According to our microarray study, CD177, a neutrophil surface molecule, appeared to be significantly upregulated in KD patients when compared to controls with epigenetic hypomethylation. After patients received IVIG treatment, CD177 mRNA levels decreased significantly. PCR validation indicated that the CD177 expression is consistent with the Transcriptome Array 2.0 results. Furthermore, the area under the curve values of CD177 between KD patients and controls is 0.937. We also observed significantly higher CD177 levels in typical KD than in incomplete presentation or KD with IVIG resistance.

CONCLUSION

In this study, we have demonstrated the epigenetic hypomethylation and increased expression of CD177 during the acute stage of KD. Furthermore, a higher expression of CD177 in KD patients with typical presentation was associated with IVIG resistance.

Distribution of distinct subsets of circulating T follicular helper cells in Kawasaki disease

Background

Kawasaki disease (KD) is an acute febrile vasculitis that primarily affects children. Previous studies have shown that both innate and adapt immune systems are involved in the immunopathogenesis of KD. The following study analyzes the distribution of the subsets of Circulating T follicular helper cells (cTfh cells) in KD patients with and without coronary artery lesions (CALs).

Methods

Twenty KD patients and fifteen healthy sex- and age- matched children were enrolled. Patients were divided into two groups depending on CALs. Blood samples were collected respectively before and after intravenous immunoglobulin (IVIG) administration. Circulating Tfh cells were categorized into three subsets by flow cytometry including cTfh1 (CXCR3 + CCR6-), cTfh2 (CXCR3-CCX6-) and cTfh17 (CXCR3-CCR6+) cells in circulating CD3 + CD4 + CXCR5 + CD45RA- T cells. Cytometric bead arrays were used to analyze the level of IFN-γ, IL-4 and IL-17A.

Results

We found that frequency of cTfh2 cells was significantly elevated in KD patients before IVIG administration with low expression of cTfh1 cells, where the ratio of cTfh2 + cTfh17/cTfh1 significantly increased. Levels of IFN-γ, IL-4 and IL-17A in KD were significantly higher compared to controls. Further analysis showed that cTfh1 cells were negatively correlated with serum CRP, whereas cTfh2 cells were positively correlated with serum CRP and ESR. Comparison of different groups showed that frequency of cTfh1 cells in CALs+ group were significantly lower compared to CALs- group. In contrast, cTfh2 cells in CALs+ group significantly increased. After IVIG administration, frequency of cTfh2 cells and the ratio significantly decreased while the frequency of cTfh1 cells significantly increased. Meanwhile, all levels of cytokines decreased.

Conclusions

Our data demonstrated that cTfh1 and cTfh2 cells participate in the pathogenesis of KD, and that the two subsets might be associated with CALs.

Decreased Steroid Hormone Receptor NR4A2 Expression in Kawasaki Disease Before IVIG Treatment

Kawasaki disease (KD) is anacute febrile coronary vasculitis disease in children. In general, this disease can be treated with a single dose of 2 g/kg intravenous immunoglobulin (IVIG). However, the best timing for administering steroid treatment in acute-stage KD is still under debate. In this study, we recruited 174 participants to survey the transcript levels of steroid hormone receptors in KD patients. The chip studies consisted of 18 KD patients that were analyzed before IVIG treatment and at least 3 weeks after IVIG administration, as well as 36 control subjects, using GeneChip® HTA 2.0. Another cohort consisting of 120 subjects was analyzed to validate qRT-PCR. Our microarray study demonstrated significant downregulated expressions of the mRNA levels of NR1A2, RORA, NR4A1-3, THRA, and PPARD in KD patients in comparision to the controls. However, these genes increased considerably in KD patients after IVIG administration. After PCR validation, our data only revealed decreased NR4A2 mRNA expression in the KD patients compared to those of the controls, which increased after they received IVIG treatment. Our study is the first to report the potential effective utilization of steroid treatment in KD. Prior to IVIG treatment, decreased steroid receptors allowed for the reduced treatment role of steroids. However, after IVIG treatment, increased steroid receptors indicate that steroids are effective as a supplementary treatment for KD.

Decreased DNA methyltransferases expression is associated with coronary artery lesion formation in Kawasaki disease

Background: Kawasaki disease (KD) is the most common acute coronary vasculitis to occur in children. Although we have uncovered global DNA hypomethylation in KD, its underlying cause remains uncertain. In this study, we performed a survey of transcript levels of DNA methyltransferases and demethylases in KD patients. Materials and Methods: We recruited 145 participants for this study. The chip studies consisted of 18 KD patients that were analyzed before undergoing intravenous immunoglobulin (IVIG) treatment and at least 3 weeks after IVIG treatment, as well as 36 control subjects, using Affymetrix GeneChip® Human Transcriptome Array 2.0. An additional study of 91 subjects was performed in order to validate real-time quantitative PCR. Results: In our microarray study, the mRNA levels of DNMT1 and DNMT3A were significantly lower while TET2 was higher in acute-stage KD patients compared to the healthy controls. Through PCR validation, we observed that the expression of DNMT1 and TET2 are consistent with the Transcriptome Array 2.0 results. Furthermore, we observed significantly lower DMNT1 mRNA levels following IVIG treatment between those who developed CAL and those who did not. Conclusion: Our findings provide an evidence of DNA methyltransferases and demethylases changes and are among the first report that transient DNA hypomethylation is induced during acute inflammatory phase of Kawasaki disease.

Aetiological Significance of Infectious Stimuli in Kawasaki Disease

Kawasaki disease (KD) is a pediatric vasculitis syndrome that is often involves coronary artery lesions (e. g., coronary artery aneurysms). Although its causal factors and entire pathogenesis remain elusive, the available evidence indicates that the pathogenesis of KD is closely associated with dysregulation of immune responses to various viruses or microbes. In this short review, we address several essential aspects of the etiology of KD with respect to the immune response to infectious stimuli: 1) the role of viral infections, 2) the role of bacterial infections and the superantigen hypothesis, 3) involvement of innate immune response including pathogens/microbe-associated molecular patterns and complement pathways, and 4) the influence of genetic background on the response to infectious stimuli. Based on the clinical and experimental evidence, we discuss the possibility that a wide range of microbes and viruses could cause KD through common and distinct immune processes.

Effectiveness of intravenous immunoglobulin alone and intravenous immunoglobulin combined with high-dose aspirin in the acute stage of Kawasaki disease: study protocol for a randomized controlled trial

BACKGROUND

Kawasaki disease (KD) is an acute febrile systemic vasculitis most commonly seen in children under 5 years old. High-dose aspirin is often administered, but the duration of such treatment varies. Many centers reduce the aspirin dose once the patient is afebrile, even before treating said patient with intravenous immunoglobulin (IVIG). However, a randomized controlled trial regarding high-dose aspirin in the acute stage of KD has not previously been carried out.

METHODS/DESIGN

This trial has been designed as a multi-center, prospective, randomized controlled, evaluator-blinded trial with two parallel groups to determine whether IVIG alone as the primary therapy in acute-stage KD is as effective as IVIG combined with high-dose aspirin therapy. The primary endpoint is defined as coronary artery lesion (CAL) formation at 6-8 weeks. Patients meeting the eligibility criteria are randomly assigned (1:1) to a test group (that receives only IVIG) or a standard group (that receives IVIG plus high-dose aspirin). This clinical trial is conducted at three medical centers in Taiwan.

DISCUSSION

Since high-dose aspirin has significant anti-inflammatory and anti-platelet functions, it does not appear to affect disease outcomes. Furthermore, it can decrease hemoglobin levels. Therefore, we have initiated this randomized controlled trial to evaluate the necessity of high-dose aspirin in the acute stage of KD.

TRIAL REGISTRATION

Kawasaki Disease Center, Kaohsiung Chang Gung Memorial Hospital, Taiwan. ClinicalTrials.gov Identifier: NCT02951234. Release Date: November 3, 2016.

An update on the role of epigenetics in systemic vasculitis

PURPOSE OF REVIEW

The purpose of this review is to discuss recent observations of epigenetic changes related to the complex pathogenesis of systemic vasculitides and their contribution to the field.

RECENT FINDINGS

There have been new observations of epigenetic changes in vasculitis and their potential role in disease pathogenesis in antineutrophil cytoplasmic antibody-associated vasculitis, giant-cell arteritis, Kawasaki disease, Behçet's disease, and IgA vasculitis. Some of this recent work has focused on the efficacy of using DNA methylation and miRNA expression as clinical biomarkers for disease activity and how DNA methylation and histone modifications interact to regulate disease-related gene expression.

SUMMARY

DNA methylation, histone modification, and miRNA expression changes are all fruitful ground for biomarker discovery and therapeutic targets in vasculitis. Current knowledge has provided targeted and suggested effects, but in many cases, has relied upon small cohorts, cosmopolitan cell populations, and limited knowledge of functional interactions. Expanding our knowledge of how these epigenetic mechanisms interact in a disease-specific and cell-specific manner will help to better understand the pathogenesis of systemic vasculitis.

Epigenetic hypomethylation and upregulation of NLRC4 and NLRP12 in Kawasaki disease

INTRODUCTION

Kawasaki disease (KD) is a type of childhood febrile systemic vasculitis. Inflammasomes control inflammatory signaling and are related with the development of KD. In this study, we performed a survey of transcripts and global DNA methylation levels of inflammasome sensors of NOD-like receptors (NLRs) and the downstream interleukin 1β (IL-1β).

MATERIALS AND METHODS

In this study, for the chip studies, we recruited a total of 18 KD patients, who we analyzed before receiving intravenous immunoglobulin (IVIG) and at least 3 weeks after IVIG treatment, as well as 36 non-fever controls by Illumina HumanMethylation 450 BeadChip and Affymetrix GeneChip® Human Transcriptome Array 2.0. A separate group of 78 subjects was performed for real-time quantitative PCR validations.

RESULTS

The expressions of mRNA levels of NLRC4, NLRP12, and IL-1β were significantly upregulated in KD patients compared to the controls (p<0.05). Once KD patients underwent IVIG treatment, these genes considerably decreased. In particular, the methylation status of the CpG sites of these genes indicated a significant opposite tendency between the KD patients and the controls. Furthermore, mRNA levels of IL-1β represented a positive correlation with NLRC4 (p=0.002). We also observed that the mRNA levels of NLRP12 were lower in KD patients who developed coronary arterial lesions (p<0.005).

CONCLUSION

This study is among the first to report epigenetic hypomethylation, increased transcripts, and the upregulation of NLRC4, NLRP12 and IL-1β in KD patients. Moreover, a decreased upregulation of NLRP12 was related to coronary arterial lesion formation in KD patients.

HAMP promoter hypomethylation and increased hepcidin levels as biomarkers for Kawasaki disease

Kawasaki disease (KD) is the most common coronary vasculitis to appear in children with anemia and has been associated with elevated plasma hepcidin levels. We recruited a total of 241 cases, including 18 KD patients, who were tested both prior to receiving intravenous immunoglobulin (IVIG) and at least 3 weeks after IVIG treatment, and 18 febrile controls, who were observed in the Illumina HumanMethylation450 BeadChip study for their CpG markers. The remaining cases consisted of another 92 KD patients and 113 controls that were used for validation by pyrosequencing. We performed a genetic functional study using Luciferase assays. A support vector machine (SVM) classification model was adopted to identify KD patients and control subjects. In this study, KD patients clearly demonstrated a significantly epigenetic hypomethylation of HAMP promoter compared to controls. After receiving IVIG treatment, the hypomethylation status in KD patients was restored, and we observed a significant opposite tendency between the DNA methylation of target CpG sites (cg23677000 and cg04085447) and the hepcidin level. Furthermore, reporter gene assays were used to detect target CpG sites, the methylation of which displayed decreased levels of HAMP gene expression. Of particular note, we developed a SVM classification model with a 90.9% sensitivity, a 91.9% specificity, and 0.94 auROC in the training set. An independent blind cohort also had good performance (96.1% sensitivity and 89.7% specificity). In this study, we demonstrate HAMP promoter hypomethylation, which upregulates hepcidin expression in KD patients. Furthermore, the reliability and robustness of our SVM classification model can accurately serve as KD biomarkers.

Innate immune responses following Kawasaki disease and toxic shock syndrome

The pathogenesis of Kawasaki disease (KD) remains unknown and there is accumulating evidence for the importance of the innate immune system in initiating and mediating the host inflammatory response. We compared innate immune responses in KD and toxic shock syndrome (TSS) participants more than two years after their acute illness with control participants to investigate differences in their immune phenotype. Toxic shock syndrome shares many clinical features with KD; by including both disease groups we endeavoured to explore changes in innate immune responses following acute inflammatory illnesses more broadly. We measured the in vitro production of interferon (IFN)-γ, tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-1 receptor antagonist (IL-1ra), and IL-10 following whole blood stimulation with toll-like receptor and inflammasome ligands in 52 KD, 20 TSS, and 53 control participants in a case-control study. Analyses were adjusted for age, sex, and unstimulated cytokine concentrations. Compared to controls, KD participants have reduced IL-1ra production in response to stimulation with double stranded RNA (geometric mean ratio (GMR) 0.37, 95% CI 0.15, 0.89, p = 0.03) and increased IL-6 production in response to incubation with Lyovec™ (GMR 5.48, 95% CI 1.77, 16.98, p = 0.004). Compared to controls, TSS participants have increased IFN-γ production in response to peptidoglycan (GMR 4.07, 95% CI 1.82, 9.11, p = 0.001), increased IL-1β production to lipopolysaccharide (GMR 1.64, 95% CI 1.13, 2.38, p = 0.01) and peptidoglycan (GMR 1.61, 95% CI 1.11, 2.33, p = 0.01), and increased IL-6 production to peptidoglycan (GMR 1.45, 95% CI 1.10, 1.92, p = 0.01). Years following the acute illness, individuals with previous KD or TSS exhibit a pro-inflammatory innate immune phenotype suggesting a possible underlying immunological susceptibility or innate immune memory.

Pirh2 mediates the sensitivity of myeloma cells to bortezomib via canonical NF-κB signaling pathway

Clinical success of the proteasome inhibitor established bortezomib as one of the most effective drugs in treatment of multiple myeloma (MM). While survival benefit of bortezomib generated new treatment strategies, the primary and secondary resistance of MM cells to bortezomib remains a clinical concern. This study aimed to highlight the role of p53-induced RING-H2 (Pirh2) in the acquisition of bortezomib resistance in MM and to clarify the function and mechanism of action of Pirh2 in MM cell growth and resistance, thereby providing the basis for new therapeutic targets for MM. The proteasome inhibitor bortezomib has been established as one of the most effective drugs for treating MM. We demonstrated that bortezomib resistance in MM cells resulted from a reduction in Pirh2 protein levels. Pirh2 overexpression overcame bortezomib resistance and restored the sensitivity of myeloma cells to bortezomib, while a reduction in Pirh2 levels was correlated with bortezomib resistance. The levels of nuclear factor-kappaB (NF-κB) p65, pp65, pIKBa, and IKKa were higher in bortezomib-resistant cells than those in parental cells. Pirh2 overexpression reduced the levels of pIKBa and IKKa, while the knockdown of Pirh2 via short hairpin RNAs increased the expression of NF-κB p65, pIKBa, and IKKa. Therefore, Pirh2 suppressed the canonical NF-κB signaling pathway by inhibiting the phosphorylation and subsequent degradation of IKBa to overcome acquired bortezomib resistance in MM cells.

Incomplete Refractory Kawasaki Disease in an Infant-A Case Report and a Review of the Literature

Kawasaki disease (KD) is a febrile vasculitis, which is commonly defined by fever and at least four specific clinical symptoms. Incomplete KD is defined by suggestive echocardiographic findings with an incomplete clinical picture. Refractory KD is diagnosed in patients resistant to intravenous immunoglobulin (IVIG). We report the case of a 6-month-old male infant admitted to our clinic for persistent fever and onset of a generalized polymorphous rash, accompanied by high fever, rhinorrhea, and cough for the past 7 days. The laboratory tests, on the day of admission, revealed leukocytosis with neutrophilia, anemia, thrombocytosis, hypernatremia, hypoalbuminemia, elevated C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR). Echocardiography showed dilation of the left anterior descending coronary artery (LAD). Based on all these findings, we established the diagnosis of KD, and we initiated IVIG and intravenous pulsed methylprednisolone, with an initial favorable outcome. However, the symptoms reappeared, and we administered a second higher single dose of IVIG, but without any clinical improvement. Moreover, the laboratory parameters and echocardiographic findings worsened. We reinitiated a longer course of intravenous methylprednisolone in a smaller dose, which had a favorable impact on the clinical, laboratory, and echocardiographic parameters. Multiple uncertainties exist related to the management of refractory KD despite the wide spectrum of therapeutic options that have been proposed. Our case demonstrates that in patients refractory to aggressive initial therapy, low or moderate doses of steroid given daily may be helpful.

Epigenetic hypomethylation and upregulation of matrix metalloproteinase 9 in Kawasaki disease

Background

Kawasaki disease (KD) is a type of febrile coronary vasculitis occurring in children. Some researchers have suggested that changes in genetic signatures, such as matrix metalloproteinases (MMPs), are critical markers for cardiovascular diseases. This study aims to provide a comprehensive survey of global DNA methylation levels and MMP transcripts of KD patients compared to control subjects.

Materials and Methods

For chips studies, we recruited a total of 18 KD patients, prior to receiving intravenous immunoglobulin (IVIG) and at least 3 weeks after IVIG treatment, as well as 18 healthy and 18 febrile control subjects. We applied Illumina HumanMethylation450 BeadChip and Affymetrix GeneChip® Human Transcriptome Array 2.0 to evaluate their CpG markers and expression levels, respectively. Then we used a separate cohort to carry out real-time quantitative PCR validations of mRNA levels.

Results

The expressions of mRNA levels of MMP-8, -9, and -25 were significantly upregulated in KD patients compared to the healthy and febrile controls. Once KD patients underwent IVIG treatment, these MMPs considerably decreased. In particular, the methylation status of CpG sites of MMP-9 indicated a significant opposite tendency between both stages of not only the KD samples but also the controls. We also observed the mRNA level of MMP-9 to be higher in KD patients with coronary arterial lesion formation.

Conclusion

This study is the first to report epigenetic hypomethylation, an increased MMP-9 transcript, and the upregulation of MMP-9 in KD patients who had formed coronary arterial lesions.

Correlation of HAMP gene polymorphisms and expression with the susceptibility and length of hospital stays in Taiwanese children with Kawasaki disease

Kawasaki disease (KD) is a form of systemic vasculitis. Regarding its pathogenesis, HAMP gene encoding hepcidin, which is significant for iron metabolism, has a vital function. In this study, we recruited a total of 381 KD patients for genotyping. Data from 997 subjects (500 subjects from cohort 1; 497 subjects from cohort 2) were used for analysis. Using TaqMan allelic discrimination, we determined five tag SNPs (rs916145, rs10421768, rs3817623, rs7251432, and rs2293689). Treatment outcome data related to such clinical phenotypes as coronary artery lesions (CAL), coronary artery aneurysms (CAA), and intravenous immunoglobulin (IVIG) effects were also collected. Furthermore, we measured plasma hepcidin levels with an enzyme-linked immunosorbent assay. We found that HAMP gene polymorphism (rs7251432, and rs2293689) was significantly correlated with KD risk and that plasma hepcidin levels both before and after IVIG treatment had a significantly positive correlation with length of hospital stays (R = 0.217, p = 0.046 and R = 0.381, p < 0.0001, respectively). In contrast, plasma hepcidin levels has a negative correlation with KD patients’ albumin levels (R = −0.27, p < 0.001) prior to IVIG treatment. This study's findings indicate that HAMP might have a role in the disease susceptibility, as well as its expressions correlated length of hospital stays, and albumin levels in Taiwanese children with KD.

Anemia in Kawasaki Disease: Hepcidin as a Potential Biomarker

Kawasaki disease (KD) is an autoimmune-like disease and acute childhood vasculitis syndrome that affects various systems but has unknown etiology. In addition to the standard diagnostic criteria, anemia is among the most common clinical features of KD patients and is thought to have a more prolonged duration of active inflammation. In 2001, the discovery of a liver-derived peptide hormone known as hepcidin began revolutionizing our understanding of anemia’s relation to a number of inflammatory diseases, including KD. This review focuses on hepcidin-induced iron deficiency’s relation to transient hyposideremia, anemia, and disease outcomes in KD patients, and goes on to suggest possible routes of further study.