A polymorphism in plasma platelet-activating factor acetylhydrolase is involved in resistance to immunoglobulin treatment in Kawasaki disease

Pharmacogenomics of coronary artery response to intravenous gamma globulin in kawasaki disease

Kawasaki disease (KD) is a multisystem inflammatory illness of infants and young children that can result in acute vasculitis. The mechanism of coronary artery aneurysms (CAA) in KD despite intravenous gamma globulin (IVIG) treatment is not known. We performed a Whole Genome Sequencing (WGS) association analysis in a racially diverse cohort of KD patients treated with IVIG, both using AHA guidelines. We defined coronary aneurysm (CAA) (N = 234) as coronary z ≥ 2.5 and large coronary aneurysm (CAA/L) (N = 92) as z ≥ 5.0. We conducted logistic regression models to examine the association of genetic variants with CAA/L during acute KD and with persistence >6 weeks using an additive model between cases and 238 controls with no CAA. We adjusted for age, gender and three principal components of genetic ancestry. The top significant variants associated with CAA/L were in the intergenic regions (rs62154092 p < 6.32E-08 most significant). Variants in SMAT4, LOC100127, PTPRD, TCAF2 and KLRC2 were the most significant non-intergenic SNPs. Functional mapping and annotation (FUMA) analysis identified 12 genomic risk loci with eQTL or chromatin interactions mapped to 48 genes. Of these NDUFA5 has been implicated in KD CAA and MICU and ZMAT4 has potential functional implications. Genetic risk score using these 12 genomic risk loci yielded an area under the receiver operating characteristic curve (AUC) of 0.86. This pharmacogenomics study provides insights into the pathogenesis of CAA/L in IVIG-treated KD and shows that genomics can help define the cause of CAA/L to guide management and improve risk stratification of KD patients.

Pharmacogenomics of Coronary Artery Response to Intravenous Gamma Globulin in Kawasaki Disease

Background

Kawasaki disease (KD) is a multisystem inflammatory illness of infants and young children that can result in acute vasculitis. The pathological walls of afflicted coronary arteries show propensity for forming thrombosis and aneurysms. The mechanism of coronary artery aneurysms (CAA) despite intravenous gamma globulin (IVIG) treatment is not known.

Methods

We performed a Whole Genome Sequencing (WGS) association analysis in a racially diverse cohort of KD patients treated with IVIG, both using AHA guidelines. We defined coronary aneurysm (CAA) (N = 234) as coronary z>2.5 and large coronary aneurysm (CAA/L) (N = 92) as z>5.0. We conducted logistic regression models to examine the association of genetic variants with CAA/L during acute KD and with persistence >6 weeks using an additive model between cases and 238 controls with no CAA. We adjusted for age, gender and three principal components of genetic ancestry. We performed functional mapping and annotation (FUMA) analysis and further assessed the predictive risk score of genomic risk loci using the area under the receiver operating characteristic curve (AUC).

Results

The top significant variants associated with CAA/L were in the intergenic regions (rs62154092 p<6.32E-08 most significant). Variants in SMAT4, LOC100127 , PTPRD, TCAF2 and KLRC2 were the most significant non-intergenic SNPs. FUMA identified 12 genomic risk loci with eQTL or chromatin interactions mapped to 48 genes. Of these NDUFA5 has been implicated in KD CAA and MICU and ZMAT4 has potential functional implications. Genetic risk score using these 12 genomic risk loci yielded an AUC of 0.86.

Conclusions

This pharmacogenomics study provides insights into the pathogenesis of CAA/L in IVIG-treated KD patients. We have identified multiple novel SNPs associated with CAA/L and related genes with potential functional implications. The study shows that genomics can help define the cause of CAA/L to guide management and improve risk stratification of KD patients.

Pharmacogenomics of intravenous immunoglobulin response in Kawasaki disease

Introduction

Kawasaki disease (KD) is a diffuse vasculitis in children. Response to high dose intravenous gamma globulin (IVIG), the primary treatment, varies according to genetic background. We sought to identify genetic loci, which associate with treatment response using whole genome sequencing (WGS).

Method

We performed WGS in 472 KD patients with 305 IVIG responders and 167 non-responders defined by AHA clinical criteria. We conducted logistic regression models to test additive genetic effect in the entire cohort and in four subgroups defined by ancestry information markers (Whites, African Americans, Asians, and Hispanics). We performed functional mapping and annotation using FUMA to examine genetic variants that are potentially involved IVIG non-response. Further, we conducted SNP-set [Sequence] Kernel Association Test (SKAT) for all rare and common variants.

Results

Of the 43,288,336 SNPs (23,660,970 in intergenic regions, 16,764,594 in introns and 556,814 in the exons) identified, the top ten hits associated with IVIG non-response were in FANK1, MAP2K3:KCNJ12, CA10, FRG1DP, CWH43 regions. When analyzed separately in ancestry-based racial subgroups, SNPs in several novel genes were associated. A total of 23 possible causal genes were pinpointed by positional and chromatin mapping. SKAT analysis demonstrated association in the entire MANIA2, EDN1, SFMBT2, and PPP2R5E genes and segments of CSMD2, LINC01317, HIVEPI, HSP90AB1, and TTLL11 genes.

Conclusions

This WGS study identified multiple predominantly novel understudied genes associated with IVIG response. These data can serve to inform regarding pathogenesis of KD, as well as lay ground work for developing treatment response predictors.

Association of Genetic Polymorphisms in Kawasaki Disease with the Response to Intravenous Immunoglobulin Therapy

Kawasaki disease (KD) is an acute febrile and systemic vasculitis disease mainly affecting children < 5 years old. Although the first case of KD was reported in 1967 and despite extensive research on KD since then, the cause of the disease remains largely unknown. The most common complications of KD are coronary artery lesions (CAL), which significantly increase the risk of coronary heart disease. The standard treatment for KD is high-dose intravenous immunoglobulin (IVIG) plus aspirin within 10 days from symptoms' appearance, which has been shown to decrease the incidence of CAL to 5-7%. Despite the benefits of IVIG, about 25% of the patients treated with IVIG develop resistance or are unresponsive to the therapy, which represents an important risk factor for CAL development. The cause of IVIG unresponsiveness has not been fully elucidated. However, the role of gene polymorphisms in IVIG response has been suggested. Herein, we comprehensively review genetic polymorphisms in KD that have been associated with IVIG resistance/unresponsiveness and further discuss available models to predict IVIG unresponsiveness.Kindly check and confirm inserted city in affiliation [1] is correctly identified.confirm.

Atopic asthma as a potentially significant but unrecognized risk factor for Kawasaki disease in children

OBJECTIVES

Childhood asthma is known to be associated with risks of both respiratory and non-respiratory infections. Little is known about the relationship between asthma and the risk of Kawasaki disease (KD). We assessed associations of asthma status and asthma phenotype (e.g. atopic asthma) with KD.

METHODS

We performed a population-based retrospective case-control study, using KD cases between January 1, 1979, and December 31, 2016, and two matched controls per case. KD cases were defined by the American Heart Association diagnostic criteria. Asthma status prior to KD (or control) index dates was ascertained by the two asthma criteria, Predetermined Asthma Criteria (PAC) and Asthma Predictive Index (API, a surrogate phenotype of atopic asthma). We assessed whether 4 phenotypes (both PAC + and API+; PAC + only; API + only, and non-asthmatics) were associated with KD.

RESULTS

There were 124 KD cases during the study period. The group having both PAC + and API + was significantly associated with the increased odds of KD, compared to non-asthmatics (odds ratio [OR] 4.3; 95% CI: 1.3 - 14.3). While asthma defined by PAC was not associated with KD, asthma defined by PAC positive with eosinophilia (≥4%) was significantly associated with the increased odds of KD (OR: 6.7; 95% CI: 1.6 - 28.6) compared to non-asthmatics. Asthma status defined by API was associated with KD (OR = 4.7; 95% CI: 1.4-15.1).

CONCLUSIONS

Atopic asthma may be associated with increased odds of KD. Further prospective studies are needed to determine biological mechanisms underlying the association between atopic asthma and increased odds of KD.

The Impact of Onset Age on Eosinophils in Kawasaki Disease

(1) Background: Kawasaki disease (KD) mainly affects children under the age of 5 years and eosinophilia in KD patients might be associated with the development of allergic diseases. We compared the age-adjusted Z-score (Z) of eosinophils and aimed to evaluate the impact of onset age on eosinophils in KD patients. (2) Methods: We divided 398 KD patients into seven age subgroups. Laboratory data and the age-adjusted Z-score of eosinophils during the phases of Kawasaki disease were analyzed. (3) Results: The absolute eosinophil count among all age groups showed significant differences in the post-intravenous immunoglobulin (IVIG) phase and throughout the course of KD with Z-score adjusted for age. Further analysis showed persistent elevation of the age-adjusted Z-score of eosinophils (Z-eosinophil) especially in the under six-month-old age subgroup. In addition, we divided the Z-eosinophil into two groups to find the relationship with coronary artery lesions (CALs). Patients with a higher eosinophil count than average age values had a higher risk of developing CALs, while those with a lower eosinophil count than average age values had a lower risk of having CALs. (4) Conclusions: These findings may provide information to clinicians to pay attention to allergic diseases during the follow-up of KD, especially for children who are younger than 6 months old at the onset of KD, and eosinophil count could be a crucial focus in KD.

Continuous cyclosporine a infusion in patients with severe Kawasaki disease

BACKGROUND

The efficacy and safety of continuous intravenous infusion of cyclosporine A (CICsA) in patients with intravenous immunoglobulin-resistant Kawasaki disease are unclear.

METHODS

Between 2010 and 2020, 83 patients with Kawasaki disease that was not responsive to intravenous immunoglobulin (total dose ≥ 4 g/kg) were enrolled. All patients were started on CICsA (3 mg/kg/day) and switched to oral cyclosporine A (CsA) (4-6 mg/kg/day). Treatment efficacy, occurrence of coronary artery lesions (CALs), and laboratory parameters were evaluated. Patients were divided into two groups according to CICsA response: the responder group (afebrile ≤24 h after CICsA without additional treatment) and the weak responder group (afebrile >24 h after CICsA requiring additional treatment).

RESULTS

Fifty-five patients became afebrile within 24 and 74 h became afebrile in less than 72 h. Adverse events included hypertension in four and hyperkalemia in two patients. Thirty-nine patients were defined as responders and 44 patients as weak responders. There were no significant differences in CAL between the two groups. In weak responders, white blood cells, neutrophils, and C-reactive protein levels were higher, and albumin, immunoglobulin G, and CsA concentration were lower than in responders, indicating that weak responders had more severe inflammatory findings. However, there were no significant differences in CAL. Logistic regression analysis revealed that the response to treatment for CICsA was associated with immunoglobulin G levels at baseline and CsA concentrations the day after CICsA.

CONCLUSION

Although CICsA required additional treatments in about half of the cases, a favorable clinical course was observed by using this strategy, especially for reducing CAL.

Predictive model based on gene and laboratory data for intravenous immunoglobulin resistance in Kawasaki disease in a Chinese population

BACKGROUND

Here, we investigated the predictive efficiency of a newly developed model based on single nucleotide polymorphisms (SNPs) and laboratory data for intravenous immunoglobulin (IVIG) resistance in Kawasaki disease (KD) in a Chinese population.

METHODS

Data relating to children with KD were acquired from a single center between December 2015 and August 2019 and used to screen target SNPs. We then developed a predictive model of IVIG resistance using previous laboratory parameters. We then validated our model using data acquired from children with KD attending a second center between January and December 2019.

RESULTS

Analysis showed that rs10056474 GG, rs746994GG, rs76863441GT, rs16944 (CT/TT), and rs1143627 (CT/CC), increased the risk of IVIG-resistance in KD patients (odds ratio, OR > 1). The new predictive model, which combined SNP data with a previous model derived from laboratory data, significantly increased the area under the receiver-operator-characteristic curves (AUC) (0.832, 95% CI: 0.776-0.878 vs 0.793, 95%CI:0.734-0.844, P < 0.05) in the development dataset, and (0.820, 95% CI: 0.730-0.889 vs 0.749, 95% CI: 0.652-0.830, P < 0.05) in the validation dataset. The sensitivity and specificity of the new assay were 65.33% (95% CI: 53.5-76.0%) and 86.67% (95% CI: 80.2-91.7%) in the development dataset and 77.14% (95% CI: 59.9-89.6%) and 86.15% (95% CI: 75.3-93.5%) in the validation dataset.

CONCLUSION

Analysis showed that rs10056474 and rs746994 in the SMAD5 gene, rs76863441 in the PLA2G7 gene, and rs16944 or rs1143627 in the interleukin (IL)-1B gene, were associated with IVIG resistant KD in a Chinese population. The new model combined SNPs with laboratory data and improved the predictve efficiency of IVIG-resistant KD.

Human Secretary Phospholipase A2 Mutations and Their Clinical Implications

Phospholipases A2 (PLA₂s) belong to a superfamily of enzymes responsible for hydrolysis of the sn-2 fatty acids of membrane phospholipids to release arachidonic acid. PLA₂s are the rate limiting enzyme for the downstream synthesis of prostaglandins and leukotrienes that are the main mediators of inflammation. The extracellular forms of this enzyme are also called the secretary phospholipase A2 (sPLA₂) and are distributed extensively in most of the tissues in the human body. Their integral role in inflammatory pathways has been the primary reason for the extensive research on this molecule. The catalytic mechanism of sPLA₂ is initiated by a histidine/aspartic acid/calcium complex within the active site. Though they are known to have certain housekeeping functions, certain mutations of sPLA₂ are known to be implicated in causation of certain pathologies leading to diseases such as atherosclerosis, cardiovascular diseases, benign fleck retina, neurodegeneration, and asthma. We present an overview of human sPLA₂ and a comprehensive compilation of the mutations that result in various disease phenotypes. The study not only helps to have a holistic understanding of human sPLA₂ mutations and their clinical implications, but is also a useful platform to initiate research pertaining to structure–function relationship of the mutations to develop effective therapies for management of these diseases.

Association between P2RY12 Gene Polymorphisms and IVIG Resistance in Kawasaki Patients

Children with Kawasaki disease (KD) resistant to intravenous immunoglobulin (IVIG) have a higher incidence of coronary artery lesions (CAL). Despite the association between Purinergic receptor P2Y12 (P2RY12) polymorphism, KD genetic susceptibility, and CAL complications being proved, few studies have assessed the relationship between P2RY12 polymorphisms and IVIG resistance in patients with KD. We recruited 148 KD patients with IVIG resistance and 611 with IVIG sensitivity and selected five P2RY12 polymorphisms: rs9859538, rs1491974, rs7637803, rs6809699, and rs2046934. A significant difference in the genotype distributions between patients was only observed for the rs6809699 A > C polymorphism (AC vs. AA: adjusted odds ratio (OR) = 0.48, 95% confidence interval (CI) = 0.27–0.84, P=0.011; AC/CC vs. AA: adjusted OR = 0.47, 95% CI = 0.27–0.83, P=0.0084). After adjusting for age and gender, the carriers of the rs6809699 C allele had OR of 0.44 to 0.49 for IVIG sensitivity (AC vs. AA: adjusted OR = 0.48, 95% confidence interval (CI) = 0.27–0.84, P=0.011; AC/CC vs. AA: adjusted OR = 0.47, 95% CI = 0.27–0.83, P=0.0084) compared to the carriers of a rs6809699 AA genotype, suggesting the protective effect of this SNP against IVIG resistance. Moreover, individuals with all five protective polymorphisms experienced a significantly decreased IVIG resistance compared to that of individuals with up to three protective polymorphisms (adjusted OR = 0.27, 95% CI = 0.13–0.57, P=0.0006). Our results suggest that the P2RY12 rs6809699 polymorphism could be used as a biomarker to predict IVIG resistance in KD patients.

The rs1051931 G>A Polymorphism in the PLA2G7 Gene Confers Resistance to Immunoglobulin Therapy in Kawasaki Disease in a Southern Chinese Population

Background: Kawasaki disease (KD) is a common cardiovascular disease in infants and young children, with fever, rash, and conjunctivitis as the main clinical manifestations, which can lead to the occurrence of coronary aneurysms. Intravenous immunoglobulin (IVIG) is the preferred treatment for KD patients, but 10-20% of patients are resistant to IVIG. Lipoprotein-associated phospholipase A 2 (Lp-PLA2) is a potential therapeutic target for coronary atherosclerotic heart disease, and the polymorphism of Phospholipase A2 Group VII (PLA2G7) is closely related to the activity of Lp-PLA2, of which rs1051931 is the strongest. Therefore, the rs1051931 polymorphism may be a predictor of IVIG resistance in KD patients. Methods: A total of 760 KD cases, including 148 IVIG-resistant patients and 612 IVIG-responsive patients, were genotyped for rs1051931 in PLA2G7, we compared the effects of rs1051931 on IVIG treatment in KD patients by odds ratios (OR) and 95% confidence interval (CI). Results: The homozygous mutation AA may be a protective factor for IVIG resistance in KD patients (adjusted OR = 3.47, 95% CI = 1.14-10.57, P = 0.0284) and is more evident in patients with KD aged <60 months (adjusted OR = 3.68, 95% CI = 1.10-12.28, P = 0.0399). Conclusions: The PLA2G7 rs1051931 G>A polymorphism may be suitable as a biomarker for the diagnosis or prognosis of IVIG resistance in KD in a southern Chinese population.

Platelet-activating factor acetylhydrolases: An overview and update

Platelet-activating factor acetylhydrolases (PAF-AHs) are unique members of the phospholipase A₂ family that can hydrolyze the acetyl group of PAF, a signaling phospholipid that has roles in diverse (patho)physiological processes. Three types of PAF-AH have been identified in mammals, one plasma type and two intracellular types [PAF-AH (I) and PAF-AH (II)]. Plasma PAF-AH and PAF-AH (II) are monomeric enzymes that are structurally similar, while PAF-AH (I) is a multimeric enzyme with no homology to other PAF-AHs. PAF-AH (I) shows a strong preference for an acetyl group, whereas plasma PAF-AH and PAF-AH (II) also hydrolyze phospholipids with oxidatively modified fatty acids. Plasma PAF-AH has been implicated in several diseases including cardiovascular disease. PAF-AH (I) is required for spermatogenesis and is increasingly recognized as an oncogenic factor. PAF-AH (II) was recently shown to act as a bioactive lipid-producing enzyme in mast cells and thus could be a drug target for allergic diseases. This article is part of a Special Issue entitled Novel functions of phospholipase A2 Guest Editors: Makoto Murakami and Gerard Lambeau.

Immunoglobulin Resistance in Kawasaki Disease

Background: The aim of this study was to identify risk factors for immunoglobulin resistance, including clinical symptoms such as arthritis and the pH of intravenous immunoglobulin. Methods: The data of children with Kawasaki disease who had received immunoglobulin were evaluated. Data regarding the brand of immunoglobulin administered were abstracted from the pharmacy records. Results: Eighty consecutive children with Kawasaki disease were evaluated (Mdn_age=28 months, 66% male). The prevalence of immunoglobulin resistance was 30%. Arthritis was a presenting symptom in the acute phase of Kawasaki disease in 8% (6/80, all male) and was seen in significant association with immunoglobulin resistance in comparison to those without arthritis (16.7% vs. 0.2%, p=0.008). Next, the immunoglobulin brand types were divided into two groups: the relatively high pH group (n=16), including Carimune (pH 6.6±0.2), and the low pH group (n=63), including Gamunex (pH 4-4.5) or Privigen (pH 4.6-5). Overall, no significant difference in immunoglobulin responsiveness was found between the low pH and the high pH groups (73% vs. 56%, p=0.193), although the low pH group showed a trend toward a larger decrease in erythrocyte sedimentation rate (p=0.048), lower steroid use (p=0.054), and lower coronary involvement (p=0.08) than those in the high pH group. Conclusions: Children presenting with arthritis in the acute phase of Kawasaki disease may be at risk for immunoglobulin resistance.

Naturally Occurring Missense Mutation in Plasma PAF-AH Among the Japanese Population

A single nucleotide polymorphism in the plasma PAF-AH enzyme, i.e., G994T, which causes the substitution of Val at amino acid 279 with Phe (V279F), has been found in the Japanese population. This enzyme preferentially degrades oxidatively modulated or truncated phospholipids; therefore, it has been suggested that this enzyme may prevent the accumulation of proinflammatory and proatherogenic oxidized phospholipids. This hypothesis is supported by the higher prevalence of the V279F mutation in patients with asthmatic and atherosclerotic diseases, as compared with healthy controls. This mutation is rare in the Caucasian population. The plasma PAF-AH mass and enzyme activity are distributed over a wide range in the plasma and they are positively correlated with low-density lipoprotein (LDL) cholesterol. However, several clinical studies in the Caucasian population have suggested that this enzyme has the opposite role. This enzyme plays an active role in the development and progression of atherosclerosis via proinflammatory and proatherogenic lysophosphatidylcholine and oxidized fatty acids produced through the oxidation of LDL by this enzyme. Thus, plasma PAF-AH is a unique enzyme with dual roles in human inflammatory diseases. In this chapter, on the basis of recent findings we describe the association between a naturally occurring missense mutation in plasma PAF-AH and human diseases especially including atherosclerosis and asthma.

Intravenous immunoglobulin, pharmacogenomics, and Kawasaki disease

Kawasaki disease (KD) is a systemic vasculitis of unknown etiology and it is therefore worth examining the multifactorial interaction of genes and environmental factors. Targeted genetic association and genome-wide association studies have helped to provide a better understanding of KD from infection to the immune-related response. Findings in the past decade have contributed to a major breakthrough in the genetics of KD, with the identification of several genomic regions linked to the pathogenesis of KD, including ITPKC, CD40, BLK, and FCGR2A. This review focuses on the factors associated with the genetic polymorphisms of KD and the pharmacogenomics of the response to treatment in patients with intravenous immunoglobulin resistance.

The role of infection in Kawasaki syndrome

Objectives

To analyse the evidence suggesting a possible infectious origin of Kawasaki syndrome (KS).

Methods

PubMed was searched for all of the studies published over the last 15 years using the key words “Kawasaki syndrome” or “mucocutaneous lymph node syndrome” and “infectious disease” or “genetics” or “vasculitis” or “pathogenesis”.

Results

Various levels of evidence support the hypothesis that KS is a complex disease triggered by an infection due to one or more pathogens. Viruses or bacteria may be the primum movens, although no specific infectious agent can be considered definitely etiological. A number of genetic polymorphisms have been identified in subjects with KS, but none of them can currently be considered a real marker of susceptibility.

Conclusions

Various data suggest that KS is intimately related to infectious diseases and that its clinical expression is influenced by predisposing genetic backgrounds, but our knowledge of the infectious agent(s) involved and the genetic characteristics of susceptible children remains only partial. Further studies are needed to address the many still open questions concerning the 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.

Ethical issues with newborn screening in the genomics era

Continued technological advances have made the prospect of routine whole-genome sequencing (WGS) imminent. To date, much of the discussion about WGS has focused on its application and use in clinical medicine. Relatively little attention has been paid to the potential integration of WGS into newborn screening programs. Given the structure and scope of these programs, it is possible that the early applications of WGS will occur in state-run newborn screening programs. Assessment of the pressing ethical issues currently facing the newborn screening community will provide insight into the challenges that lie ahead in the genomics era.

Association of CCR2-CCR5 haplotypes and CCL3L1 copy number with Kawasaki Disease, coronary artery lesions, and IVIG responses in Japanese children

Background

The etiology of Kawasaki Disease (KD) is enigmatic, although an infectious cause is suspected. Polymorphisms in CC chemokine receptor 5 (CCR5) and/or its potent ligand CCL3L1 influence KD susceptibility in US, European and Korean populations. However, the influence of these variations on KD susceptibility, coronary artery lesions (CAL) and response to intravenous immunoglobulin (IVIG) in Japanese children, who have the highest incidence of KD, is unknown.

Methodology/Principal Findings

We used unconditional logistic regression analyses to determine the associations of the copy number of the CCL3L1 gene-containing duplication and CCR2-CCR5 haplotypes in 133 Japanese KD cases [33 with CAL and 25 with resistance to IVIG] and 312 Japanese controls without a history of KD. We observed that the deviation from the population average of four CCL3L1 copies (i.e., < or > four copies) was associated with an increased risk of KD and IVIG resistance (adjusted odds ratio (OR)  = 2.25, p = 0.004 and OR = 6.26, p = 0.089, respectively). Heterozygosity for the CCR5 HHF*2 haplotype was associated with a reduced risk of both IVIG resistance (OR = 0.21, p = 0.026) and CAL development (OR = 0.44, p = 0.071).

Conclusions/Significance

The CCL3L1-CCR5 axis may play an important role in KD pathogenesis. In addition to clinical and laboratory parameters, genetic markers may also predict risk of CAL and resistance to IVIG.

Functional Consequences of Mutations and Polymorphisms in the Coding Region of the PAF Acetylhydrolase (PAF-AH) Gene

In the past several years a number of alterations in the PAF-AH/PLA₂G7/LpPLA₂ gene have been described. These include inactivating mutations, polymorphisms in the coding region, and other genetic changes located in promoter and intronic regions of the gene. The consequences associated with these genetic variations have been evaluated from different perspectives, including in vitro biochemical and molecular studies and clinical analyses in human subjects. This review highlights the current state of the field and suggests new approaches that can be used to evaluate functional consequences associated with mutations and polymorphisms in the PAF-AH gene.

Molecular genetics of Kawasaki disease

Kawasaki disease (KD) is a leading cause of acquired cardiac disease of children in the developed countries. The pathogen that triggers this perplexing disease is still unknown after 40 y from the first description. Epidemiologic findings have made us believe that there are considerable genetic components in the etiology and some candidate genetic variations, which confer susceptibility to KD or risk for coronary artery lesions have been identified. However, most of them remain to be definitively confirmed by replication studies with large cohorts. In this article, I review the candidate gene association studies to date. I also introduce our recent findings in genome-wide approach, which revealed the importance of Ca2+/nuclear factor of activated T-cells pathway in the pathogenesis of KD.

Biology of platelet-activating factor acetylhydrolase (PAF-AH, lipoprotein associated phospholipase A2)

INTRODUCTION

This article is focused on platelet-activating factor acetylhydrolase (PAF-AH), a lipoprotein bound, calcium-independent phospholipase A(2) activity also referred to as lipoprotein-associated phospholipase A(2) or PLA(2)G7. PAF-AH catalyzes the removal of the acyl group at the sn-2 position of PAF and truncated phospholipids generated in settings of inflammation and oxidant stress.

DISCUSSION

Here, I discuss current knowledge related to the structural features of this enzyme, including the molecular basis for association with lipoproteins and susceptibility to oxidative inactivation. The circulating form of PAF-AH is constitutively active and its expression is upregulated by mediators of inflammation at the transcriptional level. This mechanism is likely responsible for the observed up-regulation of PAF-AH during atherosclerosis and suggests that increased expression of this enzyme is a physiological response to inflammatory stimuli. Administration of recombinant forms of PAF-AH attenuate inflammation in a variety of experimental models. Conversely, genetic deficiency of PAF-AH in defined human populations increases the severity of atherosclerosis and other syndromes. Recent advances pointing to an interplay among oxidized phospholipid substrates, Lp(a), and PAF-AH could hold the key to a number of unanswered questions.

The CCR5 (-2135C/T) polymorphism may be associated with the development of Kawasaki disease in Korean children

BACKGROUND

Kawasaki disease (KD) is an acute vasculitis syndrome of unknown etiology that frequently affects small to medium size arteries. C-C chemokine receptor 5 (CCR5) is a chemokine receptor that binds C-C chemokines. This study investigated the association of the CCR5 (-2135C/T) polymorphism with KD in Korean children.

METHODS

The study population consisted 189 Korean children with KD and 194 Korean children with congenital heart disease (CHD). CCR5 (-2135C/T) polymorphism genotypes were determined using the single-base extension method.

RESULTS

The allele frequencies of the CCR5 (-2135C/T) polymorphism differed significantly between CHD children and KD children (-2135T/T, 16.75% vs. 30.05%, aOR 2.14, 95% CI 1.31-3.51). The tested laboratory parameters differed significantly between the KD and CHD groups. The development of coronary artery aneurysm in KD patients was not associated with the CCR5 polymorphism.

CONCLUSIONS

Our findings suggest that the T allele at the CCR5 (-2135C/T) polymorphism might be associated with the development of KD in Korean children but does not appear to be associated with the development of coronary artery aneurysm.

Pharmacogenetics and paediatric drug development: issues and consequences to labelling and dosing recommendations

The area of pharmacogenetics (PGt) is evolving rapidly. However, ongoing efforts in this field are not aligned with the requirements for the inclusion of clinically relevant findings into the label, especially with reference to paediatric indications. Clinical research in children poses unique issues from a practical and technical perspective, but many challenges can be overcome by applying advanced study design and data analysis methods. When investigating the role of PGt factors on treatment effect, all features that influence drug response must be taken into account. Yet, PGt often has a privileged status in research protocols, with PGt factors evaluated independently from other determinants of response, instead of being regarded as other demographic or clinical covariates (e.g., age, renal function). At present, guidelines to incorporate PGt findings into label statements are lacking in part because this is a new and incompletely understood area. This situation is no longer acceptable. To achieve the potential that PGt can offer to drug development and ultimately to drug prescription, academia, industry and regulatory agencies need to pool resources on the revision of study design and data analysis requisites, bringing in model-based methodologies to enable accurate interpretation of results and provide appropriate labelling recommendations.

A single nucleotide polymorphism in the plasma PAF acetylhydrolase gene and risk of atherosclerosis in Japanese patients with peripheral artery occlusive disease

BACKGROUND

Plasma PAF-acetylhydrolase (PAF-AH) gene polymorphisms (G994 --> T in exon 9) and the resulting deficiency of enzyme activity were identified in the Japanese population. The objective of this study was to assess the joint effect of the polymorphism and hypercholesterolemia on risk of atherosclerosis.

METHODS AND RESULTS

We performed a case-control study including 150 patients who underwent operation for peripheral arterial occlusive disease (PAOD) and 158 controls matched for age and sex. Genomic DNA was analyzed for the mutant allele by a specific polymerase-chain reaction. Plasma PAF-AH activity was measured in both groups. The patients with multiple atherosclerotic diseases showed higher levels of PAF-AH activities than the patients with only peripheral artery occlusive disease among normal genotypes. PAOD patients were assessed either with or without polymorphism or hypercholesterolemia in regard to accompanying coronary artery disease or stroke. The prevalence of the polymorphism was significantly more frequent in the patients with PAOD. The plasma PAF-AH activity was correlated with total cholesterol and LDL level, and inversely related with HDL in normal genotype (GG) PAOD patients. However, neither the correlation nor the inverse relation was found in patients with the polymorphism. Patients with both hypercholesterolemia and the polymorphisms revealed a relative risk for other atherosclerotic disease of 11.5 (6.0-40.3) compared with normal genotype and normal lipid level.

CONCLUSION

The plasma PAF-AH gene polymorphism and hypercholesterolemia may interact and increase the risk of atherosclerosis.

Update on pediatric vasculitis

PURPOSE OF REVIEW

The purpose of this review is to provide an overview of the recent research and progress made in the field of pediatric vasculitis.

RECENT FINDINGS

Over the past year, researchers have described several polymorphisms in Henoch-Schonlein purpura and Kawasaki Disease as well as the association between various vasculitides and infections. International and multidisciplinary efforts in Kawasaki Disease have resulted in recommendations for its diagnosis, treatment, and long-term management to improve patient care and further increase global collaboration. Researchers are investigating the role of inflammation and its role in endothelial health and atherosclerosis. Treatment regimens continue to improve, with the use of different immunosuppressive medications; however, we continue to have incomplete treatment successes.

SUMMARY

Vasculitides are rare conditions with significant morbidity and mortality whose prognosis has improved with newer diagnostic modalities and treatments; however, we continue to have insufficient knowledge of vasculitides and lack unambiguous diagnostic criteria. As technology continues to progress it is clear that a single cause of these diseases may be an oversimplification: the genetic makeup of individuals, as well as various environmental exposures, are of vital importance in the pathophysiology and evolution of disease processes, as well as response to therapy. Efforts should continue to improve international multicenter collaboration and interdisciplinary efforts to help solve this ever-growing puzzle.