Genome-wide linkage and association mapping identify susceptibility alleles in ABCC4 for Kawasaki disease

Effectiveness of two same-manufacturer intravenous immunoglobulin for Kawasaki disease

BACKGROUND

To investigate whether two brands of intravenous immunoglobulin (IVIG) from the same manufacturer lead to varied effects when administered to patients with Kawasaki disease.

(KD) METHODS

Clinical characteristics, laboratory data, IVIG response, and coronary arteries change were analyzed between two groups.

RESULTS

We included 158 KD cases. The mean age at KD diagnosis was 23 ± 1.39 (range, 2-95) months. In the first IVIG course, 18 (11.4 %) patients were unresponsive. TBSF (brand T) and Privigen (brand P) were administered to 94 and 64 patients, respectively. The brand P group had a significantly longer fever (P < 0.001) and hospitalization (P = 0.007) durations after the therapy and a higher number of IVIG unresponsiveness (P = 0.016) than the brand T group. In the multivariate logistic regression analysis, a high Formosa score (≥3, Odds ratio [OR], 4.939; 95 % confidence interval [CI], 1.199-20.337; P = 0.027), high levels of CRP (≥12 mg/L, OR: 4.257,95 % CI,1.265-14.322; P = 0.019), and treatment with brand P (OR, 3.621; 95 % CI, 1.029-12.677; P = 0.045) were independent risk factors for IVIG unresponsiveness.

CONCLUSIONS

Compared with brand T, brand P prolonged the fever and hospitalization durations after IVIG treatment and increased the proportion of IVIG treatment unresponsiveness, but it did not infer the coronary arteries sequelae.

Cardiac involvement and cardiovascular risk factors in pediatric primary systemic vasculitides

Pediatric primary systemic vasculitides are a complex group of diseases. Vasculitis subgroups are mainly determined according to the size of the predominantly affected vessels. In patients with primary systemic vasculitis, the location of vascular involvement, the size of the vessels, the extent of vascular damage, and the underlying pathology determine the disease phenotype and severity. Cardiac involvement is rare in some pediatric vasculitis, such as IgA vasculitis and polyarteritis nodosa, while it is more common in some others like Kawasaki disease and Takayasu arteritis. On the other hand, chronic inflammation in the setting of systemic vasculitis forms a major cardiovascular risk factor. Accelerated atherosclerosis and the tendency to thrombosis are the main issues determining the cardiovascular risks in pediatric systemic vasculitis. Early diagnosis and treatment are essential in these patients to minimize morbidity and mortality. In this review, we aimed to raise physicians' awareness of cardiac involvement and cardiovascular risks in pediatric patients with primary systemic vasculitis.

Comparison of Previous Infectious and Allergic Diseases Between Patients with Kawasaki Disease and Propensity Score-matched Controls: A Nationwide Cohort Study

OBJECTIVE

To determine whether previous infectious and allergic diseases are associated with the development of Kawasaki disease in children.

STUDY DESIGN

This nationwide, population-based, case-control study used data from the Korean National Health Insurance claims database. The entire cohort consisted of patients younger than 5 years of age diagnosed with Kawasaki disease and 1:5 propensity score-matched controls from 2013 to 2019. The epidemiologic features and previous infectious or allergic diseases between the 2 groups were compared, and potential factors that could influence the association were identified.

RESULTS

In total, 32 964 patients diagnosed with Kawasaki disease and 164 820 controls were included. Patients with Kawasaki disease had more frequent diagnoses of previous sepsis or bacteremia (OR 1.41), acute pyelonephritis (OR 1.10), and otitis media (OR 1.24). In addition, Kawasaki disease was associated with previous diagnoses of atopic dermatitis (OR 1.05), urticaria (OR 1.08), and asthma (OR 1.05). The association between previous infectious or allergic diagnoses and Kawasaki disease was more prominent in younger patients (<2 years). However, intravenous immunoglobulin resistance, sex, and region of residence were not significant factors that consistently influenced the association between previous infectious or allergic diseases and Kawasaki disease.

CONCLUSIONS

Despite the increased rates of previous infectious and allergic diseases in patients with Kawasaki disease compared with controls, the association between allergic diseases and Kawasaki disease was weaker in our cohort than in previous studies.

Associations between the spatiotemporal distribution of Kawasaki disease and environmental factors: evidence supporting a multifactorial etiologic model

The etiology of Kawasaki Disease (KD), the most common cause of acquired heart disease in children in developed countries, remains elusive, but could be multifactorial in nature as suggested by the numerous environmental and infectious exposures that have previously been linked to its epidemiology. There is still a lack of a comprehensive model describing these complex associations. We present a Bayesian disease model that provides insight in the spatiotemporal distribution of KD in Canada from 2004 to 2017. The disease model including environmental factors had improved Watanabe-Akaike information criterion (WAIC) compared to the base model which included only spatiotemporal and demographic effects and had excellent performance in recapitulating the spatiotemporal distribution of KD in Canada (98% and 86% spatial and temporal correlations, respectively). The model suggests an association between the distribution of KD and population composition, weather-related factors, aeroallergen exposure, pollution, atmospheric concentration of spores and algae, and the incidence of healthcare encounters for bacterial pneumonia or viral intestinal infections. This model could be the basis of a hypothetical data-driven framework for the spatiotemporal distribution of KD. It also generates novel hypotheses about the etiology of KD, and provides a basis for the future development of a predictive and surveillance model.

Homozygous of MRP4 Gene rs1751034 C Allele Is Related to Increased Risk of Intravenous Immunoglobulin Resistance in Kawasaki Disease

Background: Kawasaki disease (KD) is a systemic vasculitis in childhood, which mainly causes damage to coronary arteries, and intravenous immunoglobulin (IVIG) is the initial therapy. IVIG resistance increased risk of coronary complication in KD. And genetic background is involved in the occurrence of IVIG resistance. Our previous study indicated the susceptibility of Multi-drug resistance protein 4 (MRP4) SNPs to KD. This study was to clarify the relationship between MRP4 polymorphisms and IVIG resistance.

Methods: We genotyped the six polymorphisms of MRP4 gene in 760 cases of KD using Taqman methods.

Results: Among the six polymorphisms, only the rs1751034 polymorphism was significantly associated with IVIG resistance in KD [CC vs. TT: adjusted odds ratio (OR) = 2.54, 95% confidence interval (CI) = 1.21–5.34; CC vs. TT/TC: adjusted OR = 2.33, 95% CI = 1.12–4.83, p = 0.023]. Combined analysis of three polymorphisms indicated that patients with 3–6 risk genotypes exhibited significantly elevated risk of IVIG resistance, when compared with those with 0–2 risk genotypes (adjusted OR = 1.52, 95% CI = 1.04–2.22, p = 0.0295). Stratified analysis revealed that in term of age and gender, rs1751034 CC carriers were associated with increased risk of IVIG resistance in those aged ≤ 60 months (adjusted OR = 2.65, 95% CI = 1.23–5.71, p = 0.0133). The presence of three or more risk genotypes was significantly associated with risk of IVIG resistance in children younger than 5 years of age and males.

Conclusion: Our results suggest that MRP4 rs1751034 CC is associated with increased risk of IVIG resistance in KD.

Association of an IGHV3-66 gene variant with Kawasaki disease

In a meta-analysis of three GWAS for susceptibility to Kawasaki disease (KD) conducted in Japan, Korea, and Taiwan and follow-up studies with a total of 11,265 subjects (3428 cases and 7837 controls), a significantly associated SNV in the immunoglobulin heavy variable gene (IGHV) cluster in 14q33.32 was identified (rs4774175; OR = 1.20, P = 6.0 × 10^-9). Investigation of nonsynonymous SNVs of the IGHV cluster in 9335 Japanese subjects identified the C allele of rs6423677, located in IGHV3-66, as the most significant reproducible association (OR = 1.25, P = 6.8 × 10^-10 in 3603 cases and 5731 controls). We observed highly skewed allelic usage of IGHV3-66, wherein the rs6423677 A allele was nearly abolished in the transcripts in peripheral blood mononuclear cells of both KD patients and healthy adults. Association of the high-expression allele with KD strongly indicates some active roles of B-cells or endogenous immunoglobulins in the disease pathogenesis. Considering that significant association of SNVs in the IGHV region with disease susceptibility was previously known only for rheumatic heart disease (RHD), a complication of acute rheumatic fever (ARF), these observations suggest that common B-cell related mechanisms may mediate the symptomology of KD and ARF as well as RHD.

A framework for understanding Kawasaki disease pathogenesis

Kawasaki disease (KD) is a common vasculitis of childhood, typically affecting children under the age of five. Despite many aspects of its presentation that bear resemblence to acute infection, no causative infectious agent has been identified despite years of intense scrutiny. Unlike most infections, however, there are significant differences in racial predilection that suggest a strong genetic influence. The inflammatory response in KD specifically targets the coronary arteries, also unusual for an infectious condition. In this review, we discuss recent hypotheses on KD pathogenesis as well as new insights into the innate immune response and mechanisms behind vascular damage. The pathogenesis is complex, however, and remains inadequately understood.

Epidemiological and clinical features of Kawasaki disease in Spain over 5 years and risk factors for aneurysm development. (2011-2016): KAWA-RACE study group

BACKGROUND

Kawasaki disease (KD) is an acute self-limited systemic vasculitis of unknown etiology affecting mainly children less than 5 years of age. Risk factors for cardiac involvement and resistance to treatment are insufficiently studied in non-Japanese children.

OBJECTIVE

This study aimed to investigate the epidemiology, clinical features and risk factors for resistance to treatment and coronary artery lesions (CAL) in KD in Spain.

METHODS

Retrospective study (May 2011-June 2016) of all patients less than 16 years of age diagnosed with KD included in KAWA-RACE network (84 Spanish hospitals).

RESULTS

A total of 625 cases were analyzed, 63% were males, 79% under 5 year-olds and 16.8% younger than 12 months. On echocardiographic examination CAL were the most frequent findings (23%) being ectasia the most common (12%). Coronary aneurysms were diagnosed in 9.6%, reaching 20% in infants under 12 months (p<0.001). A total of 97% of the patients received intravenous immunoglobulin (IVIG) with a median number of days from fever onset to IVIG administration of 7.2. A second dose was given to 15.7% and steroids to 14.5% patients. Only 1.4% patients received infliximab. No deaths were reported. A multivariate analysis identified anemia, hypoalbuminemia, hyponatremia, higher creatinine and procalcitonin as independent risk factors for treatment failure and length under 103 cm, hemoglobin < 10.2 mg/dL, platelets > 900,000 cells/mm3, maximum temperature < 39.5°C, total duration of fever > 10 days and fever before treatment ≥ 8 days as independent risk factors for developing coronary aneurysms.

CONCLUSIONS

In our population, children under 12 months develop coronary aneurysms more frequently and children with KD with anemia and leukocytosis have high risk of cardiac involvement. Adding steroids early should be considered in those patients, especially if the treatment is not started before 8 days of fever. A score applicable to non-Japanese children able to predict the risk of aneurysm development and IVIG resistance is necessary.

ABCC4 Variants Modify Susceptibility to Kawasaki Disease in a Southern Chinese Population

A previous family-based linkage study revealed that Kawasaki disease (KD) was associated with variations of the ATP-binding cassette subfamily C member 4 (ABCC4) gene in most European populations. However, significant differences exist among ethnic populations in European and Chinese subjects; therefore, whether ABCC4 variants indicate susceptibility to KD in Chinese children is unclear. The purpose of this research was to evaluate correlations between ABCC4 gene polymorphisms and susceptibility to KD in a Southern Chinese population. We genotyped six polymorphisms (rs7986087, rs868853, rs3765534, rs1751034, rs3742106, and rs9561778) in 775 KD patients and 774 healthy controls. Ninety-five percent confidence intervals (95% CIs) and odds ratios (ORs) were used to assess the strength of each association. We found that the rs7986087 T variant genotype was associated with significantly higher susceptibility to KD (adjusted OR = 1.30, 95% CI = 1.05–1.60 for rs7986087 CT/TT). However, the rs868853 T variant genotype was associated with significantly lower susceptibility to KD (adjusted OR = 0.74, 95% CI = 0.59–0.92 for rs868853 CT/CC). Compared with the patients with 0–4 ABCC4 risk genotypes, the patients with 5-6 ABCC4 risk genotypes had a significantly increased risk of KD (adjusted OR = 1.63, 95% CI = 1.07–2.47), and this risk was more significant in the subgroups of females, subjects aged 12–60 months, and individuals with coronary artery lesions. These results indicate that specific single-nucleotide polymorphisms in the ABCC4 gene may increase susceptibility to KD in a Southern Chinese population.

TBXA2R rs4523 G allele is associated with decreased susceptibility to Kawasaki disease

Kawasaki disease is a multi-system vasculitis and a primary cause of acquired heart disease among children. Genetic factors may increase susceptibility to Kawasaki disease. TBXA2R is a G-protein-coupled receptor that participates in tissue inflammation and is associated with susceptibility to several diseases, but its relevance in Kawasaki disease is unclear. We genotyped TBXA2R (rs1131882 and rs4523) in 694 Kawasaki disease cases and 657 healthy controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the intensity of the associations. We found a significantly decreased risk of Kawasaki disease associated with TBXA2R rs4523 G variant genotypes (AG vs AA: adjusted OR = 0.788, 95%CI = 0.626-0.993; GG vs AA: adjusted OR = 0.459, 95%CI = 0.258-0.815; AG/GG vs AA: adjusted OR = 0.744, 95%CI = 0.595-0.929; GG vs AG/AA: adjusted OR = 0.497, 95% CI = 0.281-0.879). In the combined analysis of the two single-nucleotide polymorphisms (SNPs), we found that individuals with two unfavorable genotypes exhibited decreased risk for Kawasaki disease (adjusted OR = 0.754, 95%CI = 0.577-0.985) compared with those who did not have or one unfavorable genotypes. This cumulative effect on protection is effect-genotype dose-dependent (p_trend = 0.022). Moreover, the combined analysis indicated that the two unfavorable genotypes were associated with a decreased risk of Kawasaki disease in children 12-60 months of age, females and the subgroup with non-coronary artery lesion (NCAL) formation compared with those who did not have or one unfavorable genotypes. In conclusion, the TBXA2R rs4523 G allele may contribute to protection against Kawasaki disease and decreased risk of coronary artery aneurysm complications in a southern Chinese population.

Kawasaki Disease

Kawasaki disease (KD) is an acute-onset systemic vasculitis of medium-sized vessels that mostly affects infants and toddlers. Globally, it is the most common form of childhood primary vasculitis. Delayed diagnosis and treatment results in coronary artery aneurysms in up to 25% of all affected individuals. Thus, KD is the most common acquired heart disease in developed countries. Here, the current understanding of clinical presentations, pathophysiological concepts, disease-associated complications, and available pharmaceutical treatment is provided and discussed in the context of available literature.

Environmental epidemiology of Kawasaki disease: Linking disease etiology, pathogenesis and global distribution

BACKGROUND

The pathogenesis of Kawasaki disease (KD) is commonly ascribed to an exaggerated immunologic response to an unidentified environmental or infectious trigger in susceptible children. A comprehensive framework linking epidemiological data and global distribution of KD has not yet been proposed.

METHODS AND FINDINGS

Patients with KD (n = 81) were enrolled within 6 weeks of diagnosis along with control subjects (n = 87). All completed an extensive epidemiological questionnaire. Geographic localization software characterized the subjects' neighborhood. KD incidence was compared to atmospheric biological particles counts and winds patterns. These data were used to create a comprehensive risk framework for KD, which we tested against published data on the global distribution. Compared to controls, patients with KD were more likely to be of Asian ancestry and were more likely to live in an environment with low exposure to environmental allergens. Higher atmospheric counts of biological particles other than fungus/spores were associated with a temporal reduction in incidence of KD. Finally, westerly winds were associated with increased fungal particles in the atmosphere and increased incidence of KD over the Greater Toronto Area. Our proposed framework was able to explain approximately 80% of the variation in the global distribution of KD. The main limitations of the study are that the majority of data used in this study are limited to the Canadian context and our proposed disease framework is theoretical and circumstantial rather than the result of a single simulation.

CONCLUSIONS

Our proposed etiologic framework incorporates the 1) proportion of population that are genetically susceptible; 2) modulation of risk, determined by habitual exposure to environmental allergens, seasonal variations of atmospheric biological particles and contact with infectious diseases; and 3) exposure to the putative trigger. Future modelling of individual risk and global distribution will be strengthened by taking into consideration all of these non-traditional elements.

The genetics of Kawasaki disease

Kawasaki disease (KD) is a complex disorder which affects genetically susceptible infants and children. Several susceptibility genes (e.g., ITPKC, CASP3, CD40 and ORAI) and chromosomal regions have been identified through genome-wide association and genome-wide linkage studies to have association with KD. Knowledge of susceptibility genes involved in the pathogenesis of KD may provide new insights into diagnosis and treatment of this condition. However, there is much that we still do not know about the genetic basis of KD.

Kawasaki disease and coronary artery aneurysms: from childhood to adulthood

Kawasaki disease is an acute, systemic vasculitis of childhood and confers a 25% risk of developing coronary artery aneurysms. Its etiology is unknown, but the incidence is increasing rapidly with linked gene polymorphisms having been identified. A constellation of symptoms, epidemics and seasonality all implicate an unidentified infective or environmental cause. Intravenous immunoglobulin therapy, aspirin and steroids all form the mainstay of acute treatment and reduces the incidence of coronary artery aneurysms if given before 7 days. However, in some, these lesions persist and require ongoing management during follow-up during childhood and into adult life. Evidence for further investigations in order to minimize complications is presented in order to minimize the myofibroblast proliferation and stenosis in the long term.

Diagnosis, Treatment, and Long-Term Management of Kawasaki Disease: A Scientific Statement for Health Professionals From the American Heart Association

BACKGROUND

Kawasaki disease is an acute vasculitis of childhood that leads to coronary artery aneurysms in ≈25% of untreated cases. It has been reported worldwide and is the leading cause of acquired heart disease in children in developed countries.

METHODS AND RESULTS

To revise the previous American Heart Association guidelines, a multidisciplinary writing group of experts was convened to review and appraise available evidence and practice-based opinion, as well as to provide updated recommendations for diagnosis, treatment of the acute illness, and long-term management. Although the cause remains unknown, discussion sections highlight new insights into the epidemiology, genetics, pathogenesis, pathology, natural history, and long-term outcomes. Prompt diagnosis is essential, and an updated algorithm defines supplemental information to be used to assist the diagnosis when classic clinical criteria are incomplete. Although intravenous immune globulin is the mainstay of initial treatment, the role for additional primary therapy in selected patients is discussed. Approximately 10% to 20% of patients do not respond to initial intravenous immune globulin, and recommendations for additional therapies are provided. Careful initial management of evolving coronary artery abnormalities is essential, necessitating an increased frequency of assessments and escalation of thromboprophylaxis. Risk stratification for long-term management is based primarily on maximal coronary artery luminal dimensions, normalized as Z scores, and is calibrated to both past and current involvement. Patients with aneurysms require life-long and uninterrupted cardiology follow-up.

CONCLUSIONS

These recommendations provide updated and best evidence-based guidance to healthcare providers who diagnose and manage Kawasaki disease, but clinical decision making should be individualized to specific patient circumstances.

Whole genome sequencing of an African American family highlights toll like receptor 6 variants in Kawasaki disease susceptibility

Kawasaki disease (KD) is the most common acquired pediatric heart disease. We analyzed Whole Genome Sequences (WGS) from a 6-member African American family in which KD affected two of four children. We sought rare, potentially causative genotypes by sequentially applying the following WGS filters: sequence quality scores, inheritance model (recessive homozygous and compound heterozygous), predicted deleteriousness, allele frequency, genes in KD-associated pathways or with significant associations in published KD genome-wide association studies (GWAS), and with differential expression in KD blood transcriptomes. Biologically plausible genotypes were identified in twelve variants in six genes in the two affected children. The affected siblings were compound heterozygous for the rare variants p.Leu194Pro and p.Arg247Lys in Toll-like receptor 6 (TLR6), which affect TLR6 signaling. The affected children were also homozygous for three common, linked (r² = 1) intronic single nucleotide variants (SNVs) in TLR6 (rs56245262, rs56083757 and rs7669329), that have previously shown association with KD in cohorts of European descent. Using transcriptome data from pre-treatment whole blood of KD subjects (n = 146), expression quantitative trait loci (eQTL) analyses were performed. Subjects homozygous for the intronic risk allele (A allele of TLR6 rs56245262) had differential expression of Interleukin-6 (IL-6) as a function of genotype (p = 0.0007) and a higher erythrocyte sedimentation rate at diagnosis. TLR6 plays an important role in pathogen-associated molecular pattern recognition, and sequence variations may affect binding affinities that in turn influence KD susceptibility. This integrative genomic approach illustrates how the analysis of WGS in multiplex families with a complex genetic disease allows examination of both the common disease–common variant and common disease–rare variant hypotheses.

Dissecting Kawasaki disease: a state-of-the-art review

Kawasaki disease (KD) is a pediatric vasculitis with coronary artery aneurysms (CAA) as its main complication. The diagnosis is based on the presence of persistent fever and clinical features including exanthema, lymphadenopathy, conjunctival injection, and changes to the mucosae and extremities. Although the etiology remains unknown, the current consensus is that it is likely caused by an (infectious) trigger initiating an abnormal immune response in genetically predisposed children. Treatment consists of high dose intravenous immunoglobulin (IVIG) and is directed at preventing the development of CAA. Unfortunately, 10-20% of all patients fail to respond to IVIG and these children need additional anti-inflammatory treatment. Coronary artery lesions are diagnosed by echocardiography in the acute and subacute phases. Both absolute arterial diameters and z-scores, adjusted for height and weight, are used as criteria for CAA. Close monitoring of CAA is important as ischemic symptoms or myocardial infarction due to thrombosis or stenosis can occur. These complications are most likely to arise in the largest, so-called giant CAA. Apart from the presence of CAA, it is unclear whether KD causes an increased cardiovascular risk due to the vasculitis itself.

CONCLUSION

Many aspects of KD remain unknown, although there is growing knowledge on the etiology, treatment, and development and classification of CAA. Since children with previous KD are entering adulthood, long-term follow-up is increasingly important. What is known: • Kawasaki disease (KD) is a pediatric vasculitis with coronary artery damage as its main complication. • Although KD approaches its 50th birthday since its first description, many aspects of the disease remain poorly understood. What is new: • In recent years, multiple genetic candidate pathways involved in KD have been identified, with recently promising information about the ITPKC pathway. • As increasing numbers of KD patients are reaching adulthood, increasing information is available about the long-term consequences of coronary artery damage and broader cardiovascular risk.

[Childhood vasculitis]

BACKGROUND

The primary vasculitides are rare conditions in childhood. The most common disease subtypes are Schönlein-Henoch purpura and Kawasaki's syndrome, which frequently have a self-limiting course. In the majority of vasculitides, the etiology remains unknown. Environmental exposure, including infections, is suspected to trigger an autoinflammatory response in predisposed individuals.

GOAL

The aim of this review is to present the various aspects of childhood vasculitis.

MATERIALS AND METHODS

Reviews and special original papers on childhood vasculitis, published classification criteria and current therapy guidelines were reviewed and summarized.

RESULTS

The classification of vasculitides in childhood has been modified from the previous adult Chapel Hill classification for vasculitides in 2008. Most therapy recommendations for children are adapted from results of studies in adults. This review covers the current classifications, pathogenesis, clinical manifestations and therapy recommendations for children.

DISCUSSION

Although etiology and pathogenesis of many vasculitides in childhood are still unknown, clarifying diagnostic methods and effective therapeutic options are available. The knowledge about various forms of disease manifestation may contribute to an early diagnosis and timely initiation of treatment, which may prevent devastating irreversible impairment.

Plasma Prostaglandin E2 Levels Correlated with the Prevention of Intravenous Immunoglobulin Resistance and Coronary Artery Lesions Formation via CD40L in Kawasaki Disease

BACKGROUND

A form of systemic vasculitis, Kawasaki disease (KD) occurs most frequently in children under the age of five years old. Previous studies have found that Prostaglandin E2 (PGE2) correlates with KD, although the related mechanisms are still unknown. CD40L may also be a marker of vasculitis in KD, so this study focuses on PGE2 and CD40L expression in KD.

MATERIALS AND METHODS

This study consisted of a total of 144 KD patients, whose intravenous immunoglobulin (IVIG)/coronary arterial lesion (CAL) formation resistance was evaluated. PGE2 levels were evaluated in vitro to study the effect of CD40L on CD4+ T lymphocytes.

RESULTS

PGE2 levels significantly increased after IVIG treatment (p<0.05), especially in patients who responded to initial IVIG treatment (p = 0.004) and for patients without CAL formation (p = 0.016). Furthermore, an in vitro study revealed that IVIG acted as a trigger for PGE2 expression in the acute-stage mononuclear cells of KD patients. According to our findings, both IVIG and PGE2 can impede surface CD40L expressions on CD4+ T lymphocytes (p<0.05).

CONCLUSIONS

The results of this study are among the first to find that plasma PGE2 is correlated with the prevention of IVIG resistance and CAL formation through CD40L in KD.

Predicting the characteristics of the aetiological agent for Kawasaki disease from other paediatric infectious diseases in Japan

Although Kawasaki disease (KD), which was first reported in the 1960s, is assumed to be infectious, its aetiological agent(s) remains unknown. We compared the geographical distribution of the force of infection and the super-annual periodicity of KD and seven other paediatric infectious diseases in Japan. The geographical distribution of the force of infection, which was estimated as the inverse of the mean patient age, was similar in KD and other paediatric viral infections. This similarity was due to the fact that the force of infection was determined largely by the total fertility rate. This finding suggests that KD shares a transmission route, i.e. sibling-to-sibling infection, with other paediatric infections. The super-annual periodicity, which is positively associated with the sum of an infectious disease's incubation period and infectious period, was much longer for KD and exanthema subitum than other paediatric infectious diseases. The virus for exanthema subitum is known to persist across the host's lifespan, which suggests that the aetiological agent for KD may also be capable of persistent infection. Taken together, these findings suggest that the aetiological agent for KD is transmitted through close contact and persists asymptomatically in most hosts.

Kawasaki disease: pathophysiology, clinical manifestations, and management

Kawasaki Disease, a systemic vasculitis of unknown origin with specific predilection for the coronary arteries, is the most common cause of childhood-acquired heart disease in western countries. Despite its world-wide incidence, the pathophysiology of this enigmatic disease is still under investigation. Diagnosis is made on a clinical basis, with supportive laboratory evidence and imaging. Once identified, timely initiation of treatment is imperative in order to quell the inflammatory response and decrease the incidence of long-term sequelae, specifically coronary artery aneurysms. Finally, longitudinal follow-up should be implemented based on risk stratification and individualized to each patient.

Management of Kawasaki disease

Kawasaki disease (KD) is an acute self-limiting inflammatory disorder, associated with vasculitis, affecting predominantly medium-sized arteries, particularly the coronary arteries. In developed countries KD is the commonest cause of acquired heart disease in childhood. The aetiology of KD remains unknown, and it is currently believed that one or more as yet unidentified infectious agents induce an intense inflammatory host response in genetically susceptible individuals. Genetic studies have identified several susceptibility genes for KD and its sequelae in different ethnic populations, including FCGR2A, CD40, ITPKC, FAM167A-BLK and CASP3, as well as genes influencing response to intravenous immunoglobulin (IVIG) and aneurysm formation such as FCGR3B, and transforming growth factor (TGF) β pathway genes. IVIG and aspirin are effective therapeutically, but recent clinical trials and meta-analyses have demonstrated that the addition of corticosteroids to IVIG is beneficial for the prevention of coronary artery aneurysms (CAA) in severe cases with highest risk of IVIG resistance. Outside of Japan, however, clinical scores to predict IVIG resistance perform suboptimally. Furthermore, the evidence base does not provide clear guidance on which corticosteroid regimen is most effective. Other therapies, including anti-TNFα, could also have a role for IVIG-resistant KD. Irrespective of these caveats, it is clear that therapy that reduces inflammation in acute KD, improves outcome. This paper summarises recent advances in the understanding of KD pathogenesis and therapeutics, and provides an approach for managing KD patients in the UK in the light of these advances.

Decreasing fertility rate correlates with the chronological increase and geographical variation in incidence of Kawasaki disease in Japan

Background

Kawasaki disease (KD) is a common cause of acquired paediatric heart disease in developed countries. KD was first identified in the 1960s in Japan, and has been steadily increasing since it was first reported. The aetiology of KD has not been defined, but is assumed to be infection-related. The present study sought to identify the factor(s) that mediate the geographical variation and chronological increase of KD in Japan.

Methods and Findings

Based upon data reported between 1979 and 2010 from all 47 prefectures in Japan, the incidence and mean patient age at the onset of KD were estimated. Using spatial and time-series analyses, incidence and mean age were regressed against climatic/socioeconomic variables. Both incidence and mean age of KD were inversely correlated with the total fertility rate (TFR; i.e., the number of children that would be born to one woman). The extrapolation of a time-series regressive model suggested that KD emerged in the 1960s because of a dramatic decrease in TFR in the 1940s through the 1950s.

Conclusions

Mean patient age is an inverse surrogate for the hazard of contracting the aetiologic agent. Therefore, the observed negative correlation between mean patient age and TFR suggests that a higher TFR is associated with KD transmission. This relationship may be because a higher TFR facilitates sibling-to-sibling transmission. Additionally, the observed inverse correlation between incidence and TFR implies a paradoxical “negative” correlation between the incidence and the hazard of contracting the aetiologic agent. It was hypothesized that a decreasing TFR resulted in a reduced hazard of contracting the agent for KD, thereby increasing KD incidence.

Can Coronary Artery Involvement in Kawasaki Disease be Predicted?

Background: Coronary artery involvement is seen in approximately 15–20% of children with Kawasaki disease. There is conflicting literature regarding the clinical and laboratory findings associated with coronary artery involvement. In this retrospective study, we attempt identification of predictive factors for coronary artery involvement at our institute and review the existing literature. Methods and results: A review of 203 patients (65% males) with Kawasaki disease was performed, of whom 33 (16.3%) had coronary artery involvement. High erythrocyte sedimentation rate, high platelet count, low hematocrit, low albumin levels, and refractory Kawasaki disease showed significant association with coronary artery involvement. High erythrocyte sedimentation rate and refractory Kawasaki disease were found to be independent predictors of coronary artery involvement. Review of literature suggested a wide range of coronary involvement (<5% to >60%), and highly conflicting clinical and laboratory associations. Conclusion: It remains difficult to accurately determine risk of coronary artery involvement, although some laboratory markers may provide information that is helpful for parental counseling and clinical follow up. Future identification of novel biomarkers and host predispositions may further our understanding of coronary artery risks and help personalize therapy for Kawasaki 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.

Genome-wide scan with nearly 700,000 SNPs in two Sardinian sub-populations suggests some regions as candidate targets for positive selection

This paper explores the genetic structure and signatures of natural selection in different sub-populations from the Island of Sardinia, exploiting information from nearly 700,000 autosomal SNPs genotyped with the Affymetrix Genome-Wide Human SNP 6.0 Array. The genetic structure of the Sardinian population and its position within the context of other Mediterranean and European human groups were investigated in depth by comparing our data with publicly available data sets. Principal components and admixture analyses suggest a clustering of the examined samples in two significantly differentiated sub-populations (Ogliastra and Southern Sardinia), as confirmed by AMOVA (F(ST)=0.011; P<0.001). Differentiation of these sub-populations was still evident when they were pooled together with supplementary Sardinian samples from HGDP and compared with several other European, North-African and Near Eastern populations, confirming the uniqueness of the Sardinian genetic background. Moreover, by applying several statistical approaches aimed at assessing differences at the SNP level, the highest differentiated genomic regions between Ogliastra and Southern Sardinia were thus investigated via an extended haplotype homozygosity (EHH)-based test to point out potential selective sweeps. Using this approach, 40 genomic regions were detected, with significant differences between Ogliastra and Southern Sardinia. These regions were subsequently investigated using a long-range haplotype test, which found significant REHH values for SNPs rs11070188 and rs11070192 in the Ogliastra sub-population. In the light of these results and the overlap of the different computed statistics, the region encompassing these loci can be considered a strong candidate to have undergone selective pressure in Ogliastra.

A functional polymorphism, rs28493229, in ITPKC and risk of Kawasaki disease: an integrated meta-analysis

Kawasaki disease (KD) is a multi-systemic vasculitis which preferentially affects infants and children. A single nucleotide polymorphism (rs28493229) in the inositol 1,4,5-trisphosphate 3-kinase C (ITPKC) was identified to be associated with the increased risk of KD; however, in more recent studies associations have been controversial. Thus, we performed a meta-analysis, integrating case-control and transmission/disequilibrium test (TDT) studies, to investigate the relationship between this polymorphism and risk of KD. A total of ten case-control and two TDT studies, comprising 3,821 cases, 12,802 controls and 949 families, were included in this meta-analysis. There was a significant association between the C allele of rs28493229 and the increased risk of KD (OR = 1.53, 95 % CI = 1.34-1.74, P < 0.001), by the random-effects model because of heterogeneity (Q = 27.67, P (heterogeneity) = 0.004). Nevertheless, it was screened out by meta-regression analysis that the coronary artery lesions (CALs) status of KD could partly explain the heterogeneity, with consistently significant associations in both subgroups after stratification by CALs status. Moreover, estimates before and after the deletion of each study were similar in sensitivity analysis, indicating robust stability of the meta-analysis. This meta-analysis reveals that the functional polymorphism rs28493229 in ITPKC significantly contributes to the risk of KD.

The role of TGF-β and myofibroblasts in the arteritis of Kawasaki disease

Inflammation of medium-sized, muscular arteries and coronary artery aneurysms are hallmarks of Kawasaki disease (KD), an acute, self-limited vasculitis of children. We previously reported that genetic variation in transforming growth factor (TGF)-β pathway genes influences both susceptibility to KD and coronary artery aneurysm (CAA) formation. TGF-β signaling has been implicated in the generation of myofibroblasts that influence collagen lattice contraction, antigen presentation, and recruitment of inflammatory cells as well as the generation of regulatory T-cells (Tregs). These processes could be involved in aneurysm formation and recovery in KD. Coronary artery tissues from 8 KD patient autopsies were stained to detect proteins in the TGF-β pathway, to characterize myofibroblasts, and to detect Tregs. Expression of proteins in the TGF-β pathway was noted in infiltrating mononuclear cells and spindle-shaped cells in the thickened intima and adventitia. Coronary arteries from an infant who died on Illness Day 12 showed α-smooth muscle actin (SMA)-positive, smoothelin-negative myofibroblasts in the thickened intima that co-expressed IL-17 and IL-6. CD8+ T-cells expressing HLA-DR+ (marker of activation and proliferation) were detected in the aneurysmal arterial wall. Forkhead box P3 (FOXP3), whose expression is essential for Tregs, was also detected in the nucleus of infiltrating mononuclear cells, suggesting a role for Tregs in recovery from KD arteritis.TGF-β may contribute to aneurysm formation by promoting the generation of myofibroblasts that mediate damage to the arterial wall through recruitment of pro-inflammatory cells. This multi-functional growth factor may also be involved in the induction of Tregs in KD.

Kawasaki disease

Kawasaki disease is a systemic vasculitis and the leading cause of acquired heart disease in North American and Japanese children. The epidemiology, cause, and clinical characteristics of this disease are reviewed. The diagnostic challenge of Kawasaki disease and its implications for coronary artery outcomes are discussed, as are the recommended treatment, ongoing treatment controversies, concerns associated with treatment resistance, and the importance of ongoing follow up.

Demographic and treatment variability of refractory kawasaki disease: a multicenter analysis from 2005 to 2009

OBJECTIVE

Approximately 10% to 15% of Kawasaki disease (KD) is refractory to treatment with initial intravenous immunoglobulin (IVIG). However, there is no consensus on pharmacologic treatment of refractory KD (rKD). Demographic characteristics of patients with rKD and regional variability in their treatment in the United States have not been reported on a large scale. The goal of this study was to describe the demographic and treatment variability in rKD by using a large multi-institutional database.

METHODS

Data were obtained for patients with KD from January 2005 to June 2009 by using the Pediatric Health Information System. Patients who received a single dose of IVIG were labeled as having standard KD (sKD) and those who required additional medications were labeled as having rKD.

RESULTS

Of the 5633 patients studied, 4818 (85.5%) received 1 dose of IVIG (sKD) and 815 (14.5%) received >1 medication (rKD). Median age was 30 months (interquartile range: 14-53) and 30 months (interquartile range: 15-54) for rKD and sKD patients, respectively (P= .438). No significant change was noted in the gender or ethnic distribution of patients between rKD and sKD groups. Seasonal distribution of rKD was comparable to sKD. IVIG was the most common (64.5%) initial medication chosen to treat rKD, followed by methylprednisolone (27.1%) and infliximab (8.3%); however, there was significant regional variability. Of patients with rKD, 81% required only 1 additional medication (after the initial IVIG) for treatment.

CONCLUSIONS

Patients with rKD have similar age, gender, ethnic, and seasonal distribution as sKD patients. IVIG is the most common initial medication chosen to treat rKD; however, there is regional variation.