A genomewide linkage analysis of Kawasaki disease: evidence for linkage to chromosome 12

ITPKC polymorphism (rs7251246 T > C), coronary artery aneurysms, and thrombosis in patients with Kawasaki disease in a Southern Han Chinese population

Objectives

Kawasaki disease (KD) is a commonly acquired pediatric systemic vasculitis disease resulting in coronary artery aneurysm (CAA). The relationship between the ITPKC polymorphism (rs7251246) and the severity and susceptibility to KD in the Han Chinese population in Southern China remains unclear.

Methods

We enrolled 262 children as controls and 221 children with KD (46 [20.8%] with intravenous immunoglobulin resistance and 82 [37.1%] with CAA). The relationship between the ITPKC rs7251246 polymorphism, KD susceptibility, and CAA formation was investigated.

Results

While the ITPKC rs7251246 T>C polymorphism was not significantly associated with KD susceptibility, it was significantly related to the CAA risk in children with KD [CC/CT vs. TT: adjusted odds ratio [OR] 2.089, 95% confidence interval [CI] 1.085-4.020]. Male children with the rs7251246 CT/TT genotype had a significantly lower risk of thrombosis [CT/TT vs. CC: adjusted OR 0.251, 95% CI 0.068-0.923]. Children with KD, especially those with CAA, had significantly downregulated ITPKC mRNA compared to healthy children. ITPKC mRNA levels were lower in children with CAA who developed thrombosis (P=0.039). In children with KD, the CC genotype showed lower mRNA levels of ITPKC (P=0.035).

Conclusion

The ITPKC rs7251246 T>C polymorphism may be a risk factor for CAA and thrombosis in children with KD in the Han Chinese population, likely due to differences in mature mRNA levels caused by interference of RNA splicing. Dual antiplatelet therapy for thrombosis is recommended for male children with the rs7251246 CC genotype.

Coronary Vasculitis Induced in Mice by Cell Wall Mannoprotein Fractions of Clinically Isolated Candida Species

Kawasaki disease (KD) is an inflammatory disease that was identified by Professor Tomisaku Kawasaki in 1961. Candida albicans-derived substances (CADS) such as the hot water extract of C. albicans and Candida water-soluble fractions (CAWS) induce coronary vasculitis similar to KD in mice. An increasing proportion of deep-seated candidiasis cases are caused by non-albicans Candida and are often resistant to antifungal drugs. We herein investigated whether the mannoprotein fractions (MN fractions) of clinically isolated Candida species induce vasculitis in mice. We prepared MN fractions from 26 strains of Candida species by conventional hot water extraction and compared vasculitis in DBA/2 mice. The results obtained revealed that the induction of vasculitis and resulting heart failure were significantly dependent on the species; namely, death rates on day 200 were as follows: Candida krusei (100%), Candida albicans (84%), Candida dubliniensis (47%), Candida parapsilosis (44%), Candida glabrata (32%), Candida guilliermondii (20%), and Candida tropicalis (20%). Even for C. albicans, some strains did not induce vasculitis. The present results suggest that MN-induced vasculitis is strongly dependent on the species and strains of Candida, and also that the MN fractions of some non-albicans Candida induce similar toxicity to those of C. albicans.

Immunogenetics of Kawasaki disease

Kawasaki disease (KD) is a medium vessel vasculitis that affects young children. Despite extensive research over the last 50 years, the etiology of KD remains an enigma. Seasonal change in wind patterns was shown to have correlation with the epidemics of KD in Japan. Occurrence of disease in epidemiological clusters, seasonal variation, and a very low risk of recurrence suggest that KD is triggered by an infectious agent. The identification of oligoclonal IgA response in the affected tissues suggests an antigen-driven inflammation. The recent identification of a viral antigen in the cytoplasm of bronchial ciliated epithelium also favors infection as the main trigger for KD. Pointers that suggest a genetic basis of KD include a high disease prevalence in North-East Asian populations, a high risk among siblings, and familial occurrence of cases. Dysregulated innate and adaptive immune responses are evident in the acute stages of KD. In addition to the coronary wall inflammation, endothelial dysfunction and impaired vascular remodeling contribute to the development of coronary artery abnormalities (CAAs) and thrombosis. Genetic aberrations in certain intracellular signaling pathways involving immune effector functions are found to be associated with increased susceptibility to KD and development of coronary artery abnormalities (CAAs). Several susceptible genes have been identified through genome-wide association studies (GWAS) and linkage studies (GWLS). The genes that are studied in KD can be classified under 4 major groups-enhanced T cell activation (ITPKC, ORAI1, STIM1), dysregulated B cell signaling (CD40, BLK, FCGR2A), decreased apoptosis (CASP3), and altered transforming growth factor beta signaling (TGFB2, TGFBR2, MMP, SMAD). The review aims to highlight the role of several genetic risk factors that are linked with the increased susceptibility to KD.

Biomarkers for Kawasaki Disease: Clinical Utility and the Challenges Ahead

Kawasaki disease (KD) has replaced acute rheumatic fever as the most common cause of acquired heart disease in children in the developed world and is increasingly being recognized from several developing countries. It is a systemic vasculitis with a predilection for coronary arteries. The diagnosis is based on a constellation of clinical findings that appear in a temporal sequence. Quite understandably, this can become a problem in situations wherein the clinical features are not typical. In such situations, it can be very difficult, if not impossible, to arrive at a diagnosis. Several biomarkers have been recognized in children with acute KD but none of these has reasonably high sensitivity and specificity in predicting the course of the illness. A line up of inflammatory, proteomic, gene expression and micro-RNA based biomarkers has been studied in association with KD. The commonly used inflammatory markers e.g. erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and total leucocyte counts (TLC) lack specificity for KD. Proteomic studies are based on the identification of specific proteins in serum, plasma and urine by gel electrophoresis. A host of genetic studies have identified genes associated with KD and some of these genes can predict the course and coronary outcomes in the affected individuals. Most of these tests are in the early stages of their development and some of these can predict the course, propensity to develop coronary artery sequelae, intravenous immunoglobulin (IVIg) resistance and the severity of the illness in a patient. Development of clinical criteria based on these tests will improve our diagnostic acumen and aid in early identification and prevention of cardiovascular complications.

Investigation of novel variations of ORAI1 gene and their association with Kawasaki disease

ORAI1 encodes a calcium channel essential in the store-operated calcium entry mechanism. A previous genetic association study identified a rare in-frame insertion variant of ORAI1 conferring Kawasaki disease (KD). To deepen our understanding of the involvement of rare variants of ORAI1 in KD pathogenesis, we investigated 3812 patients with KD and 2644 healthy individuals for variations in the protein-coding region of ORAI1. By re-sequencing the study participants' DNA, 27 variants with minor allele frequencies (MAFs) < 0.01 that had not been examined in the previous study were identified. Although no significant association with KD was observed either in single-variant analyses or in a collapsing method analysis of the 27 variants, stratification by MAFs, variant types, and predicted deleteriousness revealed that six rare, deleterious, missense variants (MAF < 0.001, CADD C-score ≥ 20) were exclusively present in KD patients, including three refractory cases (OR = ∞, P = 0.046). The six missense variants include p.Gly98Asp, which has been demonstrated to result in gain of function leading to constitutive Ca²⁺ entry. Conversely, five types of frameshift variants, all identified near the N terminus and assumed to disrupt ORAI1 function, showed an opposite trend of association (OR = 0.35, P = 0.24). These findings support our hypothesis that genetic variations causing the upregulation of the Ca²⁺/NFAT pathway confer susceptibility to KD. Our findings also provide insights into the usefulness of stratifying the variants based on their MAFs and on the direction of the effects on protein function when conducting association studies using the gene-based collapsing method.

Tratamiento farmacológico de la enfermedad de Kawasaki

Introducción. La enfermedad de Kawasaki corresponde a una vasculitis sistémica de origen desconocido y su principal complicación es la formación de aneurismas coronarios.Objetivo. Realizar una revisión actualizada de la literatura acerca del tratamiento farmacológico de la enfermedad de Kawasaki.Materiales y métodos. Se realizó una búsqueda estructurada de la literatura en las bases de datos ProQuest, EBSCO, ScienceDirect, PubMed, LILACS, Embase, Trip Database, SciELO y Cochrane Library con los términos “Kawasaki disease AND therapeutics”, “Kawasaki disease AND treatment” y “Mucocutaneous Lymph Node Syndrome AND therapeutics”, en inglés y con sus equivalentes en español.Resultados. Se encontraron 51 artículos con información relevante para el desarrollo de la presente revisión.Conclusiones. El diagnóstico y el tratamiento oportuno de la enfermedad de Kawasaki son fundamentales para la prevención de las complicaciones coronarias. El tratamiento incluye la terapia combinada de ácido acetilsalicílico más inmunoglobulina G, la cual reduce la incidencia de aneurismas coronarios. Por su parte, las terapias con corticosteroides y otros fármacos inmunosupresores son alternativas utilizadas en el tratamiento de la enfermedad de Kawasaki resistente a inmunoglobulina.

The possible link between coeliac and Kawasaki diseases in Brazil: a cross-sectional study

BACKGROUND

Kawasaki disease (KD) is a self-limited acute systemic vasculitis of unknown aetiology that predominantly affects infants and young children eventually associated with immunological abnormalities. Coeliac disease (CD) is an inflammatory autoimmune disease characterised by a permanent gluten intolerance, which affects genetically susceptible individuals of any age group, and can cause intestinal and systemic symptoms. Association of CD with KD has been previously described in a single study that disclosed a surprisingly high prevalence of CD in children with a history of KD.

OBJECTIVE

To confirm the existence of a higher prevalence of CD among individuals with a history of KD, which would turn the screening for CD in patients with history of KD highly advisable.

SETTING

Children with history of KD, diagnosed and followed at the Rheumatology Clinic of the Children's Hospital of Brasilia (Brasilia, Brazil).

PARTICIPANTS

This study included 110 children with history of KD and a control group composed of 110 presumably healthy children.

INTERVENTIONS

Participants underwent anti-transglutaminase and anti-endomysial antibodies tests and genetic typing for the presence of CD predisposing alleles (HLA-DQ2 and DQ8). Jejunal biopsy was performed when necessary, according the European Society of Paediatric Gastroenterology, Hepatology and Nutrition guidelines.

RESULTS

Diagnosis of CD was confirmed in one (0.91%) patient with KD by positive serological tests, presence of predisposing alleles and CD typical lesions on duodenal biopsy. All serological tests were negative among the controls. The prevalence of CD predisposing alleles among patients with KD was 29.09%, similar to the prevalence found among controls, 33.64%.

CONCLUSION

The detected CD prevalence (0.91%) does not confirm the existence of an association between KD and CD since this prevalence is similar to that found in the general population (≃1%).

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

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

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.

Simultaneous development of Kawasaki disease following acute human adenovirus infection in monozygotic twins: A case report

BACKGROUND

The etiology of Kawasaki disease (KD) remains unknown. However, many studies have suggested that specific genetic factors and/or some infectious agents underlie the onset of KD. Previous studies have suggested that human adenovirus (HAdV) is one of the triggering pathogens of KD. Here, we report monozygotic twin boys who sequentially developed KD in conjunction with acute HAdV type 3 (HAdV-3) infection.

CASE PRESENTATION

The patients were four-year-old monozygotic twin boys. The elder brother developed a high fever and was diagnosed with HAdV infection with an immunochromatographic kit for HAdV (IC-kit). He was transferred to our institute after persistent fever for 7 days. On admission, he already fulfilled all the diagnostic criteria for KD. His laboratory data were as follows: WBC, 9700/μl; CRP, 2.42 mg/dl; IFN-γ, 99.8 pg/ml; and TNF-α, 10.9 pg/ml. He received intravenous immunoglobulin (IVIG) and aspirin and responded well, with no coronary artery abnormalities. The younger brother, who was also IC-kit-positive, was hospitalized on the same day as his elder brother after persistent fever for 3 days. His data on admission were as follows: WBC, 12,600/μl; CRP, 5.54 mg/dl; IFN-γ, 105.0 pg/ml; and TNF-α, 33.6 pg/ml. Although he developed all of the typical KD symptoms by day 4, his fever subsided spontaneously on day 6 without IVIG or aspirin. However, he developed a dilation of the coronary artery in the region of the left circumflex artery bifurcation on day 10. His coronary artery dilation had resolved 3 months after onset. HAdV-3 DNA was detected with PCR in stool samples from both patients, and HAdV3 was isolated from the younger brother's stool sample. Serum neutralizing antibodies to AdV3 were also significantly elevated in both patients, suggesting seroconversion.

CONCLUSIONS

There have been few reports of the simultaneous development of KD in monozygotic twins. Notably, both twins had an acute HAdV-3 infection immediately before they developed KD. These cases strongly suggest that KD was triggered by HAdV-3 infection, and they indicate that specific immune responses to some pathogens (such as HAdV-3), arising from genetic susceptibility, play a critical role in the pathogenesis of KD.

Variations in ORAI1 Gene Associated with Kawasaki Disease

Kawasaki disease (KD; MIM#61175) is a systemic vasculitis syndrome with unknown etiology which predominantly affects infants and children. Recent findings of susceptibility genes for KD suggest possible involvement of the Ca²⁺/NFAT pathway in the pathogenesis of KD. ORAI1 is a Ca²⁺ release activated Ca²⁺ (CRAC) channel mediating store-operated Ca²⁺ entry (SOCE) on the plasma membrane. The gene for ORAI1 is located in chromosome 12q24 where a positive linkage signal was observed in our previous affected sib-pair study of KD. A common non-synonymous single nucleotide polymorphism located within exon 2 of ORAI1 (rs3741596) was significantly associated with KD (P = 0.028 in the discovery sample set (729 KD cases and 1,315 controls), P = 0.0056 in the replication sample set (1,813 KD cases vs. 1,097 controls) and P = 0.00041 in a meta-analysis by the Mantel-Haenszel method). Interestingly, frequency of the risk allele of rs3741596 is more than 20 times higher in Japanese compared to Europeans. We also found a rare 6 base-pair in-frame insertion variant associated with KD (rs141919534; 2,544 KD cases vs. 2,414 controls, P = 0.012). These data indicate that ORAI1 gene variations are associated with KD and may suggest the potential importance of the Ca²⁺/NFAT pathway in the pathogenesis of this disorder.

Recent Advances in Kawasaki Disease

Kawasaki disease (KD) is characterized with acute systemic vasculitis, occurs predominantly in children between 6 months to 5 years of age. Patients with this disease recover well and the disease is self-limited in most cases. Since it can lead to devastating cardiovascular complications, KD needs special attention. Recent reports show steady increases in the prevalence of KD in both Japan and Korea. However, specific pathogens have yet to be found. Recent advances in research on KD include searches for genetic susceptibility related to KD and research on immunopathogenesis based on innate and acquired immunity. Also, search for etiopathogenesis and treatment of KD has been actively sought after using animal models. In this paper, the recent progress of research on KD was discussed.

CD84 is markedly up-regulated in Kawasaki disease arteriopathy

The major goals of Kawasaki disease (KD) therapy are to reduce inflammation and prevent thrombosis in the coronary arteries (CA), but some children do not respond to currently available non-specific therapies. New treatments have been difficult to develop because the molecular pathogenesis is unknown. In order to identify dysregulated gene expression in KD CA, we performed high-throughput RNA sequencing on KD and control CA, validated potentially dysregulated genes by real-time reverse transcription-polymerase chain reaction (RT-PCR) and localized protein expression by immunohistochemistry. Signalling lymphocyte activation molecule CD84 was up-regulated 16-fold (P < 0·01) in acute KD CA (within 2 months of onset) and 32-fold (P < 0·01) in chronic CA (5 months to years after onset). CD84 was localized to inflammatory cells in KD tissues. Genes associated with cellular proliferation, motility and survival were also up-regulated in KD CA, and immune activation molecules MX2 and SP140 were up-regulated in chronic KD. CD84, which facilitates immune responses and stabilizes platelet aggregates, is markedly up-regulated in KD CA in patients with acute and chronic arterial disease. We provide the first molecular evidence of dysregulated inflammatory responses persisting for months to years in CA significantly damaged by KD.

The roles of Ca2+/NFAT signaling genes in Kawasaki disease: single- and multiple-risk genetic variants

Ca²⁺/nuclear factor of activated T-cells (Ca²⁺/NFAT) signaling pathway may play a crucial role in Kawasaki disease (KD). We investigated 16 genetic variants, selected by bioinformatics analyses or previous studies, in 7 key genes involved in this pathway in a Chinese population. We observed a significantly or marginally increased KD risk associated with rs2720378 GC + CC genotypes (OR = 1.39, 95% CI = 1.07–1.80, P = 0.014) or rs2069762 AC + CC genotypes (OR = 1.28, 95% CI = 0.98–1.67, P = 0.066), compared with their wild type counterparts. In classification and regression tree analysis, individuals carrying the combined genotypes of rs2720378 GC or CC genotype, rs2069762 CA or CC genotype and rs1561876 AA genotype exhibited the highest KD risk (OR = 2.12, 95% CI = 1.46–3.07, P < 0.001), compared with the lowest risk carriers of rs2720378 GG genotype. Moreover, a significant dose effect was observed among these three variants (P_trend < 0.001). In conclusion, this study implicates that single- and multiple-risk genetic variants in this pathway might contribute to KD susceptibility. Further studies on more comprehensive single nucleotide polymorphisms, different ethnicities and larger sample sizes are warranted, and the exact biological mechanisms need to be further clarified.

Update on Kawasaki disease: epidemiology, aetiology and pathogenesis

Kawasaki disease is an acute systemic vasculitis predominantly affecting young children. It is due to an abnormal host response to as yet unidentified infectious trigger(s). Kawasaki disease may cause coronary artery damage, long-term cardiovascular morbidity and occasionally mortality, especially if the diagnosis is missed or timely treatment is not given. This is the first of two updates on Kawasaki disease. Here we review recent advances in epidemiology, possible aetiologies, host susceptibility and pathogenesis of this fascinating condition.

Understanding the pathogenesis of Kawasaki disease by network and pathway analysis

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

A genome-wide sib-pair linkage analysis of ossification of the posterior longitudinal ligament of the spine

Ossification of the posterior longitudinal ligament of the spine (OPLL) is a common musculoskeletal disease among people after middle age. The OPLL presents with serious neurological abnormalities due to compression of the spinal cord and nerve roots. The OPLL is caused by genetic and environment factors; however, its etiology and pathogenesis still remain to be elucidated. To determine the susceptibility loci for OPLL, we performed a genome-wide linkage study using 214 affected sib-pairs of Japanese. In stratification analyses for definite cervical OPLL, we found loci with suggestive linkage on 1p21, 2p22-2p24, 7q22, 16q24 and 20p12. Fine mapping using additional markers detected the highest non-parametric linkage score (3.43, P = 0.00027) at D20S894 on chromosome 20p12 in a subgroup that had no complication of diabetes mellitus. Our result would shed a new light on genetic aspects of OPLL.

Can a systems biology approach unlock the mysteries of Kawasaki disease?

Kawasaki disease (KD) is a systemic inflammatory illness of childhood that particularly affects the coronary arteries. It can lead to coronary artery aneurysms, myocardial infarction, and sudden death. Clinical and epidemiologic data support an infectious cause, and the etiology remains unknown, but recent data support infection with a 'new' virus. Genetic factors influence KD susceptibility; the incidence is 10-fold higher in children of Asian when compared with Caucasian ethnicity. Recent research has identified genes affecting immune response that are associated with KD susceptibility and outcome. A re-examination of the pathologic features of KD has yielded a three process model of KD vasculopathy, providing a framework for understanding the KD arterial immune response and the damage it inflicts and for identifying new therapeutic targets for KD patients with coronary artery abnormalities. The researcher is faced with many challenges in determining the pathogenesis of KD. A systems biology approach incorporating genomics, proteomics, transcriptomics, and microbial bioinformatics analysis of high-throughput sequence data from KD tissues could provide the keys to unlocking the mysteries of this potentially fatal illness of childhood.

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.

Rate, associated factors and outcomes of recurrence of Kawasaki disease in Ontario, Canada

BACKGROUND

Previous studies on recurrence of Kawasaki disease (KD) have mostly been limited to Japan, which has an incidence of KD 8-10-fold higher than North America. The aim of the present study was to determine the rate of KD recurrence for patients in Ontario, to identify factors potentially associated with increased odds of recurrence, and to compare the clinical course and outcomes of index and recurrent KD episodes.

METHODS

Review was undertaken of all patients with recurrence of KD identified in Ontario, Canada, from 1995 to 2006. All patients with recurrence of KD (defined as at least three clinical signs of KD in addition to fever ≥ 5 days), presenting ≥ 14 days after the return to baseline from the index episode were included.

RESULTS

A total of 1010 patients were followed for 5786 patient-years. During this period a total of 17 recurrent episodes in 16 patients were identified at a median of 1.5 years after the initial episode (2 weeks-5 years). Rate of recurrence of KD was 2.9 episodes/1000 patient-years, which is higher than the expected annual incidence of KD in the same age group (26.2/100,000 per year). No factors associated with increased risk of recurrence were identified, perhaps due to the small number of events. Clinical course and outcomes of the index and recurrent KD episodes were similar.

CONCLUSIONS

A previous history of KD should increase the index of suspicion for future episodes of KD to allow for rapid recognition, treatment and to achieve optimal outcomes.

Kawasaki disease: laboratory findings and an immunopathogenesis on the premise of a "protein homeostasis system"

Kawasaki disease (KD) is a self-limited systemic inflammatory illness, and coronary artery lesions (CALs) are a major complication determining the prognosis of the disease. Epidemiologic studies in Asian children suggest that the etiologic agent(s) of KD may be associated with environmental changes. Laboratory findings are useful for the diagnosis of incomplete KD, and they can guide the next-step in treatment of initial intravenous immunoglobulin non-responders. CALs seem to develop in the early stages of the disease before a peak in inflammation. Therefore early treatment, before the peak in inflammation, is mandatory to reduce the risk of CAL progression and severity of CALs. The immunopathogenesis of KD is more likely that of acute rheumatic fever than scarlet fever. A hypothetical pathogenesis of KD is proposed under the premise of a "protein homeostasis system"; where innate and adaptive immune cells control pathogenic proteins that are toxic to host cells at a molecular level. After an infection of unknown KD pathogen(s), the pathogenic proteins produced from an unknown focus, spread and bind to endothelial cells of coronary arteries as main target cells. To control the action of pathogenic proteins and/or substances from the injured cells, immune cells are activated. Initially, non-specific T cells and non-specific antibodies are involved in this reaction, while hyperactivated immune cells produce various cytokines, leading to a cytokine imbalance associated with further endothelial cell injury. After the emergence of specific T cells and specific antibodies against the pathogenic proteins, tissue injury ceases and a repair reaction begins with the immune cells.

The Molecular Biology and Treatment of Systemic Vasculitis in Children

Primary systemic vasculitides are rare in childhood but are associated with significant morbidity and mortality. The cause of the majority of vasculitides is unknown, although it is likely that a complex interaction between environmental factors, such as infections and inherited host responses, triggers the disease and determines the vasculitis phenotype. Several genetic polymorphisms in vasculitides have now been described, which may be relevant in terms of disease predisposition or development of disease complications. Treatment regimens continue to improve with the use of different immunosuppressive medications and newer therapeutic approaches such as biologic agents. This chapter reviews recent studies shedding light on the pathogenesis of vasculitis with emphasis on molecular biology where known, and summarizes current treatment strategies. We discuss new emerging challenges particularly with respect to the long-term cardiovascular morbidity for children with systemic vasculitis and emphasize the importance of future international multicenter collaborative studies to further increase and standardize the scientific base investigating and treating childhood vasculitis.

Kawasaki disease in monozygotic twins

Multiple lines of evidence suggest that susceptibility to Kawasaki disease (KD) is influenced by host genetics. Subclinical coronary artery vasculitis may be present in monozygotic twins who are discordant for clinical signs of KD. Health care providers should consider laboratory testing and echocardiography in both monozygotic twins when only one twin presents with clinical KD.

Identification of novel susceptibility Loci for kawasaki disease in a Han chinese population by a genome-wide association study

Kawasaki disease (KD) is an acute systemic vasculitis syndrome that primarily affects infants and young children. Its etiology is unknown; however, epidemiological findings suggest that genetic predisposition underlies disease susceptibility. Taiwan has the third-highest incidence of KD in the world, after Japan and Korea. To investigate novel mechanisms that might predispose individuals to KD, we conducted a genome-wide association study (GWAS) in 250 KD patients and 446 controls in a Han Chinese population residing in Taiwan, and further validated our findings in an independent Han Chinese cohort of 208 cases and 366 controls. The most strongly associated single-nucleotide polymorphisms (SNPs) detected in the joint analysis corresponded to three novel loci. Among these KD-associated SNPs three were close to the COPB2 (coatomer protein complex beta-2 subunit) gene: rs1873668 (p = 9.52×10⁻⁵), rs4243399 (p = 9.93×10⁻⁵), and rs16849083 (p = 9.93×10⁻⁵). We also identified a SNP in the intronic region of the ERAP1 (endoplasmic reticulum amino peptidase 1) gene (rs149481, p(best) = 4.61×10⁻⁵). Six SNPs (rs17113284, rs8005468, rs10129255, rs2007467, rs10150241, and rs12590667) clustered in an area containing immunoglobulin heavy chain variable regions genes, with p(best)-values between 2.08×10⁻⁵ and 8.93×10⁻⁶, were also identified. This is the first KD GWAS performed in a Han Chinese population. The novel KD candidates we identified have been implicated in T cell receptor signaling, regulation of proinflammatory cytokines, as well as antibody-mediated immune responses. These findings may lead to a better understanding of the underlying molecular pathogenesis of KD.

Analysis of positional candidate genes in the AAA1 susceptibility locus for abdominal aortic aneurysms on chromosome 19

BACKGROUND

Abdominal aortic aneurysm (AAA) is a complex disorder with multiple genetic risk factors. Using affected relative pair linkage analysis, we previously identified an AAA susceptibility locus on chromosome 19q13. This locus has been designated as the AAA1 susceptibility locus in the Online Mendelian Inheritance in Man (OMIM) database.

METHODS

Nine candidate genes were selected from the AAA1 locus based on their function, as well as mRNA expression levels in the aorta. A sample of 394 cases and 419 controls was genotyped for 41 SNPs located in or around the selected nine candidate genes using the Illumina GoldenGate platform. Single marker and haplotype analyses were performed. Three genes (CEBPG, PEPD and CD22) were selected for DNA sequencing based on the association study results, and exonic regions were analyzed. Immunohistochemical staining of aortic tissue sections from AAA and control individuals was carried out for the CD22 and PEPD proteins with specific antibodies.

RESULTS

Several SNPs were nominally associated with AAA (p < 0.05). The SNPs with most significant p-values were located near the CCAAT enhancer binding protein (CEBPG), peptidase D (PEPD), and CD22. Haplotype analysis found a nominally associated 5-SNP haplotype in the CEBPG/PEPD locus, as well as a nominally associated 2-SNP haplotype in the CD22 locus. DNA sequencing of the coding regions revealed no variation in CEBPG. Seven sequence variants were identified in PEPD, including three not present in the NCBI SNP (dbSNP) database. Sequencing of all 14 exons of CD22 identified 20 sequence variants, five of which were in the coding region and six were in the 3'-untranslated region. Five variants were not present in dbSNP. Immunohistochemical staining for CD22 revealed protein expression in lymphocytes present in the aneurysmal aortic wall only and no detectable expression in control aorta. PEPD protein was expressed in fibroblasts and myofibroblasts in the media-adventitia border in both aneurysmal and non-aneurysmal tissue samples.

CONCLUSIONS

Association testing of the functional positional candidate genes on the AAA1 locus on chromosome 19q13 demonstrated nominal association in three genes. PEPD and CD22 were considered the most promising candidate genes for altering AAA risk, based on gene function, association evidence, gene expression, and protein expression.

Kawasaki disease: novel insights into etiology and genetic susceptibility

Kawasaki disease (KD) is a vasculitis of young childhood that particularly affects the coronary arteries. Molecular analysis of the oligoclonal IgA response in acute KD led to production of synthetic KD antibodies. These antibodies identify intracytoplasmic inclusion bodies in acute KD tissues. Light and electron microscopic studies indicate that the inclusion bodies are consistent with aggregates of viral proteins and RNA. Advances in molecular genetic analysis and completion of the Human Genome Project have sparked a worldwide effort to identify genes associated with KD. A polymorphism of one such gene, ITPKC, a negative regulator of T cell activation, confers susceptibility to KD in Japanese populations and increases the risk of developing coronary artery abnormalities in both Japanese and U.S. children. Identification of the etiologic agent and of genes conferring KD susceptibility are the best means of improving diagnosis and therapy and enabling prevention of this important disorder of childhood.

Cardiac ischemia in pediatric patients

Cardiac ischemia in children is usually not an isolated disease in an otherwise normally formed coronary artery but is part of more complex congenital or acquired diseases. Although cardiac ischemia is not a frequent occurrence, it must be recognized as a serious, life-threatening event. This article lists and characterizes major causes of cardiac ischemia in children, describes signs and symptoms of each, and provides therapeutic considerations.

Matrix metalloproteinase haplotypes associated with coronary artery aneurysm formation in patients with Kawasaki disease

Aneurysms of the vascular wall represent a final common pathway for a number of inflammatory processes, including atherosclerosis and idiopathic vasculitis syndromes. Kawasaki disease (KD) is an acute, self-limited vasculitis in children and the leading cause of acquired coronary artery aneurysms. We sought to identify shared molecular mechanisms of aneurysm formation by genotyping eight polymorphisms in matrix metalloproteinase (MMP)-1, 3, 7, 12 and 13 in the gene cluster on Chr.11q22, whose gene products have been implicated in aneurysm formation or are known to have elastase activity. We genotyped 482 US-UK KD patients (aneurysm+: n=111, aneurysm-: n=371) and tested our findings in an independent cohort of 200 Japanese KD patients (aneurysm+: n=58, aneurysm-: n=142). Analysis of the five MMP genes identified modest trends in allele and genotype frequencies for MMP-3 rs3025058 (-/T) and haplotypes containing MMP-3 rs3025058 (-/T) and MMP-12 rs2276109 (A/G) (nominal P=2 to 4 × 10(-5)) that conferred increased risk of aneurysm formation in US-UK subjects. This finding was validated in Japanese subjects and suggests the importance of this locus in aneurysm formation in children with KD. The region encompassing these risk haplotypes is a prime candidate for resequencing to look for rare genetic variation that may influence aneurysm formation.

Repeated systematic surveillance of Kawasaki disease in Ontario from 1995 to 2006

BACKGROUND

Rising incidences of Kawasaki disease (KD) have been reported worldwide. Reported herein are the results of 4 triennial KD surveillances conducted in Ontario.

METHODS

Between 1995 and 2006 all hospitals in Ontario were asked on 4 occasions to identify all patients with discharge diagnoses of KD and report incident cases.

RESULTS

The latest surveillance identified 697 new KD patients (100% response rate) for a total of 2378 KD patients through all 4 surveillances. Yearly incidence was 26.2/100,000 for <5 years old, 6.7/100,000 for 5-9 years old and 0.9/100,000 for 10-14 years old. KD incidence significantly increased from 1995 to 2006, although the increase seemed to plateau between the 3rd and 4th surveillance. There was an increase in the proportion of patients diagnosed with incomplete KD and a significant reduction in the rate of coronary artery abnormalities, possibly due to better disease recognition and treatment. Hospitals reporting <20 cases per surveillance were found to be more likely to report cases with incomplete KD. These patients were also less likely to be treated with i.v. immunoglobulin and aspirin but were more likely to be treated with antibiotics, suggesting uncertainties regarding diagnosis and management of KD patients in those centers.

CONCLUSIONS

The incidence of KD in Ontario is possibly one of the highest outside of Asia and has been rising since 1995. Although the most recent surveillance demonstrated improved cardiac outcomes, treatment delays or absence thereof continue to be a problem. Effective diagnosis and prompt treatment remain critical aspects of KD management.

Identification of susceptibility genes for Kawasaki disease

Kawasaki disease is an acute febrile illness of infants and children with unknown etiology. Coronary artery lesions occurring in 20-25% of untreated patients of KD has made KD a leading cause of acquired heart diseases of childhood in developed countries. High prevalence in East Asian countries is one of the epidemiological features of KD and has suggested genetic factors underlying the disease pathogenesis. We tried to identify genetic variants relevant to KD susceptibility by sibpair linkage study and linkage diseuilibrium mapping with SNPs and found that inositol 1,4,5-trisphosphate 3-kianse C gene is a susceptibility gene for KD. We also found the negative regulatory role of ITPKC in TCR signaling and the mechanism by which the responsible SNP in intron 1 of the gene affects transcripts level of ITPKC. Our findings highlighted the importance of Ca(2+)/NFAT pathway in the pathogenesis of KD and shed light on the possibility of immuno-suppressants targeting the pathway as a therapeutic strategy for KD.

Pathogenesis and management of Kawasaki disease

Kawasaki disease (KD) is an acute systemic inflammatory illness of young children that can result in coronary artery aneurysms, myocardial infarction and sudden death in previously healthy children. Clinical and epidemiologic features support an infectious cause, but the etiology remains unknown four decades after KD was first identified by Tomisaku Kawasaki. Finding the cause of KD is a pediatric research priority. We review the unique immunopathology of KD and describe the current treatment. New research has led to identification of viral-like cytoplasmic inclusion bodies in acute KD tissues; this finding could lead to identification of the elusive etiologic agent and result in significant advances in KD diagnosis and treatment. Current management of acute KD is based upon prospective, multicenter treatment trials of intravenous immunoglobulin (IVIG) with high-dose aspirin. Optimal therapy is 2 g/kg IVIG with high-dose aspirin as soon as possible after diagnosis during the acute febrile phase of illness, followed by low-dose aspirin until follow-up echocardiograms indicate a lack of coronary abnormalities. The addition of one dose of intravenous pulse steroid has not been shown to be beneficial. For the 10-15% of patients with refractory KD, few controlled data are available. Options include repeat IVIG (our preference), a 3-day course of intravenous pulse methylprednisolone, or infliximab (Remicade). Patients with mild-to-moderate coronary abnormalities should receive an antiplatelet agent such as low-dose aspirin (3-5 mg/kg/day) or clopidogrel (1 mg/kg/day up to 75 mg), and those with giant (approximately 8 mm diameter) or multiple coronary aneurysms should receive an antiplatelet agent with an anticoagulant such as warfarin or low-molecular-weight heparin. Acute coronary obstruction requires acute thrombolytic therapy with a surgical or percutaneous interventional procedure.

Common variants in CASP3 confer susceptibility to Kawasaki disease

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

Recent advances in the understanding and management of kawasaki disease

Kawasaki disease (KD) is an acute systemic inflammatory illness of childhood that can result in coronary artery aneurysms, myocardial infarction, and sudden death. Clinical and epidemiologic data point to an unknown infectious agent as the cause. We discovered that an oligoclonal IgA immune response is present in arterial tissue in acute KD. Synthetic versions of prevalent IgA antibodies in the KD arterial wall identify cytoplasmic inclusion bodies in acute KD ciliated bronchial epithelium and other inflamed KD tissues. Light and electron microscopic studies show that the inclusion bodies are consistent with aggregates of viral protein and RNA, and are likely formed by the KD etiologic agent. KD susceptibility is likely to be polygenic. Treatment of gammaglobulin nonresponders usually consists of additional intravenous immunoglobulin, methylprednisolone, and/or infliximab. Additional data regarding KD pathogenesis are urgently needed to provide other targets for therapy for those patients at highest risk of developing coronary artery abnormalities.

Programmed death-1 (PD-1) gene polymorphisms lodged in the genetic predispositions of Kawasaki Disease

The purpose of this study is to investigate the association of programmed death-1 gene (PD-1) polymorphisms with genetic predispositions to Kawasaki disease (KD). A total of 73 patients with KD and 100 healthy controls were enrolled from 2007 to 2008. Two single nucleotide polymorphisms of the PD-1 gene, rs41386349 and rs2227981, were analyzed. Higher T allele frequency of rs41386349 was found in the patient group than the control group (p = 0.007, odds ratio (OR) = 1.9, 95% CI = 1.2-2.9). PD-1 rs2227981 polymorphism was not significant in patients with KD comparing with the control group (p = 0.4, OR = 1.2 (0.8-1.9)). Furthermore, no difference of PD-1 polymorphisms between patients with coronary artery dilatation (CAD) and those without CAD was found. Our data support the possibility that PD-1 gene polymorphism may be related with the genetic susceptibility of KD in Korean population.

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.