An epidemic of Kawasaki syndrome in Hawaii

Pharmacogenomics of intravenous immunoglobulin response in Kawasaki disease

Introduction

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

Method

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

Results

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

Conclusions

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

Association of Kawasaki disease with urbanization level and family characteristics in Taiwan: A nested case-control study using national-level data

Kawasaki disease (KD) is an inflammatory vasculitis disorder of unknown etiology. It is a rare but fatal disease and the leading cause of acquired coronary heart disease in children under the age of 5 years. We examined the association of KD with the demographics of family members, parents' characteristics, and perinatal factors in Taiwanese children. This nested case-control study used data from Taiwan's Health and Welfare Data Science Center and initially included children born in Taiwan between January 1, 2006, and December 31, 2015 (n = 1,939,449); the children were observed for KD development before the age of 5 years (n = 7870). The control group consisted of children without KD who were matched with each KD case by sex and birth date at a ratio of 8:1. The odds ratio (ORs) of the aforementioned associations were estimated using conditional logistic regression. The risk of KD decreased in children with younger parents [<25 years; younger maternal age, OR = 0.72, 95% confidence interval (CI), 0.66-0.79; younger paternal age, OR = 0.68, 95% CI, 0.59-0.78], lower socioeconomic status, more than 2 siblings (OR = 0.80, 95% CI, 0.73-0.89), and siblings with a history of KD (OR = 4.39, 95% CI, 3.29-5.86). Children living in suburban (OR = 0.95, 95% CI, 0.90-1.00) and rural (OR = 0.81, 95%CI, 0.74-0.90) areas exhibited a lower risk of KD than children living in urban areas. In conclusion, a higher incidence rate of KD was observed in children aged <5 years who had an urban lifestyle, had siblings with KD, were born to older mothers, and belonged to high-income and smaller families. Parental allergic or autoimmune diseases were not associated with the risk of KD.

Seasonality and geographical distribution of Kawasaki disease among Black children in the Southeast United States

Introduction

Kawasaki Disease (KD) is a leading cause of pediatric acquired heart disease in the United States, affecting up to 7,000 children annually. Seasonal variation, an epidemiological characteristic of KD, has previously been reported predominantly among Asian children; however, little is known about the epidemiology and seasonality of KD of Black children within the U.S.

Methods

Electronic medical records were abstracted from 529 hospitalized KD patients admitted to a single tertiary center in Alabama between 2005 and 2019. Medical charts were reviewed to confirm KD diagnosis following American Heart Association criteria. Cases were stratified by the month of diagnosis date to assess seasonality, and statewide distribution of incidence is reported at county level using geographical spatial analysis. Comparisons were performed between Black patients and White patients with KD.

Results

The average number of KD cases per year was 35. Approximately, 60% were males and 44% were White children (N = 234), 45% were Black children (N = 240) and 11% were other races (N = 55). Black children were younger than White children at KD admission (median age 32 vs. 41 months respectively, p = 0.02). Overall, the highest rates of cases occurred between January and April. When stratifying by race, cases started to rise in December among White children with the highest rates between February and April with a peak in March. Among Black children cases were high during the winter season (January-April) with a peak in April. Similarly high rates also occurred in June, July and November. There were no differences in geographical distribution of cases by race.

Conclusion

KD incidence among White children in Alabama follows a seasonal cycle similar to other regions in the U.S. However, sustained incidence and additional peaks outside of the usual KD seasonality were seen among Black children with KD. Further studies are needed to investigate differential triggers between races.

Characteristics of Children With Kawasaki Disease-Like Signs in COVID-19 Pandemic: A Systematic Review

Recent studies have shown that several children diagnosed with COVID-19 have developed Kawasaki Disease (KD)-like symptoms. This systematic review aims to assess the demographic, laboratory, and clinical characteristics of children with KD-like syndrome during the COVID-19 pandemic and evaluate efficacy of treatments and patients' outcome. A comprehensive search was carried out systematically through PubMed, Scopus, and Web of Science (WoS), medRxiv, and bioRxiv by two reviewers independently for all studies or preprints data on the demographic, laboratory, and clinical characteristics of children with K.D-like signs during the COVID-19 outbreak. Overall, 378 studies were identified by the systematic search, of which 25 studies were included in the study. The included studies involved 599 patients in total. Thirteen studies (52%) were case reports or case series, and the rest (48%) were cohort studies. In 19 studies, patients were diagnosed with Multisystem inflammatory syndrome in children (MIS-C). In 16 studies COVID-19 was diagnosed in all patients based on their polymerase chain reaction result, serological findings, and computed tomography results. Higher C-reactive protein and erythrocyte sedimentation rate level were the most prevalent laboratory findings. In most studies, patients had leucopenia with marked lymphopenia, hypoalbuminemia, and increased ferritin, as well as hyponatremia. Abnormal echocardiography and respiratory outcomes were the most common clinical outcomes. In 11 studies, all patients required intensive care unit admission. Findings of the present systematic review show that the incidence of KD-like syndrome in the COVID-19 pandemic increased significantly. Moreover, this study offers new insights in the KD-like syndrome pathogenesis and clinical spectrum during COVID-19 pandemic.

A Protein Epitope Targeted by the Antibody Response to Kawasaki Disease

BACKGROUND

Kawasaki disease (KD) is the leading cause of childhood acquired heart disease in developed nations and can result in coronary artery aneurysms and death. Clinical and epidemiologic features implicate an infectious cause but specific antigenic targets of the disease are unknown. Peripheral blood plasmablasts are normally highly clonally diverse but the antibodies they encode are approximately 70% antigen-specific 1-2 weeks after infection.

METHODS

We isolated single peripheral blood plasmablasts from children with KD 1-3 weeks after onset and prepared 60 monoclonal antibodies (mAbs). We used the mAbs to identify their target antigens and assessed serologic response among KD patients and controls to specific antigen.

RESULTS

Thirty-two mAbs from 9 of 11 patients recognize antigen within intracytoplasmic inclusion bodies in ciliated bronchial epithelial cells of fatal cases. Five of these mAbs, from 3 patients with coronary aneurysms, recognize a specific peptide, which blocks binding to inclusion bodies. Sera from 5/8 KD patients day ≥ 8 after illness onset, compared with 0/17 infant controls (P < .01), recognized the KD peptide antigen.

CONCLUSIONS

These results identify a protein epitope targeted by the antibody response to KD and provide a means to elucidate the pathogenesis of this important worldwide pediatric problem.

Kawasaki Disease: Global Burden and Genetic Background

Kawasaki disease (KD) is a childhood vasculitides associated with serious coronary artery lesions. It is the most common cause of pediatric acquired heart disease in developed countries, and is increasingly reported from many rapidly industrializing developing countries. The incidence varies widely among different nations and is highest in North-East Asian countries, where almost 1 in 100 children in Japan having the disease by age of 5, where the lowest incidence reported in sub-Saharan Africa. The etiology of KD is still uncertain; interaction between a genetic predisposition and several environmental and immunological factors has been hypothesized. Several susceptibility genes were identified to be associated with the development of KD and increased risk of coronary artery lesions. Gene-gene associations and alteration of deoxyribonucleic acid (DNA) methylation are also found to play key roles in the pathogenesis and prognosis of KD. This article will focus on the global epidemiological patterns of KD, and the currently known genetic predisposition.

Non-arrhythmic causes of sudden death: A comprehensive review

Sudden cardiac death (SCD) is a major public health issue in the United States and worldwide. It is estimated to affect between 1 and 1.5 million patients worldwide annually, with the global burden expected to rise due to the concomitant rise in coronary artery disease in the developing world. Although arrhythmic causes of SCD such as ventricular tachycardia and ventricular fibrillation are common and well-studied, non-arrhythmic causes are also important, with diverse etiologies from ischemia-related structural heart disease to non-ischemic heart diseases, non-atherosclerotic coronary pathologies, and inflammatory states. Recent research has also found that risk factors and/or demographics predispose certain individuals to a higher risk of non-arrhythmia-related SCD. This review discusses the epidemiology, mechanisms, etiologies, and management of non-arrhythmic SCD.

The Epidemiology and Pathogenesis of Kawasaki Disease

Epidemiologic and clinical features of Kawasaki Disease (KD) strongly support an infectious etiology. KD is worldwide, most prominently in Japan, Korea, and Taiwan, reflecting increased genetic susceptibility among Asian populations. In Hawaii, KD rates are 20-fold higher in Japanese ethnics than in Caucasians, intermediate in other ethnicities. The age distribution of KD, highest in children < 2 yo, lower in those < 6 months, is compatible with infection by a ubiquitous agent resulting in increasing immunity with age and with transplacental immunity, as with some classic viruses. The primarily winter-spring KD seasonality and well-documented Japanese epidemics with wave-like spread also support an infectious trigger. We hypothesize KD pathogenesis involves an RNA virus that usually causes asymptomatic infection but KD in a subset of genetically predisposed children. CD8 T cells, oligoclonal IgA, and upregulation of cytotoxic T cell and interferon pathway genes in the coronaries in fatal KD also support a viral etiology. Cytoplasmic inclusion bodies in ciliated bronchial epithelium identified by monoclonal antibodies made from oligoclonal IgA heavy chains also supports a viral etiology. Recent availability of "second generation" antibodies from KD peripheral blood plasmablasts may identify a specific viral antigen. Thus, we propose an unidentified ("new") RNA virus infects bronchial epithelium usually causing asymptomatic infection but KD in a subset of genetically predisposed children. The agent persists in inclusion bodies, with intermittent respiratory shedding, entering the bloodstream via macrophages targeting coronaries. Antigen-specific IgA plasma cells and CD8 T cells respond but coronaries can be damaged. IVIG may include antibody against the agent. Post infection, 97-99% of KD patients are immune to the agent, protected against recurrence. The agent can spread either from those with asymptomatic primary infection in winter-spring or from a previously infected contact who intermittently sheds the agent.

Is Kawasaki disease an infectious disorder?

Although the etiology of Kawasaki disease (KD) is largely unknown, a large body of clinical, epidemiologic, immunologic, pathologic and ultrastructural evidence suggests that an infectious agent triggers a cascade that causes the illness. However, this elusive infectious agent remains unidentified at present. Increasingly sensitive molecular methods for identifying microbial nucleic acids and proteins in tissue samples continue to rapidly emerge, and these methods should be utilized in studies on KD etiology as they become available. Identifying the etiology of this enigmatic disease remains the single most important research goal in the field, and accomplishing this goal is the best means to improve diagnosis, treatment and prevention of this potentially fatal childhood disease.

Recent Advances in Kawasaki Disease - Proceedings of the 3rd Kawasaki Disease Summit, Chandigarh, 2014

Kawasaki disease (KD) is the most common cause of acquired heart disease in children in Japan, North America and Europe. It is now being increasingly recognized from the developing countries as well. If not diagnosed and treated in time, KD can result in coronary artery abnormalities in approximately 15-25% cases. The long-term consequences of these abnormalities may manifest in adults as myocardial ischemia and congestive heart failure. Intravenous immunoglobulin (IVIg) remains the drug of choice for treatment of KD, but several new agents like infliximab, cyclosporine, glucocorticoids and statins are now being increasingly used in these patients. While echocardiography has been the preferred imaging modality hitherto, CT coronary angiography has emerged as an exciting new supplementary option and provides an entirely new dimension to this disease. The incidence of KD has shown a progressive increase in several countries and it is likely that this disease would impact public health programmes in the near future even in the developing countries.

Association of Kawasaki disease with tropospheric winds in Central Chile: is wind-borne desert dust a risk factor?

It has been found that Kawasaki disease (KD) cases diagnosed in Japan, Hawaii and San Diego, USA increase when tropospheric wind patterns arrive from central Asia, suggesting a common, wind-borne causal agent. We analyzed KD cases hospitalized in Santiago, Chile to look for associations with local, regional and large scale meteorological variables. We compiled monthly data of KD incidence rates, local meteorological variables, large scale wind patterns and several El Niño Southern Oscillation (ENSO) indices for 2001-2010; we considered standardized anomalies in all analyses and used linear time series models to account for data autocorrelation. We found that meteorological variables explain 38% of variance in KD rates. A unit increase in northerly wind at 3 lagged months, temperature at 1 and 3 lagged months and monthly change of ENSO 4 index are associated with changes in KD rates of 0.203 (95% CI 0.049-0.358), 0.181 (95% CI 0.014-0.347), 0.192 (95% CI 0.030-0.353) and -0.307 (95% CI -0.458-0.156), respectively. These results are robust when northerly wind level is changed or when a shorter period (2005-2010) is used to estimate model parameters. We found a statistical association of KD at Santiago, Chile with tropospheric, northerly wind patterns suggesting that dust transported from the Atacama Desert could include a causative agent. A novel result is that ENSO dynamics also explain part of KD variability with a decrease in KD when La Niña is dissipating or El Niño is on the rise; hence climate scale dynamics might be taken into account in future studies worldwide - at least as a potential explanatory variable that may confound KD seasonality on a global scale.

Viral infections associated with Kawasaki disease

BACKGROUND/PURPOSE

Kawasaki disease (KD) is a disease of unknown cause. To investigate the infectious etiology of Kawasaki disease, we initiated a prospective case-control study to investigate possible links between common viral infections and Kawasaki disease.

METHODS

We enrolled 226 children with KD and 226 age- and sex-matched healthy children from February 2004 to March 2010. Throat and nasopharyngeal swabs were taken for both viral isolation and polymerase chain reaction (PCR) for various viruses.

RESULTS

The mean age of the 226 KD cases was 2.07 years, and the male to female ratio was 1.43 (133 boys to 93 girls). Their mean fever duration was 7.5 days with a mean peak temperature of 39.7°C. In addition to the typical symptoms of fever, neck lymphadenopathy, lip fissure and/or strawberry tongue, skin rash, nonpurulent bulbar conjunctivitis, palm/sole erythema, and induration followed by periungual desquamation, these KD cases also exhibited cough (69%), rhinorrhea (58%), and diarrhea (45%). Cases of KD had a significantly higher positive rate of viral isolation in comparison with the control group (7.5% vs. 2.2%, p = 0.02). Compared with the control group, cases of KD were more likely to have overall positive rates of viral PCR (50.4% vs. 16.4%, p < 0.001) and for various viruses including enterovirus (16.8% vs. 4.4%, p < 0.001), adenovirus (8.0% vs. 1.8%, p = 0.007), human rhinovirus (26.5% vs. 9.7%, p < 0.001), and coronavirus (7.1% vs. 0.9%, p = 0.003).

CONCLUSION

We found that some common respiratory viruses, such as adenoviruses, enteroviruses, rhinoviruses, and coronaviruses, were associated with KD cases.

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.

Kawasaki syndrome and factors associated with coronary artery abnormalities in California

BACKGROUND

Kawasaki syndrome (KS) occurs in children <18 years of age and is the leading cause of acquired heart disease among children in the United States. Understanding the epidemiology of KS and factors associated with coronary artery abnormalities (CAA) may lead to timely diagnosis and treatment of KS and could limit CAA.

METHODS

Epidemiologic characteristics, including risk factors for the development of CAA, among KS and incomplete KS patients <18 years of age with onset during 2000-2009 reported by the California Department of Public Health to the Centers for Disease Control and Prevention's national KS surveillance system were analyzed.

RESULTS

A total of 2056 KS and incomplete KS patients <18 years of age were reported during 2000-2009. The median age of patients was 2 years; 60% of patients were male. Of 1818 patients with race information reported, 56% were white and 28% were Asian/Pacific Islander. Ninety-eight percent of patients received intravenous immunoglobulin. Of 1843 patients with information on cardiac complications, 89 (5%) had coronary artery aneurysms and 341 (19%) had CAA. Characteristics associated with the occurrence of CAA in KS patients were male sex, Asian/Pacific Islander race, age <1 year or 9-17 years, and not receiving intravenous immunoglobulin treatment before the fifth day of illness.

CONCLUSIONS

This study suggests that intravenous immunoglobulin treatment before the fifth day of illness may reduce CAA among KS patients. Timely diagnosis and treatment of KS continue to be important in reducing the occurrence of cardiac complications.

Histo-blood group gene polymorphisms as potential genetic modifiers of the development of coronary artery lesions in patients with Kawasaki disease

Abnormal immunological responses to certain microbial agents may play a crucial role in the pathogenesis of Kawasaki disease (KD). The association studies between histo-blood group genes (Lewis and ABO blood types) and various types of infectious diseases or vasculopathy have been carried out based on the fact that glycosylated antigens could directly mediate microbial infections. We attempted to clarify the role of blood type antigens in the development of KD and coronary artery lesions in KD patients. The subjects included 164 KD patients enrolled from 1998 to 2003 (1st group), 232 patients from 2004 to 2009 (2nd group), and 223 healthy children and 118 patients with growth hormone deficiency as controls. The genotyping of the FUT2 and FUT3 genes, and ABO genotypes, was determined with the TaqMan SNP assay and allele-specific polymerase chain reaction. No significant differences were observed in the genotypes and allele frequencies of the FUT2 and FUT3 genes between the groups. The frequency of the BB blood genotype was significantly higher in KD patients with coronary artery lesions in the 1st and 2nd groups than in the controls (17% and 14% vs. 5%, P = 0.0020). This is the first report to investigate the roles of ABO and Lewis blood types in the development of KD, and in the formation of coronary artery lesions in KD patients. These data suggest that the ABO blood type may play a role in the development of coronary artery lesions in KD patients.

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.

Treatment of Kawasaki disease: analysis of 27 US pediatric hospitals from 2001 to 2006

OBJECTIVES

We sought to analyze trends in admissions and to describe therapies used for acute Kawasaki disease over a 6-year period.

METHODS

The Pediatric Health Information System provides patient data including demographic variables, International Classification of Diseases, Ninth Revision codes, and services billed to patients. Patient identifiers enable tracking of medication use in and across multiple admissions within a center. We analyzed data for patients with (1) a diagnosis code for Kawasaki disease, (2) intravenously administered immunoglobulin treatment during hospitalization, and (3) discharge between January 1, 2001, and December 30, 2006, from 27 hospitals contributing complete data over the study period.

RESULTS

During the study period, 5197 Kawasaki disease admissions were identified for 4811 patients; numbers increased 32.6% from 2001 (n = 678) to 2006 (n = 899). Retreatment with intravenous immunoglobulin was administered to 712 patients (14.8%) over the study period. Other antiinflammatory therapies included intravenously administered methylprednisolone (5.8%), orally administered prednisone (2.8%), and infliximab (1%). Use of infliximab steadily increased from 0.0% (0 of 678 patients) in 2001 to 2.3% (21 of 899 patients) in 2006. Coronary artery aneurysms were coded for 3.3% of patients. Male patients, patients <1 year of age, and Hispanic patients were significantly more likely to have coding for coronary artery aneurysms.

CONCLUSIONS

Our report provides the first large multicenter description of agents used in the treatment of intravenously administered immunoglobulin-resistant Kawasaki disease in the United States. Trends include increased numbers of admissions attributable to Kawasaki disease and increased usage of infliximab.

The Asian dermatologic patient: review of common pigmentary disorders and cutaneous diseases

The Asian patient with Fitzpatrick skin types III-V is rarely highlighted in publications on cutaneous disorders or cutaneous laser surgery. However, with changing demographics, Asians will become an increasingly important group in this context. Although high melanin content confers better photoprotection, photodamage in the form of pigmentary disorders is common. Melasma, freckles, and lentigines are the epidermal disorders commonly seen, whilst nevus of Ota and acquired bilateral nevus of Ota-like macules are common dermal pigmentary disorders. Post-inflammatory hyperpigmentation (PIH) occurring after cutaneous injury remains a hallmark of skin of color. With increasing use of lasers and light sources in Asians, prevention and management of PIH is of great research interest. Bleaching agents, chemical peels, intense pulsed light (IPL) treatments, and fractional skin resurfacing have all been used with some success for the management of melasma. Q-switched (QS) lasers are effective for the management of epidermal pigmentation but are associated with a high risk of PIH. Long-pulsed neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers and IPL sources pose less of a PIH risk but require a greater number of treatment sessions. Dermal pigmentary disorders are better targeted by QS ruby, QS alexandrite, and QS 1064-nm Nd:YAG lasers, but hyper- and hypopigmentation may occur. Non-ablative skin rejuvenation using a combination approach with different lasers and light sources in conjunction with cooling devices allows different skin chromophores to be targeted and optimal results to be achieved, even in skin of color. Deep-tissue heating using radiofrequency and infra-red light sources affects the deep dermis and achieves enhanced skin tightening, resulting in eyebrow elevation, rhytide reduction, and contouring of the lower face and jawline. For management of severe degrees of photoaging, fractional resurfacing is useful for wrinkle and pigment reduction, as well as acne scarring. Acne, which is common in Asians, can be treated with topical and oral antibacterials, hormonal treatments, and isotretinoin. Infra-red diode lasers used with a low-fluence, multiple-pass approach have also been shown to be effective with few complications. Fractional skin resurfacing is very useful for improving the appearance of acne scarring. Hypertrophic and keloid scarring, another common condition seen in Asians, can be treated with the combined used of intralesional triamcinolone and fluorouracil, followed by pulsed-dye laser. Esthetic enhancement procedures such as botulinum toxin type A and fillers are becoming increasingly popular. These are effective for rhytide improvement and facial or body contouring. We highlight the differences between Asian skin and other skin types and review conditions common in skin of color together with treatment strategies.

Searching for the cause of Kawasaki disease--cytoplasmic inclusion bodies provide new insight

Although Kawasaki disease (KD) is the most common cause of acquired heart disease in children in the developed world, its aetiology remains unknown. In this Opinion, Anne Rowley and colleagues discuss evidence, including recently identified cytoplasmic inclusion bodies, which suggests that KD is caused by an infectious agent.

Kawasaki disease (KD) has emerged as the most common cause of acquired heart disease in children in the developed world. The cause of KD remains unknown, although an as-yet unidentified infectious agent might be responsible. By determining the causative agent, we can improve diagnosis, therapy and prevention of KD. Recently, identification of an antigen-driven IgA response that was directed at cytoplasmic inclusion bodies in KD tissues has provided new insights that could unlock the mysteries of KD.

Epidemiology and etiology of Kawasaki disease

Kawasaki disease was first reported in Japan in 1967 by Dr. Tomisaku Kawasaki. It has since been recognized worldwide, and in at the United States and Japan is the most important cause of acquired heart disease in children, surpassing other more recognized conditions such as rheumatic fever, endocarditis and myocarditis. It is primarily a disease of children less than 5 years of age but has been reported in older children and adults. Risk factors for the illness include Asian ancestry, male gender and certain familial predispositions. Observations such as similarity to certain exanthematous infectious diseases, temporal-geographic clustering of cases and seasonality in incidence favors an infectious etiology. Pathology and pathogenesis of the disease indicate that it is a medium-sized artery vasculitis that results from a dramatic immune activation that in most cases reversed by immune modulating agents such as intravenous immunoglobulin. Unfortunately, the etiology of the illness remains obscure, although recent studies favor a possible viral etiology.

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

Kawasaki disease (KD) is an acute systemic vasculitis syndrome that primarily affects infants and young children. The cause of KD is largely unknown, but its higher incidence in the Asian population and increased risk in patients' families suggests the existence of underlying genetic factors. To determine the loci of a susceptibility gene for KD, a genomewide linkage analysis with affected sib pairs was performed on 78 family samples collected from all over Japan. Multipoint linkage analysis using MAPMAKER/SIBS 2.0 identified evidence of linkage on 12q24 [maximum lod score (MLS) = 2.69]. Possible linkage (MLS > 1.0) was also found on 4q35, 5q34, 6q27, 7p15, 8q24, 18q23, 19q13, Xp22, and Xq27. This is the first large-scale study of the genetic susceptibility to KD, and our results, combined with the accumulated knowledge of the human genome, could greatly promote research on identification of the molecular pathogenesis of KD.

Human coronavirus NL63 is not detected in the respiratory tracts of children with acute Kawasaki disease

Kawasaki disease (KD) is a self-limited, systemic vasculitis of children for which an infectious trigger is suspected. Recently, an association between KD and human coronavirus (HCoV)-New Haven (NH) was reported, on the basis of polymerase chain reaction (PCR) with primers that also amplified HCoV-NL63. We investigated the possible association between these HCoVs in the respiratory tract and KD by reverse-transcriptase (RT) PCR and viral culture in a geographically and ethnically diverse population. Only 1 (2%) of 48 patients with acute KD was positive by RT-PCR for HCoV-NL63/NH in a nasopharyngeal swab. These data do not support an association between these HCoVs and KD.

Kawasaki disease: what is the epidemiology telling us about the etiology?

Kawasaki disease (KD) is an important and common inflammatory vasculitis of early childhood with a striking predilection for the coronary arteries. It is the predominant cause of paediatric acquired heart disease in developed countries. Despite 40 years of research, the aetiology of KD remains unknown and consequently there is no diagnostic test and treatment is non-specific and sub-optimal. The consensus is that KD is due to one or more widely distributed infectious agent(s), which evoke an abnormal immunological response in genetically susceptible individuals. The epidemiology of KD has been extensively investigated in many populations and provides much of the supporting evidence for the consensus regarding etiology. These epidemiological data are reviewed here, in the context of the etiopathogenesis. It is suggested that these data provide additional clues regarding the cause of KD and may account for some of the continuing controversies in the field.

Kawasaki disease hospitalizations in a predominantly African-American population

This is a descriptive study of the occurrence of Kawasaki disease (KD) in an urban population that was a majority of African Americans. Records of 189 children (mean age, 2.9 +/- 2.2 years [range: 2 months to 11.1 years]) hospitalized for KD over 8 years (January 1, 1992 to December 31, 1999) were reviewed and data analyzed. One hundred thirty-six (72%) were African American (AA), 43 (23%) were white, and 9 (5%) children were "others.'' The annual frequency was 15 for AA and 7.7 for white per 100,000 5-year-old children. Coronary artery abnormalities (CAA) were reported in 21 (11%) children (18 [13.2%] of 136 AA, and 3 [4.7%] of 43 whites [p=0.095]). AA children with CAA were older than their white counterparts (26 to 24 vs. 5 to 2.8 months, p=0.03). There was a higher occurrence in winter and spring (110 cases [58%] vs. 79 cases [42%]) compared to summer and fall. KD occurrence was positively associated with average monthly snowfall (r=0.35, p=0.004) and inversely associated with average monthly temperature (r = - 0.2, p=0.048). African-American children were more likely to be hospitalized for KD compared to white children. The association of KD with temperature and precipitation suggest that it is influenced by environmental factors.

Kawasaki syndrome in Hawaii

OBJECTIVE

To describe the incidence and epidemiology of Kawasaki syndrome (KS) in Hawaii.

METHODS

Retrospective analysis of the State Inpatient Database for Hawaii residents hospitalized with KS during 1996 through 2001.

RESULTS

During 1996 through 2001, 267 persons younger than 18 years of age living in Hawaii were hospitalized with KS; 226 (84.6%) were younger than 5 years of age. The average annual incidence for KS was 45.2 per 100,000 children younger than 5 years of age. The incidence was higher for children younger than 1 year of age than for those 1-4 years of age (74.3 and 37.5 per 100,000). The KS incidence for Asian and Pacific Islander children and for White children was 70.9 and 35.3 per 100,000, respectively. Incidence was highest among Japanese American children living in Hawaii (197.7 per 100,000). Honolulu County had the most KS patients (85.0%) and the highest incidence (53.1 per 100,000) among Hawaii counties. For children younger than 5 years of age hospitalized with KS, the median length of stay was 2 days, and the median hospital charge was $9379.

CONCLUSION

During 1996 through 2001, the annual incidence rate for KS among children younger than 5 years of age in Hawaii was the highest in the United States. The incidence among Japanese American children in Hawaii was higher than that among other racial groups in the state and when compared with children living in Japan.

CD40 ligand gene and Kawasaki disease

Kawasaki disease (KD) is an acute systemic vasculitis syndrome of infants and young children. Although its etiology is largely unknown, epidemiological findings suggest that genetic factors play a role in the pathogenesis of KD. To identify genetic factors, affected sib-pair analysis has been performed. One of the identified peaks was located on the Xq26 region. A recent report of elevated expression of CD40 ligand (CD40L), which maps to Xq26, during the acute-phase KD, and its relationship to the development of coronary artery lesions (CAL) prompted us to screen for polymorphism of CD40L and to study the association of the gene to KD. A newly identified SNP in intron 4 (IVS4+121 A>G) is marginally over-represented in KD patients as compared to controls (109/602, 18.1 vs 111/737, 15.1%). When male KD patients with CAL were analyzed as a patient group, the SNP was significantly more frequent than in controls (15/58, 25.9%, vs 111/737, 15.1%, OR=2.0, 95% CI=1.07-3.66; P=0.030). Interestingly, this variation was extremely rare in a control Caucasian population (1/145, 0.7%). Our results suggest a role of CD40L in the pathogenesis of CAL and might explain the excess of males affected with KD.

Pulmonary symptoms in Kawasaki disease

The diagnosis of Kawasaki disease is based on 6 clinical criteria, 5 of which must be fulfilled. The presence of uncommon symptoms in addition to the classic criteria can be as misleading as the lack of common ones. Here we report 2 infants with marked pulmonary symptoms in the course of Kawasaki disease who were initially diagnosed with pneumonia.

Microorganisms resistant to free-living amoebae

Free-living amoebae feed on bacteria, fungi, and algae. However, some microorganisms have evolved to become resistant to these protists. These amoeba-resistant microorganisms include established pathogens, such as Cryptococcus neoformans, Legionella spp., Chlamydophila pneumoniae, Mycobacterium avium, Listeria monocytogenes, Pseudomonas aeruginosa, and Francisella tularensis, and emerging pathogens, such as Bosea spp., Simkania negevensis, Parachlamydia acanthamoebae, and Legionella-like amoebal pathogens. Some of these amoeba-resistant bacteria (ARB) are lytic for their amoebal host, while others are considered endosymbionts, since a stable host-parasite ratio is maintained. Free-living amoebae represent an important reservoir of ARB and may, while encysted, protect the internalized bacteria from chlorine and other biocides. Free-living amoebae may act as a Trojan horse, bringing hidden ARB within the human "Troy," and may produce vesicles filled with ARB, increasing their transmission potential. Free-living amoebae may also play a role in the selection of virulence traits and in adaptation to survival in macrophages. Thus, intra-amoebal growth was found to enhance virulence, and similar mechanisms seem to be implicated in the survival of ARB in response to both amoebae and macrophages. Moreover, free-living amoebae represent a useful tool for the culture of some intracellular bacteria and new bacterial species that might be potential emerging pathogens.

Advances in Kawasaki disease

Recent studies have increased our understanding of the etiopathogenesis of Kawasaki disease (KD). The inflammatory infiltrate in KD coronary artery aneurysms has been shown to consist of CD8 T lymphocytes, macrophages, and IgA plasma cells, consistent with an immune response to an intracellular pathogen with a mucosal portal of entry. The identification of an oligoclonal IgA response in the vascular wall and the detection of a KD-associated antigen in inflamed KD tissues using a synthetic antibody derived from KD oligoclonal IgA antibodies have provided new approaches to identification of the etiologic agent. Highly effective therapy has evolved for KD, even in the absence of identification of the etiologic agent. The existence of incomplete KD cases remains a significant diagnostic dilemma for the clinician.

CONCLUSION

The development of a diagnostic test, more specific therapy, and ultimate prevention of this potentially fatal illness of childhood are dependent upon continued advances in determining the etiopathogenesis of this fascinating disorder.

Cutaneous diseases in Asians

Atopic dermatitis, nummular dermatitis, dyshidrosis, and melasma seem to be more common in Asians, whereas psoriasis and skin cancer are less common. In addition, there are less common skin conditions that are usually seen in Asians, including Mongolian spot, nevus of Ota, nevus of Ito, Kawasaki disease, primary cutaneous amyloidosis, Kikuchi-Fujimoto disease, and LCAI. Awareness of these less common cutaneous disorders can be helpful, especially for clinicians who work in areas with a large Asian population.

Kawasaki syndrome hospitalizations in the United States, 1997 and 2000

OBJECTIVE

To estimate the incidence and describe the epidemiologic characteristics of Kawasaki syndrome (KS) among children in the United States.

METHODS

Hospital discharge records with a KS diagnosis among patients <18 years of age were obtained from the 1997 and 2000 Kids' Inpatient Database and weighted to estimate the number and rate of KS-associated hospitalizations for the United States.

RESULTS

In 2000, approximately 4248 hospitalizations associated with KS occurred in the United States, and the median age of patients at admission was 2 years. Children <5 years of age accounted for 3277 of these KS hospitalizations (77%) and had a KS hospitalization rate of 17.1 per 100,000 children. This rate was similar to the 1997 rate of 17.6 per 100,000 children. The KS hospitalization rate was significantly higher for infants <1 year of age than for children 1 to 4 years of age (19.8 and 16.4 per 100,000 children, respectively). The rate of KS hospitalizations among children aged <5 years was highest among Asian and Pacific Islander children and was followed by the rate for black children (39.0 and 19.7 per 100,000 children, respectively). No deaths associated with KS were reported among hospitalized children. The median charge for a KS hospitalization was 7779 dollars (mean 10,725 dollars) and the total annual charges for KS hospitalizations in 2000 were approximately 35 million dollars among children <5 years of age.

CONCLUSIONS

Among children <5 years of age, the annual KS-associated hospitalization rates were similar for 1997 and 2000. The epidemiologic characteristics and hospitalization rates for KS at a national level were consistent with those reported from earlier studies, suggesting that the incidence for KS has not markedly changed in the United States during the past decade.

Parachlamydiaceae: potential emerging pathogens

Parachlamydiaceae, which naturally infect amoebae, form a sister taxon to the Chlamydiaceae on the basis of the Chlamydia-like cycle of replication and 80% to 90% homology of ribosomal RNA genes. Because intra-amoebal growth could increase the virulence of some intracellular bacteria, Parachlamydiaceae may be pathogenic. Arguments supporting a pathogenic role are that Chlamydia pneumoniae, a well-recognized agent of pneumonia, was shown to infect free-living amoebae and that another member of the Chlamydiales, Simkania negevensis, which has 88% homology with Parachlamydia acanthamoebae, has caused pneumonia in adults and acute bronchiolitis in infants. The recent identification of a 16S rRNA gene sequence of a Parachlamydiaceae from bronchoalveolar lavage is additional evidence supporting potential for pathogenicity.

Legionella-like and other amoebal pathogens as agents of community-acquired pneumonia

We tested serum specimens from three groups of patients with pneumonia by indirect immunofluorescence against Legionella-like amoebal pathogens (LLAPs) 1-7, 9, 10, 12, 13; Parachlamydia acanthamoeba strains BN 9 and Hall's coccus; and Afipia felis. We found that LLAPs play a role (albeit an infrequent one) in community-acquired pneumonia, usually as a co-pathogen but sometimes as the sole identified pathogen.

Relationship of climate, ethnicity and socioeconomic status to Kawasaki disease in San Diego County, 1994 through 1998

BACKGROUND

Kawasaki disease (KD) is the most common cause of acquired heart disease in children in the United States. By monitoring trends in patient numbers and demographics during a 5-year period, we were able to explore the relationship between climate, ethnicity, socioeconomic status and susceptibility to KD.

METHODS

We conducted active surveillance for all patients hospitalized with KD in San Diego County from 1994 through 1998. Data on seasonal variation in monthly rainfall and temperature were obtained from the US Meteorological Service. Patient sex, age, date of admission and self-reported ethnicity were identified from patient medical records. Socioeconomic status was assessed on the basis of insurance status among patients hospitalized at a single institution.

RESULTS

During the 5-year period there were 169 cases of KD in San Diego County. The overall annual incidence of KD in children < 5 years of age ranged from 8.0 to 15.4/100 000. KD incidence was inversely associated with average monthly temperature (r = -0.47, P < 0.001) and positively associated with average monthly precipitation (r = -0.52, P < 0.001). Asian/Pacific Islanders < 5 years of age were 2.7 times as likely and Hispanics were one-third as likely to be hospitalized for KD than children from all other ethnic groups combined. Children with private or military insurance in all ethnic groups were more likely to have a diagnosis of KD than children with government assistance or no insurance. After controlling for insurance status, only Asian/Pacific Islanders remained at increased risk (rate ratio, 2.14) for KD relative to all other ethnic groups combined.

CONCLUSION

KD is a common childhood vasculitis of unknown etiology. The skewed ethnic distribution and seasonality are consistent with the hypothesis that KD is an infectious disease that is influenced by environmental and genetic factors.

Kawasaki disease: A brief history

Tomisaku Kawasaki published the first English-language report of 50 patients with Kawasaki disease (KD) in 1974. Since that time, KD has become the leading cause of acquired heart disease among children in North America and Japan. Although an infectious agent is suspected, the cause remains unknown. However, significant progress has been made toward understanding the natural history of the disease and therapeutic interventions have been developed that halt the immune-mediated destruction of the arterial wall. We present a brief history of KD, review progress in research on the disease, and suggest avenues for future study. Kawasaki saw his first case of KD in January 1961 and published his first report in Japanese in 1967. Whether cases existed in Japan before that time is currently under study. The most significant controversy in the 1960s in Japan was whether the rash and fever sign/symptom complex described by Kawasaki was connected to subsequent cardiac complications in a number of cases. Pathologist Noboru Tanaka and pediatrician Takajiro Yamamoto disputed the early assertion of Kawasaki that KD was a self-limited illness with no sequelae. This controversy was resolved in 1970 when the first Japanese nationwide survey of KD documented 10 autopsy cases of sudden cardiac death after KD. By the time of the first English-language publication by Kawasaki in 1974, the link between KD and coronary artery vasculitis was well-established. KD was independently recognized as a new and distinct condition in the early 1970s by pediatricians Marian Melish and Raquel Hicks at the University of Hawaii. In 1973, at the same Hawaiian hospital, pathologist Eunice Larson, in consultation with Benjamin Landing at Los Angeles Children's Hospital, retrospectively diagnosed a 1971 autopsy case as KD. The similarity between KD and infantile periarteritis nodosa (IPN) was apparent to these pathologists, as it had been to Tanaka earlier. What remains unknown is the reason for the simultaneous recognition of this disease around the world in the 1960s and 1970s. There are several possible explanations. KD may have been a new disease that emerged in Japan and emanated to the Western World through Hawaii, where the disease is prevalent among Asian children. Alternatively, KD and IPN may be part of the spectrum of the same disease and clinically mild KD masqueraded as other diseases, such as scarlet fever in the preantibiotic era. Case reports of IPN from Western Europe extend back to at least the 19th century, but, thus far, cases of IPN have not been discovered in Japan before World War II. Perhaps the factors responsible for KD were introduced into Japan after the World War II and then reemerged in a more virulent form that subsequently spread through the industrialized Western world. It is also possible that improvements in health care and, in particular, the use of antibiotics to treat infections caused by organisms including toxin-producing bacteria reduced the burden of rash/fever illness and allowed KD to be recognized as a distinct clinical entity. Itsuzo Shigematsu, Hiroshi Yanagawa, and colleagues have conducted 14 nationwide surveys in Japan. These have indicated that: 1) KD occurred initially in nationwide epidemics but now occurs in regional outbreaks; 2) there are approximately 5,000 to 6,000 new cases each year; 3) current estimates of incidence rates are 120 to 150 cases per 100,000 children <5 years old; 4) KD is 1.5 times more common in males and 85% of cases occur in children <5 years old; and 5) the recurrence rate is low (4%). In 1978, David Morens at the Centers for Disease Control and Prevention published a case definition based on Kawasaki's original criteria. The Centers for Disease Control and Prevention developed a computerized database in 1984, and a passive reporting system currently exists in 22 states. Regional investigations and national surveys suggest an annual incidence of 4 to 15 cases per 100 000 children <5 years o

Head and neck manifestations of Kawasaki disease

Kawasaki disease, also known as acute infantile febrile mucocutaneous lymph node syndrome, is a self-limited vasculitic disease of infants and young children. The cause of the disease remains uncertain. Within the constellation of signs and symptoms, there are numerous otolaryngologic manifestations. The following represents the largest series of patients in the otolaryngology literature, involving 155 confirmed cases of Kawasaki disease as treated at our institution during the last 10 years. The demographic data, clinical pictures of the typical and atypical forms of the illness, as well as the laboratory values, therapy and complications are discussed.

Kawasaki syndrome

Kawasaki syndrome is a fascinating worldwide illness of young children. This acute self-limited vasculitis has become the most common cause of acquired heart disease in children in the United States and Japan. KS causes significant coronary artery disease that may lead to myocardial infarction and sudden death. Clinical and epidemiologic features of KS support an infectious cause, but the etiology remains unknown. Clearly, additional research on the cause of KS and its pathogenesis is needed urgently to allow for improved diagnosis; more specific therapy; and, ultimately, prevention of the disorder.

Kawasaki syndrome

Kawasaki syndrome (KS) is an acute, sometimes fatal vasculitis of young children. KS has replaced acute rheumatic fever as the most common cause of acquired heart disease in children in the United States. The illness is manifested by prolonged fever, conjunctival injection, enanthem, exanthem, erythema and swelling of the hands and feet, and cervical adenopathy. These acute features of illness are self-limiting, but coronary artery abnormalities occur in 20% of untreated patients. The etiology of the illness is unknown, but its clinical and epidemiologic features are most consistent with an infectious cause. Common cardiovascular manifestations of the illness include myocarditis, pericardial effusion, and coronary artery aneurysm formation. Treatment with intravenous gamma globulin (IVGG) and aspirin within the first 10 days of illness reduces the prevalence of coronary artery abnormalities from 20% in those treated with aspirin alone to 4%. Patients who develop coronary artery aneurysms, particularly those who develop giant coronary artery aneurysms, may suffer myocardial infarction secondary to thrombosis or stenosis in the abnormal vessel. Additional research to determine the cause of KS is urgently needed to allow for improved diagnosis, more specific therapy, and prevention of the disorder.