Recurrence of Kawasaki disease and Epstein-Barr virus infection

Emerging evidence of microbial infection in causing systematic immune vasculitis in Kawasaki disease

Kawasaki disease (KD) is a systematic vasculitis that is often complicated by coronary artery lesions and is a leading cause of acquired heart disease in developed countries. Previous studies have suggested that genetic susceptibility, together with an inducing infectious agent, could be involved in KD pathogenesis; however, the precise causative agent of this disease remains unknown. Moreover, there are still debates concerning whether KD is an infectious disease or an autoimmune disease, although many studies have begun to show that various pathogens functioning as critical inducers could activate different kinds of immune cells, consequently leading to the dysfunction of endothelial cells and systematic vasculitis. Here in this review, we attempt to summarize all the available evidence concerning pathogen infections associated with KD pathogenesis. We also discuss the related mechanisms, present a future perspective, and identify the open questions that remain to be investigated, thereby providing a comprehensive description of pathogen infections and their correlations with the host immune system in leading to KD.

Kawasaki Disease as the Immune-Mediated Echo of a Viral Infection

Although the etiology of Kawasaki disease (KD) remains elusive, the available evidence indicates that the primum movens may be a dysregulated immune response to various microbial agents, leading to cytokine cascade and endothelial cell activation in patients with KD. Documented infections by different viruses in many individual cases have been largely reported and are discussed herein, but attempts to demonstrate their causative role in the distinctive KD scenario and KD epidemiological features have been disappointing. To date, no definite link has been irrefutably found between a single infection and KD.

Kawasaki disease: pathophysiology and insights from mouse models

Kawasaki disease is an acute febrile illness and systemic vasculitis of unknown aetiology that predominantly afflicts young children, causes coronary artery aneurysms and can result in long-term cardiovascular sequelae. Kawasaki disease is the leading cause of acquired heart disease among children in the USA. Coronary artery aneurysms develop in some untreated children with Kawasaki disease, leading to ischaemic heart disease and myocardial infarction. Although intravenous immunoglobulin (IVIG) treatment reduces the risk of development of coronary artery aneurysms, some children have IVIG-resistant Kawasaki disease and are at increased risk of developing coronary artery damage. In addition, the lack of specific diagnostic tests and biomarkers for Kawasaki disease make early diagnosis and treatment challenging. The use of experimental mouse models of Kawasaki disease vasculitis has considerably improved our understanding of the pathology of the disease and helped characterize the cellular and molecular immune mechanisms contributing to cardiovascular complications, in turn leading to the development of innovative therapeutic approaches. Here, we outline the pathophysiology of Kawasaki disease and summarize and discuss the progress gained from experimental mouse models and their potential therapeutic translation to human disease.

This Review outlines the pathophysiology of Kawasaki disease and discusses the progress gained from experimental mouse models and their potential therapeutic translation to human disease.

Kawasaki disease is a childhood systemic vasculitis leading to the development of coronary artery aneurysms; it is the leading cause of acquired heart disease in children in developed countries.

The cause of Kawasaki disease is unknown, although it is suspected to be triggered by an unidentified infectious pathogen in genetically predisposed children.

Kawasaki disease might not be a normal immune response to an unusual environmental stimulus, but rather a genetically determined unusual and uncontrolled immune response to a common stimulus.

Although the aetiological agent in humans is unknown, mouse models of Kawasaki disease vasculitis demonstrate similar pathological features and have substantially accelerated discoveries in the field.

Genetic and transcriptomic analysis of blood samples from patients with Kawasaki disease and experimental evidence generated using mouse models have demonstrated the critical role of IL-1β in the pathogenesis of this disease and the therapeutic potential of targeting this pathway (currently under investigation in clinical trials).

Aetiological Significance of Infectious Stimuli in Kawasaki Disease

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

Kawasaki disease, Epstein-Barr virus and coronary artery aneurysms

AIM

To establish whether infection with Epstein-Barr virus (EBV) contributed to the development of coronary artery lesions in a six year old child with an aneurysm and stenoses of the coronary arteries and suspected Kawasaki disease.

METHODS

Postmortem paraffin wax sections of the coronary artery and myocardium were examined by in situ hybridisation for expression of EBER-1 (EBV-encoded RNA-1). Positive controls consisted of an EBV positive case of Hodgkin disease and a case of posttransplantation lymphoma.

RESULTS

No EBER-1 positive cells were identified in either myocardium or walls of the coronary artery.

CONCLUSIONS

Although EBV has been implicated in the aetiology of Kawasaki disease and development of coronary artery lesions, this process was not confirmed in this patient. It is likely that an unusual immunological reaction to a primary EBV infection with suspected deregulation of T helper cell activity leads to severe coronary artery damage in early childhood.

A case-control study of recurrent Kawasaki disease using the database of the nationwide surveys in Japan

In spite of many reports of recurrent Kawasaki disease, little information about the risk factors associated with recurrence is available. We conducted a case-control study on 150 cases of recurrent Kawasaki disease and 1173 pair-matched controls selected from the database of nationwide surveys of the same disease in Japan. Items observed were: sex, age, use of intravenous gamma globulin, and cardiac sequelae at the first episode. Sex and cardiac sequelae did not affect the risk of recurrence. One- to 2-year-old children were more likely to be affected again than infants (odds ratio [OR] = 1.42; 95% confidence interval [CI], 0.94-2.13), and children who were 3 years of age or older were less likely to experience a recurrence than infants (OR = 0.59; 95% CI, 0.34-1.02). Intravenous gamma globulin therapy at the first episode increased the risk for recurrence of Kawasaki disease within 12 months (OR = 2.66, 95% CI, 1.06-6.66). However, it did not affect recurrences 12 months after the first episode (OR = 1.02; 95% CI, 0.53-1.97).

CONCLUSION

Patients with Kawasaki disease treated with intravenous gamma globulin are 2.66 times as likely to be affected by the disease again within 12 months as those treated without intravenous gamma globulin.

Incidence rate of recurrent Kawasaki disease in Japan

To calculate the incidence of recurrent Kawasaki disease and to discuss some potential risk factors for its recurrence, we observed a cohort consisting of those followed-up since the first episode of the disease. A total of 4560 persons, with 16,500.4 person-years were observed from the second month after the first episode of the disease to the end of 1989. The mean observation period was 3.62 years. The overall incidence rate was 5.21 per 1000 person-years, with a higher incidence within the 2 years from the first episode; although not statistically significant, the incidence was higher among males and those who experienced the first episode at < or = 2 years of age. The possibility of i.v. gamma globulin therapy being one of the risk factors was negated by a stratified analysis to control confounding factors but supported by univariate analysis.

Detection of Epstein-Barr virus DNA in cardiac and aortic tissues from chronic, active Epstein-Barr virus infection associated with Kawasaki disease-like coronary artery aneurysms

We describe three patients with chronic, active Epstein-Barr virus infection associated with Kawasaki disease-like coronary artery aneurysms. The Epstein-Barr virus genome was detected in three cardiac tissue samples and one aortic tissue sample examined by means of the polymerase chain reaction. These findings suggest that chronic Epstein-Barr virus infection may play a pathogenic role in the development of coronary artery aneurysms.

Kawasaki disease and Epstein-Barr virus

We report the results of virological (serological and molecular biological) studies of Epstein-Barr virus (EBV) in patients with Kawasaki disease (KD). Forty-nine (86%) of 57 Kawasaki disease patients and 15 (68%) of 22 patients with recurrent Kawasaki disease had serological evidence of primary Epstein-Barr virus infection during the first month after the onset of their disease based on the results of a sensitive method of detecting antibody to viral capsid antigen (VCA). The serological response to EBV was significantly low and transient. EBV sequences were identified directly in peripheral blood mononuclear cell (PBMC) DNA samples from 23 (56%) of 41 KD patients within 2 weeks after onset by means of the polymerase chain reaction (PCR). EBV sequences were also detected in 10 (83%) of 12 repeatedly tested KD patients within 3 months after onset. In contrast, only 7 (18%) of 40 control DNA samples were PCR-positive. These virological studies indicate that an unusual EBV-cell interaction may occur in KD.