Identification of rare coding variants associated with Kawasaki disease by whole exome sequencing

Kawasaki disease (KD) is an acute pediatric vasculitis that affects genetically susceptible infants and children. To identify coding variants that influence susceptibility to KD, we conducted whole exome sequencing of 159 patients with KD and 902 controls, and performed a replication study in an independent 586 cases and 732 controls. We identified five rare coding variants in five genes (FCRLA, PTGER4, IL17F, CARD11, and SIGLEC10) associated with KD (odds ratio [OR], 1.18–4.41; p = 0.0027–0.031). We also performed association analysis in 26 KD patients with coronary artery aneurysms (CAAs; diameter > 5 mm) and 124 patients without CAAs (diameter < 3 mm), and identified another five rare coding variants in five genes (FGFR4, IL31RA, FNDC1, MMP8, and FOXN1), which may be associated with CAA (OR, 3.89–37.3; p = 0.0058–0.0261). These results provide insights into new candidate genes and genetic variants potentially involved in the development of KD and CAA.

IgA Levels Are Associated with Coronary Artery Lesions in Kawasaki Disease

Background and Objectives@#Kawasaki disease (KD) is an acute systemic vasculitis that affects the coronary arteries. Abnormal immune reactions are thought to contribute to disease pathogenesis. The effect of immunoglobulin (Ig) isotype (IgG, IgA, IgM, and IgE) on inflammatory data and clinical outcomes of patients with KD was examined. @*Methods@#Ig levels in 241 patients with KD were measured during the acute, subacute, convalescent, and normal phases of the disease. @*Results@#Compared with reference Ig values, IgG, IgA, and IgM levels were significantly higher in the subacute phase, while IgE levels were elevated in 73.9% (178/241) of patients with KD in all clinical phases. However, high IgE levels were not associated with clinical outcomes, including intravenous immunoglobulin unresponsiveness and coronary artery lesions (CALs).Significantly more CALs were observed in the high IgA group than in the normal IgA group (44.7% vs. 20.8%, respectively; p<0.01). In addition, IgA levels in the acute phase (p=0.038) were 2.2-fold higher, and those in the subacute phase were 1.7-fold higher (p <0.001), in the CAL group than in the non-CAL group. IgA concentrations increased along with the size of the coronary artery aneurysm (p <0.001). Furthermore, there was a strong correlation between IgA levels and CAL size (r=0.435, p<0.001), with a high odds ratio of 2.58 (p=0.022). @*Conclusions@#High IgA levels in patients with KD are prognostic for the risk of CALs.

IgA Levels Are Associated with Coronary Artery Lesions in Kawasaki Disease

Background and Objectives@#Kawasaki disease (KD) is an acute systemic vasculitis that affects the coronary arteries. Abnormal immune reactions are thought to contribute to disease pathogenesis. The effect of immunoglobulin (Ig) isotype (IgG, IgA, IgM, and IgE) on inflammatory data and clinical outcomes of patients with KD was examined. @*Methods@#Ig levels in 241 patients with KD were measured during the acute, subacute, convalescent, and normal phases of the disease. @*Results@#Compared with reference Ig values, IgG, IgA, and IgM levels were significantly higher in the subacute phase, while IgE levels were elevated in 73.9% (178/241) of patients with KD in all clinical phases. However, high IgE levels were not associated with clinical outcomes, including intravenous immunoglobulin unresponsiveness and coronary artery lesions (CALs).Significantly more CALs were observed in the high IgA group than in the normal IgA group (44.7% vs. 20.8%, respectively; p<0.01). In addition, IgA levels in the acute phase (p=0.038) were 2.2-fold higher, and those in the subacute phase were 1.7-fold higher (p <0.001), in the CAL group than in the non-CAL group. IgA concentrations increased along with the size of the coronary artery aneurysm (p <0.001). Furthermore, there was a strong correlation between IgA levels and CAL size (r=0.435, p<0.001), with a high odds ratio of 2.58 (p=0.022). @*Conclusions@#High IgA levels in patients with KD are prognostic for the risk of CALs.

Etiology and treatment of chest pain in children and adolescents

Chest pain is a very common symptom in pediatric patients. Although children with chest pain are relatively unlikely to be suffering from significant cardiac diseases, it is important not to overlook life-threatening diseases. Complete history taking and physical examination––which involves identifying the duration of pain, onset, character, associated symptoms, and aggravating factors––are extremely important. The most common causes of pediatric chest pain are idiopathic and musculoskeletal, while less than 3% of cases are of cardiac origin. Recent studies indicate that chest pain resulted from psychosomatic disorders increases in non-cardiac chest pain in children and adolescents. The reassurance of the benign nature of chest pain is enough in most cases of non-cardiac chest pain in children and adolescents. When echocardiography is performed on patients with exertional chest pain, it is important to confirm the origin of coronary artery to exclude any coronary anomaly. Exertional chest pain, combined syncope, and symptoms of myocardial ischemia should raise the suspicion of significant cardiac diseases. When the chest pain is accompanied by red flag signs, physicians must refer the patients to a pediatric cardiologist.

Infliximab Treatment for Intravenous Immunoglobulin-resistant Kawasaki Disease: a Multicenter Study in Korea

BACKGROUND AND OBJECTIVES: We investigated the status of infliximab use in intravenous immunoglobulin (IVIG)-resistant Kawasaki disease (KD) patients and the incidence of coronary artery aneurysms (CAAs) according to treatment regimens. METHODS: Between March 2010 and February 2017, 16 hospitals participated in this study. A total of 102 (32.3±19.9 months, 72 males) who received infliximab at any time after first IVIG treatment failure were enrolled. Data were retrospectively collected using a questionnaire. RESULTS: Subjects were divided into two groups according to the timing of infliximab administration. Early treatment (group 1) had shorter fever duration (10.5±4.4 days) until infliximab infusion than that in late treatment (group 2) (16.4±4.5 days; p 5). Overall response rate to infliximab was 89/102 (87.3%) and the incidence of significant CAA was lower in group 1 than in group 2 (1/42 [2.4%] vs. 17/60 [28.3%], p < 0.001). CONCLUSIONS: This study suggests that the early administration of infliximab may reduce the incidence of significant CAA in patients with IVIG-resistant KD. However, further prospective randomized studies with larger sample sizes are required.

Assessment of the Clinical Heterogeneity of Kawasaki Disease Using Genetic Variants of BLK and FCGR2A

BACKGROUND AND OBJECTIVES: Patients with Kawasaki disease (KD) are clinically heterogeneous because its diagnosis is based solely on clinical observation and there are no definitive biomarkers. We dissected the clinical heterogeneity of KD patients using the KD-associated genetic variants. METHODS: We performed a genetic association analysis in several KD subgroups categorized by clinical characteristics using the KD-associated variants of the B lymphoid tyrosine kinase (BLK; rs6993775) and Fc gamma receptor II a (FCGR2A; rs1801274) in a large number of case (n=1,011) and control (n=4,533) samples. RESULTS: BLK and FCGR2A were very significantly associated with KD in Korean KD patients (odds ratio [OR],1.48; p=4.63×10⁻¹¹ for BLK, and OR, 1.26; p=1.42×10⁻⁴ for FCGR2A). However, in KD subgroup analysis, we found that neither BLK nor FCGR2A were associated with either incomplete Kawasaki disease (iKD) type patients or those older than 5 years of age (p>0.2), suggesting that patients with iKD or those older than 5 years of age are a unique subgroup of KD. In genetic association analysis after excluding iKD patients and those older than 5 years old, we found that BLK was associated with all KD subgroups, whereas FCGR2A was specifically associated with male KD patients younger than 1 year of age (OR, 2.22; p=2.35×10⁻⁵). CONCLUSIONS: KD is a clinically and genetically heterogeneous disease. These findings will provide new insights into the clinical and genetic heterogeneity of KD.

Assessment of the Clinical Heterogeneity of Kawasaki Disease Using Genetic Variants of BLK and FCGR2A

BACKGROUND AND OBJECTIVES@#Patients with Kawasaki disease (KD) are clinically heterogeneous because its diagnosis is based solely on clinical observation and there are no definitive biomarkers. We dissected the clinical heterogeneity of KD patients using the KD-associated genetic variants.@*METHODS@#We performed a genetic association analysis in several KD subgroups categorized by clinical characteristics using the KD-associated variants of the B lymphoid tyrosine kinase (BLK; rs6993775) and Fc gamma receptor II a (FCGR2A; rs1801274) in a large number of case (n=1,011) and control (n=4,533) samples.@*RESULTS@#BLK and FCGR2A were very significantly associated with KD in Korean KD patients (odds ratio [OR],1.48; p=4.63×10⁻¹¹ for BLK, and OR, 1.26; p=1.42×10⁻⁴ for FCGR2A). However, in KD subgroup analysis, we found that neither BLK nor FCGR2A were associated with either incomplete Kawasaki disease (iKD) type patients or those older than 5 years of age (p>0.2), suggesting that patients with iKD or those older than 5 years of age are a unique subgroup of KD. In genetic association analysis after excluding iKD patients and those older than 5 years old, we found that BLK was associated with all KD subgroups, whereas FCGR2A was specifically associated with male KD patients younger than 1 year of age (OR, 2.22; p=2.35×10⁻⁵).@*CONCLUSIONS@#KD is a clinically and genetically heterogeneous disease. These findings will provide new insights into the clinical and genetic heterogeneity of KD.

Infliximab Treatment for Intravenous Immunoglobulin-resistant Kawasaki Disease: a Multicenter Study in Korea

BACKGROUND AND OBJECTIVES@#We investigated the status of infliximab use in intravenous immunoglobulin (IVIG)-resistant Kawasaki disease (KD) patients and the incidence of coronary artery aneurysms (CAAs) according to treatment regimens.@*METHODS@#Between March 2010 and February 2017, 16 hospitals participated in this study. A total of 102 (32.3±19.9 months, 72 males) who received infliximab at any time after first IVIG treatment failure were enrolled. Data were retrospectively collected using a questionnaire.@*RESULTS@#Subjects were divided into two groups according to the timing of infliximab administration. Early treatment (group 1) had shorter fever duration (10.5±4.4 days) until infliximab infusion than that in late treatment (group 2) (16.4±4.5 days; p 5). Overall response rate to infliximab was 89/102 (87.3%) and the incidence of significant CAA was lower in group 1 than in group 2 (1/42 [2.4%] vs. 17/60 [28.3%], p < 0.001).@*CONCLUSIONS@#This study suggests that the early administration of infliximab may reduce the incidence of significant CAA in patients with IVIG-resistant KD. However, further prospective randomized studies with larger sample sizes are required.

Circular RNA as a Possible Novel Biomarker for Kawasaki Disease

No abstract available.

Can iron be a risk factor for coronary lesions in Kawasaki disease? / 소아과

No abstract available.

High antistreptolysin O titer is associated with coronary artery lesions in patients with Kawasaki disease / 소아과

PURPOSE: In Kawasaki disease (KD) patients, coronary artery complications, incomplete and refractory types occur more frequently in patients with streptococcal or other bacterial/viral infections. Recently, we observed a higher incidence of coronary lesions in KD patients with high anti-streptolysin O (ASO) titer. Therefore, we hypothesized that KD patients diagnosed with concurrent streptococcal infection have poor prognoses, with respect to treatment response and development of coronary artery lesions. METHODS: A retrospective review was performed in 723 patients with KD who were admitted to 2 major hospitals between June 2010 and September 2017. RESULTS: Among 723 patients with KD, 11 initially showed an elevated ASO titer (>320 IU/mL) or elevated follow-up ASO titer after treatment. Of these patients, 5 showed no response to the first intravenous immunoglobulin treatment, 3 had abnormalities of the coronary arteries. This is a significantly higher proportion of patients with a high ASO titer (n=3, 27.3%) than those with a normal ASO titer (n=53 [7.4%], P=0.047). A severe clinical course was seen in 81.8% of patients in the high ASO group versus 14.5% of patients in the normal ASO group. CONCLUSION: It is not certain whether acute streptococcal infection may cause KD, but this study revealed that KD with high ASO titers showed higher rates of severe clinical course. It may be helpful to analyze concurrent streptococcal infection in patients with a severe clinical course.

New Therapeutic Target for Pulmonary Arterial Hypertension

No abstract available.

Identification of LEF1 as a Susceptibility Locus for Kawasaki Disease in Patients Younger than 6 Months of Age

Kawasaki disease (KD) is an acute febrile vasculitis predominately affecting infants and children. The dominant incidence age of KD is from 6 months to 5 years of age, and the incidence is unusual in those younger than 6 months and older than 5 years of age. We tried to identify genetic variants specifically associated with KD in patients younger than 6 months or older than 5 years of age. We performed an age-stratified genome-wide association study using the Illumina HumanOmni1-Quad BeadChip data (296 cases vs. 1,000 controls) and a replication study (1,360 cases vs. 3,553 controls) in the Korean population. Among 26 candidate single nucleotide polymorphisms (SNPs) tested in replication study, only a rare nonsynonymous SNP (rs4365796: c.1106C>T, p.Thr369Met) in the lymphoid enhancer binding factor 1 (LEF1) gene was very significantly associated with KD in patients younger than 6 months of age (odds ratio [OR], 3.07; p(combined) = 1.10 × 10⁻⁵), whereas no association of the same SNP was observed in any other age group of KD patients. The same SNP (rs4365796) in the LEF1 gene showed the same direction of risk effect in Japanese KD patients younger than 6 months of age, although the effect was not statistically significant (OR, 1.42; p = 0.397). This result indicates that the LEF1 gene may play an important role as a susceptibility gene specifically affecting KD patients younger than 6 months of age.

Multicenter, Single-Arm, Phase IV Study of Combined Aspirin and High-Dose “IVIG-SN” Therapy for Pediatric Patients with Kawasaki Disease

BACKGROUND AND OBJECTIVES: Intravenous immunoglobulin-SN (IVIG-SN) is a new human immunoglobulin product. Its safety is ensured by pathogen-elimination steps comprising solvent/detergent treatment and a nanofiltration process. This multicenter clinical study was designed to evaluate the efficacy and safety of combined aspirin and high-dose IVIG-SN therapy in pediatric patients with Kawasaki disease (KD). SUBJECTS AND METHODS: We evaluated coronary artery lesions (CALs) at 2 and 7 weeks after administering IVIG-SN; total fever duration; and variations in erythrocyte sedimentation rate, N-terminal pro B-type natriuretic peptide or B-type natriuretic peptide, and creatine kinase-myocardial band level before and after treatment with IVIG-SN (2 g/kg). Adverse events were monitored. RESULTS: Forty-five patients were enrolled, three of whom were excluded according to the exclusion criteria; the other 42 completed the study. The male:female ratio was 0.91:1, and the mean age was 29.11±17.23 months. The mean fever duration before IVIG-SN treatment was 6.45±1.30 days. Although most patients had complete KD (40 patients, 90.91%), four had atypical KD (9.09%). After IVIG-SN treatment, one patient (2.38%) had CALs, which was significantly lower than the incidence reported previously (15%) (p=0.022), but not significantly different from recent data (5%). There were no serious adverse events, though 28 patients (63.64%) had mild adverse events. Three adverse drug reactions occurred in 2 patients (eczema, anemia, and increased eosinophil count), all of which were transient. CONCLUSION: IVIG-SN treatment in patients with KD was safe and effective.

Mycoplasma Infection as a cause of Persistent Fever after Intravenous Immunoglobulin Treatment of Patients with Kawasaki Disease: Frequency and Clinical Impact / 감염과화학요법

BACKGROUND: Mycoplasma is a common cause of respiratory infections and may require differential diagnosis from Kawasaki disease (KD). In this study, we investigated the frequency and clinical manifestations of mycoplasma infection in patients with KD. MATERIALS AND METHODS: Medical records of 375 in-patients admitted for treatment during the acute stage of KD, were collected, and reviewed retrospectively. Of these patients, 152 (40.5%) were also tested for recent mycoplasma infection. Patients with positive results (anti-mycoplasma IgM Ab >1:640 or cold agglutinin >1:64) were designated as the case group (n = 37, 24.3%) whereas those with negative results were designated as the control group (n = 115, 75.7%). Clinical findings of the two groups were compared. RESULTS: Patients in the case group were older than those in the control group (mean age, 48.2 ± 32.1 months, vs. 31.7 ± 21.7 months; P = 0.001). There were significant differences between the case and control groups in the changes in the extremities (78.3% vs. 57.4%, respectively; P = 0.031), and in fever duration (6.5 ± 2.5 days vs. 5.4 ± 1.5 days; P = 0.047). Of the 37 patients with positive mycoplasma testing, 7 (18.9%) had persistent fever even after the symptoms and signs of systemic inflammation (acute phase of KD) had been resolved. These patients were positive for mycoplasma infection during further evaluation of persistent fever, and all of them responded to macrolide antibiotics. CONCLUSIONS: We found that mycoplasma infection is somewhat related to KD. When fever persists after resolution of the acute stage of KD, mycoplasma infection may be considered as a possible cause of fever in preschool-aged children.

Severe Skin Lesions or Arthritis May be Associated with Coronary Artery Lesions in Kawasaki Disease

PURPOSE: Kawasaki disease (KD) shows a variety of clinical signs of multi-system involvement, including clinical diagnostic criteria. It is unknown that the severity of the clinical signs is associated with the risk of coronary artery lesions (CALs). We wanted to evaluate clinical characteristics and the risk of CALs in the patient groups who had severe skin lesions or those with arthritis. METHODS: We retrospectively reviewed the medical records of 220 KD patients who were treated with intravenous immunoglobulin (IVIG). We compared clinical and laboratory data between the group with severe skin lesions (n=52) and those with mild or no skin lesions (n=168), and between the group with arthritis (n=6) and those without arthritis (n=214). RESULTS: The mean age of total patients was 2.23±1.87 years of age, and the male-to-female ratio was 1.5:1 (138/82). Among 220 patients, 52 patients had CALs (23.6%), and 29 patients (13.2%) showed incomplete KD. The patients with CALs had a higher mean age, longer total fever duration, and higher rate of IVIG non-responsiveness. The patient group with severe skin lesions showed a higher mean age (P<0.001), more prolonged fever duration (P=0.041), higher frequency of CALs (P=0.033), higher WBC, neutrophil, and neutrophil-to-lymphocyte ratio levels, compared to the patient group without severe skin lesions. The patients with arthritis had a tendency of further treatment with methylprednisolone or infliximab. CONCLUSIONS: The frequency of CALs was higher in patient group with severe skin lesions. Our results suggest that the intensity of clinical signs of KD such as skin rash, cervical lymphadenopathy and possibly arthritis may be associated the risk of CALs.

Analysis of clinical characteristics and causes of chest pain in children and adolescents / 소아과

PURPOSE: Chest pain is common in children and adolescents and is a reason for referral to pediatric cardiologists. Although most cases of chest pain in these age groups are benign and do not require treatment, timely diagnosis is important not to miss life-threatening diseases requiring prompt treatment. We investigated certain clinical characteristics that may be useful in the diagnosis of such critical diseases. METHODS: Patient medical records between July 2006 and September 2013 were retrospectively examined. We included 517 patients who presented with chest pain to the Department of Pediatrics at Kyung Hee University Hospital in Gangdong. RESULTS: Most cases of chest pain were idiopathic in origin (73.6%), followed by cases with respiratory (9.3%), musculoskeletal (8.8%), cardiac (3.8%), gastrointestinal (2.9%), and psychiatric (1.4%) causes. In 6 patients (1.2%) with air-leak syndrome including pneumothorax or pneumomediastinum, the pain was abrupt, continuous, and lasted for a short period of 1-2 days after onset in the older adolescents. Of the patients with cardiac pain, 13 had cardiac arrhythmias (65.0%), 6 had congenital heart diseases (30%), and 1 had coronary aneurysms caused by Kawasaki disease (5.0%). One patient with atrial flutter had only symptoms of syncope and chest pain. CONCLUSION: The abrupt, continuous chest pain of a short duration in the older children was characteristic of air-leak syndrome. In patients with pneumomediastinum, radiological diagnosis was difficult without careful examination. Combined syncope should not be neglected and further cardiac workup is essential in such patients.

Comparison of growth and pubertal progression in wild type female rats with different bedding types

PURPOSE: Endocrine-disrupting chemicals interfere with the endocrine system and therefore affect growth and pubertal progression. The study aim was to compare the growth and pubertal progression in wild-type female rats with different bedding types. METHODS: Twenty 5-week-old female wild-type Sprague Dawley rats were randomly assigned to two groups with different bedding types: one group received wood shaving bedding, while a second group received corncob bedding. We determined crown-rump length and body weight as anthropometric measurements and assessed the serum growth hormone (GH) and estradiol levels. The gh1 mRNA expression levels were compared using quantitative real time transcription polymerase chain reaction. The estrous cycle was evaluated by vaginal smear. RESULTS: The anthropometric measurements were not significantly different between the two groups. The mean relative expression of the gh1 gene was lower in the corncob bedding group than that in the wood shaving group (P=0.768). Meanwhile serum GH and estradiol were increased in the wood shaving bedding group; however this difference was not statistically significant. The time to first estrus and the length of the estrous cycle were increased in the corncob bedding group; the proportion of normal estrous cycles was also decreased. These findings indicate irregularities in the estrous cycle. CONCLUSION: Endocrine-disrupting chemicals in corncob bedding might be associated with time to first estrus and length of the estrous cycle. Therefore, the type of bedding should be considered as a factor affecting pubertal progression in rodents.

Consortium-Based Genetic Studies of Kawasaki Disease in Korea: Korean Kawasaki Disease Genetics Consortium

In order to perform large-scale genetic studies of Kawasaki disease (KD) in Korea, the Korean Kawasaki Disease Genetics Consortium (KKDGC) was formed in 2008 with 10 hospitals. Since the establishment of KKDGC, there has been a collection of clinical data from a total of 1198 patients, and approximately 5 mL of blood samples per patient (for genomic deoxyribonucleic acid and plasma isolation), using a standard clinical data collection form and a nation-wide networking system for blood sample pick-up. In the clinical risk factor analysis using the collected clinical data of 478 KD patients, it was found that incomplete KD type, intravenous immunoglobulin (IVIG) non-responsiveness, and long febrile days are major risk factors for coronary artery lesions development, whereas low serum albumin concentration is an independent risk factor for IVIG non-responsiveness. In addition, we identified a KD susceptibility locus at 1p31, a coronary artery aneurysm locus (KCNN2 gene), and the causal variant in the C-reactive protein (CRP) promoter region, as determining the increased CRP levels in KD patients, by means of genome-wide association studies. Currently, this consortium is continually collecting more clinical data and genomic samples to identify the clinical and genetic risk factors via a single nucleotide polymorphism chip and exome sequencing, as well as collaborating with several international KD genetics teams. The consortium-based approach for genetic studies of KD in Korea will be a very effective way to understand the unknown etiology and causal mechanism of KD, which may be affected by multiple genes and environmental factors.

Update of genetic susceptibility in patients with Kawasaki disease / 소아과

Kawasaki disease (KD) is an acute systemic vasculitis that predominantly affects children, and can result in coronary artery lesions (CAL). A patient with KD who is resistant to treatment with intravenous immunoglobulin (IVIG) has a higher risk of developing CAL. Incomplete KD has increased in prevalence in recent years, and is another risk factor for the development of CAL. Although the pathogenesis of KD remains unclear, there has been increasing evidence for the role of genetic susceptibility to the disease since it was discovered in 1967. We retrospectively reviewed previous genetic research for known susceptibility genes in the pathogenesis of KD, IVIG resistance, and the development of CAL. This review revealed numerous potential susceptibility genes including genetic polymorphisms of ITPKC, CASP3, the transforming growth factor-beta signaling pathway, B lymphoid tyrosine kinase, FCGR2A, KCNN2, and other genes, an imbalance of Th17/Treg, and a range of suggested future treatment options. The results of genetic research may improve our understanding of the pathogenesis of KD, and aid in the discovery of new treatment modalities for high-risk patients with KD.