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.

PurposeDuring the late autumn to winter season (October to December) in the Republic of Korea, respiratory syncytial virus (RSV) is the most common pathogen causing lower respiratory tract infections (LRTIs). Interestingly, in 2014, human coronavirus (HCoV) caused not only upper respiratory infections but also LRTIs more commonly than in other years. Therefore, we sought to determine the epidemiology, clinical characteristics, outcomes, and severity of illnesses associated with HCoV infections at a single center in Korea.Materials and MethodsWe retrospectively identified patients with positive HCoV respiratory specimens between October 2014 and December 2014 who were admitted to Severance Children’s Hospital at Yonsei University Medical Center for LRTI. Charts of the patients with HCoV infection were reviewed and compared with RSV infection.ResultsDuring the study period, HCoV was the third most common respiratory virus and accounted for 13.7% of infections. Coinfection was detected in 43.8% of children with HCoV. Interestingly, one patient had both HCoV-OC43 and HCoV-NL63. Mild pneumonia was most common (60.4%) with HCoV, and when combined with RSV, resulted in bronchiolitis. Two patients required care in the intensive care unit. However, compared with that of RSV infection, the disease course HCoV was short.ConclusionInfections caused by HCoVs are common, and can cause LRTIs. During an epidemic season, clinicians should be given special consideration thereto. When combined with other medical conditions, such as neurologic or cardiologic diseases, intensive care unit (ICU) care may be necessary.

Objectives Kawasaki disease (KD) is an acute systemic vasculitis of unknown aetiology that affects infants and young children. Recent reports of elevated serum high mobility group box 1 (HMGB1) level during the acute phase of KD and its relationship to poor response to IVIG treatment suggest a possible association of HMGB1 polymorphisms with KD. We investigated the association between the polymorphisms of the HMGB1 gene, KD susceptibility, coronary artery lesions, and KD response to IVIG treatment. Methods Whole genome sequencing of the HMGB1 gene was performed to identify causative variants. Two tagging single nucleotide polymorphisms of the HMGB1 gene were selected using linkage disequilibrium analysis. The tagging single nucleotide polymorphisms were genotyped using the TaqMan Allelic Discrimination assay in a total of 468 subjects (265 KD patients and 203 controls). Results The HMGB1 single nucleotide polymorphisms were not associated with KD susceptibility. However, in KD patients, there was a significant association of rs1412125 with coronary artery lesions formation in the recessive model (GG vs AA + GA: odds ratio = 4.98, 95% CI = 1.69–14.66, P = 0.005). In addition, rs1412125 was associated with IVIG resistance in the recessive (GG vs AA + GA: odds ratio = 4.11, 95% CI = 1.38–12.23, P = 0.017) and allelic models (G vs A: odds ratio = 1.80, 95% CI = 1.06–3.06, P = 0.027). Conclusion The rs1412125 in HMGB1 might be a risk factor for the development of coronary artery lesions and IVIG resistance in KD patients.