Shoichi Shibuta

A genome-wide association study identifies three new risk loci for Kawasaki disease

We performed a genome-wide association study (GWAS) of Kawasaki disease in Japanese subjects using data from 428 individuals with Kawasaki disease (cases) and 3,379 controls genotyped at 473,803 SNPs. We validated the association results in two independent replication panels totaling 754 cases and 947 controls. We observed significant associations in the FAM167A-BLK region at 8p22-23 (rs2254546, P = 8.2 × 10−21), in the human leukocyte antigen (HLA) region at 6p21.3 (rs2857151, P = 4.6 × 10−11) and in the CD40 region at 20q13 (rs4813003, P = 4.8 × 10−8). We also replicated the association of a functional SNP of FCGR2A (rs1801274, P = 1.6 × 10−6) identified in a recently reported GWAS of Kawasaki disease. Our findings provide new insights into the pathogenesis and pathophysiology of Kawasaki disease.

Cyclosporin A treatment for Kawasaki disease refractory to initial and additional intravenous immunoglobulin.

Background: There are still no definite treatments for refractory Kawasaki disease (KD). In this pilot study, we evaluated the use of cyclosporin A (CyA) treatment in patients with refractory KD. Methods: We prospectively collected clinical data of CyA treatment (4–8 mg/kg/d, oral administration) for refractory KD patients using the same protocol among several hospitals. Refractory KD is defined as the persistence or recurrence of fever (37.5°C or more of an axillary temperature) at the end of the second intravenous immunoglobulin (2 g/kg) following the initial one. Results: Subjects were enrolled out of 329 KD patients who were admitted to our 8 hospitals between January 2008 and June 2010. Among a total of 28 patients of refractory KD treated with CyA, 18 (64.3%) responded promptly to be afebrile within 3 days and had decreased C-reactive protein levels, the other 4 became afebrile within 4 to 5 days. However, 6 patients (21.4%) failed to become afebrile within 5 days after the start of CyA and/or high fever returned after becoming afebrile within 5 days. Although hyperkalemia developed in 9 patients at 3 to 7 days after the start of CyA treatment, there were no serious adverse effects such as arrhythmias. Four patients (1.2%), 2 before and the other 2 after the start of CyA treatment, developed coronary arterial lesions. Conclusion: CyA treatment is considered safe and well tolerated, and a promising option for patients with refractory KD. Further investigations will be needed to clarify optimal dose, safety, and timing of CyA treatment.

ITPKC and CASP3 polymorphisms and risks for IVIG unresponsiveness and coronary artery lesion formation in Kawasaki disease

Functional single-nucleotide polymorphisms (SNPs) in inositol 1,4,5-trisphosphate 3-kinase C (ITPKC) (rs28493229) and caspase-3 (CASP3) (rs113420705; formerly rs72689236) are associated with susceptibility to Kawasakis disease (KD). To evaluate the involvement of these 2 SNPs in the risk for intravenous immunoglobulin (IVIG) unresponsiveness, we investigated 204 Japanese KD patients who received a single IVIG dose of 2 g kg−1 (n=70) or 1 g kg−1 daily for 2 days (n=134). The susceptibility allele of both SNPs showed a trend of overrepresentation in IVIG non-responders and, in combined analysis of these SNPs, patients with at least 1 susceptible allele at both loci had a higher risk for IVIG unresponsiveness (P=0.0014). In 335 prospectively collected KD patients who were treated with IVIG (2 g kg−1), this 2-locus model showed a more significant association with resistance to initial and additional IVIG (P=0.011) compared with individual SNPs. We observed a significant association when all KD patients with coronary artery lesions were analyzed with the 2-locus model (P=0.0031). Our findings strongly suggest the existence of genetic factors affecting patients’ responses to treatment and the risk for cardiac complications, and provide clues toward understanding the pathophysiology of KD inflammation.

Detection of Multiple Superantigen Genes in Stools of Patients with Kawasaki Disease

OBJECTIVES To investigate whether superantigens (SAgs) are involved in the development of Kawasaki disease (KD) by examining SAg genes in the stool of patients with KD. STUDY DESIGN Stool specimens were obtained from 60 patients with KD and 62 age-matched children (36 children with acute illness and 26 healthy children). Total DNA was extracted from these stool samples. Using polymerase chain reaction, we examined genes of 5 SAgs: streptococcal pyrogenic exotoxin-A (SPE-A), SPE-C, SPE-G, SPE-J, and toxic shock syndrome toxin-1. RESULTS At least 1 of the 5 SAg genes was detected in 42 (70%) specimens from patients with KD, 14 (38.9%) from the febrile group, and 7 (26.9%) from the healthy group. The detection rate between subjects with and without KD was of at least 1 of the 5 SAg genes (P < .001), and more than 2 SAg genes were significantly different (P = .002). CONCLUSIONS SAg may be involved in the development of KD; data suggest that multiple SAgs may trigger KD.

Inflammatory cytokine profiles during Cyclosporin treatment for immunoglobulin-resistant Kawasaki disease

BACKGROUND Kawasaki disease (KD) is an acute systemic vasculitis occurring in medium-sized arteries, especially coronary arteries. Patients with KD who fail to respond to standard therapy with intravenous immunoglobulin (IVIG) face a higher risk of developing coronary artery lesions. Cyclosporin A (CsA) is one treatment option for IVIG-resistant KD. However, the mechanism of its suppression of inflammation in patients with KD remains unknown. METHODS AND RESULTS We analyzed time-line profiles of multiple inflammatory cytokines in sera of 19 patients treated with CsA (4 mg/kg/day, p.o., 14 days) after additional IVIG. Trough concentration of CsA in blood was maintained between 60 and 200 ng/ml. We examined serum samples before, on day 7, and at the end (day 14) of CsA treatment. Assays were conducted using a Milliplex kit®. Fourteen patients responded to CsA and became afebrile within 5 days (Responders), although five patients were regarded as Non-responders. Serum transitional levels of IL-6 (p<0.001), sIL-2R (p<0.001), sTNFRII (p<0.001), and G-CSF (p<0.001) reflect disease severity. In Non-responders, average levels of IL-6 at day 7 (43.5 vs. 13.8 pg/ml, p<0.001) and average levels of sIL-2R at day 14 (21.3 vs. 3.31 pg/ml, p=0.014) were significantly higher than those in Responders. CONCLUSION CsA treatment effectively reduced the persisting serum inflammatory cytokines in most of the IVIG-resistant KD patients. Soluble IL-2R suppression implies a mechanism explaining the effects of CsA.

Marker of T‐cell activation is elevated in refractory Kawasaki disease

Background:  The aim of this study was to investigate whether T‐cell activation is involved in the pathogenesis of Kawasaki disease (KD) resistant to intravenous immunoglobulin (IVIG) treatment.

Variations in ORAI1 Gene Associated with Kawasaki Disease

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

Epidemiologic features and prognostic factors of coronary artery lesions associated with Kawasaki disease based on a 13-year cohort of consecutive cases identified by complete enumeration surveys in Wakayama, Japan.

Background To clarify the contribution of patient age to the development of coronary artery lesions (CALs) associated with Kawasaki disease (KD), epidemiologic features and prognostic factors were investigated using hospital-based complete enumeration surveys in a specific area. Methods Consecutive KD cases identified between October 1999 and September 2012 in Wakayama Prefecture, Japan, were analyzed. The primary outcome measure was the presence/absence of CALs (giant aneurysm, mid- or small-sized aneurysm, and dilatation) on echocardiography 1 month after disease onset. Demographics and medical treatment factors were compared between the patients with and without CALs. Odds ratios (ORs) and 95% confidence intervals (CIs) of explanatory variables (age, gender, and factors related to high-dose intravenous immunoglobulin treatment) for the development of CALs were determined. Results The median age of the 1415 patients (796 males, 619 females) was 25 months after excluding 2 children of foreign residents; 2.2% of the patients had a past history of KD, and 1.8% showed incomplete presentation. CALs were observed in 3.3% (4.0% of males, 2.3% of females; P = 0.080). The ORs of CALs among patients <11 months old (3.0, 95% CI 1.4–6.6) and those >48 months old (3.1, 95% CI 1.5–6.6) were significantly higher than values in 11- to 48-month-olds. Conclusions The effect of patient age on the development of CALs was found to be U-shaped, with the bottom at ages 11 to 48 months. This finding was based on a 13-year cohort of consecutive KD cases in a specific area with little selection bias and is consistent with previously reported results.

Evaluation of Coronary Arterial Lesions Due to Kawasaki Disease Using Optical Coherence Tomography

Optical coherence tomography (OCT) is a high-resolution intracoronary arterial imaging modality. We describe 2 patients who were admitted to undergo coronary angiography and OCT for follow-up of Kawasaki disease with coronary artery aneurysms. OCT clearly demonstrated thrombus, stenosis, fibrotic intimal thickening with lamellar calcification, and partial disappearance of the tunica media at the aneurysm site. In addition, focal calcification, intimal thickening, and medial irregularity were observed even in regions of coronary arterial walls that appeared to be normal using coronary angiography. OCT is useful for evaluating coronary arterial sequelae of Kawasaki disease.

Water retention in the acute phase of Kawasaki disease: relationship between oedema and the development of coronary arterial lesions

Despite intravenous immunoglobulin therapy, a certain percentage of patients with Kawasaki disease (KD) still develop coronary arterial lesions (CAL). In an effort to find new combined therapies to reduce the incidence of CAL, we focused on the oedema which can be an important sign of the increased vascular permeability in KD. A total of 127 patients with KD were included in the retrospective study. Serial weekly changes in serum sodium and albumin levels from the 1st to the 4th week of illness were examined. In addition, the maximum rate of increase in body weight from admission to the 14th day of illness was evaluated. Serum sodium levels (mEq/l) in only the 2nd week of illness were significantly lower in patients with CAL than in those without CAL (mean ± SD, 135.5±4.5 versus 138.0±2.4, P <0.05). Serum albumin levels in all 4 weeks were significantly lower in patients with CAL than in those without CAL ( P <0.001). The maximum rate (%) of increase in body weight from admission to the 14th day of illness was significantly higher in patients with CAL than in those without CAL (ranges and median values, 0–12.3 (7.0) versus 0–10.3 (3.2), P <0.001). Conclusion:these results suggest that water retention in the acute phase of Kawasaki disease may be a risk factor for CAL, and water intake of both infusion and oral intake should be kept to a minimum in order to avoid progressive oedema.