Takafumi Honda

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.

Prognostic Impact of Vascular Leakage in Acute Kawasaki Disease

Background Increased microvascular permeability is an initial step of Kawasaki disease (KD). We reported that vascular endothelial growth factor (VEGF) might play a role in the vascular leakage of KD. In fatal KD, plasma leakage was extensively documented at VEGF‐positive microvessels. Increases in vascular leakage cause hypoalbuminemia and noncardiogenic edema. However, the prognostic impact of vascular leakage in KD remains unclear. Methods and Results We compared 76 patients who became afebrile within 5 days after starting intravenous gamma globulin (IVGG) (2 g/kg over 5 days) (IVGG‐responsive) with 27 patients who did not respond (IVGG‐resistant). Baseline levels of serum VEGF and albumin were similar between the groups. After IVGG, VEGF levels increased (P<0.0001) and albumin levels decreased (P<0.00001) in both groups. However, the IVGG‐resistant group had higher VEGF levels (P=0.029) and severe hypoalbuminemia (P<0.00001) compared with the IVGG‐responsive group. Coronary aneurysms were documented in 12 patients from the IVGG‐resistant group but not in the IVGG‐responsive group. Then IVGG‐resistant patients were divided into 2 subgroups according to the presence (n=12) or absence (n=15) of coronary aneurysms. There was no difference between subgroups in age, sex, laboratory data including albumin, and retreated doses of IVGG. However, body weight gain after IVGG was documented in patients who subsequently developed coronary aneurysms (P=0.003) but not in those who did not (P=0.967). Conclusions These results suggest that vascular leakage may be a key feature of KD pathophysiology. The present study may provide better insights into the pathogenesis and treatment of patients resistant to IVGG in acute KD. (Circulation. 2003;108:325‐330.)

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.

Alleviation of Myocardial Ischemia After Kawasaki Disease by Heparin and Exercise Therapy

Background—Heparin promotes angiogenesis. We evaluated the effects of combined treatment with heparin and exercise on myocardial ischemia in the chronic stage of Kawasaki disease. Methods and Results—This study was conducted in 7 patients (aged 6 to 19 years) who had a totally occluded coronary artery and stress-induced myocardial ischemia in the collateral-dependent areas. Twice-daily exercise using a bicycle ergometer was performed with increments of 0.5 W/kg every 3 minutes up to maximal exertion for 10 days. Heparin, which immediately increased circulating hepatocyte growth factor, was given intravenously 10 minutes before each exercise period. Newly developed myocardial infarction, ventricular tachyarrhythmia, anginal attack, or hemorrhagic complication was not observed in any patient. Dipyridamole-loading single photon emission computed tomography documented improved myocardial perfusion in the collateral-dependent areas and a significant reduction in total defect scores in all patients after the completion of 20 sessions (P =0.01). In control patients who did not receive the heparin-exercise therapy, however, stress defect scores remained unchanged (n=1) or increased (n=2) during follow-up. Computerized quantitative coronary angiography provided evidence that the heparin-exercise therapy increased the diameter of the occluded artery to which collaterals terminated (P =0.001) but not that of the reference artery with which collaterals were not connected (P =0.96). Conclusions—The findings suggest that a series of heparin and exercise treatments over 10 days may have a dramatic effect on the alleviation of myocardial ischemia in collateral-dependent regions. This may be a safe, noninvasive revascularization therapy for patients with coronary artery occlusion in the chronic stage of Kawasaki disease.

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.

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.

Early induction of interleukin‐5 and peripheral eosinophilia in acute pneumonia in Japanese children infected by pandemic 2009 influenza A in the Tokyo area

A novel influenza A (2009 H1N1) virus has led to a worldwide pandemic. A significant number of patients with pneumonia have been reported, although its pathogenesis remains to be elucidated. To determine its pathogenesis, we evaluated serum interleukin (IL)‐5 and peripheral eosinophil counts in patients with acute pneumonia caused by the 2009 H1N1 virus. During the period from October to December 2009, 40 patients with laboratory‐confirmed 2009 H1N1 pneumonia were under investigation. Their mean age at presentation was 6.8 years. The most characteristic finding was the early development of hypoxemic respiratory distress in the first 24 hr after the onset of fever. Bronchial mucous plugs included eosinophils in addition to neutrophils, even in patients without allergies. Serum IL‐5 levels were elevated in 20 out of 24 patients (83%) whose samples were obtained in the first 24 hr after the onset of fever (26.5 ± 20.1 pg/mL), independent of the presence of underlying allergies. In contrast, induction of IL‐5 was not documented in sera from eight patients with laboratory‐confirmed 2009 H1N1 virus who developed neurological complications, but without lower respiratory infection (2.1 ± 0.7 pg/mL, P < 0.001 vs acute pneumonia). Peripheral eosinophilia was characteristic in acute pneumonia, but not in patients without a lower respiratory infection. There was a marked difference in the induction of IL‐5 in 2009 H1N1 patients who developed acute pneumonia, compared with those without a lower respiratory infection. IL‐5 may play a role in the early phase of acute pneumonia caused by the 2009 H1N1 virus in Japanese children.

WU polyomavirus detected in respiratory tract specimens from young children in Japan

Polyomaviruses (PyV) WU and KI are reportedly associated with respiratory tract disease (RTD) worldwide but their incidence is unclear in Japan. In a 2 year prospective study, WU/KIPyV were detected in 48 (13.9%) and in five (1.4%) of 345 children hospitalized with lower RTD, respectively. The seasonal distribution was observed in spring and early summer. Other respiratory viruses were co‐detected in 51% of PyV‐positive patients, but eight (2.3%) of the WUPyV‐positive patients were negative for other known pathogens.

Marked pleural and pericardial effusion with elevated Vascular Endothelial Growth Factor production: an uncommon complication of Kawasaki disease.

Kawasaki disease (KD) is an acute febrile systemic vasculitis that often occurs in young children. KD inflammation initially involves microvessels. During this initial process, increased microvascular permeability is an important event in KD vasculitis. 1 For example, edematous changes of extremities are a striking feature of KD and occur within the first 5 days of illness. Endothelial gap formation and subendothelial edema are documented in the skin, suggesting the presence of vascular permeability. 2 However, pleural and pericardial effusion is rarely observed in acute KD. 3,4 We describe a KD patient with marked pleural and pericardial effusion, which may be related to microvascular hyperpermeability of KD. Serum free Vascular Endothelial Growth Factor 165 (VEGF 165 ) level was elevated, which might play a role in vascular and tissue hyperpermeability. Corticosteroid was dramatically effective for this condition, without coronary artery abnormalities.