New biomarkers of Kawasaki disease identified by urine proteomic analysis.

Kawasaki disease (KD) is an acute systemic vasculitis that mainly afflicts infants and young children. The symptoms of KD are similar to those of various febrile diseases. Here, we attempted to develop accurate diagnostic biomarkers of KD by performing urine proteomic analysis of samples from healthy controls, patients with KD, and patients with another febrile disease, pneumonia (two patients). We identified differentially expressed proteins (DEPs) in KD as compared to normal controls. We also constructed functional annotation and protein-protein interaction (PPI) networks of DEPs in KD and pneumonia. DEPs common to both KD and pneumonia were identified, as well as DEPs specific to KD. Compared to normal control, 43 and 62 DEPs were identified in KD and pneumonia, respectively. Serine hydroxymethyltransferase 1 is a hub protein of the KD-specific PPI network. Thirteen DEPs common to both KD and pneumonia and 30 DEPs specific to KD were identified. Of these, the expression of eight DEPs could cluster normal and pneumonia samples into one group and cluster KD samples into another group based on hierarchical clustering. Our study identified several DEPs that may play a role in KD and that may serve as diagnostic biomarkers to distinguish patients with KD from both normal control and other febrile diseases.

Urine proteomics for discovery of improved diagnostic markers of Kawasaki disease.

Kawasaki disease (KD) is a systemic vasculitis of unknown etiology. Absence of definitive diagnostic markers limits the accuracy of clinical evaluations of suspected KD with significant increases in morbidity. In turn, incomplete understanding of its molecular pathogenesis hinders the identification of rational targets needed to improve therapy. We used high-accuracy mass spectrometry proteomics to analyse over 2000 unique proteins in clinical urine specimens of patients with KD. We discovered that urine proteomes of patients with KD, but not those with mimicking conditions, were enriched for markers of cellular injury such as filamin and talin, immune regulators such as complement regulator CSMD3, immune pattern recognition receptor muclin, and immune cytokine protease meprin A. Significant elevations of filamin C and meprin A were detected in both the serum and urine in two independent cohorts of patients with KD, comprised of a total of 236 patients. Meprin A and filamin C exhibited superior diagnostic performance as compared to currently used markers of disease in a blinded case-control study of 107 patients with suspected KD, with receiver operating characteristic areas under the curve of 0.98 (95% confidence intervals [CI] of 0.97-1 and 0.95-1, respectively). Notably, meprin A was enriched in the coronary artery lesions of a mouse model of KD. In all, urine proteome profiles revealed novel candidate molecular markers of KD, including filamin C and meprin A that exhibit excellent diagnostic performance. These disease markers may improve the diagnostic accuracy of clinical evaluations of children with suspected KD, lead to the identification of novel therapeutic targets, and allow the development of a biological classification of Kawasaki disease.

A novel anti-peroxiredoxin autoantibody in patients with Kawasaki disease.

Antibodies to the anti-oxidative peroxiredoxin (Prx) enzymes occur in both systemic autoimmune disease and vasculitis in adulthood. Because increased oxidative stress induces vasculitis in Kawasaki disease (KD), autoimmunity to Prxs in patients with KD was investigated. The presence of antibodies to Prx 1, 2 and 4 was analyzed by ELISA and Western blot. Of 30 patients with KD, 13 (43.3%) possessed antibodies to Prx 2, whereas these antibodies were present in only 1 of 10 patients (10.0%) with sepsis (4 with purulent meningitis and 6 with septicemia). In contrast, antibodies to Prx 1 and 4 were not detected in either group. There was no significant correlation among the titers of the three antibodies. Clinical parameters were compared between anti-Prx 2-positive and -negative patients. The presence of anti-Prx 2 antibodies correlated with a longer period of fever and poor response to high-dose γ-globulin therapy in patients with KD. Anti-Prx 2-positive patients had significantly greater excretion of urinary 8-isoprostaglandin than did anti-Prx 2-negative patients. These results provide the first evidence for an antibody to Prx 2 in patients with KD. They also suggest that this antibody might serve as a marker of disease severity and be involved in the pathophysiology of vasculitis in some patients with KD.

A diagnostic algorithm combining clinical and molecular data distinguishes Kawasaki disease from other febrile illnesses.

BACKGROUND: Kawasaki disease is an acute vasculitis of infants and young children that is recognized through a constellation of clinical signs that can mimic other benign conditions of childhood. The etiology remains unknown and there is no specific laboratory-based test to identify patients with Kawasaki disease. Treatment to prevent the complication of coronary artery aneurysms is most effective if administered early in the course of the illness. We sought to develop a diagnostic algorithm to help clinicians distinguish Kawasaki disease patients from febrile controls to allow timely initiation of treatment. METHODS: Urine peptidome profiling and whole blood cell type-specific gene expression analyses were integrated with clinical multivariate analysis to improve differentiation of Kawasaki disease subjects from febrile controls. RESULTS: Comparative analyses of multidimensional protein identification using 23 pooled Kawasaki disease and 23 pooled febrile control urine peptide samples revealed 139 candidate markers, of which 13 were confirmed (area under the receiver operating characteristic curve (ROC AUC 0.919)) in an independent cohort of 30 Kawasaki disease and 30 febrile control urine peptidomes. Cell type-specific analysis of microarrays (csSAM) on 26 Kawasaki disease and 13 febrile control whole blood samples revealed a 32-lymphocyte-specific-gene panel (ROC AUC 0.969). The integration of the urine/blood based biomarker panels and a multivariate analysis of 7 clinical parameters (ROC AUC 0.803) effectively stratified 441 Kawasaki disease and 342 febrile control subjects to diagnose Kawasaki disease. CONCLUSIONS: A hybrid approach using a multi-step diagnostic algorithm integrating both clinical and molecular findings was successful in differentiating children with acute Kawasaki disease from febrile controls.

Urinary cytokines and renal Doppler study in Kawasaki disease.

OBJECTIVE: To investigate whether renal vasculitis is the sole cause or merely a contributing cause of renal inflammation in Kawasaki disease (KD). STUDY DESIGN: This prospective study in a university medical center in Taiwan enrolled 24 children with KD between June 2004 and November 2005. All patients underwent a technetium-99 m dimercaptosuccinic acid scintigraphy single-photon emission computed tomography scan, the results of which were used to group the patients with KD as with or without renal involvement. Urine samples underwent a cytokine analysis. Renal Doppler ultrasonography was used to evaluate renal vasculitis by measuring the pulsatility index (PI) and resistance index (RI). RESULTS: Ten of the 24 patients (42%) with renal inflammatory foci were the study group; the remainder composed the control group. Urinary interleukin (IL)-6 levels were significantly higher in the study group (496.7 +/- 310.9 vs 115.0 +/- 65.9 ng/g urinary creatinine; P < .01), as were PI values (1.85 +/- 0.70 vs 1.44 +/- 0.53; P < .05). Urinary IL-6 levels and PI values were significantly (P < .05) correlated. CONCLUSIONS: Increased urinary IL-6 and elevated renal Doppler measures suggest that immune-mediated vasculitis is one of the mechanisms causing renal inflammation in KD.

Pyuria is not always sterile in children with Kawasaki disease.

BACKGROUND: Although Kawasaki disease (KD) often presents with sterile pyuria, bacterial pyuria (urinary tract infection [UTI]) occasionally occurs. METHODS: This was a retrospective cohort study of 285 children with KD diagnosed between 1995 and 2005. Among these patients, a total of 210 patients underwent routine urine tests and 75 children underwent urine culture tests. This study was conducted to investigate the incidence, clinical manifestations, management and outcome of KD with pyuria. RESULTS: The incidence of pyuria was 29.5% (62/210). Among the 75 children undergoing urine culture tests, 34 had sterile pyuria (45.3%), eight had bacterial pyuria (10.7%), two had UTI without pyuria (2.7%) and 31 had neither pyuria nor UTI (41.3%). When pyuria was used as a predictor of KD with UTI, the positive and negative predictive values were 19% and 93.9%, respectively. There were no significant differences in demographic data, clinical presentations, laboratory results, duration of fever, ratio of resistant KD or risk level, except in the nitrite test, between both groups. CONCLUSIONS: Pyuria was not always sterile in patients with KD. Although there was no different clinical phenotype or coronary outcome in KD patients with or without UTI, we suggest that UTI should be considered and evaluated in KD patients with pyuria, a positive nitrite test or a positive result of urine culture. If UTI is definitively diagnosed, the patient should be treated for a UTI as well as for KD and complete post-UTI work-up is recommended.

IVIG reduced vascular oxidative stress in patients with Kawasaki disease.

BACKGROUND: Oxidative stress (OS) contributes to the acute phase of Kawasaki disease (KD) in a manner that is as yet unknown. In the present study OS in the acute phase of KD was investigated by measuring urinary 8-iso-prostaglandin F2alpha (8-iso-PG) and evaluating its correlation to the efficacy of intravenous immunoglobulin (IVIG) administration. METHODS AND RESULTS: The 62 patients with acute phase of KD were enrolled, as well as 20 healthy children (HC) and 20 with acute febrile illness (FI). Urinary samples were obtained before and after administration of IVIG. The HC and FI groups also had inflammatory markers evaluated at the same time. The 8-iso-PG was significantly elevated in the 62 KD patients (719 +/-335 pg/mg Cr) without IVIG administration compared with those with FI (583 +/-213 pg/mg Cr) as well as HC (443 +/-288 pg/mg Cr) (P<0.01). 40 patients were given 3 different regimens of IVIG: 16 received 2 g/kg for 1 day; 17 received 1 g/kg for 1 day; 7 received 400 mg . kg(-1) . day(-1) for 5 days. All regimens of IVIG reduced the 8-iso-PG level at 7 days after initiation. CONCLUSIONS: OS provokes vasculitis in KD, the activation of which was reduced by IVIG. The urinary level of 8-iso-PG is a useful marker of the effectiveness of IVIG in the acute phase of KD.

Kawasaki's disease, acrodynia, and mercury.

A superantigen or autoimmunity has been hypothesized to be the main cause of the Kawasaki's Disease but the etiology is unknown. Medical literature, epidemiological findings, and some case reports have suggested that mercury may play a pathogenic role. Several patients with Kawasaki's Disease have presented with elevated urine mercury levels compared to matched controls. Most symptoms and diagnostic criteria which are seen in children with acrodynia, known to be caused by mercury, are similar to those seen in Kawasaki's Disease. Genetic depletion of glutathione S-transferase , a susceptibility marker for Kawasaki's Disease, is known to be also a risk factor for acrodynia and may also increase susceptibility to mercury . Coinciding with the largest increase (1985-1990) of thimerosal (49.6% ethyl mercury) in vaccines, routinely given to infants in the U.S. by 6 months of age (from 75microg to 187.5microg), the rates of Kawasaki's Disease increased ten times, and, later (1985-1997), by 20 times. Since 1990 88 cases of patients developing Kawasaki's Disease some days after vaccination have been reported to the Centers of Disease Control (CDC) including 19% manifesting symptoms the same day. The presented pathogenetic model may lead to new preventive- and therapeutic strategies for Kawasaki's disease.

Endogenous nitric oxide production in Kawasaki disease.

To evaluate in vivo nitric oxide production in Kawasaki disease (KD), urinary nitrite/nitrate (NOx) excretion was measured in 8 children with KD (age 1.1-2.7 years). Urinary NOx excretion was 0.66 +/- 0.22 mmol mmol-1 creatinine (mean +/- SD) in the 8 children with KD in the initial stages. The levels were significantly increased compared with those of 12 age-matched healthy control subjects (0.35 +/- 0.08 mmol mmol-1 creatinine). Urinary Nox excretion was serially determined in four patients. For each patient, there was a further rise in urinary NOx excretion from baseline levels coincident with the administration of intact-type gammaglobulin and aspirin. With clinical and laboratory improvement, however, urinary NOx excretion declined to the normal range. These findings suggest that endogenous nitric oxide production is enhanced in children with acute KD. Further studies are needed to clarify the role of nitric oxide in the pathogenesis and clinical course of KD.

Increased generation of cysteinyl leukotrienes in Kawasaki disease.

Endogenous cysteinyl leukotriene synthesis was assessed in 10 patients with Kawasaki disease and 10 healthy controls by measuring excretion of leukotriene E4 (LTE4) in urine. LTE4 was increased more than fivefold in patients with Kawasaki disease compared with controls (median (range) 55.3 (31.8-120.6) v 10.2 (7.1-14.9) nmol/mol creatinine); this suggests that cysteinyl leukotrienes are involved in the pathophysiology of Kawasaki disease. Leukotriene synthetase inhibition or receptor antagonism may therefore offer a new potential therapeutic approach in children with this disease.

Increased levels of urinary interleukin-6 in Kawasaki disease.

Kawasaki disease (KD) often presents with abnormal urinary findings, such as aseptic pyuria, mild proteinuria and microscopic haematuria. In this study, we measured urinary interleukin-6 (IL-6) by a sensitive sandwich ELISA assay using mouse monoclonal antibodies against recombinant IL-6 to elucidate the role of IL-6 in the pathogenesis of renal lesions in KD. Serum IL-6 levels were increased in acute KD as well as in febrile controls. Importantly, urinary IL-6 levels were consistently elevated in patients with acute KD, but much lower in febrile controls. Urinary IL-6 levels returned steadily to normal during the convalescent phase. In addition to IL-6, urinary levels of N-acetyl-beta-D-glucosaminidase (NAG) and beta 2-microglobulin (beta 2-mg) were also elevated during the acute phase of this disease. Eosinophils and macrophages were identifiable in urinary sediments from these patients. The increased levels of urinary IL-6 in combination with increased NAG and beta 2-mg seemed to suggest the presence of certain renal parenchymal lesions with cellular infiltration during the acute phase of the disease. IL-6 may serve as clinically useful parameter for the detection and monitoring of the renal involvement in KD.

Urinary neopterin as a predictive marker of coronary artery abnormalities in Kawasaki syndrome.

We investigated whether urinary neopterin concentrations respond to the pathological conditions (especially coronary artery dilatation) of Kawasaki syndrome. All of 29 children with Kawasaki syndrome had very high urinary neopterin concentrations. Increased urinary neopterin concentrations coincided with fever and with monocytosis in peripheral blood. The urinary neopterin excretion peaking within the first 8 days after onset correlated with the development of coronary artery dilatation. Increased urinary neopterin concentrations indicate that cell-mediated immunity is activated in patients with Kawasaki syndrome. Endogenous interferon-gamma and activation of monocytes/macrophages may play a role in the pathogenesis of Kawasaki syndrome. Not only do neopterin concentrations correlate with symptoms in the acute phase of Kawasaki syndrome, they also act as a predictive marker of coronary artery abnormalities in affected patients.

Digoxin-like immunoreactive substance in urine of patients with mucocutaneous lymph node syndrome (MCLS).

Levels of digoxin-like immunoreactive substance (DLIS) and dehydroepiandrosterone sulfate (DHEA) in urine from patients with mucocutaneous lymph node syndrome (MCLS) were measured by radioimmunoassay. Because DLIS of stored samples was often below the level of detection by conventional immunoassay, the authors used 80% ammonium sulfate and extraction with phosphate buffer and then 80% hot ethanol. To study the origin of raised levels of DLIS in urine, the synthesis of DLIS by cultured human umbilical vein endothelial cells (HUVEC) was tested in vitro. The correlation between DLIS and DHEA levels was not significant. Mean levels of urinary DLIS corrected for creatinine in the patients with MCLS were significantly higher than in both normal and diseased controls. The culture medium of HUVEC was found to contain DLIS activity. These results show that MCLS should be added to the clinical states associated with an increased urinary concentration of DLIS and that the endothelial cells are one source of DLIS in man.

Tumor necrosis factor-alpha inhibitory activity in urine of Kawasaki disease.

Recently it has been reported that naturally occurring inhibitors of tumor necrosis factor alpha (TNF-alpha) were demonstrated in urine of some acute febrile patients. We investigated whether TNF-alpha inhibitory activity in urine increases during acute Kawasaki disease (KD). TNF-alpha inhibitory activities in urine were measured by a cytotoxicity assay on the TNF-susceptible cell line L929. KD patients had increased TNF-alpha inhibitory activities in urine during the acute stage and returned to a normal range during the convalescent stage. Our results suggest that the TNF-alpha inhibitor in urine is part of the regulatory system of TNF-alpha, which might be responsible for vascular injury during acute KD.

Bilirubinuria: an early indicator of gallbladder hydrops associated with Kawasaki disease.

We report four cases of gallbladder hydrops associated with Kawasaki disease diagnosed over a 7.5 year period. Despite varying clinical presentations, all four of these patients had the common finding of bilirubinuria prior to clinical symptoms or at the time of admission. Review of 40 other cases of Kawasaki disease without evidence of hydrops over this time period revealed that urinalysis had been performed in each and bilirubinuria was present in only one case. Bilirubinuria appears to be an early indicator of hydrops in these patients.

Intracytoplasmic inclusions in urinary sediment cells from a patient with mucocutaneous lymph node syndrome (Kawasaki disease). A case report.

An intracytoplasmic inclusion seen in cells in the urinary sediments of a patient with the mucocutaneous lymph node syndrome (Kawasaki disease) is described. Cytochemical features suggested that the inclusion-bearing cells may be derived from mononucleated phagocytic cells. The presence of these cells may be related to the acute febrile phase of the disease.

Urine mercury levels in Kawasaki disease.

Six patients with diagnostic criteria for Kawasaki disease had abnormally high urinary excretions of mercury. They were compared by age, sex, and geographic location with matched controls. Improvement of one patient was temporally related to chelation of mercury with penicillamine. There are numerous clinical similarities between acrodynia and Kawasaki disease and the appearance of the mucocutaneous lymph node syndrome (Kawasaki disease) has been related temporally and geographically to environmental pollution with mercury. The mucocutaneous lymph node syndrome (Kawasaki disease) may represent a disease caused by environmental pollution with mercury, or clinical symptoms compatible with Kawasaki disease may indicate environmental exposure to mercury.