Arterial immune protein expression demonstrates the complexity of immune responses in Kawasaki disease arteritis.

A more complete understanding of immune-mediated damage to the coronary arteries in children with Kawasaki disease (KD) is required for improvements in patient treatment and outcomes. We recently reported the transcriptional profile of KD coronary arteritis, and in this study sought to determine protein expression of transcriptionally up-regulated immune genes in KD coronary arteries from the first 2 months after disease onset. We examined the coronary arteries of 12 fatal KD cases and 13 childhood controls for expression of a set of proteins whose genes were highly up-regulated in the KD coronary artery transcriptome: allograft inflammatory factor 1 (AIF1), interleukin 18 (IL-18), CD74, CD1c, CD20 (MS4A1), Toll-like receptor 7 (TLR-7) and Z-DNA binding protein 1 (ZBP1). Immunohistochemistry and immunofluorescence studies were performed to evaluate protein expression and co-localization, respectively. AIF1 was expressed transmurally in KD arteritis and localized to macrophages and myeloid dendritic cells. CD74, which interacts with major histocompatibility complex (MHC) class II on antigen-presenting cells, localized to the intima-media. CD1c, a marker of myeloid dendritic cells, was expressed in a transmural pattern, as were IL-18 and CD20. ZBP1 and TLR-7 were up-regulated compared to controls, but less highly compared to the other proteins. These findings provide evidence of antigen presentation and interferon response in KD arteritis. In combination with prior studies demonstrating T lymphocyte activation, these results demonstrate the complexity of the KD arterial immune response.

CD84 is markedly up-regulated in Kawasaki disease arteriopathy.

The major goals of Kawasaki disease (KD) therapy are to reduce inflammation and prevent thrombosis in the coronary arteries (CA), but some children do not respond to currently available non-specific therapies. New treatments have been difficult to develop because the molecular pathogenesis is unknown. In order to identify dysregulated gene expression in KD CA, we performed high-throughput RNA sequencing on KD and control CA, validated potentially dysregulated genes by real-time reverse transcription-polymerase chain reaction (RT-PCR) and localized protein expression by immunohistochemistry. Signalling lymphocyte activation molecule CD84 was up-regulated 16-fold (P < 0·01) in acute KD CA (within 2 months of onset) and 32-fold (P < 0·01) in chronic CA (5 months to years after onset). CD84 was localized to inflammatory cells in KD tissues. Genes associated with cellular proliferation, motility and survival were also up-regulated in KD CA, and immune activation molecules MX2 and SP140 were up-regulated in chronic KD. CD84, which facilitates immune responses and stabilizes platelet aggregates, is markedly up-regulated in KD CA in patients with acute and chronic arterial disease. We provide the first molecular evidence of dysregulated inflammatory responses persisting for months to years in CA significantly damaged by KD.

Angiogenesis in fatal acute Kawasaki disease coronary artery and myocardium.

Angiogenesis has been shown to be dysregulated in coronary artery (CA) aneurysms in the chronic phase of Kawasaki disease (KD). Neovascularization may occur in inflammatory-related vascular diseases because many angiogenesis mediators are secreted by inflammatory cells. We hypothesized that inflammation of the acute KD CA aneurysm could lead to dysregulation of angiogenesis mediators and subsequent neovascularization. To investigate this hypothesis, acute fatal KD cardiac tissues were immunostained for angiogenic inducers and inhibitors. Microvessel density was determined and the degree of inflammation assessed. Marked inflammation and angiogenesis were found in acute KD CA aneurysms and myocardium, with the highest microvessel density seen in patients who died 2-3 weeks after onset of the disease. Expression of proangiogenic proteins was higher than expression of inhibitors in KD CA aneurysms and myocardium. Angiogenesis mediators were localized to inflammatory cells in the myointima, adventitia, and myocardium. We conclude that significant neovascularization occurs in acute KD CA aneurysms and myocardium much sooner after onset of the disease than has been previously reported, that multiple angiogenesis factors are involved, and that dysregulation of angiogenesis likely contributes to KD vasculopathy.

Recent developments and controversies in Kawasaki disease.

In the developed world, Kawasaki disease is currently the leading cause of pediatric acquired heart disease. To date, the etiologic agent remains unknown. Many hypotheses regarding the etiology exist, and debate continues as to whether the inflammatory response of Kawasaki disease results from a superantigen or a conventional antigen. A variety of growth factors, proteinases, and cytokines have been identified that are involved in the pathogenesis of coronary artery disease in Kawasaki disease. These findings are leading to novel treatment strategies in Kawasaki disease, including platelet glycoprotein receptor inhibitors and monoclonal antibody to tumor necrosis factor-alpha. The role of corticosteroids remains controversial, and ongoing clinical trials are evaluating its efficacy. Additional studies have focused on newer non-invasive methods of evaluating children with coronary artery disease as alternatives to coronary catheterization. We review recent developments and controversies in exploring the etiology, pathogenesis, diagnosis, and management of Kawasaki disease.

Coronary artery bypass grafting for Kawasaki disease.

Five patients with a history of Kawasaki disease underwent coronary revascularization at Children's Memorial Hospital (1988-2000). Acute disease occurred at 11 weeks to 5 years of age and revascularization procedures were performed at 8 months to 12 years (mean 6 years; interval from disease onset 5 months to 9 years). Surgical indications included abnormal stress testing with angiographic confirmation of severe coronary artery stenosis (n = 3), severe coronary artery stenosis with echocardiographic evidence of intracoronary thrombus (n = 1), and ischemic electrocardiogram changes and ventricular tachycardia during angiography (n = 1). All revascularization procedures used internal thoracic arteries including one free internal thoracic artery graft. There were no postoperative deaths (follow-up 1 month to 11 years). All patients are asymptomatic. One patient developed myocardial ischemia 4 years postoperatively with occlusion of the circumflex coronary artery (not previously grafted). This was treated successfully with percutaneous coronary angioplasty and stent placement. All grafts are patent with the exception of a single right internal thoracic artery graft which underwent involution 30 months postprocedure with concurrent recannulization of the right coronary artery. Coronary revascularization should be considered in the young patient with severe coronary abnormalities secondary to Kawasaki disease.

Staphylococcus lugdunensis: an emerging cause of ventriculoperitoneal shunt infections.

Staphylococcus lugdunensis, a coagulase-negative staphylococcus first described in 1988, has gained recognition as an organism with considerable pathogenic capability in adults. In contrast to the indolent presentation characteristic of other coagulase-negative staphylococci, S. lugdunensis infections resemble the aggressive behavior of Staphylococcus aureus. Although the organism has been isolated from a wide variety of infections in adults, it is a very rare cause of pediatric infections. We describe the first two pediatric patients who developed ventriculoperitoneal shunt infections caused by S. lugdunensis. These cases suggest that coagulase-negative staphylococci should be identified to the species level and that, if S. lugdunensis is identified, greater morbidity compared to that associated with other coagulase-negative staphylococcal shunt infections should be anticipated. A longer course of therapy is recommended for S. lugdunensis infections.

Surface and cytoplasmic immunoglobulin expression in circulating B-lymphocytes in acute Kawasaki disease.

Kawasaki disease (KD) is an acute vasculitis of young childhood predominantly affecting the coronary arteries. IgA plasma cells have been found to infiltrate vascular and nonvascular tissues in fatal acute KD. To determine whether IgA B-lymphocytes were increased in the peripheral blood of patients with KD, we performed three-color flow cytometry to detect surface and cytoplasmic immunoglobulin expression (IgA, IgM, IgD, and IgG) of peripheral B-lymphocytes in KD patients during the acute, subacute, and convalescent stages of illness and in age-matched febrile and afebrile pediatric controls. Surprisingly, absolute numbers of B-lymphocytes expressing IgA were found to be significantly lower in peripheral blood of acute KD patients compared with febrile and afebrile pediatric controls. These findings indicate that IgA plasma cells are not present in KD tissue as a result of excess numbers of these IgA B-lymphocytes in peripheral blood. We speculate that IgA B-lymphocytes are selectively withdrawn from the peripheral circulation into KD target tissues as part of a specific IgA immune response.

CD8 T lymphocytes and macrophages infiltrate coronary artery aneurysms in acute Kawasaki disease.

The pathogenesis of coronary arterial inflammation in acute Kawasaki disease (KD) is unclear. To test the hypothesis that the KD vascular lesion is an activated T lymphocyte-dependent process, immunohistochemical studies were done on coronary artery aneurysms from 8 fatal acute KD cases by using antibodies to CD45RO (activated or memory T lymphocyte), CD8 (cytotoxic T lymphocyte), CD4 (helper T lymphocyte), HAM56 (macrophage), and CD20 (B lymphocyte). Acute KD coronary arteritis was characterized by transmural infiltration of CD45RO T lymphocytes with CD8 T lymphocytes predominating over CD4 T lymphocytes. Macrophages were present primarily in the adventitial layer; B lymphocytes were notably absent. These data lend support to the hypotheses that KD results from infection with an intracellular pathogen, such as a virus, whose antigens are presented by major histocompatibility complex class I molecules, and that CD8 T lymphocytes and macrophages are important in the pathogenesis of KD coronary aneurysms.

Nosocomial infection rates in US children's hospitals' neonatal and pediatric intensive care units.

BACKGROUND: Few data are available on nosocomial infections (NIs) in US children's hospitals' neonatal or pediatric intensive care units. The Pediatric Prevention Network (PPN) was established to improve characterization of NIs in pediatric patients and to develop and test interventions to decrease NI. METHODS: Fifty participating children's hospitals were surveyed in 1998 to determine NI surveillance methods used and neonatal intensive care unit (NICU) and pediatric intensive care unit (PICU) 1997 NI rates. Data were collected on standardized forms and entered and analyzed by using SPSS for Windows. RESULTS: Forty-three (86%) children's hospitals returned a completed questionnaire. All reported conducting NICU and PICU NI surveillance (range, 2-12; median, 12 months). Nineteen children's hospitals provided NICU NI rate data in one or more formats suitable for comparison. Denominators used for NICU NI rate calculations varied: 17 reported overall NI by patient-days; 19 reported bloodstream infection (BSI) by central venous catheter (CVC)-days, and 8 reported BSI by patient-days. Sixteen (16) children's hospitals reported NICU BSI data stratified by CVC-days and birth-weight cohort, and ventilator-associated pneumonia (VAP) by birth weight cohort was reported by 12. Twenty-four children's hospitals reported PICU NI rate data in one or more formats suitable for comparison. Denominators used for PICU NI rate calculations also varied: 20 reported overall NI rates by patient-days; 23 reported BSI rates by CVC-days, and 10 reported BSI rates by patient-days; 24 reported VAP by ventilator-days; and 15 reported urinary tract infections (UTIs) by urinary catheter-days. Median overall NI rates per 1000 patient days were 8.9 in NICUs and 13.9 in PICUs. Median NICU NI device-associated rates by birth weight (>2500 g, 1501-2500 g, 1001-1500 g, and

Severe neonatal enteroviral hepatitis treated with pleconaril.

Neonatal enteroviral hepatitis carries high morbidity and mortality. We treated three full term neonates with severe enteroviral hepatitis with pleconaril on an open label compassionate use protocol. Each mother had history of a viral-like syndrome within 1 week before delivery. The neonates presented at 4 to 5 days of age with fulminant hepatic failure with severe coagulopathy, and each yielded an echovirus. All were treated with pleconaril (VP63843) at 5 mg/kg every 8 h by nasogastric tube. Two of the three neonates with life-threatening enteroviral hepatitis recovered fully. Further experience with pleconaril for neonatal enteroviral hepatitis is warranted.

Critical evaluation of a CLIA-waived streptococcal antigen detection test in the emergency department.

STUDY OBJECTIVE: We compare the performance of a Clinical Laboratory Improvement Amendments (CLIA)-waived antigen detection test (ADT) analyzed in the emergency department and a CLIA moderately complex ADT performed in the hospital microbiology laboratory. METHODS: Samples from throat swabs were obtained using a double-headed Culturette II (Becton Dickinson Medical Systems, Sparks, MD) from a consecutive sample of 322 patients 3 years or older who presented to the ED of a university-affiliated pediatric referral hospital with the complaint of sore throat during 1998. One swab was transported to the microbiology laboratory and analyzed using a CLIA moderately complex ADT; negative results were confirmed using sheep blood agar culture. The second swab remained in the ED where a nurse conducted a CLIA-waived ADT. The accepted standard for documentation of group A beta-hemolytic streptococcal (GABHS) infection was either a positive moderately complex ADT or culture result. The time of specimen collection, as well as the time the ED results and microbiology laboratory results were available to treating physicians, were recorded. Main outcome measures were concordance (kappa statistic), sensitivity, and turnaround time (Mann-Whitney U test). RESULTS: Three hundred twenty-two patients (mean age 7.5 years) had both ADTs performed. One hundred one (31%) patients had documented GABHS in the microbiology laboratory; 83 (82%) had a positive ADT result in the microbiology laboratory, and 18 (18%) had a positive culture result after a negative moderately complex ADT result. In 299 patients or 93% (95% confidence interval [CI] 90.8%, 95.8%) of patients, the waived ADT and the moderately complex ADT results were concordant (kappa 0.82; 95% CI 0.78, 0.86; P <.001). The sensitivity of the waived ADT was 80%; the sensitivity of the moderately complex ADT approximated 82% (difference of 2%; 95%CI -3%, 7%). The median times from swab specimen collection to availability of ADT results were 10 minutes (range 3 to 37 minutes) for the waived ADT and 35 minutes (range 5 to 162 minutes) for the moderately complex ADT (P <.001) with a difference of 25 minutes (95% CI 22.4, 27.6 minutes). CONCLUSION: In this study, an ED CLIA-waived rapid streptococcal throat test performed as well as its equivalent CLIA-regulated laboratory test. Further, the ED test provided results more rapidly than the laboratory test. Our results also validate previous work that negative rapid throat test results in pediatric patients in the ED should be confirmed by standard throat culture.

Circulating cardiac troponin I levels in Kawasaki disease.

In addition to the vascular findings of Kawasaki disease (KD), clinical, electrocardiographic, and/or echocardiographic signs of myocarditis are recognizable in the acute phase of KD in many patients. The mechanism of myocarditis and an association with the development of subsequent coronary artery abnormalities in KD is unknown. Previous studies of serum cardiac troponin I (cTnI) measurements in pediatric populations have suggested a possible utility of measurements in diagnosis and follow-up of KD. We designed a retrospective study to evaluate cTnI measurements during acute KD and to assess the predictive value of cTnI measurements in acute KD for the subsequent development of coronary artery abnormalities. Twenty-nine children were studied. Group 1 consisted of 15 KD patients who developed coronary artery abnormalities as detected by transthoracic echocardiographic evaluation. Group 2 consisted of 14 KD patients with persistently normal coronary artery findings on echocardiograms. A control group consisted of 11 children, none of whom were known to have had clinical findings of KD or myocarditis. The mean cTnI values for all three groups were lower than the values suggestive of cardiac damage: group 1 = 0.11 +/- 0.16 ng/ml, group 2 = 0.15 +/- 0.34 ng/ml, and control = 0.04 +/- 0.08 ng/ml. The current study demonstrates that there is no significant elevation of cTnI in KD patients. Additionally, there is no correlation between cTnI measurements and the finding of myocarditis, as reflected by decreased cardiac function, or the subsequent development of coronary artery abnormalities.

Oligoclonal IgA response in the vascular wall in acute Kawasaki disease.

Kawasaki Disease (KD) is a potentially fatal acute vasculitis of childhood. Although KD is the leading cause of acquired heart disease in children in developed nations, its pathogenesis remains unknown. We previously reported the novel observation that IgA plasma cells infiltrate the vascular wall in acute KD. We have now examined the clonality of this IgA response in vascular tissue from three fatal cases of KD to determine whether it is oligoclonal, suggesting an Ag-driven process, or polyclonal, suggesting nonspecific B cell activation or a response to a superantigen. We first sequenced VDJ junctions of 44 alpha genes isolated from a primary, unamplified KD vascular cDNA library. Five sets of clonally related alpha sequences were identified, comprising 34% (15 of 44) of the isolated alpha sequences. Furthermore, point mutations consistent with somatic mutation were detected in the related sequences. Next, using formalin-fixed coronary arteries from two additional fatal KD cases, we sequenced VDJ junctions of alpha genes isolated by RT-PCR, and a restricted pattern of CDR3 usage was observed in both. We conclude that the vascular IgA response in acute KD is oligoclonal. The identification of an oligoclonal IgA response in KD strongly suggests that the immune response to this important childhood illness is Ag-driven.

Recent developments in Kawasaki disease.

Kawasaki disease is now being recognized as the leading cause of acquired heart disease in children in North America and Japan. This review discusses the recent developments and controversies in Kawasaki disease. Increasing evidence has supported an infectious etiology for Kawasaki disease; however, the debate continues as to whether the inflammatory response results from a conventional antigen or a superantigen. Recent immunohistochemistry findings suggest many vascular growth factors then play a role in the formation of the coronary artery lesions. Many studies have focused on the identification and therapy for patients resistant to conventional therapy, as well as the long-term prognosis of Kawasaki disease survivors. The recent advances in Kawasaki disease are helping to provide some clues in the etiology, pathogenesis and therapy for Kawasaki disease.

IgA plasma cell infiltration of proximal respiratory tract, pancreas, kidney, and coronary artery in acute Kawasaki disease.

The etiology and pathogenesis of Kawasaki disease (KD) remain unknown. As previously reported, in US patients with acute KD, IgA plasma cells (PCs) infiltrate the vascular wall. To determine whether IgA PCs are increased at mucosal sites in KD and to determine whether other nonvascular KD tissues are infiltrated by IgA PCs, the cells were immunolocalized and quantitated in tissue sections taken from 18 US and Japanese patients who died of acute KD and from 10 age-matched controls. IgA PCs were significantly increased in the trachea of patients who died of acute KD, compared with controls (P<.01), a finding that was similar to findings in children with fatal respiratory viral infection. IgA PCs also infiltrated coronary artery, pancreas, and kidney in all KD patients. These findings strongly support entry of the KD etiologic agent through the upper respiratory tract, resulting in an IgA immune response, with systemic spread to vascular tissue, pancreas, and kidney.

Kawasaki disease in older children and adolescents.

Features of 28 patients older than 8 years of age with acute Kawasaki disease were reviewed. Observations included a predominance of male patients and white patients, delays in diagnosis of acute Kawasaki disease, presence of additional signs and symptoms, and a substantial incidence of coronary artery abnormalities (21%) including mild transient changes.

Myocardial injury in children with respiratory syncytial virus infection.

OBJECTIVE: Respiratory syncytial virus (RSV) infection is associated with a number of extrapulmonary manifestations, including a sepsis-like syndrome characterized by any combination of hypothermia, fever, apnea, hypovolemia, and myocardial dysfunction. We hypothesized that RSV can have a direct injurious effect on the myocardium of infants and children that can be detected by the presence of cardiac troponin I (cTnI), a highly sensitive and specific marker of myocardial injury, in the blood of patients infected with the virus. DESIGN: Serial cTnI measurements were obtained from patients admitted with documented RSV infection to the pediatric intensive care unit (PICU). PARTICIPANTS: Data were collected and analyzed from 22 RSV infected patients and 11 control patients. RESULTS: Elevated levels of cTnI were detected in 54.5% (12/22) of the study population during their PICU admission. The average cTnI level was significantly higher in the RSV infected group than in controls. There was a significant association between the presence of a positive troponin assay and the occurrence of a cardiovascular event, the need for inotropic support, and the requirement of mechanical ventilation. Patients who required inotropic support had a significantly higher cTnI level than the rest of the study population. CONCLUSION: A large percentage of children admitted to the PICU with RSV infection have myocardial damage as detected by the use of commercially available troponin assays. Additionally, in a portion of these patients, this damage is clinically significant, leading to cardiovascular instability and the need for inotropic support.