Williamsia muralis bacteraemia in a patient with Fanconi anaemia after haematopoietic cell transplantation.

Introduction: Williamsia muralis is an environmental bacterium first detected in 1999. Infections with W. muralis isolated have been reported in two elderly patients, and were associated with the surgical intervention of artificial objects. We present a case of bacteraemia caused by W. muralis following haematopoietic cell transplantation (HCT). Case presentation: A 10-year-old Japanese boy presented with fever and the swelling of the left cheek 8 days after HCT for the treatment of Fanconi anaemia. Gram-positive, rod-shaped bacteria were isolated from the blood cultures after 5 days incubation. 16S rRNA sequencing, but not mass spectrometry, identified a strain of W. muralis (1 414 bp, %ID 100 %). The phlegmon did not respond to antimicrobial therapy, but remitted with defervescence after a successful engraftment with teicoplanin and meropenem therapy on day 16 after HCT. The patient experienced recurrence of the bacteraemia, leading to central venous catheter (CVC) line removal. The same strain of W. muralis was isolated from the cultured tip of the CVC. To our knowledge, this is the first reported case of W. muralis bacteraemia and was complicated by CVC infection after HCT. Conclusion: W. muralis bacteraemia developed in an immunocompromised child. Introduction of artificial objects into the body raises a risk of rare infection with slowly growing environmental bacteria.

Assessment of Pediatric Admissions for Kawasaki Disease or Infectious Disease During the COVID-19 State of Emergency in Japan.

Importance: The development of Kawasaki disease (KD) has been suggested to be associated with droplet- or contact-transmitted infection; however, its triggers and transmission modes remain to be determined. Under an epidemic of SARS-CoV-2, the COVID-19 state of emergency in Japan served as a nationwide social experiment to investigate the impact of quarantine or isolation on the incidence of KD. Objective: To assess the role of droplet or contact transmission in the etiopathogenesis of KD. Design, Setting, and Participants: This multicenter, longitudinal, cross-sectional study was conducted from 2015 to 2020 at Fukuoka Children's Hospital and 5 adjacent general hospitals. The number of admissions for KD and infectious diseases were analyzed. Participants were pediatric patients admitted to the participating hospitals for KD or infectious diseases. Exposures: Quarantine and isolation owing to the COVID-19 state of emergency. Main Outcomes and Measures: The primary end points were the ratios of patients with KD to patients with respiratory tract or gastrointestinal infections admitted from April to May in 2015 to 2019 and 2020. A Poisson regression model was used to analyze them. Results: The study participants included 1649 patients with KD (median [interquartile range] age, 25 [13-43] months; 901 boys [54.6%]) and 15 586 patients with infectious disease (data on age and sex were not available for these patients). The number of admissions for KD showed no significant change between April and May in 2015 to 2019 vs the same months in 2020 (mean [SD], 24.8 [5.6] vs 18.0 [4.0] admissions per month; 27.4% decrease; adjusted incidence rate ratio [aIRR], 0.73; 95% CI, 0.48-1.10; P = .12). However, the number of admissions for droplet-transmitted or contact-transmitted respiratory tract infections (mean [SD], 157.6 [14.4] vs 39.0 [15.0] admissions per month; 75.3% decrease; aIRR, 0.25; 95% CI, 0.17-0.35; P < .001) and gastrointestinal infections (mean [SD], 43.8 [12.9] vs 6.0 [2.0] admissions per month; 86.3% decrease; aIRR, 0.14; 95% CI, 0.04-0.43; P < .001) showed significant decreases between April and May in 2015 to 2019 vs the same months in 2020 (total, 12 254 infections). Thus, the ratio of KD to droplet- or contact-transmitted respiratory tract and gastrointestinal infections incidence in April and May 2020 was significantly increased (ratio, 0.40 vs 0.12; χ21 = 22.76; P < .001). Conclusions and Relevance: In this study, the significantly increased incidence of KD compared with respiratory tract and gastrointestinal infections during the COVID-19 state of emergency suggests that contact or droplet transmission is not a major route for KD development and that KD may be associated with airborne infections in most cases.

Reduction in the Number of Varicella-Zoster Virus-Specific T-Cells in Immunocompromised Children with Varicella.

Varicella zoster virus (VZV) causes a life-threatening infection in immunocompromised hosts. The immune response to VZV of healthy subjects has been rigorously assessed, but little is known about that of immunocompromised individuals. This study aimed to clarify the primary response to VZV infection in immunocompromised children. This prospective study enrolled six immunocompromised children (median age, 33 months; range, 20-62) receiving steroids or immunosuppressants, and 10 immunocompetent children (median age, 32 months; range, 15-81) with varicella. The immunocompromised children were three patients with acute lymphoblastic leukemia, two recipients with liver transplantation and one patient with juvenile idiopathic arthritis. Interferon-γ-producing CD69+T-cells produced by VZV stimulation (VZV-specific T-cells) were studied during the acute or convalescent phase. To further address the direct effect of immunosuppressants, we analyzed the number of VZV-specific T-cells after stimulating peripheral blood mononuclear cells obtained from healthy adults with live-attenuated VZV with or without prednisolone, cyclosporine-A, or tacrolimus. The circulating numbers of lymphocytes in the convalescent stage but not acute stage were lower in immunocompromised children compared with immunocompetent children. In the acute stage, immunocompromised patients showed lower VZV-specific CD8+T-cell counts than immunocompetent subjects. In contrast, in the convalescent phase, immunocompromised patients had lower VZV-specific CD4+T-cell counts than immunocompetent hosts. The in vitro culture of activated lymphocytes with prednisolone or immunosuppressants significantly decreased the proportion of VZV-specific CD4+T-cells. In conclusion, the decreased numbers of VZV-specific CD8+T-cells during the acute phase and VZV-specific CD4+T-cells during the convalescent phase of disease may account for severe varicella in immunocompromised children.

Prognostic factors for survival of herpes simplex virus-associated hemophagocytic lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) occurs in neonates with disseminated infection of herpes simplex virus (HSV). Little has been reported on the control of rapid HLH progression. We studied the cytokine profile and genetic basis of two index cases with divergent outcomes after early treatment of type 2 HSV infection. One survivor had fever and elevated serum levels of tumor necrosis factor (TNF)-α, interleukin-6 (IL-6), interferon (IFN)-ß, and IFN-γ at diagnosis. The other neonate had no fever or TNF-α production, but significant IL-6 or IFN responses during the treatment course, and died 19 days after birth. Among 16 reported cases of neonatal HSV-HLH including index cases, eight deceased neonates experienced significantly less fever at presentation (p = 0.028), lower platelet counts (p = 0.019), and lower ratios of soluble IL-2 receptor (sIL-2R) to ferritin levels (p = 0.044) than eight survivors. The 100-day overall survival rates were significantly higher in patients with fever (p = 0.004), > 100 × 109/L of platelet counts (p = 0.035) or > 20 of sIL-2R/ferritin ratio at diagnosis (p = 0.004). The first febrile and cytokine responses to HSV infection predict the early outcome of neonatal HSV-HLH.

Transition of Bacterial Diversity and Composition in Tongue Microbiota during the First Two Years of Life.

Newborns are constantly exposed to various microbes from birth; hence, diverse commensal bacteria colonize the oral cavity. However, how or when these bacteria construct a complex and stable ecosystem remains unclear. This prospective cohort study examined the temporal changes in bacterial diversity and composition in tongue microbiota during infancy. We longitudinally collected a total of 464 tongue swab samples from 8 infants (age of <6 months at baseline) for approximately 2 years. We also collected samples from 32 children (aged 0 to 2 years) and 73 adults (aged 20 to 29 years) cross-sectionally as control groups. Bacterial diversities and compositions were determined by 16S rRNA gene sequencing. The tongue bacterial diversity in infancy, measured as the number of observed operational taxonomic units (OTUs), rapidly increased and nearly reached the same level as that in adults by around 80 weeks. The overall tongue bacterial composition in the transitional phase, 80 to 120 weeks, was more similar to that of adults than to that of the early exponential phase (EEP), 10 to 29 weeks, according to analysis of similarities. Dominant OTUs in the EEP corresponding to Streptococcus peroris and Streptococcus lactarius exponentially decreased immediately after EEP, around 30 to 49 weeks, whereas several OTUs corresponding to Granulicatella adiacens, Actinomyces odontolyticus, and Fusobacterium periodonticum reciprocally increased during the same period. These results suggest that a drastic compositional shift of tongue microbiota occurs before the age of 1 year, and then bacterial diversity and overall bacterial composition reach levels comparable to those in adults by the age of 2 years.IMPORTANCE Evaluating the development of oral microbiota during infancy is important for understanding the subsequent colonization of bacterial species and the process of formation of mature microbiota in the oral cavity. We examined tongue microbiota longitudinally collected from 8 infants and found that drastic compositional shifts in tongue microbiota occur before the age of 1 year, and then bacterial diversity and overall bacterial composition reach levels comparable to those in adults by the age of 2 years. These results may be helpful for preventing the development of various diseases associated with oral microbiota throughout life.

Late-onset sepsis and encephalopathy after bicycle-spoke injury: a case report.

BACKGROUND: Bicycle-spoke injuries rarely cause late complications of infection, including sepsis and sepsis-associated encephalopathy, with appropriate treatments. CASE PRESENTATION: We experienced a 2-year-old girl who developed the signs of encephalopathy with fever 6 months after a spoke-injury. On admission, the injured skin was inflamed with cellulitis. The blood culture was positive for methicillin-sensitive Staphylococcus aureus. Electroencephalogram showed diffuse slow-wave activity. Diffusion-weighted magnetic resonance imaging detected a high-intensity lesion with decreased diffusivity at the right frontal cortex. She received immunoglobulin and combined antibiotics treatments in the intensive care unit, and successfully overcame the sepsis-associated encephalopathy without neurological impairments. CONCLUSION: This is the first report demonstrating that sepsis and its associated encephalopathy occurs in a remote period after the bicycle-spoke injury.

An acute encephalopathy with reduced diffusion in BRAF-associated cardio-facio-cutaneous syndrome.

BACKGROUND: Cardio-facio-cutaneous syndrome (CFCS) is a rare genetic disorder characterized by cardiovascular anomalies, dysmorphic faces, ectodermal abnormalities and developmental delays. Mutations in BRAF and other RAS-MAPK pathway-associated genes are commonly identified in patients with CFCS. While this molecular pathway is known to be associated with neuro-inflammatory conditions, only one case with CFCS has been reported thus far to develop acute encephalopathy in childhood. CASE REPORT: A 3-year-old boy with dysmorphic features and mild psychomotor delay developed acute encephalopathy. After a 45-min long, generalized seizure, the magnetic resonance imaging revealed that the restricted diffusion signals spread to the bilateral subcortical white matters on day 1 of illness. Despite the 14 days of intensive care, the acute symptoms of encephalopathy left him intractable epilepsy and severe neurocognitive impairments. The whole-exome sequencing analysis identified a de novo heterozygous mutation of BRAF (NM_004333:p.Thr241Met) in this case. CONCLUSION: The present case suggests that the hyperactive condition of ERK signals might augment the development of acute encephalopathy and post-encephalopathic epilepsy in childhood.

Streptococcus pyogenes-purpura fulminans as an invasive form of group A streptococcal infection.

BACKGROUND: Streptococcus pyogenes is an uncommon pathogen of purpura fulminans, and the pathogenesis of S. pyogenes-purpura fulminans remains unclear because of paucity of cases. We reported a pediatric case of S. pyogenes-purpura fulminans with literature review of the disease. CASE PRESENTATION: A 3-year-old boy showed limping, lethargy and acral gangrene within 24 h. A diagnosis of S. pyogenes-purpura fulminans was made for bacterial isolation from throat and peripheral blood. Intensive therapy led to a survival with amputation of the left distal metatarsal bone, and normal development. The isolated M12 carried no mutation of csrS/R or rgg. Thrombophilia or immunodeficiency was excluded. DISCUSSION: Twelve-reported cases (9 pediatric and 3 elderly) of S. pyogenes-purpura fulminans started with shock and coagulopathy. Five patients age < 8 years had no underlying disease and survived. One youngest and two immunocompromised patients died. CONCLUSION: Streptococcus pyogenes-acute infectious purpura fulminans is a distinctive rare form of aggressive GAS infections.

A childhood-onset intestinal toxemia botulism during chemotherapy for relapsed acute leukemia.

BACKGROUND: Botulism is a potentially fatal infection characterized by progressive muscle weakness, bulbar paralysis, constipation and other autonomic dysfunctions. A recent report suggested that cancer chemotherapy might increase the risk for the intestinal toxemia botulism in both adults and children. CASE PRESENTATION: We report a 5-year-old boy, who developed general muscle weakness, constipation, ptosis and mydriasis during the third induction therapy for relapsed acute myeloid leukemia. He had recent histories of multiple antibiotic therapy for bacteremia and intake of well water at home. Repeated bacterial cultures identified Clostridium botulinum producing botulinum neurotoxin A. Botulinum toxin A was isolated from his stools at 17, 21, and 23 days after the onset. Symptoms were self-limiting, and were fully recovered without anti-botulinum toxin globulin therapy. CONCLUSION: This is the second report of a pediatric case with cancer chemotherapy-associated intestinal toxemia botulism. Our case provides further evidence that the immunocompromised status due to anti-cancer treatments increases the risk for the development of botulism at all ages in childhood.

Clinical efficacy of cycling empirical antibiotic therapy for febrile neutropenia in pediatric cancer patients.

BACKGROUND: Febrile neutropenia (FN) is the main treatment-related cause of mortality among children with cancer, as the prolonged use of broad-spectrum antibiotics can lead to antibiotic resistance in these patients. Antibiotic cycling has been reported to limit the emergence of antibiotic-resistant bacteria among adult patients. However, no studies have evaluated pediatric patients with FN. METHODS: Between September 2011 and February 2014, 126 pediatric cancer patients were admitted to our center for chemotherapy and/or hematopoietic stem cell transplantation and were included in this study. Retrospective and prospective data collection were performed before and after antibiotic cycling, respectively. Between September 2011 and November 2012 (before antibiotic cycling was implemented), intravenous cefpirome was used as the empirical therapy for FN. Between December 2012 and February 2014 (after antibiotic cycling was implemented), the monthly antibiotic cycling involved intravenous piperacillin-tazobactam (PIPC/TAZ), intravenous meropenem or ciprofloxacin (CPFX), and intravenous cefepime in that order. For children aged ≥13 years, the monthly cycling involved intravenous PIPC/TAZ, and CPFX was administered. RESULTS: The detection rates for extended-spectrum ß-lactamase producers in blood and stool culture samples decreased significantly after the implementation of antibiotic cycling (0.33/1000 patient-days vs 0/1000 patient-days, p = 0.03; 1.00/1000 patient-days vs 0/1000 patient-days, p < 0.01; respectively). CONCLUSION: Antibiotic cycling was associated with a decreased emergence of multidrug-resistant microbes.

Evaluation of Teicoplanin Trough Values After the Recommended Loading Dose in Children With Associated Safety Analysis.

BACKGROUND: This study evaluated whether the recommended teicoplanin loading dose (3 loading doses of 10 mg/kg every 12 hours) achieves a 15-30 µg/mL trough levels in 26 children (2-16 years). In addition, we examined the incidences of renal impairment and hepatic dysfunction in children treated with teicoplanin. METHODS: This retrospective study was conducted between October 2008 and March 2014. RESULTS: The percentage of patients with a trough level <10 and <15 µg/mL were 15.4% (4/26) and 46.2% (12/26), respectively. There were significant correlations between age and concentration/cumulative loading dose (C/D) ratio (P = 0.045), serum creatinine and C/D ratio (P < 0.001) and estimated glomerular filtration rate and C/D ratio (P = 0.005). Serum creatinine was significantly lower when trough levels were <15 µg/mL compared with ≥15 µg/mL. The incidences of renal impairment and hepatic dysfunction were 2.3% and 5.8%, respectively, with no significant difference between <20 and ≥20 µg/mL trough-level groups. CONCLUSIONS: The recommended loading dose may be insufficient to achieve 15-30 µg/mL in children with normal renal function. In addition, the target trough level ≥20 µg/mL for deep-seated infections seems to be safe in children.

Memory B-Cell Pools Predict the Immune Response to Pneumococcal Conjugate Vaccine in Immunocompromised Children.

BACKGROUND: The immune responses to pneumococcal conjugate vaccine (PCV) are low in immunocompromised hosts. The effect of memory B cells on the immune response to PCV remains elusive. METHODS: In this prospective study, 53 children who received 7-valent PCV were enrolled. Antipneumococcal immunoglobulin G (IgG) levels and opsonization index (OI) titers, along with lymphocyte subsets, were investigated in immunocompromised and immunocompetent hosts. Immunocompromised patients comprised 8 hematopoietic stem cell transplant recipients (group A) and 9 immunosuppressive therapy recipients (group B), and controls consisted of 14 children aged >1 year (group C) and 22 infants (group D). RESULTS: Serotype-specific IgG concentrations and OIs in group A were lower than those in group C. These did not differ among groups B, C, and D. The rates of achieving immunity (defined as an IgG level of 1.0 µg/mL and an OI of 8) in group A were also lower than in group C. Despite the sustained numbers of total T cells and B cells, CD27(+) B-cell and CD4(+) T-cell counts in group A were lower than those in group C. In group B, the immunoglobulin D-expressing CD27(-) B-cell count was only lower than that in group C. CONCLUSIONS: Circulating numbers of CD27(+) B cells, rather than CD4(+) T cells, may predict the effective PCV responses in immunocompromised children.

Identification of Pathogenic Cardiac CD11c+ Macrophages in Nod1-Mediated Acute Coronary Arteritis.

OBJECTIVE: Nod1 is an intracellular pattern recognition receptor for bacterial peptidoglycan fragments. We previously reported that a synthetic Nod1 ligand, FK565, induced acute coronary arteritis in mice similar to that of Kawasaki disease. However, the molecular mechanisms underlying this characteristic inflammation have remained elusive. APPROACH AND RESULTS: We found that CD11c(+)MHC class II(+) cells accumulated in the heart of FK565-treated mice before arteritis development. Morphological features and gene expression signatures of the cardiac CD11c(+)MHC class II(+) cells suggested that this population is closely related to macrophages, and thus, we designated them cardiac CD11c(+) macrophages. Nod1 in nonhematopoietic cells, rather than hematopoietic cells, was required for the increase of cardiac CD11c(+) macrophages and arteritis development. Among nonhematopoietic cells, cardiac endothelial cells produced a large amount of chemokines in response to FK565. Endothelial cell-specific blockade of Nod1 signaling suppressed FK565-induced expression of these chemokines, accumulation of cardiac CD11c(+) macrophages, and subsequent coronary arteritis development. We also found that CCR2(+)Ly6C(hi) inflammatory monocytes in peripheral blood supplied precursors of cardiac CD11c(+) macrophages. CCR2-deficient mice or pertussis toxin-treated mice exhibited decreased numbers of cardiac CD11c(+) macrophages and reduced arteritis. CONCLUSIONS: These results suggest that Ly6C(hi) monocytes are recruited to FK565-activated endothelial cells to generate cardiac CD11c(+) macrophages, which play a pivotal role in the pathogenesis of acute coronary arteritis.

Activation of an innate immune receptor, Nod1, accelerates atherogenesis in Apoe-/- mice.

Atherosclerosis is essentially a vascular inflammatory process in the presence of an excess amount of lipid. We have recently reported that oral administration of a nucleotide-binding oligomerization domain (Nod)-1 ligand, FK565, induced vascular inflammation in vivo. No studies, however, have proven the association between Nod1 and atherosclerosis in vivo. To investigate a potential role of NOD1 in atherogenesis, we orally administered FK565 to apolipoprotein E knockout (Apoe(-/-)) mice for 4 wk intermittently and performed quantification of atherosclerotic lesions in aortic roots and aortas, immunohistochemical analyses, and microarray-based gene expression profiling of aortic roots. FK565 administration accelerated the development of atherosclerosis in Apoe(-/-) mice, and the effect was dependent on Nod1 in non-bone marrow origin cells by bone marrow transplantation experiments. Immunohistochemical studies revealed the increases in the accumulation of macrophages and CD3 T cells within the plaques in aortic roots. Gene expression analyses of aortic roots demonstrated a marked upregulation of the Ccl5 gene during early stage of atherogenesis, and the treatment with Ccl5 antagonist significantly inhibited the acceleration of atherosclerosis in FK565-administered Apoe(-/-) mice. Additionally, as compared with Apoe(-/-) mice, Apoe and Nod1 double-knockout mice showed reduced development of atherosclerotic lesions from the early stage as well as their delayed progression and a significant reduction in Ccl5 mRNA levels at 9 wk of age. Data in the present study show that the Nod1 signaling pathway in non-bone marrow-derived cells contributes to the development of atherosclerosis.

Kawasaki disease-specific molecules in the sera are linked to microbe-associated molecular patterns in the biofilms.

BACKGROUND: Kawasaki disease (KD) is a systemic vasculitis of unknown etiology. The innate immune system is involved in its pathophysiology at the acute phase. We have recently established a novel murine model of KD coronary arteritis by oral administration of a synthetic microbe-associated molecular pattern (MAMP). On the hypothesis that specific MAMPs exist in KD sera, we have searched them to identify KD-specific molecules and to assess the pathogenesis. METHODS: We performed liquid chromatography-mass spectrometry (LC-MS) analysis of fractionated serum samples from 117 patients with KD and 106 controls. Microbiological and LC-MS evaluation of biofilm samples were also performed. RESULTS: KD samples elicited proinflammatory cytokine responses from human coronary artery endothelial cells (HCAECs). By LC-MS analysis of KD serum samples collected at 3 different periods, we detected a variety of KD-specific molecules in the lipophilic fractions that showed distinct m/z and MS/MS fragmentation patterns in each cluster. Serum KD-specific molecules showed m/z and MS/MS fragmentation patterns almost identical to those of MAMPs obtained from the biofilms formed in vitro (common MAMPs from Bacillus cereus, Yersinia pseudotuberculosis and Staphylococcus aureus) at the 1st study period, and from the biofilms formed in vivo (common MAMPs from Bacillus cereus, Bacillus subtilis/Bacillus cereus/Yersinia pseudotuberculosis and Staphylococcus aureus) at the 2nd and 3rd periods. The biofilm extracts from Bacillus cereus, Bacillus subtilis, Yersinia pseudotuberculosis and Staphylococcus aureus also induced proinflammatory cytokines by HCAECs. By the experiments with IgG affinity chromatography, some of these serum KD-specific molecules bound to IgG. CONCLUSIONS: We herein conclude that serum KD-specific molecules were mostly derived from biofilms and possessed molecular structures common to MAMPs from Bacillus cereus, Bacillus subtilis, Yersinia pseudotuberculosis and Staphylococcus aureus. Discovery of these KD-specific molecules might offer novel insight into the diagnosis and management of KD as well as its pathogenesis.

The utility of biomarkers in differentiating bacterial from non-bacterial lower respiratory tract infection in hospitalized children: difference of the diagnostic performance between acute pneumonia and bronchitis.

The aim of this study is to investigate the utility of several biomarkers in differentiating bacterial community-acquired lower respiratory tract infection (CA-LRTI) from non-bacterial CA-LRTI in children and the difference of their diagnostic performance between pneumonia and bronchitis. A retrospective cohort study composed of 108 pediatric patients hospitalized for CA-LRTI was performed during 2010-2013. Based on the findings of chest X-ray and sputum samples, patients were divided into 4 categories, group of bacterial pneumonia or bronchitis, and non-bacterial (viral or etiology-unknown) pneumonia or bronchitis. Peripheral white blood cell and neutrophil counts, and serum C-reactive protein (CRP) and procalcitonin (PCT) levels were compared among the 4 groups. Finally, 54 patients were the subject of this study. In the patients with pneumonia, serum CRP and PCT levels were significantly elevated in the group of bacterial pneumonia (CRP: p = 0.02, PCT: p = 0.0008). The area under the receiver operating characteristic curve for PCT for distinguishing between bacterial and non-bacterial pneumonia was the largest, and sensitivity, specificity, positive predictive value and negative predictive value of PCT were best among 4 markers. On the other hand, in the patients with bronchitis, neutrophil count was significantly decreased in non-bacterial bronchitis whereas no significant differences of WBC count, CRP level or PCT level were seen. In conclusion, PCT was the most useful marker to differentiate bacterial pneumonia whereas neutrophil count contributed most to the discrimination of bacterial bronchitis. The diagnostic performance of biomarkers may be different between pneumonia and bronchitis.

Nod1 ligands induce site-specific vascular inflammation.

OBJECTIVE: The goal of this study was to investigate the effects of stimulants for a nucleotide-binding domain, leucine-rich repeat-containing (NLR) protein family on human artery endothelial cells and murine arteries. METHODS AND RESULTS: Human coronary artery endothelial cells were challenged in vitro with microbial components that stimulate NLRs or Toll-like receptors. We found stimulatory effects of NLR and Toll-like receptor ligands on the adhesion molecule expression and cytokine secretion by human coronary artery endothelial cells. On the basis of these results, we examined the in vivo effects of these ligands in mice. Among them, FK565, 1 of the nucleotide-binding oligomerization domain (Nod)-1 ligands induced strong site-specific inflammation in the aortic root. Furthermore, coronary arteritis/valvulitis developed after direct oral administration or ad libitum drinking of FK565. The degree of the respective vascular inflammation was associated with persistent high expression of proinflammatory chemokine/cytokine and matrix metallopeptidase (Mmp) genes in each tissue in vivo by microarray analysis. CONCLUSIONS: This is the first coronary arteritis animal model induced by oral administration of a pure synthetic Nod1 ligand. The present study has demonstrated an unexpected role of Nod1 in the development of site-specific vascular inflammation, especially coronary arteritis. These findings might lead to the clarification of the pathogenesis and pathophysiology of coronary artery disease in humans.

[Alveolar rhabdomyosarcoma of unknown origin mimicking acute leukemia at the initial presentation].

A 14-year-old boy presented with a short history of general fatigue. Laboratory examination of the peripheral blood revealed white blood cells 11,300/microl, hemoglobin 10.4 g/dl, platelets 45,000/microl, fibrinogen < 50 mg/dl, fibrin/fibrinogen degradation products 536 microg/ml and lactate dehydrogenase 1,684 U/l. A bone marrow aspirate contained 89.6% of undifferentiated tumor cells. A hematological malignancy was suspected and the patient was treated with idarubicin and cytarabine. However, further examination revealed that tumor cells were positive for CD56 and lacked lineage markers of lymphoid or myeloid cells. They were positive for PAS, HHF35 and desmin, and negative for MPO. Reverse transcriptase polymerase chain reaction demonstrated PAX3/FKHR fusion transcripts, confirming the diagnosis of alveolar rhabdomyosarcoma. Radiological examination revealed only one enlarged lymph node being 1.5 cm in diameter at the paraaortic region in the abdomen, and failed to find a primary tumor. After three courses of chemotherapy containing etoposide, cyclophosphamide, pirarubicin, cisplatin and vincristine, tumor cells were eradicated from the bone marrow. The patient received an allogeneic bone marrow transplantation eight months after diagnosis, although he died of hepatic veno-occlusive disease on day 21. Alveolar rhabdomyosarcoma often develops in older children and younger adults, and its bone marrow infiltration may mimic acute leukemia.