The CXCL10-CXCR3 axis plays an important role in Kawasaki disease.

The precise pathogenesis of Kawasaki disease remains unknown. In an attempt to elucidate the pathogenesis of KD through the analysis of acquired immunity, we comprehensively examined the immunophenotypic changes in immune cells such as lymphocytes and monocytes along with various cytokines, focusing on differences between pre- and post- treatment samples. We found high levels of CXCL9 and CXCL10 chemokines that decreased with treatment, which coincided with a post-treatment expansion of Th1 cells expressing CXCR3. Our results show that the CXCL10-CXCR3 axis plays an important role in the pathogenesis of KD.

Analytical and clinical evaluation of a point-of-care molecular diagnostic system and its influenza A/B assay for rapid molecular detection of the influenza virus.

Recently, rapid molecular detection systems have been used for point-of-care testing for the diagnosis of influenza worldwide. Here, we evaluated the performance of the cobas Liat system and the cobas Influenza A/B assay (Liat) using fresh nasopharyngeal samples collected from a Japanese population between December 2017 and February 2018. The performance of the examination was compared with that of antigen testing and a conventional polymerase chain reaction (nested-PCR) method. A total of 159 patients were included in this study, and 77 tested positive using Liat. The concordance rate between Liat and nested PCR was 97.5%. The median time between the ordering of testing and completion of molecular analyses using Liat was 30 min (interquartile range: 28-35 min). The overall sensitivity and specificity of antigen testing were 57.1% and 100%, respectively. The duration from symptom onset to examination did not alter antigen testing sensitivity. The current study demonstrates the high performance of Liat for the rapid molecular identification of the influenza virus.

Implementation of Point-of-Care Molecular Diagnostics for Mycoplasma pneumoniae Ensures the Correct Antimicrobial Prescription for Pediatric Pneumonia Patients.

Mycoplasma pneumoniae is a leading causative pathogen of pneumonia among pediatric patients, and its accurate diagnosis may aid in the selection of appropriate antimicrobial agents. We established a rapid reporting system of a polymerase chain reaction (PCR) examination for M. pneumoniae that enables physicians to obtain test results approximately 90 minutes after ordering the test. In this study, we evaluated the impact of this system on antimicrobial prescriptions for pediatric pneumonia patients after its implementation from May 2016 to April 2017. In total, we identified 375 pediatric pneumonia patients, and the results of the rapid PCR examinations for Mycoplasma pneumoniae were reported immediately in 90.7% of patients (340/375), with physicians able to use these results to decide on patients' management before the prescription of antimicrobial agents. Of the 375 pediatric pneumoniae patients, M. pneumoniae was detected in 223 (59.5%). Among the 223 M. pneumoniae-positive pneumonia cases, antimicrobial agents for atypical pathogens (macrolides, tetracyclines or quinolones) were prescribed in 97.3% (217/223) at the initial evaluation, and their prescription rates increased to 99.1% (221/223) during management. In contrast, antimicrobial agents for atypical pathogens were prescribed only in 10.5% of 152 M. pneumoniae-negative pneumonia cases at the initial evaluations, and only 1 additional case was prescribed clarithromycin for persistent symptoms during management. In conclusion, we show that molecular technology could be applicable in the field of point-of-care testing in infectious disease, and its implementation will ensure the correct antimicrobial prescription for pediatric pneumonia patients.

Pulmonary interstitial emphysema due to respiratory syncytial virus infection.

Pulmonary interstitial emphysema (PIE) primarily affects premature infants on positive pressure ventilation. PIE is rarely reported in infants and children in the absence of mechanical ventilation and/or associated respiratory infection. We report a case of PIE in a 22-month-old girl who had severe respiratory distress due to respiratory syncytial virus infection. Chest computed tomography showed cystic lung lesions mimicking congenital cystic adenomatoid malformation. The cystic lesions spontaneously resolved after conservative treatment. Based on the clinical course and the chronological changes on imaging, the cystic lung lesions were diagnosed as localized persistent PIE.

Serum resistin concentrations in children with Kawasaki disease.

OBJECTIVE: Human resistin is expressed strongly in monocytes or macrophages rather than in adipocytes and may play a pivotal role in inflammation. We hypothesize that resistin levels are elevated in patients with Kawasaki disease (KD) in the acute phase and may be associated with the disease severity. DESIGN AND SUBJECTS: Serum resistin concentrations were measured in 44 Japanese children with KD and 17 age-matched healthy children. All the KD patients were given both aspirin and a single dose of intravenous immunoglobulin (IVIG). RESULTS: The serum resistin levels at baseline in KD children were significantly higher than those in controls [33.0 (21.6-45.3) vs. 14.8 (12.4-18.6) ng/mL, P < 0.001]. After IVIG therapy, serum resistin levels were significantly decreased to normal control levels. No significant difference in baseline resistin levels was found between the high-risk group and the low-risk group of coronary artery aneurysms. CONCLUSIONS: We confirmed that resistin was an acute inflammatory protein, but its concentrations were unlikely to predict the prognosis of disease in acute KD patients.

Clinical features and seasonal variations in the prevalence of macrolide-resistant Mycoplasma pneumoniae.

BACKGROUND: Mycoplasma pneumoniae is a common pathogen causing pneumonia; macrolide-resistant strains are rapidly spreading across Japan. However, the clinical features of macrolide-resistant M. pneumoniae pneumonia have not been well established. Here, we evaluated the clinical characteristics and seasonal variations in the prevalence of M. pneumoniae with macrolide-resistant mutations (MRM). METHODS: The monthly prevalence of MRM in M. pneumoniae strains isolated from May 2016 to April 2017 was retrospectively analyzed, and the clinical characteristics of pneumonia cases with MRM were compared to those of cases without MRM. The M. pneumoniae isolates and point mutations at site 2063 or 2064 in domain V of 23S rRNA were evaluated by the GENECUBE system and GENECUBE Mycoplasma detection kit. RESULTS: Mycoplasma pneumoniae infection was identified in 383 cases, including 221 cases of MRM (57.7%). The MRM prevalence was 86.3% (44/51) between May and July 2016, demonstrating an apparent decrease in September 2016, subsequently reaching 43.0% (34/79) in November 2016. Mycoplasma pneumoniae pneumonia was diagnosed in 275 cases, including 222 pediatric and 53 adult cases. Macrolide use preceding evaluation was found to be the only feature of MRM pneumonia cases both in children (odds ratio [OR] 3.86, 95% confidence interval [CI]:1.72-8.66) and in adults (OR 7.43, 95% CI: 1.67-33.1). CONCLUSIONS: The determination rate of MRM varied widely throughout the year, and our study demonstrated the challenges in predicting M. pneumoniae with MRM based on clinical features at diagnosis. Therefore, continuous monitoring of the prevalence of MRM is warranted, which may help in selecting an effective treatment.

Mild encephalitis/encephalopathy with a reversible splenial lesion: evaluation by diffusion tensor imaging. Two case reports.

Mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) is a clinico-radiological syndrome with a very particular clinical course. Three patients with MERS were evaluated by various sequences of magnetic resonance imaging with diffusion tensor imaging. Initial diffusion-weighted imaging showed reduction in the apparent diffusion coefficient values in the lesions, which completely resolved with the elimination of symptoms. However, diffusion anisotropy of the lesions showed no remarkable abnormalities in the early or delayed phases. These results may indicate that white matter architecture is preserved in both early and delayed phases in MERS.