Efficiency of the novel quenching-probe PCR method to detect 23S rRNA mutations in children with Mycoplasma pneumoniae infection.

An automated rapid molecular diagnostic kit (Smart Gene Myco) was recently developed for individual detection of Mycoplasma pneumoniae (MP) genes. This new testing approach requires no special equipment and skills and can be completed within 50 min. We prospectively evaluated this diagnostic kit, along with other conventional tests, for pneumonia diagnosis in children. Samples from 98 children (50 boys and 48 girls; aged 1-14 years; mean: 4.7 ± 2.1 years; median: 4 years) clinically diagnosed with pneumonia were tested for MP using real-time polymerase chain reaction (RT-PCR) as a reference method. Results from three molecular diagnostic tests, serum anti-MP antibodies, and MP culture were compared to RT-PCR data. Among the 98 children, 38 were positive for MP. All molecular diagnostic results showed complete concordance with the RT-PCR data. The sensitivity of the culture was 64%, whereas the sensitivities of the ImmunoCard Mycoplasma and SERODIA Myco II kits were lower (39% and 29%, respectively). Furthermore, a significant positive correlation was found between MP copy numbers and the culture test sensitivity (r = 0.95, p = 0.048). Macrolide-resistance mutations in the 23S ribosomal RNA gene were detected in 24 of 38 children using Smart Gene Myco based on quenching-probe PCR, which was confirmed by direct sequencing, revealing all mutations as A2063G. This is the first study to evaluate the clinical utility of the Smart Gene Myco kit, demonstrating that it is a fast and reliable method to support timely therapeutic decisions in children with MP pneumonia.

Large-vessel vasculitis induced by granulocyte colony-stimulating factor administration after chemotherapy.

Granulocyte colony-stimulating factor (G-CSF) is a relatively new drug that is used for recovery of chemotherapy-associated neutropenia. It is known to cause bone pain, headache and fatigue as side-effects; however, large-vessel vasculitis is extremely rare and its relation with G-CSF remains unknown. We describe a 49-year-old woman in whom arteritis developed after chemotherapy and subsequent G-CSF administration. She had experienced pinealoma 3 months ago and received surgery and chemotherapy, leading to neutropenia. After administration of lenograstim at 100 µg/day for 1 week, high fever and neck pain appeared. White blood cell count and serum levels of C-reactive protein and interleukin-6 were increased to 37,930/µL, 23.71 mg/dL, and 241 pg/mL, respectively. Contrast-enhanced computed tomography revealed thickened walls of large vessels including the bilateral common carotid artery (CCA), right brachiocephalic artery, and ascending aorta. Ultrasonography showed wall thickening of the CCA (maximum of intima media thickness: right, 2.9 mm; left, 3.2 mm). As differential diagnoses, infection, chemotherapy, autoimmune diseases, and cancer were considered other than G-CSF. Blood culture tests, lumbar puncture, ß-D-glucan tests, and tests for viral antibodies indicated no active infection, and autoantibodies were negative. Empirical antibiotic therapy was ineffective. The score of Naranjo's algorithm to lenograstim was 6, indicating "probable" causality. Considering the clinical course and test results, we made a diagnosis of G-CSF-associated arteritis and commenced glucocorticoid therapy, which drastically improved the symptoms and inflammation. Clinicians should be aware of this uncommon but significant complication of GCS-F administration, for which glucocorticoid treatment can be a useful therapeutic option.

Critical Endothelial Regulation by LRP5 during Retinal Vascular Development.

Vascular abnormalities in the eye are the leading cause of many forms of inherited and acquired human blindness. Loss-of-function mutations in the Wnt-binding co-receptor LRP5 leads to aberrant ocular vascularization and loss of vision in genetic disorders such as osteoporosis-pseudoglioma syndrome. The canonical Wnt-ß-catenin pathway is known to regulate retinal vascular development. However, it is unclear what precise role LPR5 plays in this process. Here, we show that loss of LRP5 function in mice causes retinal hypovascularization during development as well as retinal neovascularization in adulthood with disorganized and leaky vessels. Using a highly specific Flk1-CreBreier line for vascular endothelial cells, together with several genetic models, we demonstrate that loss of endothelium-derived LRP5 recapitulates the retinal vascular defects in Lrp5-/- mice. In addition, restoring LRP5 function only in endothelial cells in Lrp5-/- mice rescues their retinal vascular abnormalities. Furthermore, we show that retinal vascularization is regulated by LRP5 in a dosage dependent manner and does not depend on LRP6. Our study provides the first direct evidence that endothelium-derived LRP5 is both necessary and sufficient to mediate its critical role in the development and maintenance of retinal vasculature.