Takefumi Yamaguchi

Prediction of the Pathogens That Are the Cause of Pneumonia by the Battlefield Hypothesis

Commensal organisms are frequent causes of pneumonia. However, the detection of these organisms in the airway does not mean that they are the causative pathogens; they may exist merely as colonizers. In up to 50% cases of pneumonia, the causative pathogens remain unidentified, thereby hampering targeting therapies. In speculating on the role of a commensal organism in pneumonia, we devised the battlefield hypothesis. In the “pneumonia battlefield,” the organism-to-human cell number ratio may be an index for the pathogenic role of the organism. Using real-time PCR reactions for sputum samples, we tested whether the hypothesis predicts the results of bacteriological clinical tests for 4 representative commensal organisms: Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas spp., and Moraxella catarrhalis. The cutoff value for the organism-to-human cell number ratio, above which the pathogenic role of the organism was suspected, was set up for each organism using 224 sputum samples. The validity of the cutoff value was then tested in a prospective study that included 153 samples; the samples were classified into 3 groups, and each group contained 93%, 7%, and 0% of the samples from pneumonia, in which the pathogenic role of Streptococcus pneumoniae was suggested by the clinical tests. The results for Haemophilus influenzae, Pseudomonas spp., and Moraxella catarrhalis were 100%, 0%, and 0%, respectively. The battlefield hypothesis enabled legitimate interpretation of the PCR results and predicted pneumonia in which the pathogenic role of the organism was suggested by the clinical test. The PCR reactions based on the battlefield hypothesis may help to promote targeted therapies for pneumonia. The prospective observatory study described in the current report had been registered to the University Hospital Medical Information Network (UMIN) registry before its initiation, where the UMIN is a registry approved by the International Committee of Medical Journal Editors (ICMJE). The UMIN registry number was UMIN000001118: A prospective study for the investigation of the validity of cutoff values established for the HIRA-TAN system (April 9, 2008).

HIRA-TAN: A real-time PCR-based system for the rapid identification of causative agents in pneumonia

UNLABELLED Identification of the causative pathogen(s) of pneumonia would allow the selection of effective antibiotics and thus reduce the mortality rate and the emergence of drug-resistant pathogens. To identify such pathogens and to obtain these benefits, it is necessary that a clinical test is rapid, accurate, easily performed, and cost-effective. Here, we devised a PCR-based test, named HIRA-TAN, which is able to discriminate therapeutic targets from commensal organisms (e.g. Streptococcus pneumoniae or Haemophilus influenzae) and to detect foreign organisms (e.g. Mycoplasma pneumoniae or Legionella pneumophila) in the sputum. The utility of this system was validated in a prospective study, using sputum samples from patients with pneumonia. 568 patients were enrolled and the HIRA-TAN assay identified the causative pathogens with an accuracy of 96.7% for H. influenzae; 93.2% for Pseudomonas aeruginosa; 80.6% for Klebsiella pneumoniae; 90.9% for Moraxella catarrhalis; 87.5% for Escherichia coli; 78.1% for MRSA and 91.6% for S. pneumoniae. Overall the HIRA-TAN procedure was able to identify the causative pathogens of pneumonia in 60% of the cases. Additionally, this procedure was able to determine when the pneumonia-causing organism was a commensal organism or a foreign organism in a single assay. The HIRA-TAN approach yielded reproducible results and provided valuable information to plan the course of treatment of pneumonia. Through the rapid identification of the causative pathogens, the HIRA-TAN will promote targeted treatments for pneumonias. CLINICAL TRIALS REGISTRATION UMIN000001694.

Salbutamol Modulates the Balance of Th1 and Th2 Cytokines by Mononuclear Cells from Allergic Asthmatics

Background: There is evidence that excessive use of inhalational β2-agonists induces the deterioration of asthma. Although the exact mechanism of this remains to be elucidated, overuse of β2-agonists may impair the Th1/Th2 balance in asthmatic airways. The aim of the present study was to evaluate whether salbutamol, a representative inhalational β2-agonist, modifies the production of Th1- and Th2-type cytokines by mononuclear cells separated from patients with asthma and healthy volunteers. Methods: Peripheral blood mononuclear cells (PBMCs) obtained from 8 healthy volunteers and 10 patients with mild persistent asthma allergic to house dust mites were treated with either salbutamol or medium alone. PBMCs were then stimulated with either medium alone, house dust mite (Dermatophagoides farina, Df) allergen or a combination of ionomycin plus phorbol 12-myristate 13-acetate ester (PMA). Concentrations of IFN-γ, IL-13, TNF-α and RANTES in the cell supernatants were measured using ELISA. Results: In PBMCs from healthy volunteers, salbutamol did not modify IFN-γ production, but increased the spontaneous production of IL-13. In contrast, salbutamol significantly inhibited the spontaneous and ionomycin- plus PMA-stimulated production of IFN-γ by PBMCs from asthmatics. Salbutamol significantly enhanced both spontaneous and Df-induced production of IL-13 by PBMCs from asthmatics. Salbutamol did not modify the production of TNF-α. Finally, salbutamol enhanced the production of RANTES induced by Df allergen in asthmatics. Conclusions: Salbutamol inhibits IFN-γ and enhances IL-13 production by PBMCs from asthmatics. These effects would promote a Th1/Th2 imbalance in the airways and may therefore contribute to the deterioration of asthma.

Phase II study of nimustine hydrochloride (ACNU) plus paclitaxel for refractory small cell lung cancer.

PURPOSE Bi-weekly administrations of nimustine hydrochloride (ACNU) plus paclitaxel were evaluated in this phase II study in patients with refractory small cell lung cancer (SCLC). METHODS Patients who had disease progression within 3 months after treatment with irinotecan (CPT-11)-containing regimens were entered. They were treated with every other week administrations of ACNU 50 mg/m(2) plus paclitaxel 110 mg/m(2) on day 1 over 2 weeks. RESULTS Twenty-four patients (20 males and 4 females, median age of 64 years, 17 patients with Eastern Cooperative Oncology Group [ECOG] performance status [PS] 0-1 and 7 patients with PS 2) participated in the trial. Of the 24 refractory patients after CPT-11 containing regimens, 17 patients had been given etoposide plus platinum. There were six partial responses, and an overall response rate of 25% (95% confidence interval, 10-46%) was obtained. The median time to progression and the median survival time after enrollment into this study were 2.8 and 5.8 months, respectively. The median overall survival from the first-line treatment was 19.5 months. The major toxicity was myelosuppression. Grade 4 neutropenia occurred in 13% of patients, and Grade 4 thrombocytopenia was observed in 13% of patients. There was one treatment-related death, attributed to pneumonitis. CONCLUSION Bi-weekly administrations of ACNU plus paclitaxel provided a practical and well-tolerated regimen that was active for CPT-11-refractory SCLC.

Changes in Airway Inflammation and Hyperresponsiveness after Inhaled Corticosteroid Cessation in Allergic Asthma

Background: Most patients with asthma are currently controlled by pharmacotherapeutic means such as inhaled corticosteroid (ICS). However, whether ICS actually induces remission of asthma remains unknown. The present study evaluates changes in airway inflammation and hyperresponsiveness in adult patients with asthma after stopping ICS. Methods: We enrolled 11 patients with allergic asthma (7 males and 4 females; mean age, 52.3 years) who had been asymptomatic and had no exacerbation by low-dose ICS. Airway hyperresponsiveness (AHR) was assessed using methacholine challenge, and induced sputum was evaluated before and every 3 months after ICS cessation during the 1-year follow-up. Results: Among the 11 asthmatics, AHR increased in 10 (90.9%) and asthma clinically relapsed in 4 (36.4%) within 1 year of ICS cessation. AHR increased in all 7 asthmatics that were sensitized to Dermatophagoides farinae and asthma clinically relapsed in 4 (57.1%) of them. Furthermore, eosinophil numbers and IL-4 concentrations in the sputum significantly increased after ICS cessation. Conclusions: Remission with normal airway response to methacholine (no AHR) might be rare in adult patients with allergic asthma, and sensitization to house dust mites appears to play an important role in relapse. Therefore, ICS cessation should be carefully considered in patients sensitive to house dust mites. Serial determination of eosinophil counts or IL-4 concentrations in sputum might be appropriate for monitoring and preventing asthma relapse in adults.