Interleukin-17 is required for T helper 1 cell immunity and host resistance to the intracellular pathogen Francisella tularensis.

The importance of T helper type 1 (Th1) cell immunity in host resistance to the intracellular bacterium Francisella tularensis is well established. However, the relative roles of interleukin (IL)-12-Th1 and IL-23-Th17 cell responses in immunity to F. tularensis have not been studied. The IL-23-Th17 cell pathway is critical for protective immunity against extracellular bacterial infections. In contrast, the IL-23-Th17 cell pathway is dispensable for protection against intracellular pathogens such as Mycobacteria. Here we show that the IL-23-Th17 pathway regulates the IL-12-Th1 cell pathway and was required for protective immunity against F.tularensis live vaccine strain. We show that IL-17A, but not IL-17F or IL-22, induced IL-12 production in dendritic cells and mediated Th1 responses. Furthermore, we show that IL-17A also induced IL-12 and interferon-gamma production in macrophages and mediated bacterial killing. Together, these findings illustrate a biological function for IL-17A in regulating IL-12-Th1 cell immunity and host responses to an intracellular pathogen.

Precordial Catch Syndrome in Elite Swimmers With Asthma.

Precordial catch syndrome is a benign cause of chest pain in children and adolescents that remains underrecognized. Because of distinctive symptoms, precordial catch syndrome is not necessarily a diagnosis of exclusion. However, a detailed history eliciting diagnostic features is important, along with a physical examination excluding other pathologic disorders. We present the cases of 2 elite swimmers with asthma who had acute episodes of precordial catch syndrome, one associated with an acute asthma exacerbation and one not, while swimming during competitive swim meets that required rescue efforts for both and eventual evaluation in the emergency department.

Reduction of lipid-laden macrophage index after laparoscopic Nissen fundoplication in cystic fibrosis patients after lung transplantation.

BACKGROUND: Lipid-laden macrophage (LLM) index could be potentially useful in assessing gastroesophageal (GE) reflux and aspiration after lung transplantation (LT) in patients with cystic fibrosis (CF). METHODS: A retrospective review of CF patients undergoing LT and/or laparoscopic Nissen fundoplication (LNF) from January 1, 2009, to December 31, 2011, was performed. RESULTS: Seventeen CF patients (nine women), mean (± SD) age 27.9 ± 7.5 yr, underwent LT with mean (± SD) pre-transplant FEV(1) of 20.9 ± 5.0% predicted. Seventy percentage (12/17) of patients underwent LNF without complications within 1-2 wk of LT. After LT, but prior to antireflux surgery, there was no significant difference in the mean (± SD) baseline LLM index (154 ± 41 vs. 146 ± 51, p = NS) between patients who were to undergo LNF and patients who did not. After LNF, a significant reduction in the mean (± SD) LLM index occurred following the procedure (154 ± 41-74 ± 54, p < 0.0001) while each patient reported resolution of symptoms of GE reflux, whereas 40% (2/5) undergoing only medical treatment reported resolution of symptoms. CONCLUSIONS: Significant reduction in the LLM index occurred after LNF in CF patients after LT that correlated with resolution of clinical symptoms of GE reflux.

Radiation exposure from diagnostic imaging in the pediatric intensive care unit.

OBJECTIVE: To determine the range of radiation exposure from diagnostic imaging in children requiring mechanical ventilation. DESIGN: Prospective, observational. SETTING: Tertiary pediatric critical care unit. PATIENTS: We enrolled pediatric critical care unit patients requiring mechanical ventilation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Thoracic radiation exposure while the patient was in the pediatric critical care unit was measured using a small, radiolucent dosimeter secured to the anterior chest wall. Demographic data, diagnoses, and number and type of radiographic procedures were recorded. Differences between exposures by admission diagnoses were analyzed by rank sum test. Relationships between exposure and risk factors were assessed using multiple linear regression and Pearson correlation. Sixty-nine subjects were enrolled over a 175-day period. Subjects experienced a mean (± SD) of 11 ± 11 days of mechanical ventilation during which they underwent a mean of 14 ± 16 chest radiographs and 5 ± 4 other plain films. Subjects who had only plain radiographic studies (CXR group) had a median thoracic exposure of 1.02 (range, 0.13-28.26) mGy and a median daily exposure of 0.16 (range, 0.02-1.99) mGy/day. Subjects who had computed tomography and/or fluoroscopy studies in addition to plain radiographs (CXR+ group) had a median total thoracic exposure of 3.71 (range, 0.77-33.41) mGy and median daily exposure of 0.37 (range, 0.04-3.71) mGy/day, both of which were significantly higher than for subjects in the CXR group. There was no significant difference in average daily exposures according to admission diagnoses and daily exposure could not be predicted from a combination of variables, including age, body mass index, gender, or length of stay. Total number of radiologic studies was correlated, as expected, with duration of ventilation (r = 0.941, p < .0001). Exposure was significantly higher in patients who underwent computed tomography scans or fluoroscopy studies than in patients who only had plain radiography. CONCLUSIONS: Ventilated pediatric intensive care unit patients experienced an average daily thoracic radiation exposure above background environmental exposure and exposure varied widely, but exposures would not be expected to cause acute or chronic toxicity. Overall patient exposures were less than that received from 1 yr of natural background radiation.

The effect of mold sensitization and humidity upon allergic asthma.

INTRODUCTION: Humidity is commonly associated with increased airway hyperresponsiveness in asthma. OBJECTIVE: To examine mold sensitization in patients with allergic asthma or allergic rhinitis and self-reports of humidity as exacerbating factors of clinical symptoms. METHODS: A retrospective, cross-sectional study at a University hospital outpatient allergy and asthma clinic was performed. A total of 106 patients with either allergic asthma or allergic rhinitis completed standard prick-puncture skin testing with 17 allergens and controls and completed standardized forms addressing trigger factors for clinical symptoms. RESULTS: Allergic asthmatics sensitized to Cladosporium were more likely to have a more severe asthma severity class (odds ratio = 4.26, confidence interval = 1.30-16.93). Sensitization to Alternaria, Cladosporium, Helminthosporium, Aspergillus and Dermatophagoides pteronyssinus in asthma was associated with higher likelihood for previous hospitalization, while sensitization to Cladosporium, Helminthosporium, Aspergillus, Dermatophagoides pteronyssinus and cockroach in asthma was associated with higher likelihood of having reduced pulmonary function based on forced expiratory volume in 1s. Furthermore, allergic asthmatics more commonly reported humidity as an exacerbating factor of symptoms than did patients only with allergic rhinitis (68.42% vs 42.86%, respectively; P < 0.05). CONCLUSION: Mold sensitization is highly associated with more severe asthma, while humidity is more of an exacerbating factor in patients with allergic asthma as compared with allergic rhinitis alone. Further delineation between mold sensitization and humidity is needed to determine whether these are independent factors in asthma.