Effect of a 10,000 EU Dose of Endotoxin in Allergic and Mildly Asthmatic Adults

The purposes of this pilot safety study are to identify a dose of inhaled Clinical Center Reference Endotoxin (CCRE) that is well tolerated by allergic subjects that induces measurable increases in neutrophil content of induced sputum that can be employed to screen large populations for susceptibility to the inflammatory effect of inhaled endotoxin.

Twenty-four or forty-eight hours (study day 1) prior to the inhalation challenge, subjects will undergo a physical examination of the ears, nose, throat and chest and will have an assessment of vital signs (temperature, pulse, respiratory rate, blood pressure), oxygen saturation, symptom score assessment and undergo spirometry to rule out acute illness prior to challenge. All female volunteers will undergo a urine pregnancy test. A similar examination will take place immediately prior to inhalation challenge with 10,000 EU of CCRE, as well as 30, 60, 120, 180, 240, 300 and 360 minutes and 24 hours after challenge (with the exception of a pregnancy test which will only be administered prior to sputum induction on study day 1). Induced sputum will be 24 to 48 hours prior to challenge, and again six hours after challenge on Study day 2. Sputum will be analyzed for PMN content, CD14 expression on airway macrophages and monocytes, soluble CD14 levels, cytokine levels in sputum and products of inflammatory cells (eosinophil, cationic protein, myeloperoxidase). Blood will be collected for a CBC and differential when the pre- challenge induced sputum is obtained and again 6 hours after challenge. Subjects will then be escorted to the GCRC for overnight admission. While on the GCRC, vital signs will be obtained every 2 hours till bedtime, then once a shift. Spirometry will not be obtained while the subject is in the GCRC, however the subject will be given symptom scoring cards. The next morning (study day 3) subjects will be discharged and escorted to the CEMALB for a final set of vital signs, spirometry, symptom scoring, and an examination by a study physician. Each volunteer will be given a symptom scoring sheet for each day up to 96 hours (4 days) after challenge. Each sheet will include the name and phone number of the study coordinator and study MD. Sample home symptom scoring sheets and instructions are included with this protocol. Between 48 and 96 hours after challenge, each volunteer will be called to determine their status, inquiring about symptoms, symptom scoring, and need for medication and/or physician visits. Between 7 and 10 days of the challenge dose, each subject will be asked to return for a study discontinuation visit. At that time temperature, pulse, systolic and diastolic BP, respiratory rate, FVC and FEV1 and SpO2 (oxygen saturation), and symptoms scores will be assessed and, if abnormal, medical evaluation as directed by the study physician will be undertaken.