- Have any medical illnesses that in the opinion of the investigators would a.) increase the risk the participant would incur by participating in the study, b.) interfere with the measured outcomes of the study, or c.) interfere with the performance of the study procedures. Examples of such diseases are: phenylketonuria, cystic fibrosis, bronchiectasis, Type 1 diabetes, hemophilia, Von Willebrands disease, sickle cell disease, cerebral palsy, rheumatoid arthritis, lupus, psoriasis, hyperimmunoglobulin E syndrome, parasite infections, Wiskott-Aldrich syndrome, or allergic bronchopulmonary aspergillosis.