Comparison of Microglial Activation in Severe Asthma and Healthy Controls

Inclusion Criteria: * Ability to understand and the willingness to sign a written informed consent document * Individuals with no health concerns that might affect the outcome of the study * Age 18-75 years of age * Ability to tolerate a simulated MRI brain scanning session * In the opinion of the investigator, capable and willing to grant written informed consent and cooperate with study procedures and requirements * High-affinity TSPO-binding genotype. Mixed (high/low) binding-affinity genotype may be included at PIs discretion * For participants with severe asthma: * Physician diagnosis of asthma for at least six months prior to screening (can be determined at the discretion of an asthma/allergy physician member of the study team) * Severe asthmatics must meet the ATS definition of severe asthma and/or be currently receiving a GINA Step 4 or 5 therapy or daily treatment of 320mcg budesonide. Therapy may include ongoing use of currently approved biologic immunomodulators Exclusion Criteria: * Current smoker (defined as more than 0.5 pack per week for the past 6 months and any smoking within two weeks of study procedures) or has a smoking history exceeding 5 pack years within the last 10 years * Currently receiving allergen immunotherapy unless on stable dose. * Use of psychotropic medication that might affect function of neurocircuitry implicated in our hypotheses (at the discretion of the PI/Co-I) * Inability to hold medications detailed in the medication hold sche…