Autism spectrum disorders (ASD) are highly disabling, persistent neurodevelopmental
disorders. There are no available treatments for core symptoms of ASD or biologically-based
clinical biomarkers. Emerging evidence indicates that levels of brain inflammation are
increased in ASD. In particular, recent work implicates hyperactivity of microglial cells,
the resident immune cells of the brain. However, the functional consequences of microglial
activation remain unknown. This study will measure microglial activation in ASD using
positron emission tomography (PET) brain imaging. Adult males with ASD (n=15) and healthy
controls (n=15) will be recruited for this study and undergo comprehensive clinical and
behavioral baseline assessment. All subjects will then undergo baseline PET imaging using a
radiotracer that labels activated microglia. Subjects with ASD will then undergo 12-week open
label treatment with minocycline, an FDA-approved antibiotic thought to block microglial
activation. PET imaging will be repeated at 12 weeks to confirm target engagement. A subset
of control subjects will also undergo repeat PET imaging to determine test-retest
reliability. During minocycline treatment, ASD subjects will be evaluated every 2 weeks for
safety, clinical impression, behavioral functioning, and measures of cognition. Results will
provide important information regarding the relationship between levels of brain
inflammation, cognitive and behavioral function in ASD.