1. Division of Pulmonary and Critical Medicine, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA.
2. The Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA.
3. Department of Immunology, Mayo Clinic, Rochester, MN 55905, USA.
4. Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905, USA.
5. Long School of Medicine, Departments of Microbiology, Immunology, and Molecular Genetics, University of Texas Health San Antonio, San Antonio, TX 78229, USA.