Dr. Posever graduated from Northwestern University Medical School and completed internship at McGaw Medical Center of Northwestern University, residency at Oregon Health Sciences University, and fellowship in rheumatology at Stanford University. His training has included research fellowships in cartilage biology at The University of Chicago and immunology at Stanford University. In addition, he has participated in over thirty clinical trials of biologic agents used for treatment of rheumatic diseases, such as osteoarthritis, rheumatoid arthritis, and systemic lupus erythematosis. His position at the University of Arizona encompasses clinical and research duties, including clinical and basic research. His clinical research interests are in development of new therapies and subset analysis of patients to allow prediction of therapy response. His basic research focuses on the therapeutic potential of naturally occurring immunologic mechanisms to limit autoimmunity (e.g., regulatory T cells) and of growth factors to stimulate cartilage regeneration.