AST is pleased to announce its guest symposium program for AAI's Immunology 2012^TM. The program, entitled "Co-stimulatory and Co-inhibitory Pathways in Transplantation", features four lectures by experts in the field. The meeting takes place in Boston from May 4-8, 2012, and the AST symposium is on May 7. Complete information, including registration and housing details, can be found on the AAI conference website at www.immunology2012.org.