The purpose of this study is to improve the applicability of islet transplantation for treatment of type 1 diabetes utilizing a novel immunosuppressive regimen centered on the use of adhesion molecule blockade with an anti-LFA-1 antibody (efalizumab). The lymphocyte-function associated antigen-1 (LFA-1) adhesion molecule is expressed on multiple cellular populations including T cells, B cells, and NK cells and is important in facilitating cell migration and homing. In addition, interaction of LFA-1 with its ligand ICAM-1 on antigen presenting cells provides a powerful costimulatory signal for T cell activation.