Allogeneic blood and marrow transplant patients are highly susceptible to invasive fungal infection prior to engraftment, due to neutropenia and mucosal injury. After engraftment, an impairment of cell mediated immunity from graft-versus-host disease (GVHD) and the use of aggressive immunosuppressive therapies, such as corticosteroids, leave patients vulnerable to invasive fungal infections. Recipients of alternate donor transplants are especially susceptible due to slow reconstitution of cell mediated immunity.