Risk stratification for invasive aspergillosis in immunocompromised patients.

Severe prolonged neutropenia, allogeneic hematopoietic stem cell or solid-organ transplantation, corticosteroids or other T cell suppressive agents, and other severe immunosuppressive factors have for many years been considered to predispose patients to invasive aspergillosis. Other conditions such as impaired innate immunity, diabetes, renal impairment, progression of the underlying malignancy, prior respiratory disease, and nosocomial or environmental exposure to fungal spores or climatic factors have recently been considered additional risk factors of invasive aspergillosis. The multiplicity of risk factors as well as the obvious synergy between them renders risk stratification difficult. An international, large-scale, multicenter, epidemiological study is necessary to develop a risk score.