The Immunocompromised Host Section has developed a series of sensitive and highly specific PCR assays for the detection of these life-threatening infections. We also have characterized the expression of cell wall derived biomarkers, (1-3)-Beta-D-glucan and galactomannan in vitro and in vivo. Laboratory animal studies indicate that these assays may complement current diagnostic modalities and allow for more accurate and earlier detection of invasive pulmonary fungal infections in immunocompromised patients.