Role of macrophages in host defense against aspergillosis and strategies for immune augmentation.

Invasive aspergillosis is a major cause of morbidity and mortality in highly immunocompromised patients with cancer. Alveolar macrophages ingest inhaled conidia (spores). Through pathogen recognition receptors that ligate fungal cell wall motifs, macrophages are able to coordinate the inflammatory response to Aspergillus species. Macrophages and dendritic cells play an important role in regulating the balance between the proinflammatory and anti-inflammatory cytokine responses that are required for recruitment and activation of neutrophils, and in augmenting or attenuating cellular immunity. Macrophages are therefore a target for immune augmentation strategies that include administration of cytokines, colony-stimulating factors, and pathogen recognition receptor ligands.