Use of granulocyte-macrophage colony stimulating factor (GM-CSF) in prevention and treatment of fungal infections

Characterization of human phagocyte-derived chitotriosidase, a component of innate immunity

Man has been found to produce highly conserved chitinases. The most prominent is the phagocyte-derived chitotriosidase, the plasma levels of which are markedly elevated in some pathological conditions. Here, we report that both polymorphonuclear neutrophils (PMNs) and macrophages (m) are a source of chitotriosidase. The enzyme is located in specific granules of human PMNs and secreted following stimulation with granulocyte macrophage colony-stimulating factor (GM-CSF). In addition, GM-CSF induces expression of chitotriosidase in m that constitutively secrete the enzyme and partly accumulate it in their lysosomes. Studies with recombinant human chitotriosidase revealed that the enzyme targets chitin-containing fungi. These findings are consistent with earlier observations concerning anti-fungal activity of homologous plant chitinases and beneficial effects of GM-CSF administration in individuals suffering from invasive fungal infections. In conclusion, chitotriosidase should be viewed as a component of the innate immunity that may play a role in defence against chitin-containing pathogens and the expression and release of which by human phagocytes is highly regulated.

Successful treatment of invasive aspergillosis in two patients with acute myelogenous leukemia

Invasive aspergillosis is a severe, devastating fungal infection that is seen in patients with hematologic malignancies and profound neutropenia. Despite aggressive treatment, the outcome is poor without neutrophil recovery. The authors describe two children with acute myelogenous leukemia (AML) with extensive invasive aspergillosis who were successfully treated both for their infection and the underlying malignancy. These patients were treated aggressively for their infections and simultaneously were able to complete treatment of their AML. Currently both patients are alive without evidence of fungal infection or AML. Patients with hematologic malignancies can survive severe, invasive aspergillosis during prolonged periods of neutropenia with a combination of antifungal and growth factor therapies, donor granulocyte infusions, and surgical debridement.