Research killing of Aspergillus fumigatus conidia by human alveolar macrophages in lung transplant patients. Influence corticosteroids

Philip B., O. Ibrahim-Granet, Stern, D. Grenet, A. Hatter, JP Latgé


Objective: To better understand the mechanisms of host defense against opportunistic pathogen Aspergillus fumigatus and pathophysiological of invasive aspergillosis, killing the conidia of A. fumigatus by alveolar macrophages in lung transplant patients was studied.

Methods: Alveolar macrophages from 19 lung transplant. Rating killing in vitro of 6:00 conidia of A. fumigatusfluorescein-labeled by the germination rate.

Results: 1) The killing of dormant conidia of A. fumigatus in vitro is low after 6 hours of incubation: 9%; 2) after phagocytosis, conidia swell (first stage of germination) inside the macrophage phagolysosome; 3) swollen conidia are killed at a higher rate by alveolar macrophages: 30%. Several factors affecting the killing were identified: a) the daily dose of prednisone> 0.25 mg / kg / day; b) total dose of prednisone> 1.5 mg / kg / day from the transplantation and c) the early period <6 months after transplantation, significantly reduce the level of killing; d) the presence of hyphae in BAL is associated with a low capacity for killing alveolar macrophages of the patient; e) the serum of patients Module killing by the MA.

Conclusion: This study is the first to assess the function of alveolar macrophages in immunocompromised patients.Swelling of the conidia of A. fumigatus is a prerequisite to the killing by alveolar macrophages. Corticosteroids alter the functions of killing human macrophages lung transplant patients.


Full conference title: 

Réunion Interdisciplinaire de Chimiothérapie Anti Infectieuse
    • RICAI 25th (2005)