The Serum Opsonin L-ficolin Is Detected in Lungs of Human Transplant Recipients Following Fungal Infections and Modulates Inflammation and Killing of Aspergillus fumigatus

Stefan Bidula, Darren W Sexton, Alireza Abdolrasouli, Anand Shah, Anna Reed, Darius Armstrong-James, Silke Schelenz

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Background. Invasive aspergillosis (IA) is a life-threatening systemic fungal infection in immunocompromised individuals that is caused by Aspergillus fumigatus. The human serum opsonin, L-ficolin, has been observed to recognize A. fumigatus and could participate in fungal defense. 

Methods. Using lung epithelial cells, primary human monocyte-derived macrophages (MDMs), and neutrophils from healthy donors, we assessed phagocytosis and killing of L-ficolin–opsonized live A. fumigatus conidia by flow cytometry and microscopy. Additionally, cytokines were measured by cytometric bead array, and L-ficolin was measured in bronchoalveolar lavage (BAL) fluid from lung transplant recipients by enzyme-linked immunosorbent assay. 

Results. L-ficolin opsonization increased conidial uptake and enhanced killing of A. fumigatus by MDMs and neutrophils. Opsonization was also shown to manifest an increase in interleukin 8 release from A549 lung epithelial cells but decreased interleukin 1β, interleukin 6, interleukin 8, interleukin 10, and tumor necrosis factor α release from MDMs and neutrophils 24 hours after infection. The concentration of L-ficolin in BAL fluid from patients with fungal infection was significantly higher than that for control subjects (P = .00087), and receiving operating characteristic curve analysis highlighted the diagnostic potential of L-ficolin for lung infection (area under the curve, 0.842; P < .0001). 

Conclusions. L-ficolin modulates the immune response to A. fumigatus. Additionally, for the first time, L-ficolin has been demonstrated to be present in human lungs.

Original languageEnglish
Pages (from-to)234-246
Number of pages13
JournalJournal of Infectious Diseases
Issue number2
Early online date22 Jan 2015
Publication statusPublished - 15 Jul 2015

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