RESUMO
BACKGROUND: Neutrophils are the most abundant cell type infiltrating the airways during severe respiratory syncytial virus (RSV) infection. Their exact role in disease pathophysiology remains enigmatic. Therefore, we determined genome-wide RNA expression profiles of local and systemic neutrophils in RSV bronchiolitis to provide further insight into local neutrophil biology. METHODS: We performed a single-center analysis, in 16 infants, admitted to the pediatric intensive care unit with severe RSV bronchiolitis. Neutrophils were isolated from blood and tracheobronchial aspirates (sputum). After low input RNA sequencing, differential expression of genes was determined followed by gene set analysis. RESULTS: Paired transcriptomic analysis of airway versus blood neutrophils showed an inflammatory phenotype, characterized by NF-kB signaling and upregulated expression of IL-6 and interferon pathways. We observed distinct expression of neutrophil activation genes (TNFSF13B, FCER1G). DISCUSSION: Our data indicate that airway neutrophils regulate their function at the transcriptional level in response to viral infection. It also suggests that local interferon drives the neutrophil response of severe RSV bronchiolitis.
Assuntos
Bronquiolite/genética , Bronquiolite/imunologia , Neutrófilos/imunologia , Infecções por Vírus Respiratório Sincicial/genética , Infecções por Vírus Respiratório Sincicial/imunologia , Transcriptoma , Fator Ativador de Células B/genética , Bronquiolite/sangue , Feminino , Humanos , Lactente , Interferons/imunologia , Pulmão/citologia , Pulmão/imunologia , Masculino , NF-kappa B/imunologia , RNA , Receptores Fc/genética , Infecções por Vírus Respiratório Sincicial/sangueRESUMO
During severe respiratory syncytial virus (RSV) bronchiolitis there is a massive influx of activated neutrophils to the lungs. An exaggerated immune response contributes to lung damage and disease severity during RSV infection. We have previously shown that normal adult neutrophil function can be modulated by agonists of SIRL-1. Here we aimed to measure the potential of two immune checkpoints: SIRL-1 and LAIR-1, to regulate the function of fresh blood and sputum neutrophils from infants with and without severe RSV bronchiolitis. We show a modest inhibition of the oxidative burst through SIRL-1 and LAIR-1, in control and RSV-infected infants. In addition, SIRL-1 and LAIR-1 inhibited neutrophil extracellular traps (NET) formation by sputum neutrophils of RSV patients. Altogether our data show that inhibitory receptors LAIR-1 and SIRL-1 can be used to regulate neutrophil function.