Reduced Type-I Interferon by Plasmacytoid Dendritic Cells and Asthma in School-Aged Children.

BACKGROUND Allergic sensitization and reduced ability to respond to viral infections may contribute to virus-induced wheeze and asthma development in young children. Plasmacytoid dendritic cells (pDC) are rare immune cells that produce type I interferons (IFN-I) and play a key role in orchestrating immune responses against viruses. OBJECTIVE To further evaluate the function of pDC in children with asthma. METHODS This study was based on a subset of 71 children from the Early Life Lung Function (ELLF) cohort at the age of 7 years. As part of the ELLF study, participants were characterized for atopic sensitization, viral infection history, and lung function testing. pDC responses to a TLR7/8 agonist were assessed in the presence or absence of anti-IgE using an in vitro assay. Responses were evaluated utilizing flow cytometry, multiplexed cytokine assays, and transcriptional analysis of isolated pDC. RESULTS pDC responses varied considerably across individuals, and those who responded with IFN-I following stimulation showed a lower proportion of asthma compared to those who responded with TNF-only. A TNF-only response was associated with increased atopy and reduced upregulation of IFN-associated genes. Anti-IgE stimulation reduced pDC activation, and the reduction was associated with baseline expression of the IgE receptor (FcεR1). A reduction in a gene module centralized around genes such as TPM2, LILRA4, and CLEC4C was also observed. CONCLUSION Together, these findings suggest that pDC responses are variable, associated with asthma, and appear influenced by environmental stimuli. This response thus appears to be an important aspect of asthma pathology in children.