IL-10-producing lung interstitial macrophages prevent neutrophilic asthma

In this study, we characterized AMs and IMs in healthy and inflammatory conditions. Pulmonary IMs constitutively produce the anti-inflammatory cytokine IL-10 through activation of the TLR4/MyD88 pathway in a microbiota-independent manner. In addition to IMs, Foxp3+ Treg cells show persistent IL-10 expression in the lung, with IL-10-producing IMs more prevalent than Foxp3+ Treg cells. IMs, but not Foxp3+ Treg cells, increased IL-10 production in house dust mite (HDM)-challenged mice, a model of human asthma. HDM-challenged Il10 –/– mice exhibited severe lung pathology characterized by neutrophilia compared with that of wild-type mice. In addition, transplantation of wild-type IMs reduced neutrophilic inflammation, goblet cell mucus production and decreased expression of lung IL-13 and Th17-related neutrophil-activating cytokines such as IL-17, GM-CSF, and TNF-α. Together these results demonstrate that IL-10-producing IMs negatively regulate Th2- and Th17-mediated inflammatory responses, helping prevent neutrophilic asthma.
Source: International Immunology - Category: Allergy & Immunology Authors: Tags: featured content Source Type: research