TNF-α–induced protein 3 levels in lung dendritic cells instruct TH2 or TH17 cell differentiation in eosinophilic or neutrophilic asthma

Background It is currently unknown why allergen exposure or environmental triggers in patients with mild-to-moderate asthma result in T H 2-mediated eosinophilic inflammation, whereas patients with severe asthma often present with T H 17-mediated neutrophilic inflammation. The activation state of dendritic cells (DCs) is crucial for both T H 2 and T H 17 cell differentiation and is mediated through nuclear factor κB activation. Ablation of TNF-α–induced protein 3 (TNFAIP3), one of the crucial negative regulators of nuclear factor κB activation in myeloid cells and DCs, was shown to control DC activation. Objective In this study we investigated the precise role of TNFAIP3 in myeloid cells for the development of T H 2- and T H 17-cell mediated asthma. Methods We exposed mice with conditional deletion of the Tnfaip3 gene in either myeloid cells (by using the lysozyme M [LysM] promotor) or specifically in DCs (by using the Cd11c promotor) to acute and chronic house dust mite (HDM)–driven asthma models. Results We demonstrated that reduced Tnfaip3 gene expression in DCs in either Tnfaip3 CD11c or Tnfaip3 LysM mice dose-dependently controlled development of T H 17-mediated neutrophilic severe asthma in both acute and chronic HDM-driven models, whereas wild-type mice had a purely T H 2-mediated eosinophilic inflammation. TNFAIP3-deficient DCs induced HDM-specific T H 17 cell differentiation through increased expression of the T H 17-instructing cytokines IL-1β, IL-6, and IL-23, whereas HDM-specific T H 2 cell differentiation was hampered by increased IL-12 and IL-6 production. Conclusions These data show that the extent of TNFAIP3 expression in DCs controls T H 2/T H 17 cell differentiation. This implies that reducing DC activation could be a new pharmacologic intervention to treat patients with severe asthma who present with T H 17-mediated neutrophilic inflammation.