Interferon-Beta (INFβ) Reprograms Pathogenic Lung Dendritic Cells in Human Chronic Lung Allograft Dysfunction (CLAD)

Abstract

Dendritic cells (DC) are central to the induction and maintenance of T regulatory cells (T-regs) and lung allograft tolerance. We previously identified a TNFR2+ subset of CD11b+CD24+CD64- lung resident DC (TNFR2+DC) in mice. TNFR2+DC is responsible for the Th2 response and inflammation in mice. Interestingly, TNFR2+DC is plastic and intra-nasal administration of IFNβ reprograms TNFR2+DC to generate T-regs in the lung and reversed lung inflammation in mice. We hypothesize that a healthy human donor lung has a phenotypically similar tolerogenic TNFR2+DC, which becomes inflammatory in CLAD, and treatment with IFNβ reprogram TNFR2+DC to a tolerogenic phenotype. Single-cell suspensions prepared from the healthy human donor lungs during the lobar transplantation, and CLAD tissue from patients undergoing re-transplantation at the University of Florida. Identification of TNFR2+DC populations and the response to IFNβ (200ng IFNβ, R&D systems INC) were investigated with fluorescent-dye-conjugated antibodies and flow cytometry analysis. We identified the TNFR2+DC population in both healthy donor lungs and CLAD lungs (n=4/group) (Figure 1A). The healthy lung TNFR2+DC constitutively express TGFβ1, IDO-1, and Arg-1, which are similar to tolerogenic DC in mouse lungs. Conversely, TNFR2+DC from CLAD patients had decreased TGFβ1, Arg-1, PD-L1, but increased IL-4 and IL-23 expression (Figure 1B). Lastly, treatment with IFNβ increased TGFβ1, Arg1, and decreased IL-4 expression in CLAD TNFR2+DC (n=2). Thus, similar to mice, treatment with IFNβ reprograms pathogenic TNFR2+DC in CLAD to phenotypically tolerogenic DC (Figure 1C). This is the first report of TNFR2+DC, a subset of lung resident DC, in healthy human lung and CLAD tissue. TNFR2+DC is plastic, and IFNβ reprograms TNFR2+DC from a pathogenic to a tolerogenic phenotype. Further studies are required to assess the utility of TNFR2+DC plasticity for achieving lung allograft tolerance.