Pediatric tolerogenic DCs expressing CD4 and immunoglobulin-like transcript receptor (ILT)-4 secrete IL-10 in response to Fc and adenosine.

We characterized a novel population of tolerogenic myeloid dendritic cells (tmDCs) defined as CD11c CD11b CD14 CD4 and immunoglobulin-like transcript receptor (ILT)-4 that are significantly more abundant in the circulation of infants and young children than in adults. TmDCs secrete the immunosuppressive lymphokine interleukin (IL)-10 when stimulated with the heavy constant region of immunoglobulins (Fc) and express high levels of the adenosine A receptor (A R), which, when activated by adenosine, inhibits the release of pro-inflammatory cytokines from most immune cells. Here we show that stimulation of the A R on tmDCs by regadenoson or N-ethylcarboxamidoadenosine (NECA) rapidly increases cyclic AMP accumulation and enhances IL-10 production under Fc stimulatory conditions.