Impact of dexamethasone on mDCs in the presence of IMiDs. (A) mDCs were incubated with LEN and/or TSLP and the indicated concentrations of dexamethasone (DEX). Annexin-V and CD86 expressions after 24-hour culture and OX40L expression after 48 hours on mDCs were analyzed by flow cytometry. Data indicate the mean fluorescence intensity (MFI), calculated by subtracting the MFI of the isotype control-treated cells from the MFI of the cells treated with the indicated monoclonal antibody. After 24 hours of culture, CCL17 concentration in the supernatants was analyzed by an ELISA. Each experiment was performed using DCs from a single donor, and data are shown as the mean ± SEM of 4 independent donors. (B) CRTH2⁺CD4⁺ T cells were cultured for 7 days with allogeneic mDCs pretreated for 24 hours with TSLP + 0.3 μM LEN in the presence or absence of the indicated concentrations of DEX. After culture, cytokine production by primed CD4⁺ T cells was measured in supernatants after restimulation for 24 hours with anti-CD3 and soluble anti-CD28 antibodies at a concentration of 10⁶ cells/mL. A single experiment was performed using DCs from 1 donor and T cells from another allogenic donor, and data are the means ± SEM of 3 independent experiments. Statistical significance was determined using a paired Student t test (**P < .01).