The androgen dihydrotestosterone (DHT) decreases pDC R-848-stimulated IFN-α production, but not TNF-α, in a dose-dependent manner. IFN-α and TNF-α production were measured by ELISA in cell-free culture supernatants from 5 × 104purified healthy adult female pDCs/well. pDC viability was measured by trypan blue exclusion and was similar in all groups (data not shown). a pDC IFN-α production due to R-848 1 μM stimulation; n = 5 independent experiments (% of pDC IFN-α production at DHT 0 μM). b pDC TNF-α production due to R-848 1 μM stimulation; n = 4 independent experiments (% of pDC TNF-α production at DHT 0 μM). Bar values and error bars are mean ± S.E.; Spearman r values and [95 % confidence intervals] are shown. Numbers above bars are mean cytokine supernatant levels (ng/ml). P-values < 0.05 were considered significant.