Retinoids inhibit the IgE-production of anti-CD40 + IL-4–stimulated human PBMC (A) and B cells (B) from normal donors. PBMC and B cells (106/mL) were incubated for 10 days in the presence of CD40 + IL-4 (1 μg/mL and 5 ng/mL) alone or in combination with all-trans RA (10−10 to 10−6 mol/L for PBMC and 10−14 to 10−8 mol/L for B cells) or 13-cis RA (10−12 to 10−6 mol/L for PBMC and 10−15 to 10−8 mol/L for B cells). IgE (pg/mL) was detected in the supernatants by ELISA, IgE in unstimulated PBMC and B cells was below 200 pg/mL and ranged after anti-CD40 + IL-4 stimulation from 2,204 to 12,846 pg/mL in PBMC and from 2,250 to 2,951 pg/mL in B cells. Values are expressed as percent of anti-CD40 + IL-4 stimulation and mean values of four experiments + SEM are shown.
