α-Amyrin increased IFNγ production in human PBMCs similar to sitosterol. Results shown are most representative of three experiments. Human PBMCs were cultured for 52 h in the presence of 50 μg/ml PHA, 2 nm cyclodextrin (carrier), and either 12 μm cholesterol or 12 μm α-amyrin. α-Amyrin, a sterol from the 4,4-dimethylsterol family, increases IFNγ production by human PBMCs dose-dependently and similar to sitosterol, a sterol of the 4-desmethylsterol family. *, p < 0.05.