IL-4/IFN-γ ratio in α-galactosylceramide (α-GalCer) stimulated peripheral blood mononuclear cells (PBMCs) evaluated by ELISPOT. PBMCs (2 × 105 cells/well) from 10 rheumatoid arthritis patients and eight healthy control individuals were stimulated with α-GalCer or no antigen for 20 hours. The number of cytokine secreting cells was calculated by subtracting the number of spots in control wells (without antigen) from the number of spots obtained in the presence of each stimulating agent. The IL-4/IFN-γ ratio is the number of IL-4 producing cells divided by the number of IFN-γ producing cells. Error bars indicate standard error of the mean.