Guarda et al. (2011a) found that IL-1β production by primary monocytes was lower in multiple sclerosis patients on IFN-β treatment than in healthy subjects, supporting the value of IFN-β therapy. Studies in mouse bone marrow-derived macrophages by Guarda et al. (2011a) suggest that IFN-β may inhibit IL-1β production through at least two mechanisms. The gene discussed is IL1B; the disease is multiple sclerosis.