Several groups, including ours, have now shown that a functionally competent CD8+ T cell compartment is required to restrict disease severity in lupus-prone mice (4–7), and subsets of CD8+ T cells have been identified that can suppress excessive CD4+ T follicular helper cell help to Bcells, which is essential for maintenance ofself tolerance (8). The gene discussed is CD8A; the disease is systemic lupus erythematosus.