The results presented here indicate that Gβγ complexes play a role in inhibiting TCR-stimulated IL-2 transcription, suggesting that they could be useful drug targets for treating autoimmune disorders in which modest increases in IL-2 have been shown to be beneficial, such as chronic graft-versus-host disease [8] and hepatitis C virus-induced vasculitis [9]. Here, CFB is linked to chronic graft versus host disease.