They have been used in cancer immunotherapy settings, acting as agonists of costimulatory molecules (4-1BB, OX40, CD28, CD40) [26–29] blocking inhibitor signals (CTLA4, PD1) [30, 31], or reducing immunity in transplant and autoimmunity models (CD200) [30]. The gene discussed is CTLA4; the disease is Autoimmunity.