This defect in the hematopoietic compartment of CopaE241K/+ mice brought out by the mixed chimeras reminded us of the pro-apoptotic effects of STING activation on immune cells and cytopenia in the SAVI mouse models (12, 20) and suggested that CopaE241K/+ mice might also be prone to immune deficiencies. The gene discussed is STING1; the disease is Immunodeficiency.