ATM and combined immunodeficiency: This held true for BMDM from mice with a combined severe combined immunodeficiency (SCID, harboring a non-functional DNA-PKcs protein, [49]) and conditional Atm deficiency background [50], while BMDM from mice with either SCID or Atm deficiency alone did not show an activated DDR after infection and had subtler differences in their genetic programs compared to wild type mice.