▁eth ical ▁issues . ▁But ▁the ▁progress ▁in ▁gene ▁ther apy ▁is ▁prom ising ▁for ▁the ▁future ▁of ▁tre ating ▁primary ▁imm un ode fic ien cies . ▁ ▁Ep ide mi ology ▁A ▁survey ▁of ▁ 1 0 , 0 0 0 ▁American ▁households ▁revealed ▁that ▁the ▁pre val ence ▁of ▁diagn osed ▁primary ▁imm un ode fic iency ▁approaches ▁ 1 ▁in ▁ 1 2 0 0 . ▁This ▁figure ▁does ▁not ▁take ▁into ▁account ▁people ▁with ▁m ild ▁imm une ▁system ▁defect s ▁who ▁have ▁not ▁received ▁a ▁formal ▁diagn osis . ▁ ▁M ilder ▁forms ▁of ▁primary ▁imm un ode fic iency , ▁such ▁as ▁select ive ▁imm un og lob ul in ▁A ▁def ic iency , ▁are ▁fairly ▁common , ▁with ▁random ▁groups ▁of ▁people ▁( such ▁as ▁otherwise ▁health y ▁blood ▁don ors ) ▁having ▁a ▁rate ▁of ▁ 1 : 6 0 0 . ▁Other ▁dis orders ▁are ▁distinct ly ▁more ▁un common , ▁with ▁inc id ences ▁between ▁ 1 : 1 0 0 , 0 0 0 ▁and ▁ 1 : 2 , 0 0 0 , 0 0 0 ▁being ▁reported . ▁ ▁Research ▁B one ▁mar row ▁trans plant ▁ ▁may ▁be ▁possible ▁for ▁Se vere ▁Com b ined ▁Im m une ▁Def ic iency ▁and ▁other ▁severe ▁imm un ode fic ien ces . ▁ ▁Vir us - specific ▁T - ly m ph ocy tes ▁( V ST ) ▁ther apy ▁is ▁used ▁for ▁patients ▁who ▁have ▁received ▁h