Page "Anti-thymocyte globulin" Paragraph 2

ATG administration very substantially reduces immune competence in patients with normal immune systems, through a combination of actions, some explicitly understood and some more hypothetical.

rATG in particular effects large reductions ( through cell lysis ) in the number of circulating T-lymphocytes, hence preventing ( or at least delaying ) the cellular rejection of transplanted organs.

However, medical opinion remains divided as to when the benefit of this profound reduction in T-cells outweighs the concomitant increased risks of infection and malignancy.