17. Patients receiving other immunosuppressive therapies such as steroids, mTOR inhibitors or tacrolimus are excluded unless: [1] part of an established post-transplant anti-rejection regime, [2] patient has confirmed anti-CFH antibody requiring immunosuppressive therapy, and [3] dose of such medications have been unchanged for at least 4 weeks prior to the screening period and throughout the Observation Period or [4] patient is experiencing an acute aHUS relapse immediately after transplant.