alloimmunization

noun

al·​lo·​im·​mu·​ni·​za·​tion ˌa-lō-ˌi-myə-nə-ˈzā-shən, -ˌnī-ˈzā- also -i-ˌmyü-nə- 

: isoimmunization

Transfusions are effective in preventing many complications of sickle cell disease, but the iron overload and alloimmunization that result from repeated transfusions can complicate treatment.

—Miguel R. Abboud, The New England Journal of Medicine