Which of the following conditions is associated with an increased risk of alloimmunization to blood group antigens?

A Pregnancy
B Sickle cell disease
C Thalassemia major
D All of the above ✓

Explanation

Pregnancy, sickle cell disease, and thalassemia major are all associated with an increased risk of alloimmunization to blood group antigens due to repeated exposure to allogenic red cells.

Source

Transfusion Medicine journal
Hematology Hematology: Blood Grouping and Crossmatching Hematology: Blood Grouping and Crossmatching Hard MEDICAL Confidence: high