Which of the following blood group antigens is associated with an increased risk of hemolysis in patients with autoimmune hemolytic anemia?

A I antigen
B i antigen ✓
C P antigen
D T antigen

Explanation

The i antigen is associated with an increased risk of hemolysis in patients with autoimmune hemolytic anemia, particularly those with cold agglutinin disease.

Source

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