Major types of RBC blood group antigens and their relationship to the RBC membrane

The three major types of RBC blood group antigens are illustrated, showing their structure and interaction with the plasma membrane. Blue denotes protein; green, sugars; and yellow, GPI. The dark blue protein covalently linked to Kell is the XK protein, required for Kell expression. Refer to UpToDate content on RBC antigens for further information and clinical relevance.