Overt immediate hemolytic transfusion reaction attributable to anti-Wr(a)

Area of Science:

• Immunology
• Transfusion Medicine
• Hematology

Background:

• The Wr(a) antigen is a low-prevalence red blood cell (RBC) antigen.
• Anti-Wr(a) antibodies are found in about 1% of healthy blood donors.
• These antibodies have been associated with varying degrees of hemolysis in transfusion reactions and hemolytic disease of the newborn (HDN).

Observation:

• This case report details an acute overt hemolytic transfusion reaction.
• The patient had pre-existing anti-Wr(a) antibodies in their serum.
• The reaction occurred after transfusion with a Wr(a+) RBC component.

Findings:

• The presence of anti-Wr(a) antibodies in a recipient led to a clinically significant hemolytic transfusion reaction.
• The transfusion of Wr(a+) RBCs to a patient with anti-Wr(a) antibodies resulted in an acute overt hemolytic event.

Implications:

• Clinicians should consider screening for anti-Wr(a) antibodies in patients with unexplained hemolytic reactions.
• Careful donor-recipient matching for the Wr(a) antigen is crucial for patients with anti-Wr(a) antibodies to prevent transfusion reactions.
• This case underscores the importance of recognizing and managing antibodies to low-prevalence antigens in transfusion medicine.