Delayed haemolytic transfusion reactions due to anti-C

Area of Science:

• Immunohaematology
• Transfusion Medicine

Background:

• Understanding red blood cell antigen-antibody reactions is crucial for safe blood transfusions.
• The Rh C antigen system plays a role in transfusion compatibility.

Observation:

• Five patients with ccDEe or ccDEE phenotypes developed haemoglobinuria after receiving C-positive blood transfusions.
• The onset of haemoglobinuria occurred 5–9 days post-transfusion and lasted 2–4 days.

Findings:

• Anti-C antibodies were present in all affected patients, though typically at low titres.
• A discrepancy was noted between the low in vivo antibody titre and the significant intravascular haemoglobin release.

Implications:

• This suggests that even low titres of anti-C can lead to clinically significant haemolytic transfusion reactions.
• Further research into the specific IgG subclasses of anti-C may explain the observed in vivo effects.