Transfusion-related immunomodulation: a second hit in an inflammatory cascade?

Area of Science:

• Immunology
• Transfusion Medicine
• Cardiovascular Surgery

Background:

• Allogeneic blood transfusions are linked to increased postoperative complications.
• Leucocytes in blood components may cause transfusion-related immunomodulation.
• Evidence suggests leucocyte-containing red blood cells (RBCs) worsen outcomes in cardiac surgery.

Purpose of the Study:

• To review evidence on leucocyte-containing RBC transfusions in surgical settings.
• To explore explanations for increased postoperative complications in cardiac surgery.
• To discuss clinical and transfusional factors influencing outcomes.

Main Methods:

• Review of 19 randomized controlled trials on allogeneic leucocytes.
• Focus on 13 trials examining leucocyte-containing RBCs in surgical settings.
• Analysis of studies specifically in cardiac surgery for heterogeneity and findings.

Main Results:

• Conflicting outcomes in non-cardiac surgery settings.
• Consistent evidence in cardiac surgery shows leucocyte-containing RBCs increase postoperative complications and mortality.
• Studies in cardiac surgery exhibit less heterogeneity.

Conclusions:

• Leucocyte-containing RBC transfusions are associated with increased mortality in cardiac surgery.
• Clinical and transfusional factors may explain these specific findings.
• Transfusions may exacerbate the systemic inflammatory response from cardiopulmonary bypass.