Transfusion immunomodulation--the case for leukoreduced and (perhaps) washed transfusions

Area of Science:

• Immunology
• Transfusion Medicine
• Critical Care Medicine

Background:

• Blood transfusions significantly impact the immune system, affecting inflammation, host defenses, and hemostasis.
• These effects can lead to increased susceptibility to infection, impaired anti-tumor immunity, and alloimmunization.
• Transfusions may also disrupt the balance between hemostasis and thrombosis through various mechanisms.

Purpose of the Study:

• To review the adverse effects of blood transfusions on the immune system and patient outcomes.
• To discuss strategies for mitigating these negative impacts, focusing on transfusion modifications.
• To highlight the importance of conservative transfusion practices.

Main Methods:

• Review of clinical, basic science, and animal model data on transfusion effects.
• Analysis of randomized trials evaluating transfusion practices.
• Focus on leukoreduction and saline washing as methods to reduce adverse outcomes.

Main Results:

• Transfusions can dysregulate innate immunity, leading to infection susceptibility.
• Cellular immune defenses against tumors are down-regulated post-transfusion.
• Transfusions can enhance B cell function, causing alloimmunization.
• Transfusions alter hemostasis and thrombosis balance.
• Conservative transfusion practices are supported by evidence.

Conclusions:

• Blood transfusions have significant, often detrimental, effects on the immune system and overall patient health.
• Modifications like leukoreduction and saline washing aim to minimize transfusion-related harm.
• Reducing red blood cell storage duration shows potential for improving outcomes in critically ill patients.