Causes of Allergic Reactions

The exact mechanism and cause of allergic transfusion reactions remains unclear. However, it is widely accepted that plasma proteins and/or biologic response modifiers in the transfused blood products play important roles. Replacement of plasma by a mixture of plasma and platelet additive solutions (PAS) in platelet concentrates has been shown to reduce the risk of a transfusion-related adverse event significantly. Washing platelets prior to transfusion is considered to provide the highest level of safety, but due to the efforts required, and the impact on platelet quality, it is not a standard procedure.