When to suspect this adverse reaction
Transfusion-related immune modulation (TRIM) is a much-debated immunosuppressive effect of red cell transfusions on innate immunity in recipients observed after red cell transfusions.
No specific signs or symptoms have been attributed to TRIM, and the incidence rate is not known.
Usual causes
It may partially be due to transfused white cells releasing cytokines or by‑products of red cell storage (such as the suspending solution or red cell biochemical changes), which lead to immune modulation.
There have been a number of reported TRIM-associated effects on the transfusion recipient, ranging from improved clinical outcomes in renal allograft transplantation to an increased rate of tumour recurrence in cancer surgery patients and an increased rate of post-operative bacterial infection.
Investigation
No specific investigation process has been defined.
What to do
The most important approach is the judicious use of blood transfusion and to follow the principles and guidance of patient blood management.
Removing donor white cells by pre-storage filtration (leucodepletion) of cellular blood components or avoiding transfusion of older red cell units may help reduce the risk of TRIM.
Updated October 2026