An Update on Transfusion Related Immunomodulation (TRIM) in a Time of COVID-19 Pandemic

Recipients' immune systems are triggered by blood and blood component therapy. Transfusion-related immunomodulation (TRIM) is a complicated immunological response to transfusion that results in immunosuppression. The mechanisms of TRIM include the presence of residual white blood cells and apoptotic cells, the infusion of immunosuppressive cytokines that are present in donor components or that occur during blood processing, the transfer of metabolically active growth factor-loaded particles and extracellular vesicles, and the presence of hemoglobin or extracellular vesicles binds to hemoglobin. TRIM variables include donor-specific factors and processing variables. TRIM can explain, at least partially, the controversial negative clinical results observed in patients with covid19. Many potential treatment methods have been used in clinical practice, including supportive interventions, immunomodulators, antiviral therapy, and infusion of convalescent plasma. Here, we summarize current potential treatments for COVID-19 infectionrelated diseases and discuss the clinical value of blood transfusion-related technologies for COVID-19 treatment in blood transfusion-related immune regulation.