X‐ray irradiation effectively inactivated lymphocytes in transfusion in vivo monitored by the bioluminescence transfusion‐associated graft‐versus‐host disease model

Abstract Background and Objectives Transfusion of cold‐stored whole blood is the preferred resuscitation method for trauma patients but may cause transfusion‐associated graft‐versus‐host disease (TA‐GVHD). Standard clinical practice to prevent this is to irradiate blood components with gamma‐rays. X‐ray irradiations are also a safe and effective alternative to gamma‐ray irradiation. We established a visual mouse model of TA‐GVHD to compare the viability and function of lymphocytes exposed to gamma‐ and x‐ray irradiation. Materials and Methods A haploidentical transplantation mouse model was established to simulate TA‐GVHD with Balb/c mice as donors and hybrid F1 CB6 mice (Balb/c × C57) as recipients. Spleen cells from Tg ‐Fluc+ Balb/c mice were isolated and irradiated with gamma‐rays and x‐rays. Lymphocyte activation, apoptosis and proliferation post phorbol 1 2‐myristate 1 3‐acetate (PMA) stimulation were evaluated. After transfusion, we monitored Fluc+ lymphocytes daily by bioluminescence imaging. Recipients were euthanized on day 21, and tissues were examined pathologically and for inflammatory cytokines. Results The viability of gamma‐ or x‐ray irradiated lymphocytes decreased significantly with slight changes in proliferation in vivo after transfusion. Compared with the non‐irradiated group, both the gamma‐ and x‐ray irradiated groups showed significantly decreased clinical scoring and inflammatory cytokine levels. The fluorescence intensity of the body and target organs was reduced after irradiation. Conclusion No recipients acquired TA‐GVHD after lymphocyte transfusion subjected to gamma‐ or x‐rays, showing that x‐rays inactivate as well as gamma rays and are suitable for irradiating whole blood.