Background:
Blood transfusion is important for life saving treatment in many patients with tolerable adverse effects. Some data suggest that transfusions might cause an increased risk for post-operative infections and a higher relapse or mortality rate in cancer patients. We investigated whether immune dysfunction might result after transfusions from the cellular components.
Methods:
We studied 5-week-old mice BALB/c (H-2d, donor), C3H/He (H-2k, recipient), and C57/BL (H-2b, third party). We obtained irradiated spleen cells (SP) from the BALB/c or C57/BL, and injected them into the C3H/He with intraperitoneal IL-2 administration. After 24 hours, we obtained bone marrow (BM), thymus and SP. We identified mixed lymphocyte proliferation (MLR) by the BrdU method and we used irradiated BALB/c SP, as a stimulator for that trial. For the analysis of immune cells, we analyzed the cell surface markers from each organ. For cytokines, we identified TNF-Ձ, IFN-Ճ, TGF-Ղ, and IL-10 by ELISA from the supernatant of the MLR.
Results:
The cell proliferation decreased according to specific H-2 complexes. There were increased CD4+CD25+ cells in the thymus. For the paracrine effects, the B-C3H SP showed ratio-dependent inhibitory effects, although the C-C3H SP inhibited some cell proliferation. There was no difference in the IFN-Ճ, TNF-Ձ and TGF-Ղ between the control and experimental groups. However, IL-10 was higher in the 1：10 ratio mixture in the control and transfused SP compared to the other groups.
Conclusion:
The results of this study suggested that the cellular components in transfusions might contribute to the immune regulatory effects by CD4+CD25+ cells after 24 hours.

Keywords: Transfusion, Immunomodulation, IL-10, CD4+CD25+ cells