Related Experiment Video
Updated: Jun 25, 2026

In Vitro and In Vivo Assessment of T, B and Myeloid Cells Suppressive Activity and Humoral Responses from Transplant Recipients
Published on: August 12, 2017
Stored red blood cell transfusion induces regulatory T cells
Joel M Baumgartner1, Christopher C Silliman, Ernest E Moore
1Department of Surgery, University of Colorado Denver, Denver, CO, USA.
Background:
Allogeneic blood transfusion mediates immunosuppression in transfused recipients by an unknown mechanism. Regulatory T cells (T(regs)) are suppressive CD4(+)CD25(+)Foxp3(+) cells with a central role in immunosuppression in trauma victims, cancer patients, and transplant recipients. We hypothesized that transfusion-related immunosuppression is, in part, mediated by induction of T(regs), and this induction is attenuated with prestorage leukoreduction and accentuated with prolonged storage.
Study Design:
Packed red blood cell (PRBC) units were obtained and 50% of PRBCs were leukoreduced (LR) before routine storage for 1 day or 42 days and the supernatant was collected. Normal human peripheral blood mononuclear cells (PBMCs) were exposed to 1-day NLR, 42-day NLR, 1-day LR, or 42-day LR PRBC supernatants or to PRBC storage solution or washed PRBC supernatant +/- anti-CD3 stimulation, and analyzed by flow cytometry for Foxp3(+) T(regs) or CD25(+)-activated T cells. PRBC supernatants and cell culture supernatants were analyzed by immunoassay for interleukin (IL)-1beta, IL-2, IL-4, IL-10, interferon-gamma, tumor necrosis factor-alpha, and transforming growth factor-beta. T(reg) activity was evaluated by suppression assay.
Results:
All PRBC groups induced T(regs) compared with control media in anti-CD3-stimulated PBMCs, without alteration by LR or prolonged storage. PRBC supernatant did not alter nonspecific T-cell activation from control media. PRBC-induced T(regs) were suppressive, inhibiting proliferation of T-responder cells. All cytokines measured decreased with storage in LR PRBC units and no cytokines were substantially elevated in cell supernatants exposed to PRBC supernatant. PRBC storage solution did not reproduce the effects of PRBC supernatant, and washed PRBC supernatant attenuated T(reg) induction.
Conclusions:
PRBC supernatant induces T(regs), but this induction is not altered by LR or prolonged storage. This induction appears to be independent of cytokines and is attenuated with washed PRBCs, implicating the plasma fraction.
Related Concept Videos
Regulation of Hematopoietic Stem Cells
Blood Transfusion and Agglutination
History
The history of blood transfusion dates back to the 17th century, when early attempts were made in animals. In 1818 James Blundell, a British doctor, performed the first successful human blood transfusion. Later in 1900, Karl...
Blood Transfusion
Blood Transfusion Overview
A blood transfusion is a medical procedure used to replace blood lost due to injury, surgery, or to treat conditions such as anemia or cancer. During a transfusion, donor blood is...
Cell-mediated Immune Responses
T Cell Types and Functions
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
T Cell Activation and Clonal Selection
Naive T cells that have not yet encountered an antigen express two primary CD...

