Absence of transfusion‐associated microchimerism in pediatric and adult recipients of leukoreduced and gamma‐irradiated blood components

Abstract

BACKGROUND Transfusion-associated microchimerism (TA-MC), the persistence of significant levels of donor leukocytes in blood recipients for prolonged periods, has been demonstrated following non-leukoreduced and leukoreduced transfusion to patients with severe traumatic injury. Development of TA-MC has not been rigorously studied in settings that do not involve massive trauma where the blood is leukoreduced and irradiated. STUDY DESIGN AND METHODS A cohort of 409 prospectively followed medical and surgical adult and pediatric female recipients of leukoreduced and mostly irradiated allogeneic red blood cell and platelet transfusions were evaluated to determine development of TA-MC. Four and eight-week post-transfusion samples were analyzed using quantitative real-time polymerase chain reaction (RT-PCR) for Y-chromosome sequences in leukocyte DNA, the marker for microchimeric cells in female blood recipients. Repeat testing was performed on Y-chromosome positive samples to confirm microchimerism (MC), and subsequent post-transfusion samples were tested to investigate persistence of MC. RESULTS On initial testing, forty of 207 (19%) adult and forty-four of 202 (22%) pediatric female blood recipients demonstrated low level MC. On repeat testing of these and additional specimens, twelve (3%) recipients demonstrated low level transient MC, but none had persistent TA-MC similar to that seen in transfused trauma patients. CONCLUSION Persistence of MC was not demonstrated in adult and pediatric recipients of leukoreduced and mostly irradiated blood components. The risk of TA-MC appears to be dependent on the clinical setting and is rare other than in patients sustaining severe traumatic injury.

Post‐engraftment blood transfusion and outcomes of bone marrow transplantation

“…Biases arising from our small sample size may contribute to the poor outcomes of transfused patients, since over 30% patients were not in remission while approximately 20% patients not needing transfusion were not in remission before allo‐BMT, although the difference was not statistically significant (Table ). Because all transfused products were irradiated before transfusion in this study, micro‐chimerism due to viable lymphocytes in blood products was not a possible cause of such inferior outcome in allo‐BMT recipients with postengraftment transfusions. Rather, the value of serum ferritin was significantly elevated at day 100 in transfused patients, suggesting that postengraftment transfusions, like pretransplant transfusions, might affect outcomes through iron overload, although the elevated ferritin in our patients was associated with not only RBC but also PLT transfusions after engraftment.…”

Donor white‐blood‐cell survival (microchimerism) following red‐blood‐cell transfusion in Australian patients with burn

“…Currently, it is unclear whether the use of leucodepleted RBC components has influenced the potential for TAM following blood transfusion. Previous studies have reported a reduction in incidence in one study while the frequency was apparently unchanged in others . It is also unclear whether trauma patients are the only affected patient group or whether other immune‐suppressed patient groups, such as burn patients, could be equally at risk of this phenomenon.…”

One size will never fit all: the future of research in pediatric transfusion medicine

“…While gamma irradiation may reduce the number of persistent donor leukocytes, there is no universally accepted “standard of practice” for transfusion of gamma irradiated blood in children. In a recent study of 207 adult and 202 pediatric female medical and surgical recipients of leukoreduced and irradiated RBCs and platelets, persistence of TA-MC (Y-chromosome) was not demonstrated at four- and/or eight-weeks post-transfusion(61). This suggests that pediatric blood recipients of non-irradiated and shorter storage aged blood components are not at increased risk for development of TA-MC.…”