Red blood cell transfusion-induced non-transferrin-bound iron promotes Pseudomonas aeruginosa biofilms in human sera and mortality in catheterized mice.

Transfusion of storage-damaged red blood cells (RBCs) increases non-transferrin-bound iron (NTBI) levels in humans. This can potentially enhance virulence of microorganisms. In this study, Pseudomonas aeruginosa replication and biofilm production in vitro correlated with NTBI levels of transfused subjects (R2 = 0·80; P < 0·0001). Transfusion of stored RBCs into catheterized mice enhanced P. aeruginosa virulence and mortality in vivo, while pre-administration of apotransferrin reduced NTBI levels improving survival (69% vs 27% mortality; P < 0·05). These results suggest that longer RBC storage, by modulating the bioavailability of iron, may increase the risk of P. aeruginosa biofilm-related infections in transfused patients.

Reliability of labeling red cell units with minor antigen historical results and process considerations.

BACKGROUND: Several approaches are used by blood centers when providing minor (non-ABO/D) antigen-negative RBCs to hospitals. Details vary but include providing results on the unit labeling intended for clinical use without retyping or providing results on packing documents or via computer query requiring confirmation. Recent regulatory changes allow labeling with historical minor antigen results, defined as previously performed by the donor center on two different donations with results linked to the donor and confirmed concordant. Here we investigate causes of discrepancies and identify critical process steps. STUDY DESIGN AND METHODS: Nine years (2009-2017) of data were reviewed for number, antigen system, and root cause of discrepancies flagged by the computer when retyping donors prior to labeling (internal discrepancies) or reported by the hospital when retested (external discrepancies). Licensed automated (CcEeK) and tube methods were used. RESULTS: Among 300,000 samples phenotyped for CcEe, K, Fya/b , Jka/b , Ss (>3 million antigens), ∼1,389,960 were repeated on 2nd donation with 397 (1/3501) discordant; 205 Fy, 118 Rh, and 74 others. Of ∼682,691 antigen-negative phenotypes provided on unit labeling, ∼37.5% (256,118) were retyped by hospitals with 29 discrepancies (1/8832), primarily Rh variants. CONCLUSION: When repeating minor antigen types by serology, discrepancies are primarily associated with weak Fyb , among Caucasian donors, and weak/partial Rh antigens in donors of African ancestry. DNA-based testing avoids these. To label with historical results, accuracy is increased by automated testing with direct computer interface. Testing on two donations with results confirmed to be concordant is not inferior to testing on the current donation.

A dual strategy to optimize hematopoietic progenitor cell collections: validation of a simple prediction algorithm and use of collect flow rates guided by mononuclear cell count.

BACKGROUND: Previous prediction algorithms to achieve target CD34+ goals have not been widely adopted, with many centers still using a set volume to process for hematopoietic progenitor cell collections. This may be because previous algorithms are challenging to implement. Additionally, no study has yet examined the utility of adjusting the collect flow rate (CFR) based on the donor's preprocedure total mononuclear cell (MNC) count, which correlates with CD34+ yield. STUDY DESIGN AND METHODS: In this retrospective analysis of mobilized allogeneic donors collected using MNC (COBE Spectra, Terumo BCT) or continuous mononuclear cell collection (CMNC) (Spectra Optia, Terumo BCT) procedures, we validated a one-step prediction algorithm to achieve the target CD34+ product dose (Appendix S1, available as supporting information in the online version of this paper). The COBE Spectra MNC Collect Flow Tool (Appendix S2, available as supporting information in the online version of this paper) was used to select the collect flow rate for both MNC and CMNC procedures. Procedural collection efficiency (CE) was compared to that of historical procedures utilizing fixed CFRs (1.0-1.5 mL/min). RESULTS: Ninety-three percent of collections achieved the target CD34+ goal using our algorithm-calculated process volumes. The remaining 7% of cases had CEs lower than the algorithm CE (0.40), and thus were below goal. Second, an MNC-based CFR improved MNC and CD34+ CEs in patients with higher MNC counts compared to our historical controls. CONCLUSION: We validated that this simple, single-step prediction algorithm achieves the target CD34+ goal in most HPC collections. Secondly, we showed that an MNC-based CFR for hematopoietic progenitor cell collections improves CE at higher MNCs; this may be preferable to a WBC-based CFR because of variability of MNC counts at a given WBC count.

'Massive transfusion protocols and the use of tranexamic acid'.

PURPOSE OF REVIEW: We review recent articles pertaining to the use of tranexamic acid (TXA) in populations at risk for massive transfusion. Although there are no recent studies that specifically examine the use of TXA in massive transfusion protocols (MTPs), there are a few studies with subgroups of massive transfusion patients. RECENT FINDINGS: In recent years, many publications have discussed outcomes and safety associated with the addition of TXA to treatment plans for bleeding pediatric, trauma, and postpartum hemorrhage patients. In general, TXA appears to decrease mortality and transfusion requirements. SUMMARY: TXA was shown to decrease mortality in several bleeding populations. It is now a common addition to MTPs. There is conflicting evidence regarding the potential of TXA as a risk factor for thrombotic events. Ongoing studies should provide additional evidence regarding the thrombotic risk of TXA in massive transfusion.

Whole Blood Transfusion: Past, Present, and Future.

Transfusion of whole blood largely was replaced by component therapy in the 1970s and 1980s. The recent military operations in Iraq and Afghanistan returned whole blood to military trauma care. Eventually, whole blood use was incorporated into some civilian trauma care. It has been utilized in several other civilian populations as well. Trials to compare whole blood to component therapy are ongoing.

Ensuring safety of the blood supply in the United States: Donor screening, testing, emerging pathogens, and pathogen inactivation.

Safety of the blood supply has been a critical aspect of the transfusion medicine field since its inception, including infections that can be passed to a blood product recipient. Reactive efforts to identify potentially infected blood products are used throughout the blood donation process and afterward. Before donation, potential donors are provided educational materials about infection risks, examined and then screened through a series of questions that help temporarily, permanently, or indefinitely defer donors who could harbor acute and/or chronic infections. During donation, aseptic technique and diversion pouches reduce the potential to introduce bacteria into the blood product. Before transfusion, the blood products are tested for several infectious diseases by serology, nucleic acid testing, or a combination. During transfusion, the patient is monitored closely, and suspected transfusion reactions should be reported and investigated. The FDA regularly publishes guidance documents to incorporate knowledge gained regarding transfusion-transmitted infections, so that information can be shared and practices updated so that transfusion-related patient care can be optimized over time. Pathogen reduction processes are being developed and deployed that provide a proactive approach to both recognized and emerging pathogens.

The outsider adverse event in transfusion: Inflammation.

In order to maintain adequate inventories of red blood cells (RBCs) for transfusion, RBC units are refrigerator-stored for variable amounts of time prior to transfusion. A subset of RBCs is damaged during prolonged storage. Clearance of these damaged RBCs is hypothesized to induce an inflammatory response in the transfusion recipient. However, there is controversy over whether RBC transfusions are in fact associated with inflammation, and more generally, whether current standards for maximal RBC storage times are safe. We will explore the evidence for and against this outsider adverse event in transfusion: whether certain RBC transfusions do or do not cause inflammation.