Because of their immature immune systems, newborns have a higher risk of transfusion-associated graft-versus-host disease, where white blood cells from the transfusion produce immune cells that attack the recipient. To prevent this life-threatening condition, red blood cell units transfused to newborns are irradiated. Irradiation makes the red blood cells more fragile, so they are more likely to release their contents (such as potassium and hemoglobin) during storage. High levels of potassium can cause cardiac problems. Our researchers tested two methods that hospitals currently use to reduce potentially harmful substances from the irradiated units transfused to newborns.
Bacterial contamination of platelet products is a serious concern in transfusion practice because platelet storage conditions allow bacteria to replicate to potentially dangerous levels. Transfusion with contaminated platelets may cause septic reactions, which are very rare but dangerous for patients. At Canadian Blood Services, all platelet products are screened for bacteria, but a low number of contaminated products escape detection. Recently, the bacterial screening procedure was modified and will improve bacterial detection.
Intravenous immunoglobulin (IVIg) is a plasma-derived drug used to treat a wide range of conditions and demand for this expensive product keeps growing. In Canada, IVIg is provided to hospitals by Canadian Blood Services. The Centre for Innovation facilitates research into IVIg to understand the pathogenesis of immune conditions treated by IVIg [e.g. immune thrombocytopenia (ITP) and fetal and neonatal alloimmune thrombocytopenia (FNAIT)], explain the poorly understood mechanisms of action of IVIg, and develop IVIG alternatives.
Apheresis machines are used to isolate autologous blood stem cells from adult donors (a.k.a. Human Progenitor Cells (HPC)). An update in HPC apheresis system technology at the Edmonton hospital led to higher HPC collection volumes as additional plasma was being collected with the stem cells. This resulted in greater DMSO (freezing solution) load to patients and unacceptably long transfusion times. Canadian Blood Services Stem Cell Manufacturing Lab had to optimize its process to maintain product quality.
“Confidential Unit Exclusion” or CUE allowed donors with risk factors for transmissible diseases to confidentially indicate that their blood may be unsafe for transfusion by placing a “do not use my blood” sticker on the record of donation. CUE was implemented in the mid-1980s, but since then testing for transmissible diseases has improved. While initial studies showed CUE had some value, more recent data suggest otherwise.
Ensuring safety and efficacy; improving utilization
Washing red blood cells before transfusion generates safer products for vulnerable patients by removing most metabolites and proteins that accumulate in the bag during storage. These metabolites can harm certain patient groups (e.g. neonates, who are more sensitive due to their small size). Until recently, Canadian Blood Services used an “open” washing system which meant products were exposed to the environment and had to be used within 24 hours. This time restriction resulted in some products being discarded before they could be used.
Cord blood (CB) units are stored frozen at -196°C until they are required for transplantation. Protocols for storage or shipping of frozen CB units can result in transient warming of the units above critical subzero temperatures, which may impact cell viability and efficacy. Protocols for thawing CB units prior to transplantation are also critical in ensuring product efficacy. Canadian Blood Services examined how different protocols for handling and thawing affected CB quality.
Beyond the big switch: Research improves manufacturing and deepens understanding of “what’s in the bag”
When Canadian Blood Services switched from manual “platelet-rich plasma” production to semi-automated “buffy-coat” platelet production, an organization-wide research effort concluded that components produced by the new method were as least as good as those produced by the old. In 2010, the new method was implemented at all Canadian Blood Services sites, but efforts to optimize the new manufacturing process were just beginning.
Doubling the 30-minute rule to reduce waste without compromising red blood cell quality and safety
Since the 1970s, blood operators have limited the length of time red blood cells (RBCs) can be exposed to uncontrolled temperatures to 30 minutes. Called the “30-minute rule”, this international standard was put in place to keep cells usable and limit bacterial growth. However, it is not always possible to transfuse a patient within 30 minutes. As a result, thousands of RBCs are discarded.
To reduce the risk of transfusion-associated graft vs. host disease in at-risk patients, red blood cells are irradiated before transfusion. The Canadian Standards Association issues guidelines regarding storage of irradiated red blood cells, but quality control tests are not performed on these units, so there are limited data on the quality of irradiated units or the appropriateness of the guidelines.