The Daily Sign-Out

Overview of red cell storage lesion in transfusion

The October 2011 CAP Today has a wonderful overview of the issues surrounding the clinical implications of the RBC storage lesion.  For non-blood bank geeks, this is an informative article and presents thoughtful insights and comments from a variety of perspectives.  It is much more accessible than the collection of articles from Transfusion in April, 2011 which I have had the best intentions of summarizing for this blog but just haven't been able to pull off.  These are really state-of-the-art translational research papers that I recommend if you're a specialist or want some more background after reading the CAP Today article.

There is also a helpful sidebar that summarizes the current and proposed red cell storage studies.

Lots to think about here--the translational research studies and clinical trials have the potential to really change blood banking and transfusion practices (or not).

AABB SmartBrief: Mismatched cord blood transplants can be effective

Studies: Mismatched cord blood, marrow transplants can be effective
Results of transplants with unrelated umbilical cord blood or mismatched bone marrow were comparable with results of transplants that used fully matched tissue, according to two studies involving patients with advanced leukemia or lymphoma. The studies, reported in Blood, found that the one-year survival rate for those who had unrelated cord-blood transplant was 54% and 62% for those who underwent mismatched bone marrow transplant. "Taken together, these results set the stage for a multicenter, randomized phase III trial to evaluate the relative risks and benefits" of such regimens, the researchers said. MedPage Today (7/9)

Henry VIII, the Kell blood group system and the McLeod syndrome

ScienceDaily (Mar. 3, 2011) — Blood group incompatibility between Henry VIII and his wives could have driven the Tudor king's reproductive woes, and a genetic condition related to his suspected blood group could also explain Henry's dramatic mid-life transformation into a physically and mentally-impaired tyrant who executed two of his wives.

http://www.sciencedaily.com/releases/2011/03/110303153114.htm#

Fascinating medical history article!  The Kell blood group system is probably the third most important blood group system (after ABO and Rh) because Kell antigens are highly immunogenic and Kell antibodies can cause hemolytic transfusion reactions and hemolytic disease of newborn.  Fortunately, only about 9% of whites and 2% of blacks are K positive; so although K antibodies are relatively common, it is also relatively easy to obtain K-negative blood for transfusion.

The Kell antigens are carried by a red cell membrane glycoprotein with a large globular extracellular C-terminal component.  The Kell protein interacts with the RBC surface membrane with a 37 kD protein XK (Kx antigen) which plays a key role in the expression of Kell antigens.  Interestingly, the gene encoding XK is located on the petite arm of the X chromosome and is near the foci for X-linked chronic granulomatous disease (CGD) and Duchenne muscular dystrophy (DMD).

The McLeod phenotype is a rare but clinically interesting variant in the Kell blood group system.  Individuals with this phenotype lack the Kx antigen and thus express reduced levels of Kell antigens.  This phenotype is associated with acatholytic RBC morphology and low-grade chronic hemolytic anemia.  Neuromuscular symptoms, as discussed in the article above with respect to good ol' 'enry, are frequently reported in patients with McLeod syndrome and may be related to lack of Kx expression.  Finally, the McLeod phenotype is associated with other rare syndromes, most frequently (as one might expect) with CGD and DMD or Becker muscular dystrophy.

Relationship between platelet storage and clinical outcomes

An article by Welsby and colleagues in the November issue of Transfusion examines the possible possible relationship between platelet storage duration of two to five days and the outcomes of patients undergoing coronary artery bypass graft surgery. The patients received one leukoreduced apheresis platelet product. The authors found no association between platelet storage age and clinical outcomes in this minimally transfused patient group. In addition to considering the possible clinical effects of platelet storage time, the editorial by Anne F. Eder, MD, PhD, and Gary Moroff, PhD, reviews the available evidence on the association between platelet transfusions and adverse outcomes. The authors of the editorial conclude that the question regarding the possible effect of platelet storage duration on clinical outcomes has been satisfied by Welsby and colleagues.

AABB Audioconferences for November: Hemorrhage in OB patients and cold agglutinins

AABB will host two audioconferences next month of interest pathologists who manage blood transfusion services.  A Nov. 3 audioconference will look at hemorrhaging in obstetric patients and describe OB transfusion protocols. Presenters will list the common causes of OB patients' hemorrhages and discuss preventive measures for these occurrences as well as review special transfusion requirements for these patients. A Nov. 17 session will provide an overview of cold agglutinins, including resolving cold-reacting allo and auto antibody issues, as well as typical clinical issues associated with cold agglutinins.

(I am a member of AABB but otherwise I gain no material benefit for passing along this info to you.)

NHLBI to fund research into storage lesion in donated blood

This is a bit "old news" but worth relaying.  In late June, the National Heart, Lung and Blood Institute announced the funding of nine grants to explore the effect of storage time on donated blood.  This is timely given recent studies that suggest increased risk of adverse cardiovascular and other organ events in people who received blood transfusions in which the storage time was greater than two weeks.

Current FDA guidelines permit liquid RBCs to be stored for up to 42 days (longer if the blood is frozen)--but the average unit of RBCs is transfused after 16 days' storage.  We at my institution consider an outdated RBC product (which is thus wasted) to be an exceptional event and call for a "root cause analysis" when this occurs--which fortunately is extremely rare.  (Plateletpheresis products are a different story for different reasons.)  Blood banks and transfusion services are between Scylla and Charybdis here: there is a chronic shortage of donated blood in the U.S. so any shortening of acceptable storage life would further exacerbate that shortage BUT there is the critical imperative to provide safe blood.

THe storage lesion in banked blood refers to the metabolic changes that occur in the RBCs during storage as well as the effects of hemolysis and shortened RBC survival with storage.  This results in the formation of RBC microparticles, release of free hemoglobin, and loss of RBC enzymatic functions--which not results in an ineffective or suboptimal therapeutic effect of the transfusion but also can cause widespread systemic deleterious effects.

These will be the first research projects to systematically examine collection, preparation, and storage practices as they relate to the RBC storage lesion.

Prevalence of HHV-8 in U.S. blood donors is low

One less thing to worry less about regarding transfusion-transmitted infections.

 

Transfusion: Prevalence of human herpesvirus 8 in healthy blood donors is low.

The first systematic study of human herpesvirus 8 in U.S. blood donors found that the prevalence of detectable genomes of HHV-8, which causes Kaposi's sarcoma, is very low in healthy donors. According to the study, featured in the May issue of Transfusion, a sensitive and quantitative real-time polymerase chain reaction assay was used to detect HHV-8 DNA from purified CD19+ B lymphocytes from 962 randomly selected U.S. whole-blood donors.

Read the abstract and editorial.

Pathologist Consults for Transfusion Issues

Over the years, I have developed a list of situations for a hospital transfusion service for which I (or the on-call pathologist) should be notified and consult with the med tech in the "blood bank."  Some of them are indeed mandatory but all of them generally are what I would described as deviations from the normal SOP.  I use my judgment on whether or not to directly call clinicians, the O.R., or go up to the floor--but when I have done any of the aforementioned, my input and advice has always been well-received.  Most of these are not emergency situations and encourage the techs to call us when it is practical even if it is in the middle of the night.  From a practical standpoint, I have learned that communication the next morning or day is by someone who was not actually involved in the situation and is handing off a scribbled note or incomplete verbal communication.  We (as pathologists) shouldn't underestimate our impact into patient care in unusual transfusion situations.

• Request for emergency release of uncrossmatched RBCs.  Although the blood needs to be out the door before I am reached, I want to know about this as soon as possible so I can speak to the clinicians and give them some reassurance and timeframes as more appropriate units are available (ABO- and then crossmatch-compatible).
• Adverse reactions to transfusion.  This is one of those mandatory situations and one in which we always issue a written report or note.  Also includes suspected transfusion-related acute lung injury (TRALI) and transfusion-transmitted infections (e.g., "look-back" and subsequent donor testing).
• High utilization of blood components.  This is the massive transfusion situation.  The anesthesiologists are fairly well-aware of the physiological sequelae of massive transfusion, so I mainly call them to get an idea of how the patient is doing so I can communicate to the blood bank on how many more units may be needed, our inventory, switching blood types, and whether or not an emergency run is needed to replenish our supply.
• Requests for specialized blood components.  This incorporates requests for washed RBCs, CMV-seronegative components, etc.  It is amazing how often such requests are made "because that is what we did in residency."  Most of these are not necessary and it provides me a "teaching moment."
• Feto-maternal hemorrhage.  The blood bank techs interpret the Kleihauer-Betke stain for the purpose of determining the appropriate dose of RhoGam and are not comfortable doing this.  We score adequately on proficiency testing but I think it touches the patient too much for them.  Anyway, I just like to know about these situations.
• Serological problems.  This includes positive DATs, newly discovered alloantibodies and autoantibodies, ABO discrepancies, etc.  This constitutes most of the day-to-day consults and mostly consists of reviewing the work-up.  I also approve send-outs to the Red Cross for additional work-ups and sign-off on the reports as they come back.  I just like knowing about these too and occasionally talking to clinicians if the work-up is delaying a patient receiving blood.
• Possibly inappropriate utilization of blood components.  This may be an emerging area for consultation but will likely be at a higher order level rather than at the direct patient care level.  Techs don't like functioning as gatekeepers and telling surgeons "no" so I encourage them to call me if something doesn't smell or sound right.

Hope you find this of help.  Your comments and questions are welcome.  Are there situations that you confront where a pathologist consultation is helpful?

Florida blood organization targets more donations from black community

from AABB Smart Briefs

The Blood Alliance in Jacksonville, Fla., has initiated a campaign that aims to increase the number of blood donations from members of the black community in order to meet the blood requirements of those with rare blood types and blood disorders, such as sickle cell disease. "In February, our focus was on African-American churches, and now we hope to challenge businesses with an African-American staff base," an official of the blood bank said.

This is a welcomed initiative to meet the challenge of providing compatible RBC products to not only sickle cell patients, who frequently develop multiple alloantibodies, but to other black patients who need antigen-negative blood for blood groups other than ABO/Rh.  Despite intensive research efforts for a blood substitute, a more practical and immediate approach is to increase donations from non-whites to address the differences observed in blood group antigen expression between different ethnic/racial groups.  It will be interesting to see how successful this initiative is or why it is different from other similar initiatives in the past.  Will track and follow-up.

FDA reports fatalities related to transfusion and blood collection for 2009

The FDA has released the summary for 2009 of transfused-related fatalities.  Of 74 transfusion-recipient fatality reports, they determined that 44 of the fatalities were transfusion-related, 22 of the fatalities were cases in which transfusion could not be ruled out as the cause of the fatality, and 8 of the fatalities were unrelated to the transfusion.

Interestingly, transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO) accounted for the highest numbers of reported fatalities, followed by non-ABO hemolytic transfusion reactions. 

Another finding of note is that there were no reports of fatal microbial infections associated with RBCs, compared to 5 reports in FY2008, which were all due to Babesia infections.

A pdf of the report can be downloaded at the link above.