Medical Alert Information

Our antibodies don't just affect our babies, they affect us too.  If you have red blood cell antibodies, you need to know that your antibodies will flare up if you are exposed to the antigen again. You need to know that you are now at high risk for a transfusion reaction 1. For this reason, you must carry a medical alert card at all times and inform all doctors of her antibody status. The same antibodies that destroy baby's blood cells because they've got the antigen, will also destroy donor blood cells. If you get injured, end up unconscious, or have some other emergency situation and need blood, it's important for the doctors to know about your antibodies so they can find compatible blood. Once you have antibodies, you will have them for life. Your body will always remember how to make them quickly if it ever finds incompatible blood. This has an antagonistic effect and can cause inflammation, high blood pressure, the destruction of donated blood (making transfusion useless), rash, fever, shock, and even death. These reactions can be immediate, or delayed over several days. Fewer than 30% of antibodies are estimated to be detectable by current methods 3. When Pessoni studied transfusion reactions and alloantibody identification rates at a hospital in Brazil, she found that 19% of alloantibodies could not be identified 4.  Even if your antibodies are too low to titer or undetectable, the medical personnel need to know about them. If they don't a hemolytic transfusion reaction occurs (more info about that below). About 20 people die in the USA each year because of them.

Once a woman has been sensitized to create alloantibodies, she will continue to produce them for the rest of her life. The detectable level of antibodies in a patient’s blood can vary from a titer as high as 4096 (or higher), to as low as <1 or “too low to titer”. In some cases, the level of antibodies will even drop to undetectable levels. This does not mean that the patient is not still sensitized, or that the patient will not produce antibodies again. Upon an additional exposure, the body will rapidly reproduce the antibodies and levels will rise again. This can result in a hemolytic transfusion reaction (HTR). Hemolytic transfusion reactions are serious complications from blood transfusions. Transfused blood cells are destroyed by the patient’s immune system negating the usefulness of the transfusion. HTR can result in the creation of anaphylatoxins, a systemic inflammatory response, hypotension, disseminated intravascular coagulation, diffuse bleeding, and disruption of microcirculation leading to renal failure and shock 1. Minor mistakes can lead to major damage. Numbers vary by paper, but up to 56% of transfusion fatalities between 1976-1985 were due to immunological hemolysis 1, ie alloantibodies. Transfusion related fatalities have decreased since 2001, but are still a prevalent issue. In 2017,7 out of 44 transfusion associated fatalities (15.9%) ABO and non-ABO alloantibodies 2. Reasons for HTRs include: human error (misidentification of a patient, product, or sample), or a weakened antibody that was not detected when the patient’s blood was crossmatched. Erwin Strobel calls this, “unavoidable” 1, but frankly, it is avoidable.

The problem facing many alloimmunized women is that they are unaware of the effects of their antibodies outside of pregnancy. Most are never told by their healthcare providers that they need a medical alert card, or that they are at a higher risk for having a hemolytic transfusion reaction (HTR). Most women are not told that they must declare their antibodies to all healthcare providers, especially in cases of surgery or other procedures where a blood transfusion is a possibility.

5 minutes to fill out a free medical alert card, or order a bracelet can literally save your life.



You can get medical alert bracelets from Etsy or a number of online retailers.


If you need a medical alert card, please fill out the Google form and a paper card will be printed and mailed to you.
 

Transfusion Reactions

Alloimmunization carries a risk of hemolytic transfusion reactions (HTR). Despite advances in technology and cross-matching, HTRs are still a problem today. For this literature review,articles from 2008-2019 that were published in peer-reviewed journals were included. The point of this section is to point out the effects of antibody evanescence, boostering, and the effects of an inability to identify alloantibodies in a timely manner.

Antibody evanescence, a term used by Balbuena-Merle and Hendrickson, is when alloantibodies decrease to below detectable levels 3. This causes problems in transfusion medicine and makes it more likely that a patient with known antibodies will have a hemolytic transfusion reaction when antibodies that are unknown to the medical professionals come roaring back to life. Fewer than 30% of antibodies are estimated to be detectable by current methods 3. When Pessoni studied transfusion reactions and alloantibody identification rates at a hospital in Brazil, she found that 19% of alloantibodies could not be identified 4. Of the antibodies that were identified, all were clinically significant (anti-Rh, anti-Kell, and anti-MNS). The conclusion of Pessoni’s work was that due to the relation ship between clinically important alloantibodies and HTRs, additional care should be taken to identify alloantibodies to improve transfusion safety 4. In cases of an unidentified alloantibody, having a medical alert card could help narrow down which antibody a patient has because historical identification results would be clearly listed on the card.

Delayed HTRs are caused in part by boostering 1. As Strobel describes, boostering is when an antibody undetectable during cross-matching is suddenly detectable again, and it happens in patients who were earlier found to have alloantibodies, but then experienced antibody evanescence. Boostering can result in the antibodies coming back in an anamnestic manner, including hyperhemolysis8. One way Strobel suggests to prevent boostering is to issue a medical alert card to all patients who have irregular antibodies 1. The purpose of this card is to present it at the time of transfusion in a different medical facility. In unconscious patients, the risk of identification errors is higher. The medical alert cards this grant wishes to create will be used as a form of confirming patient identification, and conveying the relevant antibodies to prevent antibody boostering as a result of antibody evanescence.

When patients have unexpected blood antibodies, they may be at a risk of delayed transfusion. When a transfusion is needed and an unexpected alloantibody pops up, additional time must be taken with cross matching and antibody identification. This time can cause significant problems in a surgical or emergent trauma situation. For surgical situations it is possible to cross match the blood ahead of time, and like Strobel suggests, conduct a second cross match 3 days later to detect any antibodies that were boosted by re-exposure to antigens 1. Ki-Ho suggests that keeping a patient registry may help in cases where rapid transfusion is needed, as would a notification system such as medical alert cards 5,. Karafin 6 and Quach concur that a national patient registry would be helpful in terms of research and reducing HTRs, in the absence of such a registry, medical alert cards would be useful for informing transfusion centers about a patient’s alloimmunization history and current treatments.

A review of current literature shows that hemolytic transfusion reactions are still a problem today and can be prevented by a medical alert card. When antibodies decrease below detectable levels, it can cause an increase in unidentification or misidentification of the alloantibodies a patient has. As a result, patients may experience delayed transfusion times. To help facilitate rapid transfusions, and avoid the anamnestic effects of antibody boostering, a medical alert card identifying known antibodies would be useful.

Additional Information

“"Acute hemolytic transfusion reactions may be either immune-mediated or nonimmune-mediated. Immune-mediated hemolytic transfusion reactions caused by immunoglobulin M (IgM) anti-A, anti-B, or anti-A,B typically result in severe, potentially fatal complement-mediated intravascular hemolysis. Immune-mediated hemolytic reactions caused by IgG, Rh, Kell, Duffy, or other non-ABO antibodies typically result in extravascular sequestration, shortened survival of transfused red cells, and relatively mild clinical reactions. Acute hemolytic transfusion reactions due to immune hemolysis may occur in patients who have no antibodies detectable by routine laboratory procedures" http://emedicine.medscape.com/article/206885-overview#showall

"Acute hemolytic transfusion reactions may be either immune-mediated or nonimmune-mediated. Immune-mediated hemolytic transfusion reactions caused by immunoglobulin M (IgM) anti-A, anti-B, or anti-A,B typically result in severe, potentially fatal complement-mediated intravascular hemolysis. Immune-mediated hemolytic reactions caused by IgG, Rh, Kell, Duffy, or other non-ABO antibodies typically result in extravascular sequestration, shortened survival of transfused red cells, and relatively mild clinical reactions. Acute hemolytic transfusion reactions due to immune hemolysis may occur in patients who have no antibodies detectable by routine laboratory procedures" http://emedicine.medscape.com/article/206885-overview#showall

Easier to understand transfusion reaction info: https://medlineplus.gov/ency/article/001303.htm
 

References

  1. Strobel E. Hemolytic Transfusion Reactions. Transfus Med Hemother. 2008;35(5):346–353. doi:10.1159/000154811
  2. Fatalities Reported to FDA Following Blood Collection and Transfusion: Annual Summary for Fiscal Year 2017. US Food and Drug Administration. https://www.fda.gov/media/124796/download. Retrieved 2019 Nov 29.
  3. Balbuena-Merle R, Hendrickson JE. Red blood cell alloimmunization and delayed hemolytic transfusion reactions in patients with sickle cell disease. Transfus Clin Biol. 2019 May;26(2):112-115. doi: 10.1016/j.tracli.2019.02.003. Epub 2019 Feb 22. PubMed PMID: 30857806.
  4. Pessoni LL, Ferreira MA, Silva JCRD, Alcântara KC. Red blood cell alloimmunization among hospitalized patients: transfusion reactions and low alloantibody identification rate. Hematol Transfus Cell Ther. 2018;40(4):326–331. doi:10.1016/j.htct.2018.04.001   
  5. Ko KH, Yoo BH, Kim KM, et al. Frequency of unexpected antibody and consideration during transfusion. Korean J Anesthesiol. 2012;62(5):412–417. doi:10.4097/kjae.2012.62.5.412
  6. Karafin MS, Westlake M, Hauser RG, et al. Risk factors for red blood cell alloimmunization in the Recipient Epidemiology and Donor Evaluation Study (REDS-III) database. Br J Haematol. 2018;181(5):672–681. doi:10.1111/bjh.15182