Empowering women to be partners in their prenatal care.
Sharing information today to save the lives of tomorrow.
Sharing information today to save the lives of tomorrow.
All About Antibodies
Isoimmunization: An Intro to Antibodies in Pregnancy
Isoimmunization: An Intro to Antibodies in Pregnancy
Empowering women to be partners in their prenatal care.
Sharing information today to save the lives of tomorrow.
Sharing information today to save the lives of tomorrow.
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.
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
Easier to understand transfusion reaction info: https://medlineplus.gov/ency/article/001303.htm
"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
- Strobel E. Hemolytic Transfusion Reactions. Transfus Med Hemother. 2008;35(5):346–353. doi:10.1159/000154811
- 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.
- 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.
- 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
- 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
- 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