Why are Males prefered over Females for Blood or Blood products donation ?

You might have come across the laboratory techincians and doctors stating the preference of  male donors especially when it comes to plasma donations and SDP donations. This has been a topic in discussion, especially when it comes to Convalescent plasma donation for covid patients.

This is not due to the mentality of sexism or personal choice. This is in order to prevent TRALI in blood product reciever.

What is TRALI ?

TRALI stands for TRANSFUSION RELATED ACUTE LUNG INJURY. TRALI occures rapidly after a blood or blood product transfusion and is often associated with the reciept of plasma or platelet products

You might have come across cases where in a patient required oxygen support after recieving blood product or after recieving multiple blood products. That is TRALI.

There can be multiple reasons of TRALI. It may be because of fluid overload or because of an allergic reaction or HLA antigen-antibody reaction.

TRALI is rare but also most common cause of transfusion related deaths.

Pregnancy and HLA ANTIBODIES

A mother’s blood can be exposed to the baby’s blood either during pregnancy or during the time of delivery. Due to this exposure of child’s antigen, the mother may develop antibodies towards these antigens. These are termed as HLA (human leucocyte anitgen) antibodies.

HLA antibodies are also found in low quantities in males and nulliparous females. [females who have never been pregnant in life  so far are termed as nulliparous females]. The presence of these HLA antibodies in a healthy individual’s blood does not cause health problems, and generally does not cause harm when transfused to patients. 

But as the number of pregnancies increase, the HLA antibodies increases significantly. There is a direct relationship between pregnancy history and having a positive test for HLA antibodies. 

These HLA antibodies may contribute to a TRALI reaction in a transfusion recipient.

HLA anitbody and TRALI 

These HLA anibodies are found in abundance on WBC(white blood cells) and platelets. These HLA antibodies may cause damage to the lung tissue leading to TRALI.

More TRALI related deaths have been reported in case of transfusion of plasma and platelet donation from ever-preganant females rather than complete blood donations.

What do recent reports suggest?

If you have a look at what the researches conducted around the world say, the results are interesting. (all the reports referred are mentioned in the source section at the end of this blog)

Some, agree to this notion that blood products of pregnant females do increase the mortality (mortality = death rates) of the recipient.

Some, conclude that blood products of ever-pregnant females increase the mortality chances in a male recipient but not in a female recipient.

Some, completely disagree with this idea that blood products of an ever-pregnant female does not affect the mortality rates of recipient irrespective of the recipient sex.  

Moreover if we try to look at nulliparous females in India, ANEMIA and IRON deficiencies are among the most common problems in females. This excludes many females from the criteria of eligible blood donors.

Hence keeping in mind the safety of the blood recipient, male donors are prefered over female donors. But this also increases the donor burden or creates a deficiency of donors for the blood and blood products.

Female blood products can undergo HLA antigen-antiboy testing in order to be eligible for blood product donation. This HLA testing needs to be conducted after every pregnancy.

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  1. https://www.redcrossblood.org/donate-blood/manage-my-donations/rapidpass/trali-information-sheet.html
  2. Biologic mechanisms and clinical consequences of pregnancy alloimmunization by Paige M Porrett.
  3. Female donors and transfusion-related acute lung injury: A case-referent study from the International TRALI Unisex Research Group by Rutger A Middelburg and others.
  4. Association of Blood Donor Sex and Prior Pregnancy With Mortality Among Red Blood Cell Transfusion Recipients by Gustaf Edgren, MD, PhD1 and others. JAMA. 2019;321(22):2183-2192.
  5. Should plasma from female donors be avoided? A population-based cohort study of plasma recipients in Sweden from 1990 through 2002 by Elsa Tynell and others.
  6. Mortality after transfusions, relation to donor sex by R A Middelburg 1, E Briët, J G van der Bom.
  7. The effect of previous pregnancy and transfusion on HLA alloimmunization in blood donors: implications for a transfusion‐related acute lung injury risk reduction strategy by Darrell J. Triulzi.
  8. Association of Blood Transfusion From Female Donors With and Without a History of Pregnancy With Mortality Among Male and Female Transfusion Recipients. Camila Caram-Deelder and others.
  9. Human Leucocyte Antigens in blood transfusion by Zorana Grubic.
  10. The role of donor antibodies in the pathogenesis of transfusion-related acute lung injury: a systematic review by Rutger A Middelburg and others.
  11. Is it possible to donate blood during pregnancy? Medically reviewed by Carolyn Kay, M.D. – Written by Jon Johnson on June 30, 2020

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