blood transfusions

The Professors' Posts

Blood Transfusions

SUSAN LECLAIR

Antibodies will work at different temperatures depending on their chemical make-up. Cold acting antibodies, for example, don't usually cause any trouble in a person who has them because they work at temperature below 65° F. They will cause trouble if you go out on a winter's day or work in cold rooms or open refrigerators/freezers a lot.

Warm acting antibodies are the bigger problem since, obviously, they work at body temperature so they will cause a reaction in the body. The first thing that needs to be done is to identify the antibody. That works about 90% of the time - that you have a clean chemical structure that you can identify. Once you know that someone has , for example and antibody to the antigen D or Anti-D, then you find a donor who does not have that antigen and voilá,you have a compatible transfusion. But - that 10% of the time is not so easy.

Sometime - especially in lymphoproliferative disorders (leukemia,lymphoma, myeloma, etc.) the lymphocytes are messed up enough that they make a "thing" that might act like an antibody but isn't . So it will bind to red cells and hemolyze them - just like real antibodies - but it cannot be identified because it is not of a good enough quality to be identified. So, in those circumstances, you do a "trial" transfusion by mixing the red cells of the patient with the plasma of the donor and the red cells of the donor with the plasma of the patient and check to see what happens. If there is hemolysis in the test tube, then you cannot use that donor blood for this patient.That is probably what they are doing for your Dad right now - trying to find someone somewhere whose blood doesn't react poorly.

Until then, the best next thing to do is to try and stop these cells from making the "thing". Steroids by any name will stop lymphocytes from making antibodies so the idea is to suppress the antibody forming capacity of the cells. Hopefully, you can do this long enough so that the thing doesn't cause any trouble when a transfusion is attempted.

Irradiating blood only damages the lymphocytes that are in the bag so to speak. Your Dad is the one who is making the antibodies so it wouldn't work.

SUSAN LECLAIR

Warning - this may just be a tad long! Many physicians don't take courses in blood banking so it is not a surprise that he has it all wrong.
The immune system has a concept called self. Self is the combination of every antigen (usually any protein over a specific weight and other stuff as well) that you possess. Anything that is not -self is regarded as foreign and should be eliminated. Methods of elimination include breaking the protein apart, killing an organism, altering the antigen's structure, and making antibodies against the antigen.
All human red cells carry antigens on and within them. For example ABO are antigens. Your ABO group antigens don't cause trouble in you since they fit the profile of self. BUT, there are lots of proteins 'out there' that look like ABO antigens. As a consequence, by the time you are 18 months old (or so), you will have made antibodies to the ABO antigens that you do not have. For example - those of you who are group A possess anti-B and those of you who are group O (which is really zero) possess both anti-A and anti-B.
Rh (or D is you use that naming system) is also an antigen but there are no naturally occurring proteins that look like Rh(D) to your immune system so you do not make antibodies to Rh(D) until and unless you are exposed to Rh(D) antigen via a blood transfusion or pregnancy. Antigen i is found on red cells and a similar protein is found on a bacteria called Mycoplasma pneumoniae. People with this infection can sometimes develop antibodies against the bacteria that will also kill off their own red cells. In addition there are over 30 more red cell antigens which your immune system thinks are ok since you have them.
All human white blood cells and platelets also carry antigens. We use a different naming process for them - the CDs. Plasma can passively carry antigens as well. For example, suppose someone drank a glass of milk prior to donation. The milk proteins are antigens and would be given to someone in the plasma. You can just imagine the reaction you would get from that if you were allergic to milk proteins!
So - suppose you got a transfusion of whole blood. You would be getting the potential of foreign antigens from red cells, white cells and plasma. To lessen that potential, you "draw off" the plasma or you wash the cells so that none of the plasma remains. That only eliminates the PLASMA proteins - not the red cell or white cell or platelet antigens.
So - now that you have washed cells, you remove the platelets and the white cells. There are several ways to eliminate white cells. You need to use at least 2 methods since granulocytes and platelets can be eliminated rather easily but lymphocytes require special handling. One way to get around the lymphocyte issue is to irradiate them, killing them. You want to do this if you suspect that the person may be a candidate for a transplant or already had one since this is the best way to lessen/stop GVH.
This means you are left with those pesky red cell antigens. The only truly compatible red cell donor for you is you. Failing that, you could try your identical (not fraternal) twin. If neither of those options is available- you are stuck with getting red cells that definitely have foreign antigens.
These red cell antigens will vary in their ability to cause you to develop antibodies. 30 ccs (1 shot glass for those of you who don't think in the metric system) of blood that is ABO incompatible will kill. 30 ccs of blood that is Rh (D) incompatible will always cause an antibody response. The others - well they vary. And , frankly so do you. Sometimes your immune system is irritated enough that even a small amount of a foreign antigen will trigger it; sometimes not.
Thus, transfusion are a crap shoot. Everytime you get one you are exposing yourself to foreign antigens and it is up to your immune system's functionality on that day to decide if the antigens are "worth" developing an antibody.

TERRY HAMBLIN

People who need lots of transfusions frequently develop antibodies against minor blood group antigens that will cause transfusion reactions unless they are fully matched. In order to fully match it usually takes longer than usual and there may be difficulty in finding the right blood.

You can have as many transfusions as you need if you are bleeding, but if you are not producing blood (and your husband seems to have pure red cell aplasia) then iron overload becomes a problem, and the patient need infusions of desferioxamine under the skin to remove the iron.

In your husband's case the doctors should have tested for the possibility of parvovirus B19 infection by a molecular (rather than an antibody) test. I expect that they have.

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