Blood Clinical Laboratory Report

[yinluan]

Hi, I received a letter from Health Sciences Authority in Singapore (Year 2011) when they tested my blood and it shows me the following :

Immunohaematology

Antibody Identification

ANTIBODY ID : ANTI-Mia

ANTI-Mia is an alloantibody commonly found in Asians.

It has on rare occassions been implicated in haemolytic transfusion reactions and haemolytic disease of newborn.

Transfusion recommendation : AHG-crossmatch compatible red cells.

I don't understand the report neither did my doctors explained this to me when I was hospitalized due to dengue fever.

Questions:

1)Does ANTI-Mia means any problem with my blood?

2) what does the transfusion recommendation refers to? AHG means?

3) what is haemolytic transfusion reactions? like if tranfusion i might

4) have reactions to certain blood even though it may be compatible like O+ blood receive O+ blood but may reject?

5) what is haemolytic diesease of newborn? does it mean that there are some complications if i was to intend to have babies?

[Malcolm Needs ☆]

Hi Linyuan,

I'm afraid there is no easy way to explain all this without using a lot of jargon that make it difficult to understand, but I will do my best.

Although most people have heard of the ABO and the Rh Blood Group Systems, there are, in fact, 30 different Blood Group Systems. Within most of these systems, there are several antigens (mostly sugars or proteins that are expressed on the surface of the red cell). For example, within the ABO Blood Group System, there are three antigens (A, B and A1 - group O individuals have no ABO antigens), however, within the Rh Blood Group System there are well over 40 different antigens.

The Mi(a) antigen is found within the MNS Blood Group System (it was the 7th antigen found within this system, which also has over 40 different antigens).

Altogether, there have been something over 350 different human red cell antigens described, although, of course, no everyone expresses everyone of these antigens on their red cells.

If you lack a particular antigen, you can make antibodies against this particular antigen (alhtough you do not make antibodies against every antigen that you lack. Very often, although not always, you have to be stimulated to produce these antigens by either having been given blood that expresses an antigen that you lack, or by carrying a baby whose red cells express an antigen that you lack (expressed because the baby inherits a gene from the father that leads to the expression of this antigen). Sometimes, however, the body produces antibodies without any apparent stimulation (such as anti-A and/or anti-, although, in reality, there are stimulants within the environment.

Now, to try to answer your questions.

1) No, there is ABSOLUTELY nothing wrong with your blood, in terms of you producing the anti-Mia. Many millions of people throughout the world produce red cell antibodies, and they are as fit as a fiddle.

2) All antibodies are proteins. There are five basic types of these (IgA, IgD, IgE, IgG and IgM). All of these basic types produce lots of different specific antibodies - in your case, the specificity is anti-Mia.

The two types we are interested in, in the world of transfusion, are IgG (which are a sort of Y shape) and IgM (which are a sort of star shape). What we are looking at, in the laboratory, is the ability for these antibodies to cause clumping (the correct word is actually agglutination) of red cells that express the corresponding antigen. In your case, your anti-Mia will cause Mi(a+) red cells to clump, but not Mi(a-) red cells to clump.

IgM antibodies tend to cause this clumping of red cells without any help.

IgG antibodies, however, are smaller than IgM antibodies, and cannot "reach across" between two red cells to cause this clumping without a "bit of help". All antibodies, as I said are proteins, and all of these are a particular kind of protein called immunoglobulins. In the case of your anti-Mia, it would appear to be an IgG antibody (from the report), and one way that we can "help" the IgG antibodies to "reach across" two red cells to cause the clumping is to perform a particular test called an indirect antiglobulin test (I won't go into details - it is fairly comlpicated to explain, but is a very sensitive test), but for this test we use a particular reagent called anti-human globulin, and this is the AHG to which the report refers. So, if you require a blood transfusion, the laboratory would test (cross-match) the proposed units by this test, using AHG, to ensure that the blood is compatible with your antibody (i.e. your antibody would NOT cause the red blood cells to clump).

If your antibody did cause the red cells to clump, and you were transfused these red cells (don't worry - this blood would NOT be given to you - that is the point of the test), then your antibody could destroy these transfused red cells, and you could become very ill indeed (I STRESS AGAIN, the point of testing the blood to be transfused to you is so that this does not happen).

Haemolytic disease of the newborn happens when you have an IgG antibody of some specificity (in your case anti-Mia) and the foetus's red cells express the corresponding antigen (in your case Mia). The antibody can cross the placenta (IgM antibodies do not) and can destroy the foetuses red cells (haemolyse them). This used to be a real problem, but nowadays, as long as the pregnancy is well-monitored and, if considered necessary for the baby's health and wellbeing, there are such interventions as early delivery or intrauterine transfusions, then the baby will be born with no problems. I must stress, however, that many women have produced red cell antibodies, of many different specificities, and have had babies that are totally unaffected, despite the fact that they express the corresponding red cell antigen on their red cells - so don't worry!

I hope this explanation helps to some degree, but, if not, say so and I, or one of the many really nice people on this site, will try to explain it in a different way.

[Deny Morlino]

Very well said Malcolm!

[Mabel Adams]

Sometimes I define an antigen as the thing that an antibody recognizes or matches up to--kind of like a lock and a key. The measles virus has measles antigens on its surface that are recognized by the antibodies the immune system makes when given measles vaccine. This means the anti-measles antibodies can attack any measles viruses that get into your system later. But the antibodies to the measles antigens can't recognize or attack the hepatitis virus antigen.

Blood cells also have antigens on their surface as Malcolm explained above, so the immune system does its job whenever it encounters something "foreign" and makes antibodies just as if the blood cell were a disease. A small amount of baby's blood may leak across the placenta into the mother's bloodstream so that the mother can sometimes make antibodies against any blood cell antigens that are on the baby's cells that are not on the mother's (we usually don't make antibodies to our own antigens). Of course, blood transfusion puts lots of "foreign" blood cells into a person's bloodstream where the immune system may make antibodies to any antigens they lack. Fortunately, the immune system is much better at making measles antibodies from a vaccine than it is at making antibodies to transfused blood cell antigens. Only about 4% of transfused patients make antibodies to other people's blood cells.

[mawyant]

Wow Malcolm, who needs reference books?

[rcollins]

Hi Yinluan,

I would recommend keeping this report with you and if you are ever hospitalized again, pass it on to your clinicians so they can alert the blood bank. It will just help guide them more quickly to the appropriate blood for you.

[webersl]

Here is a shorter version of the answers. These are geared more toward a patient who may not be a native speaker of English, and less toward a learning scientist:

Questions:

1)Does ANTI-Mia means any problem with my blood?

No problem for your blood or your health. But, your doctor(s) and the laboratory/transfusion service need to be told about the Anti-Mia if you need a transfusion in the future, or if you get pregnant, because they will need to be ready to take special precautions.

2) what does the transfusion recommendation refers to? AHG means?

This comment is directed to the laboratory, blood bank, or transfusion service. It tells them that if they want to give you a blood transfusion, special testing is required in order to find a transfusion that is right for you (compatible). Most people can accept any unit of blood that matches their ABO type. But for you, they will need to do more testing to make sure that the blood also matches your Anti-Mia. AHG is the name of the special test.

3) what is haemolytic transfusion reactions? like if tranfusion i might have reactions to certain blood even though it may be compatible like O+ blood receive O+ blood but may reject?

Yes. That is why it is important for your doctor and the transfusion service or blood bank to know about your anti-Mia. They will be able to select blood that will NOT cause a haemolytic transfusion reaction.

5) what is haemolytic diesease of newborn? does it mean that there are some complications if i was to intend to have babies?

Yes, it is possible, but not certain. Remember, the report said that it is RARE. It is possible that your antibody may begin to destroy the baby's blood while the baby is still growing inside you. Your pregnancy doctor needs be told about your antibody (Anti-Mia). If he knows about it, then he will carefully watch the baby for any sign of problems and then he can take action to prevent harm to the baby. If the doctor sees anything starting to become a problem, as Malcom said, he can do some things to prevent the harm: deliver the baby early or give a transfusion to the baby while the baby is still inside you.

As the report said, this is most common among Asian populations. So, if you are traveling or living in a non-Asian country, the doctors and transfusion services (the part of the lab that supplies the blood that will be transfused to you) may be less familiar with this antibody. It will be even more important that you make SURE you have repeatedly told your doctor and the transfusion service the name of this antibody - Anti-Mi(a).

[Mabel Adams]

What a great post! I hope the patient has come back to read it.