Blood type

[Temperature101]

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Which of the following is true concerning type B negative blood?

A. Type B negative blood will make antibodies that attack type A antigens but not type B antigens.

B. Type B negative blood will make antibodies that attack type B antigens but not type A antigens.

C. Type B negative blood will make antibodies that attack type O antigens only

D. Type B negative blood will make antibodies that attack both type A and type O antigens.

Answer is A.
What do they mean by putting negative after type B? I know type B blood has B antigens, therefore, the immune system does not make antibodies against it. Even if they had said type B blood without putting the negative after it, the answer will be the same. My question is what is the difference between a type B negative blood and a simple type B blood?

 

[tryp]

Rhesus factor negative. In this question, the rhesus factor status doesn't seem to be relevant, but a full blood type generally states both ABO type and rhesus D antigen status.

 

[Temperature101]

Rhesus factor negative. In this question, the rhesus factor status doesn't seem to be relevant, but a full blood type generally states both ABO type and rhesus D antigen status.

Can you tell me when the rhesus factor is relevant?

 

[tryp]

The biggest example is in hemolytic disease of the newborn, where the mother is Rh- and the baby is Rh+. The mother produces high titre IgG against the fetal RBCs from the second incompatible pregnancy onwards, causing anything from mild anemia to hydrops fetalis. It can be prevented by giving RhoGam during the pregnancy to sop up the fetal RBCs before the mother is exposed.

 

[tryp]

It doesn't have any relevance in terms of ABO incompatibility - it's independent of ABO - it can just cause its own form of incompatibility in some cases.

 

[SAvoodoo]

Can you tell me when the rhesus factor is relevant?

long story short: pregnancy and blood transfusions.

slightly longer explanation. R factor negative people will make antibodies against r factor positive blood so if you are ABO negative and get ABO positive blood you get an immune reaction to the donor blood. in pregnancy this is a very big deal because if the baby is R+ and the mom is R- the mom will make antibodies against the fetal blood and attack it, not a good situation.

a very simplified explanation at a very non medical site that should help a little bit: http://pregnancy.about.com/od/rhfactor/a/Rh-Factor-in-Pregnancy.htm

 

[MedPR]

Type B negative = has B antigens and no Rh antigen = makes antibodies against A and Rh. So if you transfuse type A positive blood, there will be a transfusion reaction due to the A antigens as well as the Rh antigen.

As above, the most important situation for Rh +/- is in erythroblastosis fetalis. Since in a typical pregnancy the only exchange of maternal and fetal blood is during birth, an Rh- mother and Rh+ first child will usually not be a problem. However, if the first child is Rh+, and the mother is Rh-, all subsequent Rh+ children will be "attacked" by the Rh- mother because the antibodies are small enough to pass through the placenta and into the fetal blood stream. Remember, this is only true for subsequent pregnancies. Typically both the maternal and fetal blood (of the first child) are tested for Rh factor. If the mother is Rh- and the fetus is Rh+, the mother will be given RhoD immunoglobulin (RhoGAM), which has a higher affinity for Rh antigen than the Rh antibodies produced in the mother. This prevents the mother's immune system from activating agains Rh+ fetuses (feti? 🙂)

So to recap, Rh incompatibility is primarily an issue in pregnancy, but it can still cause transfusion reactions. It typically doesn't, or isn't as prevalent as in pregnancy, because blood transfusions can be of a single type of cell. For instance, you can transfuse only RBCs, which are not themselves Rh+ or Rh-, so (as I think someone else above said) Rh factor is not relevant to ABO compatibility.

To answer your original question about "simple type B blood," there is an ABO type as well as a Rh+/- type. Everyone is either A, B, AB, O, and negative or positive. So if you have type B blood, you are either B+ or B-, if you have type A; A+ or A-. Same is true for AB and O.


And yes, the answer to this question is the same for type B+ and type B-.