You make this question rather difficult to answer without knowing... a) what level class is this for? (high school biology or chemistry? freshman course in college? nursing course? advanced college course or graduate school?)
...and... knowing how much you already know. Have you, for example read - - just for starters...
http://en.wikipedia.org/wiki/GlycoproteinDo you have an understanding of what some (or all) of the following terms?
white blood cell recognition, immune system, antibodies (immunoglobulins), antigens, the major histocompatibility complex (or MHC) T cells, glycoprotein IIb/IIIa, platelets, Erythropoietin (EPO)
Revising your question to help respondents know what LEVEL if information you are seeking... and to what extent you have already begun to help yourself... is step one.
And then understanding what you are supposed to know about "blood transplants" would be very important in preparing any answer(s) for you. They are not routinely called that - - usually "bone marrow transplants" or (hematopoietic) stem cell transplants - - for leukemias or other cancers or other serious blood disorders (and in some cases, for some "non-blood" disorders)
At many, many different levels... glycoproteins would play a key role in "sllowing" the "graft" (transplanted cells") to "take", in the determination of whether platelts had regained (sufficient number, mostly... but also) proper clotting function, and of course the role of erythropoietin in promoting red cell production.