Blood transfusion reactions and transplant rejection: Pathology review

35 year old Adam is brought to the emergency department by an ambulance after being involved in a motor vehicle crash. Upon examination, you notice that he is significantly bleeding from his thigh, so you decide to give him a blood transfusion. Five minutes later, he develops shortness of breath, one episode of nonbloody vomiting, and a diffuse rash with erythematous borders starts to appear all over his body. Also, his blood pressure drops to 60 over 40 millimeters of mercury. Some days later, you see 50 year old Jack, who’s complaining of fever, malaise, and a decreased production of urine for the past two days. On further questioning, Jack tells you that he underwent a kidney transplantation one month ago. Upon examination, you realize that he has a high blood pressure of 150 over 80 millimeters of mercury. You decide to perform a biopsy of his transplanted kidney, which reveals a dense lymphocytic infiltrate.

Okay, based on the initial presentation, Adam seems to have some form of blood transfusion reaction, which includes any adverse event that occurs following blood transfusion. Jack, on the other hand, seems to be experiencing some form of transplant rejection, which is when the immune system of the recipient attacks the transplanted organ or graft.

All right, let’s start with blood transfusion reactions. For your tests, there are six blood transfusion reactions that you need to be aware of, including anaphylactic or allergic transfusion reaction, acute hemolytic transfusion reaction, delayed hemolytic transfusion reaction, febrile nonhemolytic transfusion reaction, transfusion-related acute lung injury, and transfusion-associated circulatory overload.

Let’s begin with the anaphylactic or allergic transfusion reaction. It is a type I hypersensitivity reaction mediated by the recipient’s IgE antibodies against plasma proteins like immunoglobulins found in transfused blood. Initially, the proteins in the donor’s plasma will be recognized by preformed IgE immunoglobulins present on the surface of mast cells, which in turn release their granules containing inflammatory mediators, such as histamine.