Blood transfusion reactions | Immunology

Blood transfusions are the most common types of transplants.

Common types of blood transfusion reactions

Type of reaction	Features
Febrile reactions	Consists of fever and chills due to the release of cytokines from donor WBCs; caused by host antibodies reacting against antigens on donor WBCs
Allergic reactions including anaphylaxis	Consists of hives, itching, rarely anaphylaxis (especially in selective IgA deficiency patients); caused by antibodies to plasma proteins or other antigens in the donor blood
Hemolytic reactions	Presents with DIC, renal failure, back or flank pain, bloody urine, hemoglobinuria, hypotension, can be fatal; due to ABO or blood group antigen mismatch; caused by host antibodies to antigen on donor RBCs
Alloimmunization	Following a previous pregnancy, blood or blood product transfusion, patients may develop alloantibodies to RBCs; during a subsequent transfusion, these alloantibodies may cause a hemolytic transfusion reaction
Transfusion related acute lung injury	It is typically seen in pneumonia, recent surgery or pulmonary illness; antibodies to HLA or leukocyte antigens in the donor, react against host WBCs and tissues causing inflammation and acute pulmonary edema

GVHD can occur after a blood transfusion. Massive transfusion may cause hypothermia, acidosis, coagulopathy and citrate toxicity. Electrolyte imbalances like hypocalcemia, hypomagnesemia, hypokalemia or hyperkalemia may occur.