Allergic/anaphylactic reaction: Type I hypersensitivity reaction against plama proteins in transfused blood. IgA-deficient individuals must receive blood products without IgA.- Urticaria, pruritus, fever, wheezing, hypotension, respiratory arrest, shock- Within minutes to 2-3 hours

Febrile nonhemolytic transfusion reaction: Two known mechanisms: type II hypersensitivity reaction with host antibodies against donor HLA and WBCs; and induced by cytokines that are created and accumulate during the storage of blood products.- Fever, headaches, chills, flushing- Within 1-6 hours

Acute hemolytic transfusion reaction: Type II hypersensitivity reaction. Intravascular hemolysis (ABO blood group incompatibility) or extravascular hemolysis (host antibody reaction against foreign antigen on donor RBCs).- Fever, hypotension, tachypnea, tachycardia, flank pain, hemoglobinuria (intravascular hemolysis), jaundice (extravascular)- Within 1 hour

Transfusion-related acute lung injury: Donor anti-leukocyte antibodies against recipient neutrophils and pulmonary endothelial cells.- Respiratory distress and noncardiogenic pulmonary edema- Within 6 hours