Purpose of review: Although anaphylactic reactions to blood products are rare, the incidence of allergic reactions to blood products is similar to the allergic reaction incidence to penicillin antibiotics, and therefore worthy of proportionate attention.
Comprehensive reviews and guidelines of the management of anaphylaxis currently do not include much information on blood products. Current guidelines for the specific management of anaphylactic transfusion reactions are contradictory as to the utility of anti-IgA testing and incomplete by not offering suggestions for the management of non-IgA related reactions.
Recent findings: Anti-IgA is not responsible for most reactions. Anti-haptoglobin antibodies are responsible for more reactions than anti-IgA in Japan, but the cause of most reactions is still not known. The incidence of reactions to platelets is the highest compared with fresh frozen plasma and red blood cells. Pre-storage white blood cell reduction of platelets does not decrease the incidence of reactions, indicating that white blood cell-derived cytokines are not responsible for most reactions.
Summary: The increased incidence of reactions to platelets compared with fresh frozen plasma suggests that a platelet-related factor may be responsible for many of the reactions. The possible role of platelet microparticles or activated platelet membranes, which carry a negative charge similar to ionic radiocontrast media, the major cause of iatrogenic anaphylactic reactions in the hospital, is explored.