Transfusion Selective IgA Deficiency

Selective IgA deficiency is defined as a decrease of serum IgA in the setting of normal serum IgM and serum IgG levels. It is the most common primary immunodeficiency. Although selective IgA deficiency is common, the majority of patients with selective IgA deficiency undergoing transfusion of blood products are asymptomatic. This is in part due to the fact that the majority of patients with selective IgA deficiency do not form anti-IgA antibodies. Even though anti-IgA antibodies have not been definitively proven to cause transfusion reactions, several reports demonstrate the pivotal role they play in these settings. Nevertheless, in the subset of patients in whom anti-IgA antibodies are formed, anaphylactic reaction to blood products may occur.