The clinical implications of selective IgA deficiency

• Published in: Journal of translational autoimmunity (Online) Vol. 2; p. 100025
• Main Authors: Swain, Samantha, Selmi, Carlo, Gershwin, M. Eric, Teuber, Suzanne S.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2019; Elsevier
• Subjects: Autoimmunity; Celiac disease; Common variable immunodeficiency; IgA; Immunodeficiency; Mucosal; Review article; Autoimmunity; Celiac disease; IgA; Common variable immunodeficiency; Mucosal; Immunodeficiency
• ISSN: 2589-9090; 2589-9090
• DOI: 10.1016/j.jtauto.2019.100025

Selective IgA deficiency (SIgAD) is the most common primary immunodeficiency but does not always result in clinical disease. This may in part be due to the definition based on serum IgA, while most IgA is secreted at mucosal surfaces, not amenable to measurement. Clinical complications include increased risk of sinopulmonary infections with bacteria and viruses, gastrointestinal infections with a predilection for Giardia lamblia, a myriad of autoimmune diseases including systemic lupus erythematosus, hyper- and hypo-thyroidism, Type 1 diabetes, celiac disease, and rarely, malignancy. SIgAD must be differentiated from IgA deficiency that may be seen with IgG2 or IgG4 deficiency, specific antibody deficiency, or as an early manifestation prior to a diagnosis of common variable immunodeficiency. Secondary IgA deficiency is increasingly recognized and may be due to medications such as anti-epileptics, or antibiotics with disruption of the microbiome which can influence IgA levels, infections or malignancies. Patients with SIgAD should be monitored at regular intervals and educated to be aware of particular complications. There is a rare chance of development of anti-IgA IgE antibodies in patients with complete deficiency, which can result in anaphylaxis if blood products with IgA are administered. Prophylactic antibiotics may be indicated in some cases, and very rarely, supplemental IgG infusions. •Selective IgA deficiency is the most common primary immunodeficiency.•It is associated with an increased risk of infections, allergic and autoimmune diseases, and rarely, malignancy.•There is a risk of transfusion reactions due to the rare development of IgE against IgA in blood products.•Treatment is supportive and directed at complications, with extremely rare use of immune globulin therapy.•Selective IgA deficiency should be considered when evaluating patients with autoimmune disorders.