IgA deficiency: what is new?Wang, Ning; Hammarström, LennartCurrent Opinion in Allergy & Clinical Immunology: December 2012 - Volume 12 - Issue 6 - p 602–608 doi: 10.1097/ACI.0b013e3283594219 PRIMARY IMMUNE DEFICIENCY DISEASE: Edited by Amos Etzioni and Ramsey L. Fuleihan Abstract Author Information Purpose of review: To summarize recent publications on clinical and genetic aspects of IgA deficiency (IgAD). Recent findings: Both major histocompatibility complex (MHC) and non-MHC genes contribute to susceptibility to the disease. The former genes appear to be located in different parts of the MHC region depending on the HLA haplotype. The latter show a marked overlap with genes associated with a variety of autoimmune disorders including Graves’ disease, systemic lupus erythematosus, type 1 diabetes and celiac disease, suggesting common pathophysiological mechanisms. Various cytokines, recently shown to include interleukin 21, can induce IgA synthesis in vitro in cells from patients with IgAD, suggesting a regulatory basis of the disease. Summary: IgAD is the most common primary immunodeficiency in the Western world with a prevalence of approximately 1 : 600 in the general population. It appears to be a polygenic disorder and several of the genes involved have recently been identified. The involvement of genes associated with autoimmunity may suggest that IgAD in itself is an autoimmune disease. Division of Clinical Immunology, Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden Correspondence to Lennart Hammarström, Karolinska Institutet, Division of Clinical Immunology, Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, 141 86 Stockholm, Sweden. Tel: +46 8 524 835 86; e-mail: Lennart.Hammarstrom@ki.se Copyright © 2012 Wolters Kluwer Health, Inc. All rights reserved.