AUTHOR=Al-Herz Waleed, Bousfiha Aziz, Casanova jean-laurent, Chapel Helen, Conley Mary Ellen, Cunningham-Rundles Charlotte, Etzioni Amos, Fischer Alain, Franco Jose, Geha Raif, Hammarstrom Lennart, Nonoyama Shigeaki, Notarangelo Luigi, Ochs Hans, Puck Jennifer, Roifman Chaim, Seger Reinhard, Tang Mimi TITLE=Primary Immunodeficiency Diseases: An Update on the Classification from the International Union of Immunological Societies Expert Committee for Primary Immunodeficiency JOURNAL=Frontiers in Immunology VOLUME=2 YEAR=2011 URL=https://www.frontiersin.org/articles/10.3389/fimmu.2011.00054 DOI=10.3389/fimmu.2011.00054 ISSN=1664-3224 ABSTRACT=We report the updated classification of primary immunodeficiency diseases, compiled by the ad hoc Expert Committee of the International Union of Immunological Societies. As compared to the previous edition, more than 15 novel disease entities have been added in the updated version. For each disorders, the key clinical and laboratory features are provided. This updated classification is meant to help in the diagnostic approach to patients with these diseases.