![person studying](/sites/default/files/styles/large/public/understandingpi.jpg?itok=Zo3vrl11)
Learn about gene therapy, an experimental treatment that is in clinical trials for several types of primary immunodeficiencies (PIs). This chapter is taken from the IDF Patient & Family Handbook for Primary Immunodeficiency Diseases, 6th Edition, copyright ©2019 by Immune Deficiency Foundation, USA.