Abstract
Primary immunodeficiency is a group of disorders associated with susceptibility to infectious agents and the development of various comorbidities. Many primary immunodeficiencies are complicated by immune dysregulation, autoinflammation, or autoimmunity which impacts multiple organ systems. Major advances in the treatment of these disorders have occurred over the last half-century, and deeper molecular understanding of many disorders combined with clinically available genetic testing is allowing for use of precision therapy for several primary immunodeficiencies. Patients with antibody deficiencies who rely on immunoglobulin replacement therapy now have many treatment options with products that are much safer and better tolerated compared to the past. Newborn screening for severe combined immunodeficiency, now implemented throughout the USA and in many countries worldwide, has lowered the age at which many patients are diagnosed with these diseases. Early diagnosis of severe combined immunodeficiency allows infants to proceed to definitive therapy such as stem cell transplantation or gene therapy prior to facing potentially life-threatening infections. While stem cell transplantation continues to carry significant risks, knowledge gained over recent decades is allowing for improved survival with less toxicity and less graft versus host disease.