ABSTRACT
Activated phosphoinositide 3-kinase δ syndrome(APDS) is an autosomal dominant inherited primary immunodeficiency disease that is caused by mutations in PIK3CD or PIK3R1 genes leading to overactivation of the PI3Kδ signaling pathway, first reported by Angulo et al in 2013. The clinical manifestations of the disease are recurrent respiratory tract infections, benign lymph node hyperplasia, autoimmune diseases, lymphoma and so on. Although most patients develop the disease in childhood, there are also reports of adult onset and asymptomatic patients. In addition, the immunophenotype of activated phosphoinositide 3-kinase δ syndrome is changeable, usually the IgA levels are reduced, the IgM levels can be normal or elevated, and the IgG levels are variable, so it is easy to be misdiagnosed at first diagnosis. There is no unified diagnostic standard at present, and timely genetic testing is required to confirm the diagnosis.