Abstract: Objective To explore the clinical features, gene mutations and treatment in patient with activated phosphoinositide 3-kinase δ syndrome(APDS). Methods The data of one patient who was diagnosed as APDS were retrospectively analyzed,and the related literatures were reviewed. The clinical features, gene mutations and treatment were summarized. Results The patient, a 9-year old Chinese girl, was hospitalized in Shandong Provincial Hospital Affiliated to Shandong First Medical University because of “recurrent cough for eight years, chronic diarrhea for three years and abnormal liver function for two years”. CT scan of the chest and abdomen demonstrated that she had hepatomegaly, splenomegaly, right middle lobe bronchiectasis and lymphoid hyperplasia, and the lung tissue in the middle lobe of the right lung was not dilated completely. The immunological features were inverted CD4+/CD8+ index, normal IgG level and increased IgM level. Sanger sequencing of PIK3CD gene confirmed a de novo mutation c.3061G>A(p.E1021K), which confirmed the diagnosis of APDS1. The child received IVIG and rapamycin treatments and experienced obvious improvement in diarrhea, lymphoproliferation, hepatomegaly, and splenomegaly. Recurrent respiratory infections were not occurred. The Wanfang Medical Database, CNKI Database and Pubmed Database were searched by keywords such as “activated phosphoinositide 3-kinase δ syndrome”“activated PI3Kδ syndrome” “PIK3CD”“PIK3R1”“APDS”. A total of 285 patients were reported all over the world, in which 43 patients were Chinese including this patient. There was only one patient with APSD2 type. Compared with the overseas patients, the incidence of bronchiectasis and higher IgM level of APDS patients in China was higher. No patients combined with malignant tumors. The hotspot mutations were c.3061 G>A(p. E1021K)in APDS1 and c.1425+1 G>(A, C, T)(p.434-475del)in APDS2, respectively. Conclusion APDS is a rare primary immunodeficiency disease characterized by antibody deficiency mainly. The patients have recurrent respiratory infections, bronchiectasis, non-neoplastic lymphoid hyperplasia, chronic diarrhea, autoimmune diseases, malignant tumor, developmental delay, CD4+/CD8+ inversion, high IgM level and variable IgG levels. IVIG can reduce respiratory tract infections and rapamycin was beneficial in the treatment of non-neoplastic lymphoproliferative. Hematopoietic stem cell transplantation can significantly improve clinical status and immune function.

Key words: Activated phosphoinositide 3-kinase δ syndrome, Immunodeficiency disease, Gene mutation, Recurrent respiratory infections, Bronchiectasis