X-linked agammaglobulinemia: investigation of clinical and laboratory findings, novel gene mutations and prevention of infective complications in long-term follow-up.

Introduction-Objective: X-linked agammaglobulinemia (XLA) is a primary immunodeficiency disease predominantly with antibody deficiency and characterized by recurrent pyogenic infections, absence of B cells and agammaglobulinemia. In this study, it is aimed to review the demographic data of our XLA patients and examine the frequency of severe bacterial and mild infections and benefits of immunoglobulin replacement therapies to reduce the rate of infections. In addition, correlations between genotypic results and clinical and laboratory findings were searched. PATIENTS AND METHODS: In this study, 20 patients who were followed-up between 1995-2019 and diagnosed with XLA by flow cytometric and genetic tests were included. Demographic data, symptoms at admission and follow-up, laboratory data and radiologic imaging findings, previous infections, immunoglobulin replacement treatments, and genetic analysis results of the patients were recorded. RESULTS: All patients in the study were male and the mean age of onset of symptoms was 60 months. The mean age at diagnosis was 72 months. A total of 19 different mutations were identified in the Bruton-tyrosine kinase gene, six of them were novel. Our eldest patient was 34 years old and the longest follow-up period was 24 years. Respiratory tract infections were the most common in the patients, only 35% of the causative agents were found in sputum cultures and H. influenzae type b (57.8%) was isolated most frequently. Both intravenous and subcutaneous immunoglobulin replacement therapies significantly reduced the number of severe bacterial infections and other mild infections. CONCLUSION: XLA is a rare pediatric primary immunodeficiency disease and affected individuals require lifelong immunoglobulin replacement therapy. Immunoglobulin replacement prevents life-threatening infections and dramatically increases survival rates. The patients with regular treatment and follow-up, reach adulthood and has a high quality of life.