Safe Subcutaneous Immunoglobulin Replacement Therapy in the Treatment of X-Linked Agammaglobulinemia Patient: A Case Report

X-linked agammaglobulinemia (XLA) or Bruton’s disease is a rare inherited disorder of the immune system: XLA is a primary immunodeficiency, occurring in 1 of 190,000 male births in the United States [1,2]. XLA represents nearly 85% of agammaglobulinemia cases, and is caused by a defect in gene, located on the X chromosome, coding for Bruton’s tyrosine kinase (BTK). BTK gene mutation causes a failure in B-lymphocytes maturation, associated with a failure of Ig heavy chain rearrangement, leading to a decrease in antibody production [2]. XLA patients may present recurrent bacterial infections as well as non-infectious complications, or exhibit heterogeneous clinical phenotypes [3]. This complex clinical outline and the variable severity of symptoms entail an early correct diagnosis to properly manage patients, with appropriate treatment [4]. Symptoms appear during the first year of life, in half of patients, and, within the age of 5 years in in more than 90% of the subjects affected [5]. XLA is diagnosed in approximately 60% of individuals who develop a severe, life-threatening infection [6].