[X-linked agammaglobulinemia: experience in a Portuguese hospital]

Abstract

Introduction: X-Linked agammaglobulinemia (XLA) is characterized by an arrest of B cell differentiation, leading to recurrent bacterial infections. Lifelong immunoglobulin replacement therapy (IRT) is indicated to prevent infections and their complications.

Material and methods: A retrospective study of patients with XLA followed in a level three hospital was performed; data was collected retrospectively by review of clinical files.

Results: XLA was diagnosed in 9 children. One (11%) had a positive family history with a prenatal diagnosis. Infection was the clinical presentation in all the others (89%), at an average age of 13 months; diagnosis was established at a mean age of 3.4 years. Acute otitis media (7/9) and pneumonia (5/9) were the most frequently observed. Seven (78%) presented serum immunoglobulin G (IgG) levels below 200mg/dL and all of them had CD19(+) B cells below 2%. Neutropenia was present at diagnosis in three patients (33%). Bruton tyrosine kinase (BTK) mutations were identified in all cases. Intravenous IRT was initiated, switched later to subcutaneous administration, in all. The mean time of follow-up was 10.7 years with cumulative time of 97 years. Eight children (89%) achieved IgG serum levels above 800 mg/dL. One presented lower values due to renal loss. No deaths occurred. After diagnosis the most frequent infections were acute otitis media (6/9). In spite of stable adequate IgG levels on IRT, two patients developed bronchiectasis.

Conclusions: XLA overall prognosis is good, as long as patients have an early and adequate treatment. However, bronchiectasis can occur even on adequate immunoglobulin replacement therapy.

Keywords: Agammaglobulinemia; Agammaglobulinemia ligada al cromosoma X; Immunoglobulins; Infección; Infection; Inmunoglobulinas; X linked agammaglobulinemia.