X-linked agammaglobulinemia: 35 years of experience in a tertiary pediatric hospital in Latin America

Abstract

Background: X-linked agammaglobulinemia (XLA) is a primary immunodeficiency characterized by arrested B cell development, leading to reduced numbers of B lymphocytes and serum immunoglobulin (Ig) levels, due to mutations in the BTK gene located on the X chromosome (Xq21.3- Xq22). The aim of this study was to describe the clinical and immunologic characteristics of patients with a diagnosis of XLA, seen in a tertiary pediatric hospital in Mexico in the department of immunodeficiency in the last 35 years.Methods: A cross-sectional, retrospective and observational study of patients diagnosed with XLA with follow-up in a reference hospital in Mexico City, in a period of January-1987 to July-2022 was performed, data related to their disease status were taken and statistical analysis were analyzed using SPSS.V.16.0.Results: Information was collected from 44 patients with the diagnosis of XLA. The age of onset was 24 months. The age at diagnosis was 60 months. A delay in diagnosis of 37 months was identified, 54 % of patients required I.V. antibiotics before diagnosis, and 45% had a family member with immunodeficiency. The mean Ig levels were IgG: 359 mg/dl, IgA: 24 mg/dl, and IgM: 25 mg/dl. The 77% had a history of bacterial infections before diagnosis, and 6% had allergic symptoms. The main infection was pneumonia in 75%, acute otitis media in 50%, sinusitis in 59%, meningitis in 13%, cutaneous abscesses in 15%, 36% percent developed complications such as bronchiectasis, and 31% sepsis. Once the diagnosis was established, all patients received Immunoglobulin replacement therapy (IRT). 47% of patients were administered antibiotic prophylaxis.Conclusions: The diagnosis of XLA should be suspected in a patient with recurrent clinical manifestations of encapsulated bacterial infections. The diagnosis is confirmed with serum immunoglobulin levels, two standard deviations below for age, when the flow cytometry is available it can help with the diagnosis. The first contact physician can make the diagnosis.