X-linked agammaglobulinemia (XLA) is a rare inherited immune deficiency characterized by absence or paucity of circulating B lymphocytes and hypogammaglobulinemia. Patients with XLA present at varying ages and have different presentations. The most common presentation is related to recurrent respiratory tract infections. Patients can also present with severe infections such as meningitis or severe sepsis.
We present a case of an 8-year-old school-going boy with a history of recurrent throat infections and bilateral suppurative otitis media. In 2021, he had an episode of severe dengue infection complicated by pancytopenia presenting with mucosal bleeding, petechiae, and purpura, requiring blood and platelet transfusion. The child developed meningitis presenting with convulsions and headaches and was hospitalized for 14 days. Immunological evaluation upon referral revealed markedly reduced serum immunoglobulins (Ig) G (<1.1 g/L), Ig M (0.20 g/L), Ig A (<0.05 g/L), and Ig E (<2.0 KU/L) levels and CD 19+ B lymphopenia (9 cells/μL). Absolute T (4022 cells/μL) and natural killer cell (397 cells/μL) counts were normal. Targeted genetic panel testing confirmed a hemizygous pathogenic variant in the BTK gene (c.62C>A), establishing a diagnosis of XLA. The patient is currently on monthly intravenous immunoglobulin (IVIG) replacement therapy and prophylactic co-trimoxazole. No episode of severe infection has been reported since the onset of treatment over a year ago. He is currently doing well on regular multidisciplinary follow-up and lung-protective strategies.
This case highlights the need to consider inborn errors of immunity in patients presenting with recurrent, severe, or unusual infections. Early immunological assessment is essential for timely diagnosis and intervention. IVIG remains the mainstay of treatment for XLA, significantly reducing morbidity from recurrent infections. IVIG is given either intravenously or subcutaneously every 3 to 4 weeks to the patient. There is also a role of prophylactic antibiotics in prevention of severe infections. Daily co-trimoxazole is a widely agreed choice of therapy. Thrice weekly azithromycin is also added to prevent respiratory exacerbations and to reduce the risk of developing bronchiectasis. Hematopoietic stem cell transplantation has been considered in some centers as a possible curative therapy.
