IgG subclass deficiency in children with recurrent infections

Area of Science:

• Pediatric Immunology
• Infectious Diseases

Background:

• Recurrent respiratory tract infections (RRTIs) in children can stem from various causes.
• While low immunoglobulin levels are a known factor, IgG subclass deficiencies may also contribute.
• IgA deficiency and generalized hypogammaglobulinemia were excluded in this cohort.

Purpose of the Study:

• To investigate IgG subclass levels in children experiencing recurrent respiratory tract infections.
• To determine the prevalence of IgG subclass deficiencies in this pediatric population.
• To assess the clinical implications and treatment response in affected children.

Main Methods:

• Analysis of IgG subclass levels (IgG1, IgG2, IgG3, IgG4) in 12 children (aged 2.5-12 years) with RRTIs.
• Clinical evaluation including assessment for bronchiectasis and history of severe pneumonia.
• Treatment response to prophylactic antibiotics and subsequent gammaglobulin therapy was monitored.

Main Results:

• A combined deficiency of IgG2 and IgG4 was found in one patient.
• Selective IgG2 deficiency was identified in another patient, resulting in a 16.6% prevalence of IgG subclass deficiency.
• Two patients with IgG subclass deficiency developed bronchiectasis secondary to severe pneumonia; however, one bronchiectasis patient had normal IgG subclass levels.

Conclusions:

• IgG subclass deficiency, particularly IgG2 deficiency, should be considered in children with unexplained recurrent infections.
• Normal serum immunoglobulin levels do not exclude the possibility of underlying IgG subclass deficiency.
• Gammaglobulin therapy may be beneficial for IgG subclass-deficient patients unresponsive to antibiotics.