Transient hypogammaglobulinemia of infancy

Transient Hypogammaglobulinemia of Infancy

Transient hypogammaglobulinemia of infancy (THI) is a primary immunodeficiency disorder characterized by a temporary decrease in the levels of immunoglobulin G (IgG) in infants. This condition is typically identified in the first few months of life and usually resolves by the age of 2 to 4 years.

Pathophysiology

THI occurs due to a delay in the maturation of the infant's immune system, specifically in the production of IgG antibodies. During the first few months of life, infants rely on maternally derived IgG, which is transferred across the placenta during pregnancy. As these maternal antibodies wane, the infant's own production of IgG may be insufficient, leading to hypogammaglobulinemia.

Clinical Presentation

Infants with THI may present with recurrent infections, particularly of the respiratory tract, such as otitis media, sinusitis, and pneumonia. However, many infants with THI remain asymptomatic and are identified incidentally during routine immunological evaluations.

Diagnosis

The diagnosis of THI is primarily based on laboratory findings and clinical history. Key diagnostic criteria include:

• Low serum IgG levels for age, with normal IgA and IgM levels.
• Normal response to vaccines, indicating functional antibody production.
• Exclusion of other causes of hypogammaglobulinemia, such as X-linked agammaglobulinemia or Common variable immunodeficiency.

Management

Management of THI is generally supportive. Most infants do not require specific treatment, as the condition is self-limiting. However, in cases of severe or recurrent infections, prophylactic antibiotics or immunoglobulin replacement therapy may be considered.

Prognosis

The prognosis for infants with THI is excellent, as the majority of affected children will develop normal immunoglobulin levels by early childhood. Long-term complications are rare.

Also see

• Primary immunodeficiency
• Immunoglobulin G
• X-linked agammaglobulinemia
• Common variable immunodeficiency

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