Immunoglobulin Replacement Therapy Guidelines

Patient Evaluation Criteria

The American Academy of Allergy, Asthma, and Immunology recommends that patients with normal IgG levels (above 500 mg/dL) do not qualify for immunoglobulin replacement therapy, as seen in this patient with IgG levels of 855 mg/dL 1
Patients must have a history of recurrent bacterial infections, impaired antibody response to pneumococcal polysaccharide vaccine, and IgG levels <500 mg/dL or ≥2 SD below the mean for age to qualify for immunoglobulin replacement therapy 1
The Centers for Disease Control and Prevention recommends pneumococcal vaccination with measurement of pre- and post-vaccination antibody titers to diagnose specific antibody deficiency 3, 4

Pneumococcal vaccination with measurement of pre- and post-vaccination antibody titers is essential for diagnosing specific antibody deficiency, and should include at least 6 serotypes present in the 23-valent polysaccharide vaccine 1, 3
IgG subclass deficiencies alone are not sufficient to justify immunoglobulin replacement therapy without documented impaired response to pneumococcal vaccination 1, 2

The patient should receive the 23-valent pneumococcal polysaccharide vaccine with measurement of pre- and post-vaccination antibody titers before considering immunoglobulin therapy 1, 4
Prophylactic antibiotics could be considered as a less invasive approach before initiating immunoglobulin therapy, particularly for patients with recurrent respiratory infections and normal total IgG levels 5

Initiating immunoglobulin therapy without completing appropriate diagnostic testing (pneumococcal vaccination and antibody response) is a common pitfall 2
Failure to recognize that normal total IgG levels with subclass deficiencies requires demonstration of impaired antibody function before immunoglobulin replacement is another common mistake 1, 2