Immunoglobulin A Deficiency, Selective

Key Features

• The most common primary immunodeficiency disorder, estimated to affect 1 in 500 individuals, although not all will be clinically symptomatic

Clinical Findings

• Most patients are asymptomatic

• Patients are most susceptible to infections with encapsulated bacteria (eg, Haemophilus influenzae, Streptococcus pneumoniae, Neisseria meningitides)

• Frequent and recurrent sinusitis, otitis, and bronchitis

• Can be associated with atopic diseases and autoimmune disorders, including Graves disease, SLE, juvenile rheumatoid arthritis, type 1 diabetes mellitus, and celiac disease

Diagnosis

• Characterized by undetectable serum IgA levels (< 7 mg/dL) with normal levels of IgG and IgM

• Some patients with undetectable levels of serum IgA may have high titers of anti-IgA antibodies and are at risk for anaphylactic reactions to IgA following exposure to it through infusions of plasma (or blood transfusions)

Treatment

• Treatment with commercial immune globulin is ineffective because IgA and IgM are present only in trace quantities in these preparations

• Antibiotics as needed for infections

• Some cases of IgA deficiency may spontaneously remit