Table 3

Primary antibody deficiency syndromes

Primary antibody deficiencyImmunoglobulin levels
Common variable immune deficiencyLow IgG, low IgA, ± low IgM with a failure to mount a significant antibody response to vaccination.44 Usually identified in first 24 months of life
X-linked agammaglobulinaemiaLow IgG, low IgA, low IgM. Often occurs in boys before the age of 2
IgG Subclass deficienciesLow IgG subgroup 1–4
Specific antibody deficiencyNormal serum levels of immunoglobulin but failure to respond to test immunisation
Selective IgA deficiencyOften symptom free. Estimated to affect 1:700 population45