As a group, antibody deficiencies represent the most common types of primary immune
deficiencies in human subjects. Often symptoms do not appear until the latter part of the first
year of life, as passively acquired IgG from the mother decreases to below protective levels.
As with the T-cell immune deficiencies, the spectrum of antibody deficiencies is broad,
ranging from the most severe type of antibody deficiency with totally absent B cells and
serum Igs to patients who have a selective antibody deficiency with normal serum Ig. In …