What causes transient hypogammaglobulinemia of infancy?

Updated: Dec 26, 2018
  • Author: Elizabeth A Secord, MD; Chief Editor: Michael A Kaliner, MD  more...
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Answer

Transient hypogammaglobulinemia of infancy

  • Transplacentally acquired maternal IgG is metabolized over several months (the half-life of immunoglobulins is 21 days) and usually falls below 0.3 to 0.4 g/L by 6 months of age. Normal infants begin making IgG shortly after birth; in some babies, this is delayed, but B-cells are present and IgG production eventually normalizes. Inadequate endogenous IgG production may remain in a prolonged deep trough at the nadir of the IgG levels, leaving the child susceptible to gastrointestinal infections, recurrent sinopulmonary infections, and frequent viral illnesses. In turn, these infections may present physiologic challenges to the vulnerable infant, further impairing the development of protective responses. Because of the rapidity of physiologic changes between ages 4 and 12 months, the trend across several IgG levels is likely a better prognostic indicator than any single level at one point in time.

  • IgG levels persistently below the 5th percentile for age is the sine qua non of this entity. Decreased levels of IgA are also common in this group, and low IgM levels may be seen, but less frequently. Most of these babies have normal lymphocyte counts for age and normal lymphocyte mitogen stimulation test results, and their IgG responses to initial protein vaccines such as DPT are frequently normal.

  • While no specific mechanism has been identified for this entity, its incidence is increased in families with other immunodeficiencies. This association suggests a genetic component

  • Generally, only prophylactic antibiotics are needed to protect these individuals. If IgG therapy is started because of intolerance or ineffectiveness of the antibiotics, it should be temporarily stopped every 3-6 months to re-assess endogenous production of immunoglobulins.


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