NCIt definition : A decreased level of serum immunoglobulins. It may be inherited or acquired. It is
caused by decreased or inefficient production of immunoglobulins from B cells or by
a decrease in the numbers of B cells themselves. Low levels of immunoglobulins will
affect the immune system's ability to combat bacterial infection. Supplementation
of immunoglobulins is needed to prevent worsening outcomes.;
Alternative definition : NCI-GLOSS: A condition in which the level of immunoglobulins (antibodies) in the blood
is low and the risk of infection is high.;