n.
Defect in immunity that impairs the body's ability to resist infection.
The immune system may fail to function for many reasons. Immune disorders caused by a genetic defect are usually evident early in life. Others can be acquired at any age through infections (e.g., AIDS ) or immunosuppression . Aspects of the immune response that may be affected include lymphocytes , other leukocytes , antibodies , and complement . Severe combined immunodeficiency (SCID), which arises from several different genetic defects, disrupts all of these. Depending on the cause, treatment for immunodeficiency may be administration of immunoglobulins, bone-marrow transplant, or therapy for the underlying disease.