Immunoglobulins are produced by B lymphocytes as part of the humoral response to foreign antigens. Immunoglobulins used in clinical practice are preparations containing antibodies, usually prepared from human plasma or serum, and mainly comprise IgG. Normal immunoglobulin, prepared from material from blood donors, contains several antibodies against infectious diseases prevalent in the general population, whereas specific immunoglobulins contain minimum specified levels of one antibody. Antibodies may also be prepared by genetic engineering techniques. Immunoglobulins are used for passive immunization, thus conferring immediate protection against some infectious diseases. They are preferred to antisera of animal origin as the incidence of adverse reaction is lower.
It is also used for agammaglobulinemia, hypogammaglobulinemia, and combination therapy with antibiotics for severe infections, idiopathic thrombocytopenic purpura (in case that distinguished hemorrhage tendency occur and transient hemostasis care is needed such as surgical treatment or delivery, when other drugs are not available), Kawasaki disease (for the prevention of complication in coronary artery), Guillain-Barre syndrome (subacute demyelinating polyneuritis).