Medical uses
Immunoglobulin therapy is used in a variety of conditions, many of which involve decreased or abolished antibody production capabilities, which range from a complete absence of multiple types of antibodies, to IgG subclass deficiencies (usually involving IgG2 or IgG3), to other disorders in which antibodies are within a normal quantitative range, but lacking in quality – unable to respond to antigens as they normally should – resulting in an increased rate or increased severity of infections. In these situations, immunoglobulin infusions confer passive resistance to infection on their recipients by increasing the quantity/quality of IgG they possess. Immunoglobulin therapy is also used for a number of other conditions, including in many autoimmune disorders such as dermatomyositis in an attempt to decrease the severity of symptoms. Immunoglobulin therapy is also used in some treatment protocols for secondary immunodeficiencies  such as human immunodeficiency virus (HIV), some autoimmune disorders (such as immune thrombocytopenia and Kawasaki disease), some neurological diseases (multifocal motor neuropathy, stiff person syndrome, multiple sclerosis and myasthenia gravis) some acute infections and some complications of organ transplantation.Immunoglobulin therapy is especially useful in some acute infection cases such as pediatric HIV infection and is also considered the standard of treatment for some autoimmune disorders such as Guillain–Barré syndrome. The high demand which coupled with the difficulty of producing immunoglobulin in large quantities has resulted in increasing global shortages, usage limitations and rationing of immunoglobulin.
Some immunoglobulin solutions also contain isohemagglutinins, which in rare circumstances can cause hemolysis by the isohemagglutinins triggering phagocytosis.In the case of less serious side effects, a patients infusion rate can be adjusted downwards until the side effects become tolerable, while in the case of more serious side effects, emergency medical attention should be sought.Immunoglobulin therapy also interferes with the ability of the body to produce a normal immune response to an attenuated live virus vaccine for up to a year, can result in falsely elevated blood glucose levels, and can interfere with many of the IgG-based assays often used to diagnose a patient with a particular infection. Routes of administration
1950s – intramuscular
After immunoglobulin therapys discovery and description in Pediatrics in 1952, weekly intramuscular injections of immunoglobulin (IMIg) were the norm until intravenous formulations (IVIg) began to be introduced in the 1980s. During the mid and late 1950s, one-time IMIg injections were a common public health response to outbreaks of polio before the widespread availability of vaccines. Intramuscular injections were extremely poorly tolerated due to their extreme pain and poor efficacy – rarely could intramuscular injections alone raise plasma immunoglobulin levels enough to make a clinically meaningful difference. 1980s – intravenous
Intravenous formulations began to be approved in the 1980s, which represented a significant improvement over intramuscular injections, as they allowed for a sufficient amount of immunoglobulin to be injected to reach clinical efficacy, although they still had a fairly high rate of adverse effects (though the addition of stabilizing agents reduced this further).