Clinical use of intravenous immunoglobulin in blood disorders.

The protective effect of passively administered immunoglobulin has been known for many years. Although its accepted use over the last 40 years has been in the prevention and treatment of infection its widest and, arguably, most important application has been in the prevention of Rhesus haemolytic disease of the newborn. However, the development over the last decade of a number of safe and effective immunoglobulin preparations for intravenous use has allowed its more widespread utilisation in clinically appropriate settings. It is now widely accepted that intravenous immunoglobulin (IVIgG) is indicated, on a repeat basis, as treatment of choice as replacement therapy for patients with primary antibody deficiency. It may also be effective, in the non-immune deficient patient, in the management of certain bacterial as well as viral infections. This is particularly the case in the pre-term neonate but may have an application in the infected intensive care patient. The benefit in these patient groups has led to a re-evaluation of the use of immunoglobulin replacement therapy in the severe secondary antibody deficiency states associated with such haematological conditions as multiple myeloma and chronic lymphocytic leukaemia. These are currently the subject of randomised, controlled studies. The observation that the use of IV IgG may be associated with effects other than passive transfer of antibody were first made by Imbach in Switzerland. While treating children with immunodeficiency he noticed that two with a coincident immune thrombocytopenia had a rapid platelet increment in close association with the immunoglobulin infusion. He subsequently confirmed that this was a rapid and predictable form of therapy in childhood idiopathic thrombocytopenic purpura (ITP) and that in some children it appeared to affect the natural history of the disease. Since these initial observations the response has been confirmed in both children and adults and extended to other immune-based haematological disorders.