By DR MICHAEL J. DEVLIN, NEUROLOGIST:
Intravenous immunoglobulin (IVIg) is a purified human blood product that is used to treat many neurological, haematological and immunological diseases. As infection combatting proteins, immunoglobulins are sourced from many thousands of blood donations that have passed through a rigorous chemical process to create a purified chemical. Blood donations are screened heavily for blood born viruses (such as hepatitis C, hepatitis B and HIV) before a donation is accepted for use. IVIg will be delivered to an infusion centre as a clear, slightly frothy liquid in glass vials. There are many different IVIg products available, all of which are produced by different companies and vary slightly in their non-active ingredients
Immunoglobulin is seen as an equally effective treatment to plasma exchange in myasthenic crisis and used as maintenance therapy in patients intolerant of other medications. How IVIg works is complex and unclear. It is thought that IVIg interacts with various aspects of the immune system (speeds up clearance of pathogenic antibodies such as acetylcholine receptor antibodies and muscarinic receptor antibodies, reduces autoimmune effect of the body’s white cells). It is thought to alter the immune system away from attacking itself. IVIg does not suppress the immune system and does not lead to opportunistic infections. In fact, it is often given to patients with immunological diseases who are prone to infections.
IVIg is delivered intravenously at a regular schedule for patients on a maintenance schedule (ie. every 4-6 weeks), with or without a loading dose. The patients response to the medication will be assessed by the specialist, and the dose changed accordingly.
Some people experience side effects during and shortly after an infusion of IVIg. Side effects are often mild and may include infusion reactions like cold and flu symptoms, rash and headache. Some side effects are serious, including a form of meningitis (aseptic meningitis), anaphylactoid reactions and venous thromboembolism (deep venous thrombosis) and kidney failure. Your doctor may prescribe medications such as paracetamol and/or an antihistamine prior to IVIg and encourage you to drink more fluid in the days around your infusion to avoid some side effects.
In 2018 very strict guidelines were imposed on doctors who prescribe IVIg. As the average dose of IVIg may cost close to $2000, and due to a worldwide shortage of blood donors, IVIg is a precious, regulated resource. Your specialist is legally required to reduce the dose and frequency of IVIg prescribed to patients with stable symptoms of myasthenia gravis every 12 months.