Immunoglobulin Infusion: Effects, Uses and Risks

What is an Immunoglobulin Infusion?

An immunoglobulin infusion is a medical therapy in which concentrated antibodies – known as immunoglobulins – are introduced directly into the body. These antibodies are derived from the blood plasma of thousands of healthy donors, purified, and processed into a standardized medicinal product. Depending on the route of administration, a distinction is made between intravenous immunoglobulin therapy (IVIG), in which the infusion is delivered directly into a vein, and subcutaneous immunoglobulin therapy (SCIG), in which the product is injected under the skin.

Immunoglobulins are a central component of the human immune system. They recognize and neutralize pathogens such as bacteria and viruses. In certain conditions, the body produces too few or no antibodies of its own, or the immune system mistakenly attacks the body's own tissue. In both cases, an immunoglobulin infusion can be used therapeutically.

Indications and Uses

Immunoglobulin infusions are used for a wide variety of medical conditions. Two main areas of application can be distinguished:

Replacement Therapy for Immune Deficiencies

In patients with congenital or acquired antibody deficiency (primary or secondary immunodeficiencies), the infusion serves as a replacement for the missing endogenous antibodies. It protects affected individuals from recurrent, severe infections. Typical conditions in which this therapy is applied include:

• Primary immunodeficiencies such as Common Variable Immunodeficiency (CVID) or Bruton agammaglobulinemia
• Secondary immunodeficiencies, e.g., following chemotherapy, in chronic lymphocytic leukemia, or multiple myeloma

Immunomodulatory Therapy

At high doses, immunoglobulins do not merely replace missing antibodies but actively modulate the immune system. They are used in the treatment of:

• Autoimmune diseases such as Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy (CIDP), and myasthenia gravis
• Inflammatory conditions such as Kawasaki disease in children
• Immune thrombocytopenic purpura (ITP), a condition in which platelets are destroyed by the body's own immune system
• Dermatomyositis and other systemic autoimmune diseases

Mechanism of Action

The precise mechanism of action of high-dose immunoglobulin therapy is complex and not yet fully understood. The following mechanisms are currently discussed:

• Neutralization of autoantibodies: The administered immunoglobulins can bind and neutralize circulating autoantibodies that would otherwise damage the body.
• Fc receptor blockade: Immunoglobulins block specific receptors on immune cells (Fc receptors), which slows the destruction of the body's own cells.
• Regulation of immune cells: The therapy influences the activity of B cells, T cells, and macrophages, thereby exerting an anti-inflammatory effect.
• Complement modulation: Activation of the complement system, which can amplify inflammation, is inhibited.

How the Treatment is Administered

Intravenous Administration (IVIG)

Intravenous immunoglobulin therapy is typically carried out in a hospital or specialized medical practice. The infusion takes several hours, depending on the dose and individual tolerability. The dosage and frequency of infusions are determined by the underlying condition and the body weight of the patient.

Subcutaneous Administration (SCIG)

Subcutaneous administration can often be carried out by the patient at home after appropriate training by medical staff. It is usually administered weekly or every two weeks and is considered particularly compatible with everyday life.

Side Effects and Risks

Immunoglobulin infusions are generally well tolerated. Nevertheless, side effects can occur, particularly at the beginning of the infusion:

• Common side effects: Headache, chills, fever, nausea, muscle pain, and changes in blood pressure
• Local reactions (with SCIG): Redness, swelling, or pain at the injection site
• Less common risks: Thromboembolic events (blood clots), renal dysfunction, hemolytic anemia, and aseptic meningitis
• Severe allergic reactions: Very rare but possible, particularly in patients with IgA deficiency

To minimize side effects, the infusion rate is kept slow at the beginning and gradually increased as tolerance is confirmed. Before the first infusion, an IgA level in the blood is typically measured.

Important Notes

The supply of immunoglobulin preparations depends on the availability of blood plasma donations. As global demand continues to rise, supply shortages can occur. The indication for therapy is therefore carefully evaluated by the treating physicians. Immunoglobulin infusions do not replace causal treatment but address the symptoms or the misdirected immune response.

References

1. European Medicines Agency (EMA): Guideline on the clinical investigation of human normal immunoglobulin for intravenous administration (IVIg). EMA/CHMP/BPWP/94038/2007 rev. 2, 2018.
2. Jolles S, Sette A, et al. – Intravenous immunoglobulin: mechanisms of action in autoimmune and inflammatory disorders. Nature Reviews Drug Discovery, 2020.
3. Orange JS, Hossny EM, Weiler CR, et al. – Use of intravenous immunoglobulin in human disease: A review of evidence by members of the Primary Immunodeficiency Committee of the American Academy of Allergy, Asthma and Immunology. Journal of Allergy and Clinical Immunology, 2006.