Immunoglobulins (Ig) also commonly known as antibodies are proteins produced by the white blood cells (B- cells) in response to an infection. The Igs released in the blood specifically identify, bind and mark the targets for destruction by the immune system. The Ig molecule’s ability to identify and specific target comes from its structure. Each Ig molecule is biosynthesized such that it has a unique region which binds to a specific target on the invading foreign body (see figure below). Therefore with this variation in structure, a pool of Ig molecules will provide immunity against a variety of viruses, bacteria and fungi. This humoral immunity (from the pool of Ig molecules) is transferrable from plasma donors to an immune deficient patient.
During the fractionation process Igs are purified from Fraction II/III precipitate. The Ig fraction undergoes a series of purification, viral inactivation and removal steps before it is made available for patient use. In addition to immune deficiencies Ig is indicated for use in several pathologies, click here to learn more.
It takes time for the immune system to synthesize Ig molecules (up to 14 days or longer since infection). Therefore an individual infected with Hepatitis B for instance will not be able to produce antibodies immediately. The disease prognosis of such infections is time sensitive. Since the immune system of the infected individual cannot produce these antibodies quickly they are infused with Ig from plasma donors. These Ig are a special subclass called hyperimmune globulins that are collected from donors who were infected in the past by the same agent or were vaccinated against it. By infusion with the hyperimmune globulins the infected individual acquires passive immunity. Hyperimmune globulins are also administered to infants with no immune system who are born to Hepatitis B positive mother. Presently hyperimmune globulin products are available for several infectious agents, click here to learn more.
- Primary Immune Deficiency (PID)
- Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)
- Idiopathic Thrombocytopenic Purpura
- Pediatric Human Immunodeficiency Virus (HIV)
- Allogenic Bone Marrow Transplantation
- B-Cell Chronic Lymphocytic Leukemia
- In addition there are almost 300 off label uses