The blood, or plasma, from each donor is carefully tested for evidence of transmissible diseases, such as AIDS or hepatitis, and any plasma sample that is even suspected of having one of those viruses is discarded. The first step in Ig production is to remove all the red and white blood cells. This is frequently done right as it comes out of the donor’s arm by a process called plasmapheresis, which collects the plasma and then returns the red and white cells directly back to the donor. Plasmapheresis is done at centers specifically designated for this purpose. Then, the immunoglobulins are chemically purified from the plasma in a series of steps. This process results in the purification of antibodies of the IgG class; only trace amounts of IgA and IgM, and other plasma proteins remain in the final product.
In the early 1980’s, new manufacturing processes were developed to make Ig preparations that could be safely injected intravenously, that is directly into the vein. Now multiple Ig preparations are licensed in the U.S. for intravenous use. Products developed for intravenous use have also been used successfully subcutaneously, which is administered under the skin, and in recent years products for subcutaneous use have been licensed. For the most part, the products are equivalent in antibody activity. However, there are some differences, which may make one particular preparation more suitable than another for a given individual. Most products contain some type of sugar or amino acid that help preserve the IgG molecules and prevent them from sticking together to form aggregates. If aggregates were present, they could cause severe side effects. Although these sugar and protein additives are harmless for most people, some of them may cause problems for specific individuals. Your prescriber is your best source of information about which product is best for you.
Purified Ig has been used for nearly 50 years and has an excellent safety record. During the purification process and with the final product, there are several steps that destroy or remove many types of viruses, including HIV, to ensure that the final Ig product cannot transmit any known infectious diseases to the patient. Thus, the final Ig product contains highly purified plasma IgG that has a broad range of specific antibodies to many types of bacteria and viruses. It is also effective in helping the white cells in the body kill bacteria, viruses and other germs that may be in the tissues or blood of the patient being treated, and is safe to administer.
