antiglobuliins

Antiglobulins are antibodies that specifically bind to other antibodies. They are also known as anti-antibodies. Typically, antiglobulins target the constant (Fc) region of immunoglobulins, although they can also recognize variable regions. The primary and most well-known type of antiglobulin is the rheumatoid factor, which is an autoantibody that targets the Fc region of IgG antibodies. This binding can lead to the formation of immune complexes.

Antiglobulins play a crucial role in immunology and clinical diagnostics. The most common application is in the antiglobulin test, also known as the Coombs test. This test is used to detect antibodies or complement proteins that are attached to the surface of red blood cells. If antibodies or complement are present on red blood cells, antiglobulins will bind to them, causing the red blood cells to agglutinate (clump together). This agglutination indicates a positive result.

The antiglobulin test has several important clinical uses. It is essential for diagnosing hemolytic disease of the newborn, where maternal antibodies attack fetal red blood cells. It is also used to investigate autoimmune hemolytic anemia, a condition where the body's immune system mistakenly attacks its own red blood cells. Furthermore, the test is used in blood transfusion compatibility testing to ensure that a recipient's plasma does not contain antibodies that will attack donor red blood cells. There are two forms of the antiglobulin test: direct, which tests red blood cells for bound antibodies, and indirect, which tests serum for antibodies that can bind to red blood cells.