Autoagglutination

Autoagglutination is a phenomenon where red blood cells clump together in the absence of any external aggregating agent. This clumping, also known as agglutination, is typically caused by the presence of autoantibodies, which are antibodies produced by the body against its own red blood cells. These autoantibodies can bind to the surface of the red blood cells, creating bridges between them and leading to their aggregation.

The most common cause of autoagglutination is the presence of cold agglutinins, which are autoantibodies that bind to red blood cells more effectively at cooler temperatures. This can lead to symptoms such as Raynaud's phenomenon, where blood flow to the extremities is reduced in cold conditions, causing pain and discoloration. Autoagglutination can also be associated with certain autoimmune diseases, infections, and some types of cancer.

Diagnosis of autoagglutination is usually made through a blood test called a direct antiglobulin test (DAT), also known as a direct Coombs test. This test detects the presence of antibodies or complement proteins bound to the surface of red blood cells. If the DAT is positive, further investigation may be needed to identify the specific autoantibody and its underlying cause.

Treatment for autoagglutination depends on the underlying cause and the severity of symptoms. In cases caused by cold agglutinins, avoiding cold exposure is often recommended. For more severe cases or those associated with underlying diseases, treatments may include medications to suppress the immune system, such as corticosteroids or rituximab, or plasmapheresis, a procedure to remove autoantibodies from the blood.