β2-microglobulin

β2-microglobulin is a small protein found on the surface of most cells, especially immune cells. It plays a role in presenting pieces of proteins (antigens) to the immune system, helping it recognize and respond to threats like infections. When cells are damaged or break down, β2-microglobulin is released into the blood. Elevated levels can indicate conditions such as kidney dysfunction or certain diseases, including some types of cancer or immune disorders. Measuring β2-microglobulin levels helps doctors assess immune system activity and kidney health, aiding in diagnosis and monitoring treatment.