BETA 2 MICROGLOBULIN (B2 M)

Beta-2 microglobulin (B2M) is a crucial protein intricately involved in the human immune system, prominently displayed on the surface of nucleated cells. It plays a pivotal role in immune surveillance. Routinely shed into the bloodstream, B2M is omnipresent in various bodily fluids, with its highest concentrations found in blood, lower levels in spinal fluid, and trace amounts in urine. Within the intricate landscape of the kidneys, B2M undergoes a dynamic journey. Passing through the blood-filtering units known as glomeruli, it then embarks on reabsorption within the renal proximal tubules—a vital process that reclaims water, proteins, vitamins, minerals, and other essential substances. In a state of normalcy, only minimal traces of B2M grace the urine. However, when the renal tubules suffer damage or succumb to disease, B2M concentrations surge. The compromised ability to reabsorb this protein leads to an elevation of B2M levels in urine. Simultaneously, damage to the glomeruli hampers their capacity to filter out B2M, causing a consequential rise in blood levels. This intricate interplay highlights the sensitivity of B2M as a marker, reflecting the health and functionality of the renal system.