β_2微球蛋白(β_2m)是一种低分子蛋白(分子量11,800)。首先由Beggarb等(1968)从肾小管疾病患者尿液中分离得到。β_2m构成细胞膜上组织相容性抗原(HLA)一部分,在正常新陈代谢过程中与HLA分离后释放入血。人体大多数细胞均能合成β_2m,正常人β_2m合成及释放速度非常恒定。血液中的β_2m可从肾小球毛细血管壁自由滤过,其中99.9%以上被近端肾小管重吸收并分解。因此,滤过的β_2m并不返回血液循环。血清 β_2 microglobulin (β_2m) is a low molecular weight protein (molecular weight 11,800). Beggarb et al. (1968) were first isolated from the urine of patients with renal tubular disease. β_2m forms part of the histocompatibility antigen (HLA) on the cell membrane and is released into the blood after separation from the HLA during normal metabolism. Most human cells can synthesize β_2m, normal β_2m synthesis and release rate is very constant. Β_2m in the blood can be freely filtered from the glomerular capillary wall, of which over 99.9% are reabsorbed by the proximal tubular and decompose. Therefore, the filtered β_2m does not return to the blood circulation. serum