What Is Beta-2 Microglobulin?

2-microglobulin is a small-molecule globulin produced by lymphocytes, platelets, and polymorphonuclear leukocytes, with a molecular weight of 11,800 and a single-chain polypeptide consisting of 99 amino acids. It is the chain (light chain) portion of the human leukocyte antigen (HLA) on the cell surface. It contains a pair of disulfide bonds in the molecule and contains no sugar; similar to the structure of the immunoglobulin stable region. It is widely found in plasma, urine, cerebrospinal fluid, saliva, and colostrum. Normal human 2-microglobulin synthesis rate and release from the cell membrane are fairly constant. 2-microglobulin can be freely filtered from the glomerulus, 99.9% is absorbed in the proximal tubules, and in renal tubular epithelial cells Decomposition and destruction; therefore, the emission of 2-microglobulin is very small under normal circumstances;

2-microglobulin is a small-molecule globulin produced by lymphocytes, platelets, and polymorphonuclear leukocytes, with a molecular weight of 11,800 and a single-chain polypeptide consisting of 99 amino acids. It is the chain (light chain) portion of the human leukocyte antigen (HLA) on the cell surface. It contains a pair of disulfide bonds in the molecule and contains no sugar; similar to the structure of the immunoglobulin stable region. It is widely found in plasma, urine, cerebrospinal fluid, saliva, and colostrum. Normal human 2-microglobulin synthesis rate and release from the cell membrane are fairly constant. 2-microglobulin can be freely filtered from the glomerulus, 99.9% is absorbed in the proximal tubules, and in renal tubular epithelial cells Decomposition and destruction; therefore, the emission of 2-microglobulin is very small under normal circumstances;

Chinese name

2 microglobulin

Foreign name

2-MG

Produce

Lymphocytes, platelets, polymorphonuclear leukocytes

Molecular mass

11.8kD

Clinical significance

Mainly used to monitor the function of proximal tubules

2 microglobulin clinical significance

The increase of serum 2-microglobulin can reflect the situation of impaired glomerular filtration function or increased filtration load;

Increased excretion of 2-microglobulin in urine may indicate renal tubular damage or increased filtration load;

In acute and chronic pyelonephritis, due to kidney damage, 2-microglobulin in urine increases,

In patients with cystitis, 2-microglobulin is normal;

Blood and urine 2-microglobulin were significantly increased in renal transplant patients, suggesting that the body had a rejection reaction. Because 2-microglobulin synthesis was accelerated, although renal clearance increased, blood 2-microglobulin was still increased. Generally, the blood 2-microglobulin rises to a peak 2 to 3 days after transplantation, and then gradually decreases. Continuous measurement of blood and urine 2-microglobulin after renal transplantation can be used as a sensitive indicator of glomerular and tubular lesions. For example, although renal transplantation has oliguria, a decrease in blood 2-microglobulin indicates a good prognosis. The increase of blood 2-microglobulin precedes Cr during rejection, and the measurement of 2-microglobulin can help diagnose the rejection that is still occurring in the subclinical stage of the kidney.

Urinary 2 microglobulin measurement also helps to distinguish upper and lower urinary tract infections. Upper urinary tract infections can easily affect the reabsorption of molecular proteins by the renal tubules, urine 2 microglobulins increase, and lower urinary tract infections 2 microglobulin. Does not rise.

2-microglobulin, abbreviated as 2-MG, is considered to be a simple, accurate, and sensitive method for measuring mild renal function and observation of curative effects in patients with diabetes. Therefore, the determination of 2-microglobulin is of clinical value.

1. The test is mainly used to monitor the function of the proximal tubules. In the case of acute tubular injury or necrosis, chronic interstitial nephritis, chronic renal failure, etc., it can make urine 2-MG significantly increase. Blood and urine 2-MG in renal transplant patients were significantly increased, suggesting that the body had rejection reactions. Continuous measurement of 2-MG after renal transplantation can be used as a sensitive indicator for evaluating glomerular and tubular function. In the early stage of diabetic nephropathy, there is a change in renal tubular function, and urine 2-G also increases.

2. During the active phase of systemic lupus erythematosus, malignant tumors of the hematopoietic system, such as chronic lymphocytic leukemia, urine 2-MG also increased. It can be measured with blood 2-microglobulin and used for the diagnosis of the above diseases. The reference value is 0 to 0.2 mg / L.

Hematuria Common diseases

= mainly due to decreased glomerular filtration function, common in acute and chronic nephritis, renal failure, etc.

= Mainly due to the apparent impairment of renal tubular reabsorption, seen in congenital proximal tubule defects, Fanconi syndrome, chronic cadmium poisoning, Wilson disease, renal transplant rejection, etc.

Mainly due to excessive production in some parts of the body or damage to the glomeruli and tubules, which are common in chronic hepatitis and diabetes. The elderly can also see elevated blood and urine 2 microglobulin.

2 microglobulin composition structure

2-microglobulin is a small-molecule globulin produced by lymphocytes, platelets, and polymorphonuclear leukocytes, with a molecular weight of 11.8 kD, and a single-chain polypeptide consisting of 99 amino acids. It is the -chain (light chain) portion of the human surface lymphocyte antigen (HLA) on the cell surface (a single-chain polypeptide). It contains a pair of disulfide bonds and contains no sugar.

It is widely found in plasma, urine, cerebrospinal fluid, saliva, and colostrum. Normal human 2-microglobulin synthesis rate and release from the cell membrane are fairly constant. 2-microglobulin can be freely filtered from the glomerulus, 99.9% is absorbed in the proximal tubules, and in renal tubular epithelial cells Decomposition and destruction; therefore, the 2-microglobulin excretion is very small under normal circumstances.