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Determination of protein fractions
Last reviewed: 23.04.2024
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Changes in the fraction of albumins. Increases in the absolute content of albumins, as a rule, are not observed.
Changes in the α 1 -globulin fraction. The main components of this fraction include α 1 -antitrypsin, α 1 -lipoprotein, acid α 1 -glycoprotein.
- An increase in the α 1 -globulin fraction is observed in acute, subacute, exacerbation of chronic inflammatory processes; liver damage; all processes of tissue decay or cell proliferation.
- Reduction of the α 1 -globulin fraction is observed with a deficiency of α 1 -antitrypsin, hypo-α 1- lipoproteinemia.
Changes in the α 2 -globulin fraction. α 2 -Fraction contains α 2 -macroglobulin, haptoglobin, apolipoproteins A, B (apo-A, apo-B), C, ceruloplasmin.
- An increase in the fraction of α 2 -globulin is observed in all types of acute inflammatory processes, especially with marked exudative and purulent character (pneumonia, empyema of the pleura, other types of purulent processes); diseases associated with the involvement of connective tissue in the pathological process (collagenoses, autoimmune diseases, rheumatic diseases); malignant tumors; in the stage of recovery from thermal burns; nephrotic syndrome; hemolysis of blood in vitro.
- Reduction of α 2 -globulin fraction is observed in diabetes mellitus, pancreatitis (sometimes), congenital jaundice of mechanical origin in newborns, toxic hepatitis.
The α-globulins include the bulk of the acute phase proteins. The increase in their content reflects the intensity of the stress reaction and inflammatory processes in the listed types of pathology.
Changes in the beta-globulin fraction. Beta-Fraction contains transferrin, hemopexin, complement components, Ig and lipoproteins (LP).
- An increase in the beta-globulin fraction is revealed in primary and secondary hyperlipoproteinemia (HLP) (especially type II), liver disease, nephrotic syndrome, bleeding ulcer of the stomach, hypothyroidism.
- Reduced values of beta-globulin content are revealed with hypo-beta-lipoproteinemia.
Changes in the γ-globulin fraction. γ-fraction contains Ig (IgG, IgA, IgM, IgD, IgE), therefore, the increase in γ-globulin content is noted during the reaction of the immunity system when antibodies and autoantibodies are produced: in viral and bacterial infections, inflammation, collagenoses, tissue destruction and burns . Significant hypergammaglobulinemia, reflecting the activity of the inflammatory process, is characteristic of chronic active hepatitis and cirrhosis of the liver. An increase in γ-globulin fraction is observed in 88-92% of patients with chronic active hepatitis (in 60-65% of patients it is very pronounced - up to 26 g / l and above). Almost the same changes are noted in patients with highly active and far-reaching cirrhosis of the liver, and often the content of γ-globulins exceeds the albumin content, which is considered a poor prognostic sign.
For certain diseases, an increased synthesis of proteins falling into the γ-globulin fraction is possible, and pathological proteins appear in the blood - paraproteins, which are detected by electrophoresis. To clarify the nature of these changes, immunoelectrophoresis is necessary. Similar changes are noted in myeloma, Waldenström's disease.
An increase in the content of γ-globulin in the blood is also observed in rheumatoid arthritis, systemic lupus erythematosus, chronic lymphocytic leukemia, endothelioma, osteosarcoma, and candidamycosis.
Reduction of γ-globulin content is primary and secondary. There are three main types of primary hypogammaglobulinemia: physiological (in children aged 3-5 months), congenital and idiopathic. The causes of secondary hypogammaglobulinemia can be numerous diseases and conditions leading to the depletion of the immune system.
A comparison of the directionality of changes in the content of albumins and globulins with changes in the total protein content suggests that hyperproteinemia is more often associated with hyperglobulinemia, while hypoproteinemia is usually due to hypoalbuminemia.
In the past, the calculation of the albumin-globulin coefficient, that is, the ratio of the fraction of albumins to the value of the globulin fraction, was widely used. Normally, this figure is 2.5-3.5. In patients with chronic hepatitis and cirrhosis of the liver, this coefficient is reduced to 1.5 and even to 1 due to a decrease in albumin content and an increase in the fraction of globulins.
In recent years, more attention has been paid to determining the content of prealbumins, especially in severe resuscitation patients who are on parenteral nutrition. Reduction in the concentration of prealbumins is an early and sensitive test of protein deficiency in the patient's body.
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