Immunoelectrophoresis of blood proteins

There are no paraproteins in the blood serum.

Immunoglobulinopathies, or gammopathies, combine a large group of pathological conditions characterized by polyclonal or monoclonal hypergammaglobulinemia. Immunoglobulins consist of two heavy (H) chains (molecular weight 50,000) and two light (L) chains (molecular weight 25,000). The chains are connected by disulfide bridges and consist of structures called domains (H - from 4, L - from 2 domains). Under the action of proteolytic enzymes, Ig is divided into fragments: the Fc fragment and the Fab fragment. Heavy chains of human Ig are represented by five structural variants, which are denoted by the letters of the Greek alphabet: γ, α, μ, δ, ε. They correspond to 5 classes Ig - G, A, M, D, E. Light chains are represented by two structurally different variants: κ (kappa) and λ (lambda), which correspond to two Ig types of each class. In each Ig molecule, both heavy and light chains are identical. All people normally have Ig of all classes and both types, but their relative content is not the same. The ratio of molecules κ and λ within different classes of Ig is also not the same. The detection of a violation of Ig or their fragments plays a crucial role in the diagnosis of monoclonal immunoglobulinopathies.

Monoclonal immunoglobulinopathy (paraproteinemia) is a syndrome expressed in the accumulation in the blood serum and / or urine of patients that are homogeneous in terms of all the physico-chemical and biological parameters of Ig or their fragments. Monoclonal Ig (paraproteins, M-proteins) is a secretion product of a single clone of B-lymphocytes (plasma cells), therefore they represent a pool of structurally homogeneous molecules having heavy chains of the same class (subclass), light chains of the same type and variable regions of the same structure. Monoclonal immunoglobulinopathies are usually divided into benign and malignant. In benign forms of monoclonal gammapathies, proliferation of plasma cells is controlled (possibly by the immune system) in such a way that clinical symptoms are absent. In malignant forms, uncontrolled proliferation of lymphoid or plasma cells occurs, which determines the clinical picture of the disease.

Classification of monoclonal immunoglobulinopathy

Category of gonorrhea	Nature of pathology	Concentration of pathological Ig in serum, g / l
B-cell malignant	Multiple myeloma, Waldenström macroglobulinemia	More than 25
	Plasmacytoma (solitary - bone and extramedullary), lymphoma, chronic lymphocytic leukemia, heavy chain disease	Significantly below 25
B-cell benign	Monoclonal gammopathies of unknown origin	Below is 25
Immunodeficiency states with imbalance of T and B-units of the immune system	Primary (Wiskott-Aldrich Syndromes, Di-Georgi, Nezalef, Severe Combined Immunodeficiency)	Below is 25
	Secondary (age-related, caused by the use of immunosuppressants, associated with oncological diseases of non-lymphoid nature (eg, colon cancer, breast cancer, prostate gland, etc.)	Below 2.5
Immunodeficiency states with imbalance of T and B-units of the immune system	Rebuilding the immune system after a red bone marrow transplant	Below is 25
	Antigenic stimulation in early ontogenesis (intrauterine infection)	Below is 25
Homogeneous immune response	Bacterial infections	Below is 25
	Autoimmune diseases, such as cryoglobulinemia, SLE, rheumatoid arthritis, etc.	Below is 25

Immunoelectrophoresis of blood serum proteins allows detecting monoclonal (pathological) IgA, IgM, IgG, chains H and L, paraproteins. With normal electrophoresis, normal Ig, heterogeneous in properties, are located in the γ zone, forming a plateau or a wide band. Monoclonal Ig, due to their homogeneity, migrate mainly to the zone γ, occasionally to the zone β and even to the region α, where they form a high peak or a clearly delineated band (M gradient).

Multiple myeloma (Rustitzky-Kahler's disease) is the most frequent paraproteinemic hemoblastosis; it is detected no less often than chronic myelo- and lymphocytic leukemia, lymphogranulomatosis and acute leukemia. The class and type of pathological Ig secreted by myeloma determines the immunochemical variant of the disease. The frequency of classes and types of pathological Ig in myeloma as a whole correlates with the ratio of classes and types of normal Ig in healthy people.

Along with the increase in the content of pathological Ig in the serum of patients with multiple myeloma, normal Ig in a reduced concentration is determined. The content of total protein is sharply increased - up to 100 g / l. The activity of the process with G-myeloma is estimated by the number of plasmocytes in the sternal point, the concentration of creatinine and calcium in the serum (their increase in calcium indicates a progression of the disease). The concentration of M-protein (in the urine it is called the Bens-Jones protein) serves as a criterion for evaluating the progression of the disease in A-myeloma. The concentration of paraproteins in the serum and urine varies during the course of the disease under the influence of therapy.

For the diagnosis of multiple myeloma, the following criteria are necessary.

Big criteria

1. Plasmacytoma by results of a biopsy.
2. Plasmocytosis in the red bone marrow (more than 30% of the cells).
3. Peaks of monoclonal (pathological) Ig in the electrophoresis of whey protein: more than 35 g / l for the peak of IgG or more than 20 g / l for the peak of IgA. Excretion of κ and λ-chains in the amount of 1 g / day or more, revealed by urine electrophoresis in a patient without amyloidosis.

Small criteria

1. Plasmocytosis in the red bone marrow of 10-30% of cells.
2. Peak PIg in serum in an amount less than that indicated above.
3. Lethal lesions of bones.
4. The concentration of normal IgM is below 0.5 g / l, IgA is below 1 g / l or IgG is below 0.6 g / l.

For the diagnosis of multiple myeloma, at least 1 large and 1 small criterion or 3 small criteria are required, with the mandatory criteria given in paragraphs 1 and 2.

To determine the stage of myeloma, the standardizing system of Dury-Salmon is used, which reflects the volume of tumor lesion.

All myeloma groups are divided into subclasses depending on the state of kidney function: A - serum creatinine concentration below 2 mg% (176.8 μmol / l), B - more than 2 mg%. In myeloma, a high concentration of β ₂ -microglobulin in the blood serum (more than 6000 ng / ml) suggests an unfavorable prognosis, as well as high LDH activity (above 300 IU / L, reaction at 30 ° C), anemia, kidney failure, hypercalcemia, hypoalbuminemia and a large tumor volume.

Diseases of the lung chains (Bence-Jones myeloma) account for approximately 20% of myeloma cases. With Bence-Jones myeloma, exclusively free light chains are formed that are detected in the urine (Bence-Jones protein), in the absence of serum pathological Ig (M-gradient).

Stages of multiple myeloma

Stage	Criteria	Tumor weight (number of cells), x10 12 / m 2
I	Small myeloma with the following criteria: The concentration of hemoglobin in the blood is higher than 100 g / l; The concentration of total calcium in the blood serum is normal (<3 mmol / l); No changes in the bones during radiography or solitary plasmacytoma of the bone; Low concentration of paraproteins in blood serum (IgG below 50 g / l, IgA below 30 g / l); L-chains (Bens-Jones protein) in urine less than 4 g / 24 h	<0.6
II	Intermediate myeloma (the criteria are between stages I and III)	0.6-1.2
III	A large myeloma with one or more of the following criteria: The concentration of hemoglobin in the blood is below 85 g / l; The concentration of total calcium in the serum above 12 mg% (3 mmol / l); Extensive lesion of the skeleton or major fractures; High concentration of paraproteins in blood serum (IgG more than 70 g / l, IgA more than 50 g / l); L-chains (Bens-Jones protein) in urine more than 12 g / 24 h.	> 1.2

Rare immunochemical variants of myeloma include non-secretory myeloma, in which paraproteins can be found only in the cytoplasm of myeloma cells, as well as diclone myeloma and M-myeloma.

Macroglobulinemia Waldenström is a chronic subleukemic leukemia of B-cell nature, morphologically represented by lymphocytes, plasmocytes and all transitional cell forms synthesizing PIgM (macroglobulin). The tumor has a low degree of malignancy. In the red bone marrow, proliferation of small basophilic lymphocytes (plasmacytoid lymphocytes) is detected, the number of mast cells is increased. The electrophoregram of serum proteins reveals an M gradient in the β- or γ-globulin zone, less often the paraprotein does not migrate in the electric field, remaining in place. Immunochemically, he represents PIgM with one type of light chain. The concentration of PIgM in the blood serum with Waldenstrom's macroglobulinemia ranges from 30 to 79 g / l. In 55-80% of patients, Bens-Jones protein is detected in the urine. The concentration of normal Ig in the blood decreases. Renal insufficiency develops infrequently.

Lymphomas. IgM secreting lymphomas are most often recorded, the second place is occupied by paraproteinemic lymphomas secreting IgG, lymphomas with IgA paraproteinemia are extremely rare. Reduction in the concentration of normal Ig (usually to a small extent) with lymphomas is recorded in most patients.

Diseases of heavy chains - B-cell lymphatic tumors, accompanied by the production of monoclonal fragments of heavy chains Ig. Diseases of heavy chains are very rare. There are 4 types of heavy chain disease: α, γ, μ, δ. The disease of heavy chains γ usually occurs in men younger than 40 years, characterized by an increase in the liver, spleen, lymph nodes, edema of the soft palate and tongue, erythema, fever. The destruction of bones, as a rule, does not develop. The concentration of pathological globulin in the blood serum is low, the ESR is normal. Lymphoid cells and plasma cells of different degrees of maturity are found in the bone marrow. The disease proceeds quickly and ends with death within a few months. Disease of heavy chains is detected mainly in the elderly, it is more often manifested by hepatosplenomegaly. Substrate tumor - lymphoid elements of varying degrees of maturity. Single cases of heavy chain disease δ are described, it proceeds as a myeloma. Severe Chain Disease α is the most common form developing mainly in children and persons under 30 years of age, 85% of cases are reported in the Mediterranean. Immunoelectrophoresis of blood serum and urine is the only method of diagnosing the disease, since a classic M-gradient on the electrophoregram of serum proteins is often absent.

Reactive paraproteinemia occurs when there is a genetic predisposition in response to bacterial and viral infections (hepatitis, CMV infection) or parasitic infestations (leishmaniasis, toxoplasmosis, schistosomiasis). This form of monoclonal immunoglobulinopathy was registered during organ transplantation, treatment with cytostatics, hereditary or acquired immunodeficiencies. Transient paraproteinemias are characterized by low serum PIg concentrations, the absence or trace amounts of the Bence-Jones protein in the urine.

Associated paraproteinemia accompanies a number of diseases in the pathogenesis of which the immune mechanisms play a role: autoimmune diseases, tumors, chronic infections. These diseases include AL-amyloidosis and cryoglobulinemia.

Idiopathic paraproteinemia occurs in elderly people and may be premiemonic conditions. In such cases, a thorough examination is necessary to identify the initial stage of the disease and prolonged dynamic observation.

Signs of benign paraproteinemia include: the absence of the Bence-Jones protein, changes in normal Ig concentration, the number of plasma cells in the punctate of red bone marrow less than 15%, lymphocytes less than 20%, serum paraprotein concentration below 30 g / l.

[1], [2], [3], [4], [5], [6], [7],