The classification of leukemias

The existing classification of acute leukemia based on the individual properties of stable cells, which are characteristic of a particular form of the disease: is a cell, of which originated leukemia, or their more differentiated progeny.

The group of acute leukemias share a common feature of: substrate tumors are young, so-called blastic, cell. The names of the different forms of acute leukemia based on the name of the normal precursors of tumor cells: myeloblasts, erythroblasts, lymphoblasts, etc.. Acute leukemia of morphologically unidentifiable blast cells called undifferentiated.

The group of chronic leukemia are differentiating tumor blood system, the main substrate of which are morphologically mature cells (eg, lymphocytes - with lymphatic leukemia, erythrocytes - with eritremii).

The appearance of the morphological characteristics of acute myeloid leukemia associated with the description in 1900 g. mieloblastov. But in the same year researchers, applying a sample guaiac, shown, mielovidnye cells that unlike the lymphoid contain cytoplasm oxidase. IN 1909 g. Shultz in "to the differential diagnosis of leukemia," pointed out the need to use to determine the nature of myeloblastic or lymphoblastic acute leukemia and chemical methods, in particular different samples oxidase. Then the morphological and cytochemical criteria were applied to prove the ownership of separate cases of acute myeloid leukemia in variant. For Example, It was shown, chloroma that occurs when myeloid leukemia Nature, only that type of myeloid cells, containing, As it became known later,, myeloperoxidase, give the characteristic green color chloroma.

IN 1913 g. Reshad, Shilling-Torgau describe morphological features of the third, monoblastic, form of acute leukemia. Much later came to be known and certain cytochemical properties of monocytes and blasts at monoblastic leukemia.

IN 1957 g. Hillestad first described acute promyelocytic leukemia, characterized by a triad of core symptoms: grit blast abundance in cells, giving them a resemblance to Promyelocytes, the severity of the hemorrhagic syndrome and speed of flow, not correctable therapy. Specific cytochemical test for acute promyelocytic leukemia has been detected in 1966 g.

IN 1964 g. Cambridge was determined cytochemical characteristic of each of the forms of acute leukemia (in the table).

The need to create a single objective classification has become particularly apparent in connection with the development of cytostatic therapy of acute leukemia.

And morphological, and cytochemical approach to classification is based on a comparison of abnormal cells with their normal precursors. Both approaches are legitimate, however, to establish a link pathological tumor cells with normal baseline elements can not focus on the variability of cells: the shape of the nucleus, its value, dimensions cytoplasm etc.. d.

With the application of new complexes cytostatics, with the advent of long-term remission, exchangeable relapses, if refractory to previously effective cytotoxic drugs became apparent variability is primarily the shape and size of the nuclei and cytoplasm of leukemia cells. Therefore, in the classification of acute leukemia need to rely on the relatively stable symptoms of the disease. This requirement of all known attributes is more suited cytochemical features of abnormal cells (The table above).

IN 1976 g. It was developed FAB- classification of the forms of acute leukemia, based on morphological characters, after which (1980) cytochemical features have been added to the cells. According to this classification release myelogenous, myelomonoblastic, promyelocytic, monoblastic, Acute leukemia lymfoblastnыy, эrytromyeloz and nedyfferentsyruemыy leukemia (The use of marker immunocytochemical reactions now allows to specify the nature of the blast cells in acute undifferentiated leukemia, in connection with which they can be attributed to acute lymphoblastic leukemia "generic" or pre-B-cell acute lymphoblastic leukemia.

Acute leukemia myeloblastnыy by FAB-classification is divided into two independent forms: with differentiation and without differentiation.

Acute leukemia Monoblastnыy also subdivided into shape with differentiation and without differentiation.

And Myeloid, and monoblastic acute leukemia differentiation criterion is the detection of bone marrow in a 3 % cells or granulocyte monocyte series, correspondingly more differentiated, than the myeloblast or monoblast.

There are six forms myeloid leukemia:

• M1 - without myeloid differentiation;
• M2-myeloid differentiation;
• MH - promielotsitarnыy;
• M4 - without myelomonocytic differentiation;
• M5 - monoblastic (and b, depending on the availability of differentiation);
• M6 - erythromyelosis;
• MO - nedyfferentsyruemыy Acute leukemia.

Lymfoblastnыy leukemia depending on the uniformity of cell size, the correct form of their nuclei is divided into three forms: L1, L2, L3.

Cytochemical identification form corresponds to that of the Cambridge classification. What is new is the selection in the FAB-classification of so-called myelopoietic dysplasia, which referred to the, one side, process, has not yet been defined as acute leukemia - the so-called refractory anemia without blastosis, whereby punctate blasts must be less than 10%, on the other hand - Acute leukemia maloprotsentnыy with the number of blasts less 30 %, including a number of forms, among which in the first place refractory anemia with blastosis.

Thus, FAB-classification of acute leukemia based on histochemical, and morphological traits (maturity cells, changes in shape of the nucleus and cytoplasm). As I mentioned above, shape of the nucleus and cytoplasm is classified regularly changing signs of acute leukemia blast cells.

Classification of chronic leukemia, as well as acute, subject to practical purposes. All forms of chronic leukemia distinguishes one feature: they are long-term (With rare exceptions) remain in step monoklonovoy benign tumors. Represent them in accordance with the name of the mature and maturing cells, which constitute the substrate of the tumor.

All can be accompanied by the development of leukemia in the bone marrow connective tissue, that leaves its imprint on the morphological identity and partly clinical picture. The development of fibrosis is not peculiar only to leukemia, It is observed in cancer, and sarcoma (negemoblastozah). Connective tissue develops a second in response to specific induction by tumor cells. Morphologically fibrous tissue cells do not bear any features and are characterized by a polyclonal atypism, t. it is. They are not tumor. When remission of acute leukemia and chronic myeloid leukemia myelofibrosis disappears.

In recent years, much has changed data on the entire group of lymphatic leukemia - acute and chronic.

Emphasis slightly different in immunological markers and response to therapy options for acute lymphoblastic leukemia:

• nor T- B-leukemia us;
• T-leukemia; B-leukemia;
• pre-B-leukemia;
• pre-T-leukemia;
• nor T-, nor B-leukemia with Ph'-chromosome.

In the group of chronic lymphocytic leukemia also highlighted several new forms, as a result became clear that re-allocation few reported form due to the new features of their treatment.

Currently, attempts are made to determine both with monoclonal antisera and poliklovalnyh, and with monoclonal antibodies, produced by hybrid, myeloid markers (like the establishment of the nature of the lymphatic cell markers) and identify with them certain forms of leukemia.

So, if the last classification of leukemias based only on certain principles of morphological, but now in addition to the morphological differences are taken into account the ability of cells to secrete specific immunoglobulins, place preferential proliferation, age of the patients, immunologic markers surface tumor cells and their behavior in culture, the nature of chromosomal abnormalities. Thus, currently accepted classification of leukemia is a list of a variety of tumors, which is often difficult to define the boundary between fact and leukemia gematosarkomoy.

Morphological basis for the division of leukemia, acute and chronic remains steadfast and does not need further discussion.

Acute leukemia

Myelogenous (spontaneous, induced - secondary)

Myelomonoblastic (basic and psevdopromielotsitarnaya form)

Monoblastic

Promyelocytic (Macro- and mikrogranulyarnaya form)

Erythroleukemia (erythroleukemia, erythroleukemia, eritromegakarioblastny)

Megacaryoblastic (basic shape and its variant with myelofibrosis)

Maloprotsentny

Lymphoblastic children (nor T-, nor the B-form; T-shape; pre-form T-; Form B; pre-B-form, nor T-, nor B-form with Ph'-chromosome)

Lymphoblastic adults (forms of the same, that of children)

Plazmoblastny

Macrophage

Nondifferentiability

Chronic leukemia

Myelogenous leukemia (options with Ph'-chromosome adults, old men and a version without Ph'-chro- MOS)

Juvenile myeloid leukemia without Ph'-chromosome

Myelogenous leukemia with Ph'-chromosome in children

Subleukemic myelosis (actually subleukemic myelosis, myelofibrosis, osteomieloskleroz)

Erythremia

Megakariocitarnый

Ungraded subleukemic myelosis (option with a high percentage of basophils)

Erythroleukemia

Monocytic (monocytic and myelomonocytic itself)

Macrophage

Mast cell

Lnmfoleykoz (shape: bone marrow, primary progressive, Benign, Tumour, T-, prolimfocitarnaâ, secretion paraprotein)

Volosatokletochnыy leukemia

Sezary's disease

The disease Waldenstrom (Waldenstrom's macroglobulinemia)

Multiple myeloma

Paraproteinemic hemoblastoses

Heavy chain disease

Disease light chains