Parentage of a red bone marrow
Myelogram is the percentage of cell elements in smears prepared from the points of the red bone marrow. The bone marrow contains two groups of cells: cells of the reticular stroma( fibroblasts, osteoblasts, fat and endothelial cells), which constitute an absolute minority in number, and cells of the hematopoietic tissue( parenchyma).The reference parameters of the myelogram are given in the table.
Currently, red bone marrow biopsy is an obligatory diagnostic method in hematology, as it allows to evaluate tissue relationships in the bone marrow.
Red bone marrow examination is conducted to confirm or establish the diagnosis of various forms of hemoblastosis and anemia. Myelogram needs to be assessed by comparing it with the picture of peripheral blood. Diagnostic value is the study of bone marrow in the defeat of its lymphogranulomatosis, tuberculosis, Gaucher's disease, Niemann-Pick, metastasis of tumors, visceral leishmaniasis. This study is widely used in dynamics to evaluate the effectiveness of the therapy.
For the study of red bone marrow, puncture of the sternum or iliac bone is made, punctures for cytological analysis are prepared from the punctate. When aspiration of the bone marrow there is always a drop of blood, the more the more the aspirate is received. The punctate is usually diluted peripheral blood by no more than 2.5 times. Symptoms of a greater degree of bone marrow dilatation by peripheral blood are as follows.
■ Poverty of punctata by cellular elements.
■ Lack of megakaryocytes.
■ A sharp increase in the leuko- / erythroblastic ratio( at a ratio of 20: 1 and above, the punctate examination is not carried out).
■ Decrease in the neutrophil maturation index to 0.4-0.2.
■ Approximation of the relative content of segmented neutrophils and / or lymphocytes to that in peripheral blood.
In the study of red bone marrow, the percentage of bone marrow elements is counted, and the absolute content of myelokaryocytes and megakaryocytes is also determined.
■ Myelokaryocytes. A decrease in the content of myelokaryocytes is observed in hypoplastic processes of various etiologies, effects on the human body of ionizing radiation, certain chemicals and drugs, etc. Particularly sharply the number of nuclear elements decreases with aplastic processes. With the development of myelofibrosis, myelosclerosis, marrow punctate is meager and the number of nuclear elements in it is also reduced. If there is syncytial connection between the bone marrow elements( in particular, with myeloma disease), the marrow punctate is difficult to obtain, therefore the content of nuclear elements in a punctate may not correspond to the true number of myelokaryocytes in the bone marrow. High content of myelokaryocytes is observed in leukemia, vitamin B12-deficiency anemia, hemolytic and posthemorrhagic anemia, that is, in diseases accompanied by bone marrow hyperplasia.
■ Megakaryocytes and megakaryoblasts are detected in small amounts, they are located around the periphery of the drug, determining their percentage in the myelogram does not reflect the true position, so they are not counted. Usually, only an approximate, subjective assessment of the relative shift in the direction of younger or mature forms is carried out. An increase in the number of megakaryocytes and megakaryoblasts can cause myeloproliferative processes and metastasis of malignant tumors in the bone marrow( especially in stomach cancer).The content of megakaryocytes also increases with idiopathic autoimmune thrombocytopenia, radiation sickness during the recovery period, chronic myelogenous leukemia. A decrease in the number of megakaryocytes and megakaryoblasts( thrombocytopenia) can cause hypoplastic and aplastic processes, in particular, for radiation sickness, immune and autoimmune processes, metastasis of malignant neoplasms( rarely).The megakaryocyte content also decreases with acute leukemia, B12-deficiency anemia, myeloma, SLE.
■ Blast cells: an increase in their number with the appearance of polymorphous ugly forms against the background of cellular or hypercellular red bone marrow is characteristic of acute and chronic leukemia.
■ Megaloblasts and megalocytes of different generations, large neutrophilic myelocytes, metamyelocytes, hypersegmented neutrophils are characteristic of vitamin B12 deficiency and folic deficiency anemia.
■ Myeloid elements: an increase in the number of their mature and immature forms( reactive bone marrow) causes intoxication, acute inflammation, purulent infections, shock, acute blood loss, tuberculosis, malignant neoplasms. Promyelocytic-myelocytic bone marrow with a decrease in the number of mature granulocytes against the background of a cellular or hypercellular reaction can cause myelotoxic and immune processes. A sharp decrease in the content of granulocytes against the background of a decrease in myelokaryocytes is characteristic of agranulocytosis.
■ Bone marrow eosinophilia is possible with allergies, helminthic invasions, malignant neoplasms, acute and chronic myeloid leukemias, and infectious diseases.
■ Monocytic cells: an increase in their number is detected in acute and chronic monocytic leukemias, infectious mononucleosis, chronic infections, malignant neoplasms.
■ Atypical mononuclear cells: an increase in their number against the background of a decrease in mature myelocaryocytes can cause viral infections( infectious mononucleosis, adenovirus, influenza, viral hepatitis, rubella, measles, etc.).
■ Lymphoid elements: an increase in their number, the appearance of holonuclear forms( the shadow of Humprecht), with the increase of cellularity of the red bone marrow, can cause lymphoproliferative diseases( chronic lymphocytic leukemia, macroglobulinemia of Waldenström, lim-fosarcoma).
■ Plasma cells: an increase in their number with the appearance of polymorphism, binuclear cells, change in the color of the cytoplasm can cause plasmacytomas( plasmoblastoma, as well as reactive states).
■ Erythrocaryocytes: an increase in their number without disturbance of maturation is observed with erythremia. An increase in the content of erythrocaryocytes and a decrease in the leucoerythropy ratio can cause posthemorrhagic anemia and most hemolytic anemias. Reducing the content of erythrocaryocytes with a decrease in the total number of myelokaryocytes and a small( relative) increase in blast cells, lymphocytes, plasmocytes cause hypoaplastic processes.
■ Cancer cells and their complexes are detected with metastases of malignant tumors.
To assess the myelogram, it is important not so much to determine the number of bone marrow elements and their percentage as their mutual relationship. The composition of the myelogram should be judged by the specially calculated bone marrow indices characterizing these relationships.
■ The erythrocaryocyte maturation index characterizes the state of the erythroid sprout, is the ratio of the percentage of normoblasts containing Hb( i.e., polychromatophilic and oxyphilic) to the total percentage of all normoblasts. The decrease in this index reflects a delay in hemoglobinization, which is observed with iron deficiency and sometimes with hypoplastic anemia.
■ The neutrophil maturation index characterizes the state of the granulocyte sprout. It is equal to the ratio of the percentage of young elements of the granular series( promyelocytes, myelocytes and metamyelocytes) to the percentage content of mature granulocytes( rod-and-seed and segment-nucleated).An increase in this index with a cell-rich red bone marrow indicates a delay in the maturation of neutrophils, in the case of bone marrow-poor cells, of an increased yield of mature cells from the bone marrow and depletion of the granulocyte-
reserve [Soboleva TN.and others, 1994].An increase in the neutrophil maturation index is observed in myeloleukemia, leukemoid reactions of the myeloid type, some forms of agranulocytosis;its decrease - with delayed maturation at the mature granulocyte stage or delay in their washout( with hypersplenism, some infectious and purulent processes).
■ The leukoerythroblastic ratio is the ratio of the sum of the percentage of all elements of the granulocyte germ to the sum of the percentage of all elements of the erythroid bone marrow. Normally, this ratio is 2: 1-4: 1, that is, in normal bone marrow the number of white cells is 2-4 times higher than the number of red cells. An increase in the index with high cellularity of the red bone marrow( more than 150x109 / L) indicates hyperplasia of the leukocyte germ( chronic leukemia);at low cellularity( less than 80х109 / l) - about reduction of red sprout( aplastic anemia) or a large admixture of peripheral blood. Reduction of the index with high cellularity of the red bone marrow indicates hyperplasia of red sprout( hemolytic anemia), at low cellularity - about the predominant reduction of granulocyte germ( agranulocytosis).The leycoerythroblastic ratio decreases with hemolytic, iron deficient, posthemorrhagic, B12-deficient anemia, increases with leukemia and, sometimes, with the inhibition of the erythroid germ in patients with hypoplastic anemia.
Algorithms for complex diagnosis of various types of anemia are presented in Fig.2-5.