Megaloblast

As megaloblastic unusually large, nuclear - and hemoglobin- containing precursor cells of erythrocytes are referred to in the bone marrow. They develop from the more hemoglobin-free promegaloblasts. The mature, enlarged red blood cells are called accordingly megalocytes.

The size of the cells can be explained by the reduced DNA synthesis capacity, which delayed cell division, while the production of RNA and cytoplasmic constituents is normally high. This leads to an asynchrony between nuclear and cell maturation, and thus a relative increase in size.

Occurrence

The occurrence of megaloblastic in a bone marrow is most often associated with a folic acid deficiency anemia or vitamin B12 deficiency anemia (pernicious anemia) associated. Both disease states are therefore grouped under the term " megaloblastic anemia " (due to the rule also enlarges the present finished erythrocytes ( macrocytes ) as " macrocytic anemia " refers to ).

You can furthermore also occur with myelodysplastic syndrome, erythroleukemia and after cytostatic application. Physiologically, they occur in the context of embryonic hematopoiesis, more precisely, it is the blood cells in the first phase ( megaloblastic hematopoiesis ) are formed in the yolk sac and body stalk of the developing seed.