Immature granulocytes

For medical students, morphology is a basic subject. We also know that we will come into contact with many types of cells in it, for example, immature granulocytes. Immature cells generally refer to various cells in the blood that have not yet matured, usually including immature lymphocytes or early, intermediate and late myelocytes or immature monocytes or immature red blood cells. With this simple understanding, let’s take a closer look at the relevant knowledge about immature granulocytes!

1. Introduction

Immature cells refer to morphologically identifiable cells at various stages in the process of cell maturation, from the earliest cells (such as primitive granulocytes and primitive erythrocytes) to mature cells (such as segmented nuclear cells and erythrocytes). There should be no immature cells in normal peripheral blood smears (band cells should also be less than 5%), and cells at each stage in normal bone marrow should be within a certain range. When the hematopoietic system is diseased, changes in cytoplasm and quantity may occur, leading to changes in the proportion of cells at each stage that are characteristic of different diseases. These changes can help diagnose the disease, which is the significance of bone marrow blood cell classification.

2. Classification

1. Immature red blood cells

The immature red blood cells in the blood smear are mainly metamyoblasts, which are mainly seen in various types of hemolytic anemia, myelodysplastic syndrome, myeloproliferative tumors, erythroleukemia, etc. Their shrunken small nuclei and rich pink cytoplasm are very easy to identify.

2. Immature granulocytes

Neutrophilic granulocytes and metamyelocytes are often the main types. Granulocytes are named after their abundant granules. The large number and density of granules are the main characteristics that distinguish them from monocytes and other cells.

3. Immature lymphocytes

The cell bodies of this type of cells are larger than those of mature lymphocytes, with less cytoplasm, more evenly stained nuclei that tend to be purple-red, and the chromatin is often fine or in small clumps.

4. Naive Monocytes

The nuclear chromatin is loosely folded.

3. Clinical significance

In normal people, primitive cells are rarely found in blood tests. Such cells may appear in the following situations: acute leukemia, myelofibrosis, myelodysplastic syndrome, myeloproliferative neoplasm, blast crisis of chronic leukemia or relapse of acute leukemia. The number of primitive cells in the blood smears of some patients will be significantly increased. Different numbers of granules and Ostwald bodies can be seen in the cytoplasm of these cells. The nuclear chromatin is loose, evenly colored, dark purple, and the nucleolus is obvious. Especially at the tail of the smear made with anticoagulated blood, it is easier to see piled or scattered primitive cells, which are usually accompanied by a history of anemia and thrombocytopenia.