What Happens When Blood Cells Don’t Form Normally?
To work correctly, your body needs healthy blood cells. It makes new ones every day. But blood cells don’t always mature like they should.
When this happens, your body sometimes makes too many, too few, or the wrong kinds of blood cells. This can lead to health problems, including some types of cancer.
How do blood cells normally mature?
Blood cells start in your bone marrow as stem cells.
When an old blood cell dies, it signals to your body that it needs to be replaced. The signal is picked up by a stem cell in your bone marrow. The stem cell matures and turns into the exact type of blood cell your body needs.
The myeloid and lymphoid pathways
The stem cell follows one of two pathways to become a fully mature blood cell.
- Myeloid pathway: A stem cell follows this path to become an RBC, platelet, granulocyte, or monocyte.
- Lymphoid pathway: A stem cell follows this path to become a lymphocyte, including B cells, T cells, and natural killer (NK) cells.
Some blood cancers and other blood disorders are named based on which of these pathways is involved.
Blast cells
Once a stem cell chooses a pathway, it starts to change into a specific type of blood cell. At this point, the cell is no longer a stem cell, but it’s not a fully mature cell either. As the cell goes through this step, it’s called a blast cell.
There are two main types of blast cells that form in the process of making a mature blood cell:
- A myeloblast is a partially mature or young blood cell moving through the myeloid pathway to become a granulocyte or monocyte.
- A lymphoblast is a partially mature or young blood cell moving through the lymphoid pathway.
Leukemias sometimes happen when certain cells stay in the blast stage and don’t mature normally.
Mature blood cells
As it moves through its chosen pathway, the blast cell continues to grow and take on more features of its final blood cell type. When it is fully mature, it does its job until its lifespan is complete and it dies off.
Image courtesy lbdipcan2015
Why do some blood cells fail to mature normally?
Several things can happen in your bone marrow that cause a blood cell to not fully mature or to be abnormal in other ways.
This includes:
- Bone marrow failure: The bone marrow stops working the way it should, and it can’t make enough healthy blood cells. This can happen because of a condition passed down from a parent (inherited) or from exposure to radiation or certain chemicals.
- Bone marrow infiltration or replacement: Something crowds out or takes over the bone marrow and pushes out the healthy blood cells. This can happen with certain types of cancer or myeloproliferative conditions.
- Bone marrow suppression: Bone marrow function is slower than normal. It isn’t making blood cells as fast as it should. Sometimes this is caused by inflammation, infection, or certain medicines (including chemo).
- Nutrition problems: Some nutrients you take in are key to helping your bone marrow stay healthy. This includes protein, iron, vitamin A, vitamin B12 (folate), copper, and zinc. Without enough of these nutrients, your body can’t make the blood cells it needs.
What problems can this cause?
When blood cells don’t form normally, it can cause serious problems. This includes infections, blood disorders, and certain types of cancer.
Infections: If WBCs don’t develop as they should, your body can’t do a good job of fighting off germs.
Blood disorders: When blood cells don’t form correctly, your body can try to correct the problem by making too few or too many of them.
- Too few blood cells can cause blood disorders like leukopenia or neutropenia (low WBCs), anemia (low RBCs), or thrombocytopenia (low platelets).
- Too many abnormal blood cells can lead to myelodysplastic syndromes, clotting disorders, and leukemia.
Certain types of cancer: When blood cells don’t form normally, this can lead to some types of cancer. Blood cancers are most common, including myelodysplastic syndromes, leukemia, lymphoma, and multiple myeloma.
Learn more
- Anatomy Gallery: Blood Cells and Bone Marrow
- Learn about your type of cancer (including if and how it is related to abnormal blood cells) in Cancer Types.
- Written by
- References
The P站视频 medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.
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American Society of Hematology (ASH). Blood Basics. Accessed at https://www.hematology.org/education/patients/blood-basics on July 11, 2025.
Sarade R, Spivak JL. Formation of Blood Cells. Merck Manual Consumer Version Online. 2024. Accessed at https://www.merckmanuals.com/home/blood-disorders/biology-of-blood/formation-of-blood-cells on July 11, 2025.
Mirza KM. Chapter 4. Hematopoiesis. In Keohane EM, Otto CN, Walenga JM. Rodak’s Hematology. 6th Ed. Elsevier, 2020: 43-61. Accessed at https://www.sciencedirect.com/science/article/abs/pii/B9780323530453000131 on July 11, 2025.
Last Revised: July 16, 2025
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