Pathophysiology

What's happening inside your body that made you get leukemia? How could this be happening when you are feeling just fine?

When CLL first begins to develop in the body, some of the white blood cells called "lymphocytes," have a change in their DNA and begin to look and act differently than they did before. They also don't die when they should - it is normal for cells in the body to die after a little while, as they are making room for fresh, new cells that you create from the food you eat! These changed lymphoctye cells that aren't dying are now called leukemia cells. The leukemia cells continue to develop in the bone marrow until there are so many of them, that they are pushed out into the bloodstream. Here in the bloodstream, they can move around freely and continue to build-up. New leukemia cells continue to grow while the old ones are not dying. The leukemia cells look and act differently than any of the other cells that were in the bloodstream before, so they do not get along well with the other body cells in the blood stream. They can prevent these other, normal cells, from functioning they way they should. When the normal cells cannot function the way they should, you do not feel well. Eventually there will be enough leukemia cells in the bloodstream that they will get pushed out into the organs. If enough leukemia cells make their way into the organ tissue, they can continue to be unfriendly to normal cells, and prevent that organ from functioning as well as it should.

All of your blood cells start out the same, as stem cells. Stem cells are named that because they have the capability to "stem" and grow into any other type of blood cell. The next step for stem cells is to become either lymphoid or myeloid, as you can see in the figure below. Depending on which type of cell is not maturing properly is how doctors determine which type of leukemia you have. This concept here is important to understand, as we will later discuss the bone marrow transplant, a major treatment for leukemia. Since we don't know exactly when, where, or why the problem happens that causes blood cells to mature incorrectly, we put brand new stem cells into a person. We are basically going back to the very beginning of blood cell growth and starting fresh.

SEER Stat Fact Sheets: Leukemia. 2015. Retrieved April 4, 2015 from http://seer.cancer.gov/statfacts/html/leuks.html

References:
What is chronic lymphocytic leukemia? 2015. Retrieved April 4, 2015, from http://www.cancer.org/cancer/leukemia-chroniclymphocyticcll/detailedguide/leukemia-chronic-lymphocytic-what-is-cll