People with MDS have abnormal bone marrow. This means the bone marrow doesn’t make enough healthy blood cells.
Bone marrow is part of the immune system, which protects us from infection and disease. The bone marrow is the spongy material found inside bones. This is where stem cells are made. Stem cells are blood cells at their earliest stage of development. All blood cells grow from stem cells. Blood cells that aren't fully developed are called blasts. As blasts develop (mature), they become one of the three types of blood cells:
- red blood cells, which carry oxygen around the body
- white blood cells, which fight infections
- platelets, which help blood to clot to prevent bleeding.
The bone marrow makes millions of blood cells every day. Developing blood cells stay inside the bone marrow. When they are fully grown, they are released into the bloodstream.