MDS is short for Myelodysplastic Syndrome. It is a rare form of blood cancer caused by a change in some of the stem cells in bone marrow.
Red blood cells, white blood cells and platelets are produced in the bone marrow. Bone marrow contains stem cells that develop into mature red and white blood cells and megakaryocytes that create platelets.. The bone marrow of an adult typically contains over a trillion blood cells at different levels of maturity, all growing from about a hundred thousand stem cells. Healthy marrow with normal stem cells produce over 100 billion new blood cells per day.
In MDS, some of the stem cells mutate and start to produce unhealthy blood cells. They can be the wrong shape, or not work properly, or get stuck in the marrow instead of crossing into the blood stream. The marrow can get clogged up with unhealthy blood cells, and become less effective. Eventually not enough healthy blood cells are being produced, and conditions like anaemia arise.
This process can be very slow, and it is possible to have no symptoms. Many people have MDS for years without need for treatment. For some, symptoms arise and can require quite a lot of treatment. There are various drugs that can slow the progress of the disease. However, the only cure is a stem cell transplant (SCT).
In an SCT an MDS patient is given chemotherapy (and sometimes radiotherapy) to kill off their stem cells in the marrow and they are then given an infusion of stem cells from a donor. The donor is selected as a close genetic match to the patient, and they donate the stem cells by having some injections to stimulate their stem cell production, and the donor stem cells are then extracted from their blood. The stem cells are given as a transfusion to the patient. The donor stem cells migrate to the bone marrow and start to replicate and grow.
You can find out more at https://mdspatientsupport.org.uk/