Frequently asked questions about clonal hematopoiesis after stem cell transplant

Frequently asked questions

• How do I know if I have clonal hematopoiesis?

  Clonal hematopoiesis is usually discovered through genetic testing of the blood. The condition is often identified by chance during medical research or within the scope of scientific research. There are usually no obvious symptoms. Clonal hematopoiesis is common in the elderly and in most cases does not cause health problems. Therefore, screening for the condition - outside of scientific research - is not routinely performed in the Netherlands.

• I participated in the Long-term HIT study, can I find out if I have clonal hemapotoiesis?

  No, this is not possible. The study data and results are anonymized and therefore cannot be linked to an individual.

• Previous research showed that stem cell transplants do not lead to changes in the DNA of donor cells. How does that relate to this news?

  Previous research showed that stem cell transplants themselves do not cause changes in the DNA of donor cells. This means that the genetic makeup of the donor stem cells, which replace the patient's blood production after transplantation, is not changed by the transplant itself.

  However, the news about clonal hematopoiesis after stem cell transplantation deals with another aspect: in clonal hematopoiesis, a stem cell with a certain DNA change starts dividing faster than stem cells without the change. This creates a group of cells with a shared DNA change. We also call this a clone. Researchers now suspect that the stem cell that eventually leads to clonal hematopoiesis was often already present in the donor, and that the transplant causes this stem cell to grow at an accelerated rate. 

   In short, although the stem cell transplant itself does not cause DNA changes in the donor stem cells, it may accelerate the growth of stem cells with certain DNA changes, leading to clonal hematopoiesis.

• How does clonal hematopoiesis affect survivors who underwent stem cell transplantation?

  We don't yet know. For example, there is evidence that clonal hematopoiesis may promote recovery after transplantation. On the other hand, the long-term presence of clonal hematopoiesis after transplantation could contribute to the side effects survivors may experience. Follow-up research has recently begun to further investigate the occurrence and possible consequences of clonal hematopoiesis.

• When will the effects become clear?

  It is not yet possible to say exactly when the long-term consequences of clonal hematopoiesis after stem cell transplantation will be fully clear. This will depend on the progress of follow-up research currently underway. Given the complexity of clonal hematopoiesis and the differences between patients, it may take some time before definitive conclusions can be drawn. It is expected that the results of the ongoing research will provide more insight into the possible long-term consequences in the coming years. This may lead to more targeted care and treatment for stem cell transplant survivors.

• Will the LATER clinic do additional screening for clonal hematopoiesis?

  No. For now, this is not necessary.

• Will stem cell transplantation as a treatment be adjusted accordingly?

  No. For now, this is not necessary.