Wiskott-Aldrich Syndrome and Stem Cells

Wiskott-Aldrich syndrome (WAS) is a rare genetic condition affecting the immune system and bone marrow which almost always affects boys. The immune system is the body’s defence against infection from enemies including bacteria, viruses, and parasites.^[1] WAS affects the production of platelets in the bone marrow.^[2] Platelets prevent excessive bleeding from cuts and breakages in blood vessels.

Wiskott-Aldrich syndrome can cause an array of issues in patients from bleeding frequently which is difficult to stop to eczema to recurrent infections including pneumonia. Additionally, those with WAS are at an increased risk of developing some autoimmune diseases and certain cancers.^[1]

Wiskott-Aldrich syndrome is an X-linked recessive condition. This means that the vast majority of people affected are male. Thankfully, even in males WAS is rare, affecting just 1 to 10 out of every 1 million boys.^[2]

Wiskott-Aldrich Syndrome Facts

• WAS almost always affects boys^[1]
• WAS is extremely rare affecting less than 10 in 1 million boys^[2]
• WAS sufferers are at increased risk of certain cancers and autoimmune diseases^[4]
• 90% of Wiskott-Aldrich syndrome sufferers are male^[3]
• Stem cell transplants using donor stem cells are successful in 9 out of 10 WAS cases treated^[5]
• There are several clinical trials investigating the application of cord blood in Wiskott-Aldrich syndrome^[6]

Wiskott-Aldrich Syndrome and Stem Cells

A stem cell transplant is the only treatment option to offer WAS patients the chance of a permanent cure. There are three types of stem cell transplant; autologous, which uses a patient’s own stem cells, allogeneic, which uses donor stem cells, and syngeneic, which uses stem cells from an identical twin.

In the case of Wiskott-Aldrich syndrome, allogeneic stem cells are preferred for transplant, especially those from a matched sibling. By injecting healthy stem cells into the blood stream of a child with WAS, the healthy cells have the chance to rebuild the blood and immune system.^[7]

Because Wiskott-Aldrich syndrome is a genetic condition, a person’s own stem cells cannot be used as treatment without gene editing, as they would otherwise still carry the faulty gene which causes the condition in the first place.

However, researchers are investigating gene therapy solutions where a child’s own stem cells are genetically modified to correct the defect before being infused back into the patient. This approach aims to allow the patient to be their own donor, potentially reducing the risks associated with donor transplants, such as rejection or Graft vs Host Disease.

A small study treated two WAS patients with genetically modified, autologous haematopoietic stem cells. After receiving the genetically modified stem cell infusion, the patients’ clinical condition improved. After the treatment, patients showed improvement in their clinical condition, with resolution of their haemorrhagic diathesis (bleeding), eczema, autoimmunity and predisposition to severe infection.^[8]

References

1. http://www.childrenshospital.org/conditions-and-treatments/conditions/w/wiskott-aldrich-syndrome/overview
2. http://www.childrenshospital.org/conditions-and-treatments/conditions/w/wiskott-aldrich-syndrome/symptoms-and-causes
3. http://patient.info/doctor/wiskott-aldrich-syndrome
4. http://www.piduk.org/specificpidconditions/welldefinedsyndromes/wiskottaldrichsyndrome
5. https://clinicaltrials.gov/ct2/results?term=wiskott-aldrich+syndrome+stem+cells&Search=Search
6. https://clinicaltrials.gov/ct2/results?term=wiskott-aldrich+syndrome+cord+blood&Search=Search
7. http://www.childrenshospital.org/conditions-and-treatments/conditions/w/wiskott-aldrich-syndrome/treatments
8. http://www.ncbi.nlm.nih.gov/pubmed/21067383
9. The Lancet. Haematology, 6(5), e239–e253. https://doi.org/10.1016/S2352-3026(19)30021-3

The information contained in this article is for information purposes only and is not intended to replace the advice of a medical expert. If you have any concerns about your health we urge you to discuss them with your doctor.