February 16, 2018

expert reaction to a conference abstract by Gang Bao on sickle cell research and genome editing

In a conference talk, at the AAAS annual conference, a researcher will discuss using CRISPR/Cas9 genome editing for sickle cell disease.

Dr Alena Pance, Senior staff scientist at the Wellcome Trust Sanger Institute, said:

“Overall, genetic correction of red blood cell diseases is not new, some of the mutations affecting haemoglobin genes have been corrected in stem cells in vitro. The advance of this report is that the corrected stem cells were introduced into the animal and followed over time.

“Perhaps the most important point about gene therapy is that because it relies on modification of the patient’s own cells, there are no issues of rejection when they are introduced back into the patient. In the context of sickle cell disease, this could be better than bone marrow transplant, which would be the only choice of long term treatment for severe cases. However, in order to assess this, it would be crucial to know whether the corrected stem cells are able to establish themselves in the bone marrow of the recipient animal to be able to assess the potential of long term effect of the therapy.

“The report is not clear about the fate of the corrected cells. It only says that the correction persisted in the stem cells but that doesn’t answer the question of whether the numbers of corrected cells persisted or increased in the bone marrow and crucially, whether they were able to continue generating healthy red blood cells and for what period of time.

“Finally, the ultimate evaluation of gene therapy will be how it compares to the traditional existing strategies, such as bone marrow transplant or induction of expression of other haemoglobin genes to make up for the deficiency of the beta globin. For this, it will be essential to know the efficiency of the correction, the expansion and persistence of the corrected cells in the body and of course the certainty that no undesirable genetic changes are taking place throughout the procedure.”

* Abstract title: ‘CRISPR/Cas9-Based Genome Editing for Treating Sickle Cell disease’ by Gang Bao.  This is a conference talk that will be discussed at the AAAS Annual Meeting on Friday 16^th February 2018. There is no paper as this is not published work, but the abstract is available on the AAAS website: https://aaas.confex.com/aaas/2018/meetingapp.cgi/Paper/21361

Declared interests

None received.