Reacción a "Reactions: Clinical trial tests gene therapy in severely immunodeficient children"

The study is excellent and the results are spectacular: they have achieved immune reconstitution in all cases (10/10). The article is scientifically very sound. The follow-up is very well done and the medical and immunological results are consistent. The procedure achieves results superior to those achieved with the standard treatment, bone marrow transplantation. 

Primary immunodeficiencies were the first genetic diseases to be treated by gene therapy, especially the most severe forms, which are lethal without treatment, called Severe Combined Immunodeficiencies (SCID). Currently, the lentiviral vectors used, such as the one used in this case, ensure a very high safety margin, with fewer side effects than the classic treatment, haematopoietic progenitor transplantation. This has made them the first-line treatment in countries with this technology (USA, UK, France, Germany, Italy, etc.). 

This is not a very novel therapy, as it has been previously tested in other primary immunodeficiencies (SCID-X, WAS, etc.) with similar results. The novelty is the pathology in which it has been used, but its use in this particular case is limited to this single disease, which is very rare.  

As for the limitations, there are basically two. Spain is the only large country in the European Union that does not have gene therapy for this type of pathology (primary immunodeficiencies) or similar (thalassaemia or other genetic blood diseases). This is due to the fragmentation of our health system, as well as the lack of a National Immunology Centre, which is available in other neighbouring countries, even those with a lower GDP than ours. 

The other limitation is due to the fact that it is a very rare variant of SCID (SCID-ART, for the Artemis protein), although in the USA it is somewhat more frequent as it is found in people of Navajo/Apache origin. There are very few cases in Spain. Each variant of the disease can only be treated with a gene therapy vector made specifically for each responsible gene. In the case of SCID, more than 40 genes are involved. 

Another limitation, although in this case a previous one, derives from the fact that in Spain, with the exception of Catalonia, screening for these diseases is not carried out in the perinatal screening, the famous heel prick test that is performed on all newborns. These treatments have an even more beneficial effect if they are done before the child starts to have serious infections, but they are also effective in children as young as possible. Both are achieved by introducing these studies into the heel prick, as is already done in the USA and in many European countries, as well as in Catalonia.