Bone Marrow Transplant is not successful all the time. So ,new paths were found out to find a treatment for SCID . Gene therapy was one of them. The first experiments in gene therapy on humans began in 1990. Two girls with ADA deficiency SCID were treated, several times, over a 2 year period, with T-cells carrying corrected DNA. Periodic tests on both girls show that their re-engineered cells are surviving and producing the ADA enzyme, but both girls continue to receive replacement enzyme therapy[1] . The results were not upto the mark but it did open a door towards better of treatment of SCID.
“In
April of 2000, an article was published in Science Magazine which
presented 2 cases of X-linked SCID which had been treated by gene
therapy. These children had no prior treatment such as bone marrow
transplantation. These 2 patients, at the time period of 10 and 11
months after therapy, were exhibiting normal growth and development
without other treatment. Their cells appeared to be working. These
results demonstrated a selective advantage existed for the corrected
cells to engraft and produce a corrected cell line. In all, 10 X-SCID
patients were treated in this trial. However, those studying and
watching gene therapy received devastating news in an article published
in Science Magazine in October 2003. Two of the boys treated had
developed a form of T-cell proliferation similar to leukemia. The
insertion of the corrected DNA into the defective cells had occurred
next to a specific leukemia inhibitor. With news of this devastating
event, most X-SCID gene therapy trials were placed on hold worldwide.
Currently, new ADA and X-SCID trails have begun or are in the process.
Obviously, caution is warranted. However, gene therapy still holds the
greatest hope for a true cure for this devastating disease.”[1]
Reference
1.http://www.scid.net/