Leukemia is a type of cancer which affects the body’s blood,
beginning with the site of blood cell synthesis--bone marrow. Anemia, leukopenia,
thrombocytopenia, swollen lymph nodes, and an enlarged liver or spleen may
indicate leukemia. This disease affects both children and adults with
approximately 1.5% of people being diagnosed at some point over their lifetime.
It is the most prevalent of all childhood cancers. Current treatments for
leukemia include chemotherapy, transfusions, and medications. However, for an
11-month-old baby with end-stage leukemia, these options had already been
exhausted. As a last effort, a novel cell therapy was tested and the results
are promising.
Research had been taking place which attempted to modify T
cells such that the patient’s immune system would target the cancerous cells. A
disadvantage of this treatment was the T cells must be isolated through an
intensive process from the infected individual themselves in order to ensure
the host cells and introduced cells would not recognize each other as foreign.
This makes a large-scale production of an effective drug impossible and
increases the cost and time required to develop the treatment. With a failing immune system and little T
cells to provide, this was time that the baby could not afford.
Fortunately, due to recent breakthroughs in genome editing,
donated T cells may be genetically modified so the patient does not need to
provide a sample. In this novel treatment, donated healthy T cells are edited
using transcription activatorlike effector nucleases to remove the T cell
receptor gene and CD52.Removal of the
receptor gene was done to ensure the added cells would not recognize the pateint’s
body as foreign and attack healthy cells. The patient was placed on an immunosuppressant
which ensured the patient’s cells would not attack the added T cells. This
antibody recognized CD52, by removing
this gene in the T cells, the immunosuppressant would not affect the activity
of the donated T cells. Additionally, the donated T cells were modified to
ensure they would attack the cancerous cells. This novel treatment was followed
by a bone marrow transplant.
This was the first treatment using this technique. Due to
the severity of this baby’s case, treatment was administered prior to finishing
testing. So far, the prognosis is good. But the persistence of the T cells and
treatment remains to be seen. Further
trials are scheduled next year, with additional genes spiced out.
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