It can repair fault in immune system cells to help them lead normal lives
By Kiran N. Kumar
For devastated parents of children born with inherited immune diseases, there is a hope to rectify and help them lead normal lives as a fault in cells of the immune system can be repaired now with a new gene editing technique.
The gene editing technique repairs a genetic problem at its source. If a mutation in a certain gene is producing a dysfunctional protein triggering an inherited disease, it delivers a copy of this gene bereft of the deleterious mutation and thereby to produce a functional protein.
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As the gene therapy is catching up now, the scientists from University College London (UCL) demonstrated a technique that could lead to new treatment for rare disease CTLA-4 insufficiency of the white blood cells – known as regulatory T cells – and those that protect the body from repeat infections and cancer – known as effector T cells.
The study, published in Science Translational Medicine, showed how it helps patients with the condition, where mutations in a gene cause these T cells to function abnormally causing their own immune system to attack tissues and organs, including blood cells.
It obliterates their immune system’s ‘memory,’ subjecting them to recurring infections by the same viruses and bacteria, sometimes leading to lymphomas, a type of blood cancer.
Although the current gene editing therapy has been developed for tackling the CTLA-4 insufficiency, researchers say it could pave for an approach suitable to tackle a host of other immune conditions in the future.
Co-senior author, Professor Emma Morris says, “Genes that play critical roles in controlling immune responses are not switched on all the time and are very tightly regulated.
“The technique we have used allows us to leave the natural mechanisms controlling gene expression intact, at the same time as correcting the mistake in the gene itself.â€
How does it work?
Taking human cells and using ‘cut’ and ‘paste’ gene editing techniques, with the help of the CRISPR/Cas system, the researchers targeted the faulty gene in T cells taken from patients with CTLA-4 insufficiency.
They repaired the errors and restored them to the levels of healthy T cells. In the case of mice, they were also able to improve symptoms of the disease with injections of gene-edited T cells.
It’s a new approach in “inborn errors of immunity,†says co-author, Professor Claire Booth at UCL as the method can reduce the risk of getting lymphoproliferative disease.
CTLA-4 is a protein produced by T cells to control the activity of the body’s immune system and most people carry two working copies of the gene responsible for producing CTLA-4, but those who have only one functional copy produce too little of it to regulate the immune system.
So far, the standard treatment for CTLA-4 insufficiency is a bone marrow transplant to replace the stem cells but transplants are risky and require high doses of chemotherapy and longer period of hospitalization. Moreover, older patients with CTLA-4 insufficiency cannot tolerate the transplant procedure.
Read: New Gene Editing Strategy Could Lead to Treatments for People Born with Inherited Diseases of the Immune System (October 26, 2022)
The new approach can improve many of the symptoms of the disease, besides being less toxic than a bone marrow transplant, insist researchers.
“Collecting the T cells is easier and, correcting the T cells is easier” and the new approach can also reduce the hospitalization period for those patients who require it.