Results of a preliminary trial have raised hopes of a new form of therapy for people suffering from Aids, which occurs in the latter stages of infection with Human Immunodeficiency Virus (HIV). The scientists are planning further research to establish whether the treatment could even rid patients of HIV infection altogether.The technique involves isolating genes which curb the spread of HIV inside the body, introducing the genes into human stem cells in a laboratory, then transplanting the stem cells into a patient's bone marrow.
In the first human trial, anti-HIV stem cells were transplanted into five Aids patients undergoing bone marrow replacement as part of treatment for a form of cancer known as lymphoma.
Small quantities of the transplanted stem cells were able to grow and produce new white blood cells resistant to HIV, resulting in an improvement in the patients' conditions.
It could take up to ten years before an effective clinical treatment could be put into widespread use.
"We are trying to prevent the immunodeficiency that is a result of HIV infection," said Dr David DiGiusto, director of haematopoietic cell therapies at City of Hope Medical Centre in Duarte, California, where the research was carried out.
"It is still an experimental treatment at the moment, but we hope that eventually we will be able to give Aids patients just one transplant and that would then protect them for life.
"We have data to show that the resistant cells are persisting in our lymphoma patients."
HIV attacks white blood cells known as T-lymphocytes, which play a central role in the immune system by fighting other forms of infection.
Over time the number of T-lymphocytes in the body decreases as the virus spreads and the immune system stops working, leading to Aids, meaning patients are no longer able to fight off infections themselves.
Bone marrow contains stem cells that are capable of forming all types of blood cells including the white blood cells that form part of the immune system.
The scientists have found they can import three genes that protect cells against attack from HIV into these blood stem cells in the laboratory.
By giving patients stem cells that carry these anti-HIV genes, the patients' bodies are able to produce new white blood cells that are resistant to attack from HIV and so able to defend the body from other forms of infection.
The trial of the new stem cell therapy was carried out in patients with Aids-related lymphoma as the cancer is commonly treated with a bone-marrow transplant. Powerful drugs are used to strip the patient of their own bone marrow, which is then replaced with cells from a donor.
The doctors behind the research are currently reluctant to expose Aids patients who do not have lymphoma to the risky bone transplant operation, but they are refining the technique in the hope of providing anti-HIV stem cell transplants to all Aids sufferers.
They are due to begin a larger trial where patients will be given greater concentrations of the anti-HIV stem cells in a bid to fight off their condition.
The researchers also hope to develop an intermediate treatment that will allow Aids patients to be given booster injections of HIV resistant white blood cells that would help to improve their ability to fight off infections.
While the ultimate hope is that the pioneering treatment could rid patients of HIV infection entirely, this might not happen if the virus, once it has been prevented from infecting white blood cells, proves able to persist elsewhere in the body.
Courtesy Telegraph.co.uk.
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