Sunday 15 February 2009

Stem Cells Pave New Ways Towards HIV Treatment

A resume of a case report from the study entitled "Long-term control of HIV by CCR5 Delta32/Delta32 stem-cell transplantation", published in the New England Journal of Medicine, on the 12th of February.

Doctors from Charité Universitätsmedizin Berlin, Germany, dealt successfully with a case of a 40-year old man, newly diagnosed with Acute Myeloid Leukemia (AML), who had also been diagnosed as positive for the Human Immunodeficiency Virus-1 (HIV-1) 10 years earlier and was receiving treatment with HAART (highly active antiretroviral therapy) for the past 4 years.

HIV-1, primarily attaches to CD4 molecule to enter the cell and subsequently, according to the type of virus, R5 HIV or X4 HIV, binds to coreceptors CCR5 and CXCR4, respectively. It has been found that a mutation known as CCR5 delta32, that causes lack in the cell expression of CCR5, has a protective effect towards the virus. People who carry this mutation in one copy in their genes, present a slower progression of the disease and those who carry it twice are remarkedly resistant to HIV-1.

The doctors from Charité Universitätsmedizin Berlin, in order to deal with the haematologic condition, they carried out a bone marrow allogeneic stem cell transplantation from an HLA-matched donor, who was also homozygous for the delta32 mutation, thus he lacked CCR5 expression.

The outcome from this transplantation was successful and after 20 months of follow-up and discontinuation of antiretroviral therapy, the patient showed no viral rebound or other illness related symptoms.

Although this outcome is very promising for HIV treatment, it doesn't consist a cure, as such transplantations imply many risks and they have lead to death several times in the past. Also, as HIV affects many cell types found in different body parts, such as brain, liver, kidneys or heart, the virus could remain hidden and to spread eventually at a later time, according to Dr. Levy, professor of University of California, San Fransisco.

In summary, this study doesn't consist a cure promise for HIV, but a new approach to the long-term control of HIV, without antiretroviral treatment and it promises further advances in the research for drug development and treatment.

Long-Term Control of HIV by CCR5 Delta32/Delta32 Stem-Cell Transplantation.
Hütter G et al. N Engl J Med. 2009 Feb 12;360(7):692-8.
Not an HIV cure, but encouraging new directions.
Levy JA. N Engl J Med. 2009 Feb 12;360(7):724-5.

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