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Cell & Gene Therapy Insights

Cell & Gene Therapy Insights

Patient free of HIV after stem cell transplant

A breakthrough study has identified that transplanting stem cells from a donor with a specific homozygous mutation in CCR5 gene could lead to HIV remission. The study presents a case report of a man with leukemia who appears to have been cured of HIV following a stem-cell transplant from a donor resistant to HIV infection.

CCR5 gene codes for a receptor on white blood cells and HIV virus enters the cells by binding to these receptors. Mutation in the CCR5 gene (CCR5Δ32) blocks the functioning of the receptor. About 1% of people of European descent have two copies of this mutation and are resistant to HIV infection.

This is the second report of its kind and the first to be cured is still in remission since the transplantation in 2008. Termed the ‘Berlin patient’, he underwent two allogeneic haematopoietic stem-cell transplantations (allo-HSCT) to treat his acute myeloid leukemia. The donor had homozygous mutation in CCR5 (CCR5Δ32/Δ32). Since total body irradiation was given along with each HSCT, it was unclear as to which factor contributed to HIV remission in this patient.

In the present study published in Nature, a collaborative research by UK’s University College London, University of Cambridge and University of Oxford used a similar strategy and have come up with a less aggressive and less toxic approach for HIV-1 remission.

An HIV-1-infected man underwent a single allo-HSCT for Hodgkin’s lymphoma using cells from a CCR5Δ32/Δ32 donor. Antiretroviral therapy, the standard treatment for HIV, was stopped 16 months after transplantation. There was no sign of HIV-1 remission 18 months after stopping the medication and all the clinical parameters proved the same.

Although data thus far shows positive sign, researchers are not completely certain whether the infection is fully cured. However, it provides strong evidence to support that single allo-HSCT with homozygous CCR5Δ32 donor cells is enough to achieve HIV-1 remission with reduced intensity conditioning and no irradiation.

This kind of treatment would only be suitable for HIV patients who need a transplant to treat leukemia or other diseases. For most HIV patients who don’t have cancer, bone-marrow transplant is not an option as it is a serious procedure that can sometimes lead to fatal complications. The risk of having a bone-marrow transplant is far greater than the risk of staying on effective antiretroviral tablets every day.

Source: HIV-1 remission following CCR5Δ32/Δ32 haematopoietic stem-cell transplantation. Gupta RK et al., Nature March 2019. Website

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