At last! Two more HIV-free patients mean Aids cure is now within grasp
Wits expert describes breakthrough as 'unbelievably exciting'
The only man to have been cured of HIV, Timothy Ray Brown, is no longer alone, it seems. Scientists have found no trace of HIV in two new patients, who, like Brown, contracted cancer and received stem cell treatments.
Two researchers involved in the studies are honorary professors at Wits University, giving SA a small but significant role in the breakthrough. Brown, known as the Berlin patient, and the two men all received stem cell donations from people with a rare gene defect called CCR5delta32.
The successful transplants were announced at the annual Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle on Monday.
Deputy director of the Wits Reproductive Health and HIV Institute Francois Venter, who attended the conference, said the research was “really unbelievably exciting”.
He said it could pave the way to a cure for HIV.
“It furthers our understanding of the complex immunology of HIV, and hopefully will get us closer to a cure. To be clear, this is not an option yet for people with HIV, even in very rich countries, but it is a major step forward.”
International Aids Society president Anton Pozniak said that “although it is not a viable large-scale strategy for a cure ... these new findings give a proof of concept that HIV is curable”.
Brown has been HIV-free for 12 years. Although traces of the virus were detected in his body, the disease never rebounded.
Until now, scientists believed that the fact that his donor missed the CCR5 gene was key to what cured him – but it was also speculated that his cure could have been connected to excessive chemotherapy and full-body radiation. Now it appears that the missing gene definitely is the key to clearing HIV from infected patients.
Like Brown, the cancer patients received a donor transplant with a gene defect, but they did not have such extensive radiation.
It was announced on Monday that the so-called London patient had stopped antiretroviral treatment for 18 months, and the second patient, from Dusseldorf in Germany, had stopped ARVs for more than three months. Except for the Berlin patient, 18 months is the longest an adult has been free of HIV. The most sensitive tests available cannot detect HIV in their bodies. The gene defect means one of the proteins in white blood cells, CCR5, is missing. HIV needs to stick to this protein before attacking and infecting a human immune cell, explained Andy Gray, a pharmacologist at the University of KwaZulu-Natal.
Without a place to stick onto the immune cell, it is hard for HIV to infect the immune system.
Scientists are not calling the two men “cured”, since HIV has the potential to hide in the body and return, but rather describe it as a “possible cure”.
The virus has the ability to hide from the immune system but then rebounds, making a cure very difficult, said Gray.
What was “so interesting” about the two cases was that the new bone marrow in the two patients was clearing HIV from the body.
Sharon Lewin, an International Aids Society governing council member, said: “Two factors are likely at play – the new bone marrow is resistant to HIV and also the new bone marrow is actively eliminating any HIV-infected cells.”
The men were identified for transplants and studied by a group of doctors and scientists who are part of IciStem, a collaborative project to guide and investigate the potential for HIV cure.
IciStem researchers professors Annemarie Wensing and Monique Nijhuis, from the University Medical Centre Utrecht, are honorary full professors at Wits University.
Venter, of the Wits Reproductive Health and HIV Institute, who works with Wensing, said: “The collaboration with Utrecht has been a delight; we have managed to combine expertise from both institutions and the National Health Laboratory Service to do some very innovative work.”
A total of 39 cancer patients with HIV on the IciStem programme have received a stem cell transplant. IciStem has identified more than 22,000 donors with the rare CCR5delta32 gene defect.
Of the 39 patients, nine received stem cells containing the genetic defect. Of those nine, only four survived, including the two patients now free of HIV. The remaining two are still on ARVs.