Is HIV really curable?

Second HIV patient worldwide is considered "cured"

Nevertheless, it is a remarkable step forward in the fight against AIDS: With a special therapy, a London patient was probably freed from the AIDS pathogen. It would be only the second person who was likely to be cured of HIV infection. The only documented "cure" of an HIV patient so far was the case of US citizen Timothy Ray Brown. He became known as the "Berlin patient" and was declared healthy after he had been treated at the Berlin Charité from 2007 onwards.

In the London patient, about two and a half years after the end of anti-HIV therapy, no functional HI virus was detectable, reports a group led by the physician Ravindra Gupta from Cambridge University in the UK. The patient, who had blood cancer in addition to HIV, had previously received a special stem cell donation. The researchers emphasize in the journal "The Lancet HIV" that stem cell therapy is a high-risk treatment that is out of the question for most HIV patients. A cure for AIDS, the immunodeficiency disease caused by the HIV virus, is basically not possible to this day.

The donor's immunity

With the help of antiretroviral drugs, which have to be taken for life, the pathogen can be kept in check and the outbreak of AIDS can be prevented in the long term. It is estimated that around 38 million people worldwide are currently living with HIV, but only 62 percent of them are receiving antiretroviral therapy. In 2018, around 800,000 HIV patients died from diseases related to the virus.

A HIV virus in the blood (illustration)

In both the London patient and the Berlin patient, the immune system was rebuilt through stem cell therapy. The stem cell donor each had a rare mutation that made them immune to the HIV virus. It means that the cells do not produce a CCR5 receptor, which most HI viruses need in order to dock on a cell in which they could multiply.

When can an HIV patient be considered cured?

"Our results show that the success of stem cell transplantation as a cure for HIV, which was first reported in Berlin patients nine years ago, can be repeated," says Gupta. The Berlin patient also had some form of blood cancer. Gupta's team examined numerous fluid and tissue samples from the London patient. The scientists found parts of the genetic make-up of HIV viruses in some samples. However, they assume that these are "fossil" strands of DNA that do not belong to a virus capable of replicating.

Time-honored buildings, cutting-edge research: Cambridge University

Much other data, such as the sharp drop in the number of HIV-specific antibodies, indicated that the virus had disappeared from the patient's body, the researchers write. In a comment, also in "The Lancet HIV", Sharon Lewin and Jennifer Zerbato from the University of Melbourne (Australia) ask when an HIV patient can be considered cured.

Medicine today knows that most viruses that survive anti-HIV therapy are defective and cannot multiply. "A cure for HIV could be better defined as 'no intact virus' than as 'no detectable virus'", write the doctors. The study by Gupta's team is encouraging, but in the end time must show whether there is actually a cure.

rb / ie (afp, dpa)