Despite the effort being put into the fight against the human immunodeficiency viruses (HIV), only one person has ever been declared functionally cured. The success of that case has been difficult to replicate, but now scientists have declared a second person has been cured of HIV, according to a new case report published today in The Lancet HIV.

A patient previously diagnosed with HIV-1, known as “the London patient,” appears to have no active viral infection in their body after receiving stem cell transplantation from donors with an HIV-resistant gene. He's now been in remission for 30 months, and mathematical modeling suggests that the probability of remission for life is extremely high. 

This is a similar method used to treat the first person cured of HIV, known as “the Berlin patient,” who was functionally cured in 2008. Just like this case, remnants of the virus' DNA remain in their tissue sample, although the researchers say these are essentially harmless “fossils” of the infection and don’t appear to be capable of reproducing the virus. 

“We propose that these results represent the second ever case of a patient to be cured of HIV,” lead author Professor Ravindra Kumar Gupta, from the University of Cambridge in the UK, said in an emailed statement. 

“Our findings show that the success of stem cell transplantation as a cure for HIV, first reported nine years ago in the Berlin patient, can be replicated.”

A previous case report from 2019 showed the London patient was experiencing sustained remission from HIV-1, although the researchers warned it was too soon to proclaim it a “cure". Despite the warning, many still reported he was "cured". Now, after being in remission for 30 months with no antiretroviral therapy, the study authors are much more confident that the patient is in life-long remission, effectively cured of the virus. 

The London patient was diagnosed with HIV in 2003 and put on antiretroviral drugs in 2012. Unfortunately, later that same year, he was diagnosed with an uncommon cancer called Hodgkin's Lymphoma and required chemotherapy. To prevent the virus from bouncing back, he received a treatment involving a stem cell transplant from a donor who carried a gene (CCR5Δ32/Δ32) that is resistant to HIV, as well as chemotherapy drugs. Unlike the Berlin patient, he didn’t require full-body irradiation or a second round of stem cell transplantation.

“Given the large number of cells sampled here and the absence of any intact virus, is the London patient truly cured? The additional data provided in this follow up case report is certainly encouraging but unfortunately in the end, only time will tell,” Professor Sharon R Lewin from the University of Melbourne in Australia, who was not directly involved in the new study, wrote in an accompanying comment article. 

This treatment, however, is not for everyone and comes with a huge reel of dangers.

“It is important to note that this curative treatment is high-risk, and only used as a last resort for patients with HIV who also have life-threatening haematological malignancies,” Professor Gupta cautions. “Therefore, this is not a treatment that would be offered widely to patients with HIV who are on successful antiretroviral treatment.” 

Most HIV patients can manage the treatment of the virus with drugs available today, and live long and healthy lives.

In a profile with the New York Times, “the London Patient” recently revealed his identity as Adam Castillejo, a 40-year-old Londoner who was born in Venezuela. Although he noted the journey was long and full of dark moments, he decided to reveal his identity and tell his story to inspire hope in others. 

“This is a unique position to be in, a unique and very humbling position,” said Castillejo.

“I want to be an ambassador of hope.”