An unnamed man in London could be the second person in history to be ever cured of HIV infection, offering hope that HIV and AIDS are curable.

In Remission For 18 Months

The patient, who prefers to remain anonymous, appears to be HIV-free after he had a special bone marrow transplant.

The Berlin patient, the first person who was completely cured of HIV, had a similar bone marrow transplant in 2007 and has since been HIV free.

The case reported in the journal Nature marks the second time doctors have used the treatment to seemingly cure HIV infection in a person's body.

Doctors who reported the case said it is still too early to say with certainty that the man has definitely been cured of HIV, but the patient has been in remission from the virus 18 months after he discontinued his antiretroviral therapy.

Preventing HIV Virus From Rebounding

The male patient was diagnosed with HIV infection in 2003. He was placed on antiretroviral therapy in 2012, but later that year, he was also diagnosed with advanced Hodgkin's Lymphoma and was treated with chemotherapy.

Chemotherapy can be effective at fighting HIV because it kills dividing cells. The patient, however, had another treatment that appears to have helped his condition.

In 2016, he underwent hematopoietic stem cell transplant from a donor who happens to have a genetic mutation that prevents expression of the HIV receptor CCR5.

The donor has two mutated copies of the CCR5 Δ32 allele, so the person is resistant to the HIV-1 virus strain that uses the CCR5 receptor since the virus cannot enter the host cells.

Replacing the immune cells with those that do not have the CCR5 receptor appears to help prevent HIV from rebounding after the treatment.

"Single allo-HSCT with homozygous CCR5Δ32 donor cells may be sufficient to achieve HIV-1 remission with reduced intensity conditioning and no irradiation, and the findings further support the development of HIV remission strategies based on preventing CCR5 expression," Eduardo Olavarria of Imperial College Healthcare NHS Trust, and colleagues wrote.

Too Early To Confirm Patient Is Cured

Regular tests confirmed the viral load of the patient is undetectable. His immune cells also remain unable to express the CCR5 receptor.

"While it is too early to say with certainty that our patient is now cured of HIV, and doctors will continue to monitor his condition, the apparent success of haematopoietic stem cell transplantation offers hope in the search for a long-awaited cure for HIV/AIDS," said Olavarria.