IN 2020, Xu Yu, Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts, USA, identified a patient, named the San Francisco Patient, with HIV who had no intact HIV viral sequences in their genome, indicating that their immune system may have eliminated the virus. Known as a sterilising cure, this extraordinary incident was the first known case of a sterilising cure without a stem cell transplant. Now, a second individual has been identified, known as the Esperanza Patient.
“These findings, especially with the identification of a second case, indicate there may be an actionable path to a sterilising cure for people who are not able to do their own,” stated Yu.
During infection, the HIV virus places copies of its genome within cells’ DNA, creating a viral reservoir. This allows the virus to effectively hide from the immune system and anti-HIV drugs. Anti-retroviral therapy (ART) works by killing the new viruses arising from this reservoir; however, ART can do nothing to attack the reservoir.
Yu and her research team have now reported a second patient with no intact HIV viral sequences found in the analysis of more than 1.19 billion blood cells and 500 million tissue cell sequences. The findings indicate that the patient’s immune system may have eliminated the HIV reservoir, achieving the sterilising cure.
The identification of two patients has allowed Yu’s team to draw comparisons between the two incidents. Yu explained how the findings suggest a role for a specific killer T cell response common to both patients. Understanding the workings of the immune system within these two patients could lead to potential treatments, allowing other patients with HIV to mimic these responses and achieve the sterilising cure.
Yu described the value of these findings: “We are now looking forward to the possibility of inducing this kind of immunity in persons on ART through vaccination, with the goal of educating their immune systems to be able to control this virus without ART.”