An HIV-infected T-cell. Image: NIAID
Generally, you don’t want to contract another serious autoimmune disease when you’re already HIV-positive. But it turns out that a patient with the extremely rare combination of both lupus and HIV is creating antibodies that might one day lead to an effective HIV vaccine.
Normally, a patient’s body will create antibodies to attempt to fight HIV, but many of them have just a narrow method of action. When the body does create what are known as broad neutralizing antibodies, the immune system will automatically target and kill them in a process that’s known as autoreactivity.
Many researchers believe that broad neutralizing antibodies are the key to creating an effective HIV vaccine, but they haven’t yet discovered a way to keep the body from automatically targeting them. An extremely rare case study in a patient might help them unlock how to do it.
With lupus, the body doesn’t know that it’s supposed to target these broad neutralizing antibodies, and so they are created in much larger numbers than they are in patients with HIV only.
It’s a possibility that Barton Haynes, the Duke University researcher who headed the case study published in the Journal of Clinical Investigation, has hypothesized for many years, based on his knowledge of how the two diseases work. The only trouble was finding a patient who who fit the bill.
"Over the years we have searched for and now have found one person with [lupus] who was also chronically infected with HIV to determine if this person could make broad neutralizing antibodies," Haynes said. "We found that the patient did indeed make these important antibodies.
The patient, a 33-year-old American woman being treated at the Duke University Medical Center (whose name is being withheld for privacy reasons), has been HIV positive for 14 years and contracted lupus eight years after finding out she was HIV-positive. Haynes discovered that, since her contraction of lupus, her viral load of HIV has remained relatively stable.
Like most people who have both lupus and HIV, the patient contracted HIV first. In fact, people with lupus aren’t immune to HIV, but they do contract it at a much lower rate than the general population, and it appears her body is fighting HIV better since she contracted lupus than it was before she did.
“The observations that HIV-1 infection is reported with disproportionately low frequency among subjects with [lupus] supports [our] hypothesis,” Haynes wrote.
His team not only identified CH98, the antibody that is useful in fighting HIV, they also were able to isolate it, meaning it might one day be used in a vaccine. Haynes has only studied this one specific patient for the effect, and finding more people with lupus and HIV isn’t easy, but the fact that he predicted that she’d be making this antibody and then found it is certainly promising.
Mattia Bonsignori, one of Haynes’ colleagues said that the research has been “critically instrumental” in understanding how antibodies can fight off the disease. "We are hopeful that these insights in lupus will aid in our implementation of strategies for designing experimental vaccines capable of overcoming the host tolerance control of broad neutralizing antibodies,” he said.