In 2007, a person with human immunodeficiency virus (HIV) was considered virtually cured of the disease. Until now, researchers were unable to duplicate the procedure, involving treatment with stem cell transplants, that resulted in the cure. Now, two more patients seem to have reached that critical milestone.
IciStem is a collaboration of scientists who study stem cell transplants as a potential HIV cure in patients who also have blood disorders. Although a cure for HIV remains elusive, IciStem recognizes three seemingly successful cases:
In all three cases, chemotherapy wasn’t effectively treating the patients’ blood cancer, so they received a bone marrow transplant from donors with a rare mutation known as CCR5-delta 32. The CCR5 protein rests on the surface of some immune cells. HIV uses it to enter and infect a cell. The mutated form of the protein actually prevents the virus from using CCR5 to enter healthy cells.
In all of the patients, it appears that the donated HIV-resistant cells replicated and replaced the cells vulnerable to HIV. As a result, only a trace of HIV material is left circulating in each person’s body.
Unfortunately, a bone marrow transplant (BMT) is not a viable treatment option for HIV-infected people who don’t have cancer. BMT requires conditioning of the body, which often leaves it prone to infection. The alternative, daily antiviral medication, is usually successful at keeping the virus under control with minimal risks.
Instead, researchers are using these findings when considering other therapies that take CCR5 into account that could be used in patients who don’t have cancer — for example, targeting and destroying CCR5 receptors. Investigators are also looking at whether an HIV-resistant donor stem cell could be given to any patient, regardless of whether they have cancer.
Approximately half of the people living with HIV have a form of the virus that relies solely on CCR5 for entry into the cell. Another form of HIV, called X4, uses a different protein to enter cells. Bone marrow transplant is not effective in people with an X4 mutation.
Researchers at the UCLA Center for AIDS Research continue to follow these exciting developments. The mission of CFAR is to create synergy among diverse research disciplines that result in significant breakthroughs in understanding, preventing and treating HIV infection.
Tags: blood disorders, bone marrow transplant, cancer, CCR5 mutation, chemotherapy, HIV, HIV/AIDS, human immunodeficiency virus, leukemia, Research, stem-cell transplants, UCLA Center for AIDS Research