Every Saturday, The CSPH highlights news or recent research in the field of human sexuality. This week we’re looking at a study presented at this past year’s International AIDS Conference in Washington, D.C. on the possible virus-eliminating effect of bone marrow transplants as seen in two HIV-positive male patients.
Dr. Daniel Kuritzkes, Chief of Infectious Diseases at Brigham and Women’s Hospital and Professor of Medicine at Harvard Medical School in Boston, led the study that found that, eight months after receiving bone marrow transplants, two men infected with human immunodeficiency virus (HIV) no longer had any traces of the virus in their lymphocytes. Both men underwent chemotherapy for blood cancers before receiving bone marrow stem cell transplants. Additionally, both also developed graft-versus-host disease and continued with their antiretroviral medications throughout and after the transplant procedures. While noting that any of these factors could theoretically explain the men’s resulting HIV-free status, the researchers state that the bone marrow transplantation combined with antiretroviral therapy is the most likely explanation.
What did it find?
Kuritzkes and his colleagues suspect that the bone marrow transplantation along with the continuation of antiretroviral therapy resulted in the elimination of HIV in both men. HIV patients on antiretroviral therapy often achieve “undetectable viral loads,” meaning there are no virus particles in their blood, but they still have latent HIV in their lymphocytes. In these cases, if the patient stops antiretroviral therapy, the latent HIV could reactivate. For these two specific bone marrow transplant patients, there were no traces of HIV in the white blood cells, indicating that even the latent HIV may have been eliminated. “We believe the transplanted cells killed off and replaced all of the patients’ own lymphocytes, including the infected cells, and the donor cells were protected from becoming infected themselves by the antiretroviral therapy they were taking throughout the transplant period,” says Kuritzkes.
Strengths and Weaknesses
This research presents another exciting possible step towards finding a cure for HIV and AIDS. “Eliminating the reservoir is the key to the cure,” says Dr. Savita Pahwa, Director of the Center for AIDS Research at the University of Miami Miller School of Medicine. However, she also stresses that it would only be possible to say these patients were “functionally cured” if the virus did not rebound when the patients went off antiretroviral therapy.
The next step, according to Kuritzkes, is to have the patients discontinue their antiretroviral medications, which would require patient consent and adherence to ethics protocols. Taking the men off these medications poses a potential health risk if their HIV viral loads increased, so close observation and monitoring would be needed. Further steps need to be taken to determine the possible role the graft-versus-host disease played as well, Kuritzkes explains. Additionally, even if the transplant procedure was found to eliminate the reservoir of latent HIV cells, bone marrow transplantation is nevertheless a very risky procedure. Kuritzkes says he does not “foresee bone marrow transplantation being performed on otherwise healthy HIV-infected patients who are doing well on [antiretroviral therapy].” As part of a larger study, Kuritzkes and his colleagues are continuing to enroll and follow HIV-positive patients who have undergone bone marrow transplants to better understand the results from the two prior patients.
While this research presents another possible pathway towards finding a cure for HIV/AIDS, for now whether the transplant procedure, the continued antiretroviral medication, the graft-versus-host disease, or a combination of some or all of these things is responsible remains unclear. Because these are preliminary results from only two male patients, it is also possible that the same findings will not appear in larger, more inclusive studies. Clearly, more research is needed to understand exactly how the HIV was affected in these cases and by what means it can be successfully treated.