Recent data published in Nature Medicine suggest that T memory stem cells express both CD4 and CCR5, and they may be the elusive HIV reservoir that most believe is the key to curing patients of the disease.
The researchers found that these cells can be readily infected with HIV, whereas normal stem cells resist infection. Among patients receiving long-term antiretroviral therapy, the levels of HIV DNA were highest in the T memory stem cells. CD4 T memory stem cells are able to live for decades unscathed while regenerating new, HIV-infected cells.
“Our findings suggest that novel, specific interventions will have to be designed to target HIV-infected T memory stem cells,” Mathias Lichterfeld, MD, of Massachusetts General Hospital and Harvard Medical School, said in a press release. “Methods of inhibiting stem cell pathways are being studied to eliminate cancer stem cells, and we are now investigating whether any of these drugs might be effective against HIV-infected T memory stem cells.”
Lichterfeld and colleagues tested blood samples that were taken from patients soon after initial infection and also several years later. The viral sequences found in T memory stem cells after 6 to 10 years of treatment were similar to those found in the circulating T cells soon after infection. The amount of HIV DNA in the cells also remained stable with time, despite a reduction of the DNA levels in other T-cell subsets.
“Identifying the reservoirs for HIV persistence is a critical step toward developing interventions that could induce a long-term remission without the need for ART, or possibly eliminate the virus entirely,” Lichterfeld said. “Although a real cure for HIV has been elusive, it is not impossible.”
Disclosure: Lichterfeld reports no relevant financial disclosures.