Two years later, two more men once diagnosed with human immunodeficiency virus (HIV) and lymphoma seem to be free of both.

Though doctors are treading lightly when declaring both patients HIV free, the virus cannot be detected displaying parallel traits of Timothy Ray Brown, also known as the "Berlin patient," the only person known to be cured of HIV.

After hearing about the success of Brown's stem cell transplant for leukemia, Dr. Timothy Henrich and colleagues at Brigham and Women's Hospital in Boston, associated with Harvard Medical School, began a search to find HIV patients with leukemia or lymphoma, who had received a bone marrow stem cell transplant. The bone marrow is the key foundation of the body's immune system cells that HIV infects and it is the expected region for physicians to look for HIV's reservoirs.

After being referred to the two patients by Dana-Farrber Cancer Institute in Boston, which is also associated with Harvard Medical School, Dr. Henrich learned both men endured multiple rounds of treatment for lymphoma, including stem cell treatments, all while continuing their HIV medications—which  turned out to be the key.

According to Dr. Daniel Kuritzkes, also of Brigham and Women's Hospital, prior to the transplant HIV DNA was present in both patients. During the transplant, the patients' cells were replaced by donor cells. Doctors suspect the donor cells killed off and replaced the disease-ridden cells.

For patient one, he has been free of the virus for two years and patient two has been free of the virus for three-and-a -half years.

The question many researchers, experts and doctors alike are currently asking is: Can the patients be told they are cured?

For now, Dr. Kuritzkes has reassured the public that both patients are continuing their AIDS medication, until they can be taken off under experimental conditions.

This study was presented at the International AIDS Conference in Washington, D.C., organizers of the conference are optimistic about what this discovery could mean