Does the Berlin Patient Hold the Secret for an End to HIV?

In 2009, scientists and researchers announced that a bone-marrow transplant had cured the so-called "Berlin patient" of HIV. At the recent XIX International AIDS Conference, they shared news that two Boston men may have also been cured of HIV, bringing the total number to three worldwide. The unexpected has happened for three HIV-positive people. The question is: how did it happen and what does it mean for people living with HIV?

"Everyone knows about this 'Berlin patient.' We wanted to see if a simpler treatment would do the same thing," Dr. Daniel Kuritzkes told MSNBC. He oversaw the study at Brigham and Women's Hospital in Boston where both men were HIV-positive and had undergone a bone marrow transplant, similar to the "Berlin patient," Timothy Ray Brown. The men had their transplant procedures between two and four years ago and both now have no detectable HIV in their blood. Before declaring them officially cured, doctors will continue to search for HIV in their tissues. At this time, the men both remain anonymous while the study continues.

The basis for this treatment approach began in 2007. Brown, an HIV-positive man from Seattle, WA, was living in Berlin, Germany, and underwent a stem cell transplantation procedure to treat leukemia. His doctor hoped to cure both diseases with a single treatment. And amazingly, the cure appears to have worked. Brown became known as the Berlin patient, the only person in the world to have been cured of HIV. Now the procedure has been repeated for two other HIV-positive cancer patients, and it is possible that they have been cured as well.

Having a stem cell or bone marrow transplant is risky business. Stem cells are the cells in the body that make blood, found in the bone marrow inside bones. When Brown decided to have the procedure, his doctor looked for people with a certain type of cell that would stop HIV. The key in the transplant's success lies in how the HIV virus moves into cells in the body. In order to move from the blood into a cell, where more HIV virus can be made and the infection can take hold, the virus has to attach to a receptor on the cell surface. Most of us have cells that have these receptors.

The bone marrow that was transplanted into Brown was from a donor who did not have the receptor. People without this receptor are rare, but they do exist. To make a long story short: no receptor, no entrance into the cell, no viral infection. As new blood cells were generated by the transplanted bone marrow, they could no longer be infected with HIV.

Even though researchers know that this isn't an approach to be used for the masses, they have continued to explore what it means for HIV treatment. The procedure used for the two Boston men had several significant differences from the procedure used to treat Brown in Berlin. Instead of stopping their anti-HIV medication for the transplant, they continued to take the drugs. But their bone marrow donors did have the receptor that allows HIV to move into cells and begin the infection.

Why, then, has their HIV begun to disappear? It is possible that because these patients were able to keep using their anti-HIV medication, the new cells from the donor did not get infected. And as the donor cells took hold in the patients' bodies, the new blood cells may have killed off the cells that were already infected with HIV.

"Words cannot begin to express my joy that two other men may have been cured of HIV," said Brown, reacting to the news of the two Boston men. His delight is easily understood. The World Health Organization reports that as of 2010 there were approximately 34 million people living with HIV. Clearly, a bone marrow transplant is not an option for most of these patients.

While antiretroviral therapy is the gold standard of treatment world wide, it keeps the virus at bay but does not cure the patient of the disease. Patients can stay healthier, but only as long as they continue their therapy. HIV is a tricky virus. It lurks out of sight in the body, ready to come back as soon as the way is clear. While bone marrow transplantation may not work for everyone, this unexpected success for three patients has provided fresh energy toward finding a cure.

"This gives us some important information. It suggests that under the cover of retroviral therapy, the cells that repopulated the patients immune system appear to be protected from becoming re-infected with HIV," said Kuritzkes in a press release. By studying situations like this, scientists gain a greater understanding of how the virus functions. To paraphrase Sun Tzu and "The Art of War," only if we know our enemy and ourselves can we win the battle.

It is frustrating to be part of a community that has been affected so deeply by a disease and still see scientists struggling to find a cure. While recent attempts may not represent a cure that can affect the millions living with HIV, they do represent a significant step forward both in hope and in understanding. Modern medicine is a process of discovery that involves creativity, dedication and unexpected breakthroughs.

"My dream is to not be the man who stands before you and says 'I am cured', but to be the man who stands before you and says, 'We are cured'," said Brown on his website. Let's hope that the people leading HIV research will, through that dedication, find a cure that can help make Brown's dream a reality.