For many years, HIV was among the most feared diseases in the world. Getting it was essentially a death sentence, and that death was especially unpleasant.

Fortunately, there have been quite a few treatments that have been developed over the years, which give those with HIV great hope. The immunotherapy treatments can, when taken properly, eliminate virtually all symptoms and allow the patient to live a largely normal life.

It is important to note, however, that this type of treatment is not a cure. If the patient ever stops taking the prescribed drugs, the HIV can quickly come back.

One of the only diseases that is more frightening than HIV is cancer, so when Timothy Ray Brown, who had HIV for years, was diagnosed with myeloid leukemia, a type of cancer, it was initially thought of as some incredibly bad luck.

The doctors treated the cancer with two stem cell transplants. Unexpectedly, they found that his HIV was gone.

Not just in remission from HIV medication, but actually gone. Cured. Even with no other medication, it would not return.

Needless to say, his case was looked at closely, and the researchers found that the stem cell donor carried a rare genetic mutation on both versions of the gene that produces the CCR5 receptor. The CCR5 receptor is a protein that is found on the surface of many different types of immune cells.

In normal people, the receptors are of a size that allows the HIV virus into them, causing problems. For those with the mutation, however, the receptors are too small for HIV to get in, making them functionally immune to HIV.

The shocking thing is that when a patient with HIV is given a stem cell transplant from someone with this rare genetic mutation, that immunity passes on, curing the HIV.

The seventh patient to be cured from HIV in this way was another surprise for doctors. The donor in this case only had one of the two CCR5 receptor genes with the HIV immunity. So, it was not expected that this would be enough to cure the HIV (the treatment was given for his cancer).

The patient also had one of two CCR5 receptors with this mutation. So, researchers believe that it may be sufficient for two of these genes in total, one from the patient and one from the donor, to cure HIV. If this turns out to be true, it would make a cure much more likely since finding someone whose stem cells are compatible and who has the necessary mutations would be much easier.

At least for now, this cure is not a standard treatment for those with HIV because stem cell transplants are very expensive and very difficult to find donors who match. The fact that less costly and easier to make medications can keep HIV in remission means that the need for this cure isn’t as strong.

For now.

This latest case, which was published in Nature, may eventually lead to a time when a true cure for HIV could become the standard. With a one-time treatment rather than a lifetime of medication, it would certainly be preferable in many situations.

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