Big news no matter the circumstances, but in case you stumble across the headline elsewhere and are tempted to think it’s a major breakthrough, I recommend reading this excellent Fox News piece for perspective. The good news, obviously: An HIV-positive patient who was treated for leukemia more than three years ago shows no signs of the virus in his system to this day. Doctors can’t be completely sure that trace amounts aren’t lying dormant somewhere in his body, but as far as they’re able to measure, it’s all gone. He’s the first patient on record to be completely cured.

The bad news: Basically everything else.

The transplant appeared to wipe out both diseases, giving hope to doctors, but Dr. Anthony Fauci, director of the National Institutes of Allergy and Infectious Diseases, who has been studying HIV/AIDS for almost 30 years, said while this is an interesting proof of concept, it’s absurdly impractical.

“It’s hard enough to get a good compatible match for a transplant like this,” Fauci told FoxNews.com, “But you also have to find compatible donor that has this genetic defect, and this defect is only found in 1 percent of the Caucasian population and zero percent of the black population. This is very rare.”…

“This is not prime time to me at all,” he said. “This is a very unusual situation that has little practical application for a simple reason. This donor not only had to be a good compatible match, but the donor had to have a genetic defect of cells that do not express the receptor that the HIV virus needs to enter the cell.”

Fauci also pointed to the fact that this transplant process is not only expensive, it’s incredibly painful and complicated, and requires the patient to start a whole new regimen of drugs.

This was no simple matter of a series of injections. We’re talking about a full bone marrow transplant, described by the Health News article linked above as “essentially rebooting the body’s immune system and creating new white blood cells.” As with any transplant, not every donor is a compatible match for every patient, not every compatible match is willing to donate, and needless to say, not every compatible donor will carry the freak HIV-resistant genetic mutation needed to cleanse the patient’s system of the virus. So you’ve got three high bars to clear right there to “cure” someone; factor in a fourth, that the procedure is expensive and time-consuming, and this looks more like an intriguing lead than something replicable on a wide scale.

Incidentally, it’s not news that some people carry a rare gene that renders them essentially immune from certain fatal diseases. If you’ve ever seen the Black Plague episode of “Secrets of the Dead” — which was the best show evah — you already know that certain European villagers during the Middle Ages inexplicably survived the Black Plague while dozens of people around them were wiped out. HIV researchers took samples from the descendants of those survivors and found an unusually high occurrence of a mutation of the gene CCR5 — which, per the Health News article, just so happens to be the same gene involved in today’s “cure” case. Hmmmm.