Scientists are proceeding cautiously, but it appears two patients may have been cleared of HIV after bone marrow transplants for lymphoma.

Two men received transplants several years ago at a hospital in Boston, throughout the transplants and recovery the patients took anti-retroviral medication. Now following extensive testing, they have both been able to stop taking formerly life-saving AIDS medicines. One patient has reportedly been free of signs of HIV for over seven weeks, the other has seemingly remained HIV-free in the 15 weeks since he went off his medication.

“While these results are exciting, they do not yet indicate that the men have been cured,” said Timothy Henrich, one of the Boston doctors who treated the patients, “long-term follow up of at least one year will be required to understand the full impact of a bone marrow transplant on HIV persistence... these findings clearly provide important new information that might well alter the current thinking about HIV and gene therapy.”

The bone marrow therapy undergone by the two recent patients bears a striking resemblance to the treatment that rid “the Berlin Patient” as he is known of HIV over five years ago. It is not a option that will be extended to ordinary HIV patients as it is extremely painful and carries a 15 per cent chance of death.

HIV often hides in bone marrow cells; researchers speculate that once the transplanted bone marrow cells replaced the patients’ original cells, the anti-retroviral drugs kept the new cells from becoming infected.