Dr. Gero Hutter in a press conference in Germany

The strange story of new hope for AIDS patients begins with a 42 year old man living in Berlin who is currently fighting off his leukaemia. As a part of his leukaemia treatments, his haematologist, Dr. Gero Hutter, deliberately replaced the patient's bone marrow cells with those from a donor who has a naturally occurring genetic mutation making his cells immune to almost all strains of HIV, the virus that causes AIDS.

Long ago, researchers discovered that some people remain uninfected despite continuously engaging in unprotected sex with HIV-positive partners. They were found to have a genetic mutation that made them practically immune to HIV. This mutation prevents a molecule called CCR5 from appearing on the cell membrane. In normal people CCR5 functions as a door letting the virus into the cell, because the HIV virus must bind with it to get inside.

Dr. Hutter recalled all the research done on the CCR5 gene and then recommended standard second-line treatment: a bone marrow transplant. But instead of choosing a random donor, he specifically chose a donor who had inherited the CCR5 mutation from both parents. Immune cells are created in the bone marrow, so theoretically, if the patient’s marrow is destroyed prior to the transplant, the new mutant bone-marrow cells could make the patient immune to HIV. The patient was ordered to stop taking AIDS drugs when the donor cells were being transplanted because the drugs may have endangered the new cells' ability to survive. The plan was to put the patient back on the drugs when the HIV returned to the blood cycle.

Surprisingly, this did not happen. Nearly two years have passed, but no standard tests have yet discovered the virus in the patient’s bloodstream, brain, or any other tissue.

This seems magical, yet this sort of treatment cannot be implemented in all HIV patients. The transplant treatment which is only given to late-stage cancer patients causes 30% of them to die. This mortality rate will prevent the treatment from being used on AIDS patients who do not have cancer. Additional issues may lay with the HIV virus' ability to evolve and mutate on its own – if enough time goes by, it might overcome the mutant cells' invulnerability. Another concern is the possibility that blocking CCR5 in patients may have unknown side effects such as increased susceptibility to various diseases.

Scientists might also try and implement their new gained knowledge using gene therapy techniques. They may be able to re-engineer a patient’s cells using gene therapy, and while many technical obstacles need to be overcome before this can happen, room for optimism remains.

TFOT has recently covered several other HIV related research studies, including the natural protein that prevents HIV from spreading, discovered by scientists at the Rockefeller University. We've also covered a discovery made by scientists from the Gladstone Institute of Virology and Immunology - a gene that may influence the production of antibodies that neutralize HIV.

For more information on the AIDS/bone marrow case please visit the original article on the Wallstreet Journal.