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Can a Bone-Marrow Transplant Halt HIV?
November 13, 2008 Health and the Environment No Comments
Human Immunodeficiency Virus (HIV) is a pathogen so wily and protean that
researchers rarely talk about “curing” infected patients, focusing instead
on treatment or prevention. But in an announcement that caused a flutter of
excitement and a wave of prudent skepticism, Berlin-based hemotologist Gero
Huetter claimed Thursday that he has cured a 42-year-old man of an HIV infection through a
bone marrow transplant.
The patient, an American citizen living in Germany, was suffering from
advanced leukemia and HIV two years ago when Huetter decided to treat the
cancer with a bone marrow transplant at Berlin’s Charité hospital. As a
side experiment, he inserted the bone marrow of a donor naturally resistant
to HIV, the virus that causes AIDS. (Researchers have long known that about
1% of Europeans carry a genetic mutation that makes their cells resistant to
HIV infection.) Bone marrow produces the cells that HIV attacks. So, the
thinking went, inserting marrow that produces HIV resistant cells might
endow the patient with a means to repel the infection. Twenty months after the
transplant, Huetter says, the man shows no signs of carrying the virus. (See stories of people surviving with HIV.)
So is this a viable cure for HIV? Not by a long shot. Even Huetter says that
bone marrow transplants, which kill around a third of patients, are so
dangerous “that they can’t be justified ethically” in anything other than
desperate situations like late-stage leukemia. Nor is it clear that
Huetter’s claim to have cured his patient is yet justified. HIV has a
frustrating ability to hide in hard-to-detect “reservoir” cells in various
parts of the body. Current anti-viral drugs, for example, can lower a
patient’s “viral load” to the point that HIV is undetectable in his or her
bloodstream. But as soon as such patients are taken off anti-virals, the
virus comes storming back.
Huetter’s patient has not received anti-virals for two years, and remains
virus-free even in the known HIV-hiding spots of brain and rectal tissue,
according to Huetter’s tests. But many researchers remain skeptical as to
whether these tests have been thorough enough. Dr. Andrew Badley, director
of the HIV and immunology research lab at the Mayo Clinic, told the
Associated Press, “a lot more scrutiny from a lot of different biological
samples would be required to say it’s not present.”
But there might be a glimmer of hope in the case. If the transplant does
prove to have been a success and can be replicated, researchers say gene
therapists might one day be able to re-engineer a patient’s cells in such a
way so as to change their bone morrow in the same way as a transplant,
except without the dangers. Such a breakthrough, if it proves possible at
all, would be “decades rather than years away,” according to Ade Fakoya, a
London-based clinician and senior advisor to the nonprofit Aids Alliance.
The treatment would also likely prove too expensive to implement in
developing countries where HIV rates are highest, although some proponents
of gene therapy say it could eventually be done cheaply through an
injection, like a vaccine. (Read a TIME cover story on AIDS.)
