Stem Cell Transplant From CCR5 Delta32 Donor Controls HIV Infection

NEW YORK (Reuters Health) Feb 11 - A case report published in The New England Journal of Medicine for February 12 illustrates the key role that chemokine receptor 5 (CCR5) plays in sustaining HIV infection, and shows how stem cell transplantation can exploit the CCR5 requirement to achieve long-term control of infection.

For a cell to become infected with HIV-1, both a CD4 receptor and a chemokine receptor, primarily CCR5, are needed. Prior research has shown that a homozygous 32-bp deletion in the CCR5 allele confers high resistance against HIV-1 acquisition.

In the current study, Dr. Hutter's team treated a patient with HIV infection and acute myeloid leukemia by transplanting him with stem cells obtained from an HLA-matched, unrelated donor who was homozygous for CCR5 delta32.

The 40-year-old patient had been diagnosed with HIV infection 10 years earlier and had been treated with highly active antiretroviral therapy for the last 4 years with no AIDS-defining illnesses. Stem cell transplantation was performed when the patient's leukemia relapsed, 7 months after presentation.

"Throughout the follow-up period, serum levels of HIV-1 RNA remained undetectable," the researchers report. Twenty months after transplantation and with discontinuation of antiretroviral therapy, the patient showed no viral rebound and was in complete remission of the leukemia, the report shows.

In a related editorial, Dr. Jay A. Levy, from the University of Southern California, San Francisco, comments that the current case report "could pave the way for innovative approaches that provide long-lasting viral control with limited toxicities for persons with HIV infection."

N Engl J Med 2009;360:692-698,724-725.