An HIV-infected man who received stem cell treatment for leukemia from a donor with natural resistance to HIV infection appears to have been cured of HIV, according to a report on the NAM aidsmap website. The treatment, which was carried out in 2007, opens the possibility of a cure for HIV infection through the use of genetically engineered stem cells.

The donor who provided the bone marrow for the transplant had a natural resistance to HIV infection due to the absence of the CCR5 co-receptor from his cells. HIV most commonly uses CCR5 as a “docking station” to enter its target CD4 cells and carriers of a genetic mutation of a portion of the CCR5 gene called CCR5-delta 32 homozygosity have a reduced risk of becoming infected with HIV.

For a period of 38 months after the stem cell transplant the patient continued to receive immunosuppressive treatment to prevent rejection of the stem cells. During this time the donor CD4 cells repopulated the mucosal immune system of the patient’s gut, accompanied by the complete disappearance of host CD4 cells. After two years the patient had the CD4 count of a healthy adult of the same age but no detectable HIV infection.

The case was first reported at the 2008 Conference on Retroviruses and Opportunistic Infections in Boston. Berlin doctors also published a detailed case history in the New England Journal of Medicine in February 2009 and have now published a follow-up report in the journal Blood saying, “It is reasonable to conclude that cure of HIV infection has been achieved in this patient.”

The success of the treatment could pave the way for the development of a cure for HIV infection through the use of genetically engineered stem cells. Due to the success of the treatment, scientists have been trying to coordinate efforts to identify CCR5-delta 32 homozygosity donors to expand the supply of stem cells carrying the genetic mutation, while several U.S. research groups have also received funding to investigate techniques for engineering and introducing these types of stem cells.

The road to a cure hasn’t been easy for the patient, Timothy Ray Brown, a U.S. citizen who lives in Berlin. While dealing with the lengthy and grueling treatment for leukemia he suffered two relapses and underwent two stem transplants. He them developed a serious neurological disorder that led to a bout of temporary blindness and memory problems. He is still undergoing physiotherapy and speech therapy but now appears to be on the road to recovery.

However, in an interview with German news magazine Stern this week when asked if it would have been better to live with HIV than to have beaten it in this way he said, “Perhaps. Perhaps it would have been better, but I don’t ask those sorts of questions anymore.”

Via NAM aidsmap