A new research suggests that the origins of HIV can be traced back millions rather than tens of thousands of years.
HIV, which causes AIDS, emerged in humans in the 20th Century, but scientists have long known that similar viruses in monkeys and apes have existed for much longer.
A genetic study shows HIV-like viruses arose in African monkeys and apes 5 million to 12 million years ago.
The research may one day lead to a better understanding of HIV and AIDS.
The HIV virus affects 34 million people worldwide.
The disease emerged during the 20th century after a HIV like virus jumped from chimps to humans.
Scientists have long known that similar viruses, known as lentiviruses, are widespread in African primates.
Past genetic research has suggested these “cousins” of the HIV-virus arose tens of thousands of years ago, but some experts have suspected this is an underestimate.
Scientists at the University of Washington in Seattle, US, and the Fred Hutchinson Cancer Research Center, also in Seattle, looked at the genetic signatures of HIV-like viruses in a number of primates, including chimps, gorillas, orangutans and macaques.
A genetic study shows HIV-like viruses arose in African monkeys and apes 5 million to 12 million years ago
Changes in genes that have evolved in the immune systems of monkeys and apes in Africa suggest the viruses arose between 5 and 16 million years ago.
The research, published in the journal PLOS Pathogens, gives clues to how the immune systems of our closest relatives evolved to fight infection.
Dr. Michael Emerman of the Fred Hutchinson Cancer Research Center said: “Our study reveals that, while primate lentiviruses may have modern consequences for human health, they have ancient origins in our non-human primate relatives.”
Early results from a US trial suggest it may be possible to use “stem cell shielding” to protect the body from the damaging effects of chemotherapy.
Chemotherapy drugs try to kill rapidly dividing cancer cells, but they can also affect other healthy tissues such as bone marrow.
The study, published in Science Translational Medicine, used genetically modified stem cells to protect the bone marrow.
The body constantly churns out new blood cells in the hollow spaces inside bone. However, bone marrow is incredibly susceptible to chemotherapy.
The treatment results in fewer white blood cells being produced, which increase the risk of infection, and fewer red blood cells, which leads to shortness of breath and tiredness.
Early results from a US trial suggest it may be possible to use "stem cell shielding" to protect the body from the damaging effects of chemotherapy
Researchers at the Fred Hutchinson Cancer Research Center, in Seattle, said these effects were “a major barrier” to using chemotherapy and often meant the treatment had to be stopped, delayed or reduced.
They have tried to protect the bone marrow in three patients with a type of brain cancer, glioblastoma.
One of the researchers, Dr. Jennifer Adair, said: “This therapy is analogous to firing at both tumor cells and bone marrow cells, but giving the bone marrow cells protective shields while the tumor cells are unshielded.”
Bone marrow was taken from the patients and stem cells, which produce blood, were isolated. A virus was then used to infect the cells with a gene which protected the cells against a chemotherapy drug. The cells were then put back into the patient.
The lead author of the report, Prof. Hans-Peter Kiem, said: “We found that patients were able to tolerate the chemotherapy better, and without negative side effects, after transplantation of the gene-modified stem cells than patients in previous studies who received the same type of chemotherapy without a transplant of gene-modified stem cells.”
The researchers said the three patients had all lived longer than the average survival time of 12 months for the cancer. They said one patient was still alive 34 months after treatment.