According to researchers from Lund University in Sweden, they have opened the way for new methods to slow the development of AIDS in HIV-1 infected patients. The authors hope that their study, published in New England Journal of Medicine, can improve treatment methods and preventive measures to fight HIV and AIDS.
HIV-1 is the most common type of the virus that causes AIDS, and when it infects someone who already struggles with the milder HIV-2, it is less aggressive. In this study, the experts examined how the disease developed in people infected with HIV-1 and those who were infected with both HIV-1 and HIV-2.
Joakim Esbjörnsson, a virologist at Lund University, said:
"The moderating effect of HIV-2 was extremely strong. The time it took to develop AIDS was around 50 percent longer for those infected with both strains than for those only carrying the HIV-1 virus. The unusually large difference makes me, as a researchers, very optimistic that it will be possible to identify new and significant approaches that can be taken to combating the development of AIDS."
The unique thing about their research, explained Hans Norrgren, researcher at Lund University and Skåne University Hospital and doctor in infectious diseases, is that not only has the investigation been carried out for more than 20 years, but they have also followed healthy people from when they were first infected with HIV-1, or both HIV-1 and HIV-2, through the development of the disease which allowed them to compare how the infection in each individual has progressed over time.
Investigations showed that there was a difference in the genetic diversity of the HIV that was linked to an early stage of HIV infection. During the development of an infection, different strains of HIV co-exist; and the closer to AIDS the infection gets to, the larger the genetic difference between them.
CD4+ T cells, which are helper cells that play a key role in the immune system that are destroyed by the HIV virus, were also examined. Participants infected with both HIV-1 and HIV-2 had an advantage with these cells. In the course of infection, dual infected patients had a higher number of CD4+ T cells making it take longer to reach low levels of those cells. This meant that it would take longer for the infection to develop into AIDS.
Patrick Medstrand, Professor of Virology at Lund University, said:
"Our results suggest that HIV-2 can activate cellular reactions which naturally check the development of AIDS. If we can map these, I think we can also uncover entirely new mechanisms that are key to the slower development of the disease. In the long run, this could lead to better preventive measures and treatments."
A unique 20-year study of 4,700 infected people in Guinea-Bissau in West Africa lies behind the discoveries.
Fredrik Månsson, a doctor in infectious diseases in Malmö and one of the researchers in the study, explained:
"Our work is the result of many people's work over many years, in particular the staff of the National Public Health Laboratory in Guinea-Bissau and the police health station in the capital Bissau, who have carried out the practical work of examining the study participants, taking samples and conducting laboratory analyses."
Like HIV-1, HIV-2 can also lead to AIDS
HIV-2, the milder strain of HIV, is found on a large scale only in West Africa. More people are infected with HIV-1 than HIV-2, and know that it is more aggressive. However, HIV-2 can also lead to AIDS. Fewer people infected with HIV-2 develop AIDS, and only about 25-30 percent of those who have received no treatment.