Mississippi babies AIDS virus forms reservoirs

HI virus apparently nests in certain tissue types in the body

07/22/2014

Sobering findings in the fight against the dangerous human immunodeficiency virus (HI virus), the trigger of the immunodeficiency syndrome AIDS. As US researchers at Harvard Medical School in Boston have found out, the virus apparently forms directly after infection in the body so-called „reservoirs“ - which, however, can not be achieved by the current medicines. Accordingly, a cure could be made more difficult again.

Animal experiments with the „Simian immunodeficiency virus“
If it comes to an infection with the Human Immunodeficiency Virus (HI virus), this nests apparently in no time in the human body - unattainable for currently available HIV drugs. To this result is now an American researcher team through animal experiments with the so-called „Simian immunodeficiency virus“ (Short: SI virus), which is considered a precursor of the HI virus and leads to AIDS-like diseases in monkeys.

Inactive pathogens only detectable after implantation in tissue
As the scientists around the virologist James Whitney from Harvard Medical School in Boston (Massachusetts) in the journal “Nature” report, would make the healing of the virus by the pathogen reservoirs in the human body considerably. The reason: Although the inactive pathogens had quickly established themselves in the tissue after infection in the animals, they were later detected in the blood. Accordingly, although the virus multiplication in the body can be slowed down by a medicamentous antiretroviral therapy (ART) - but since the pathogens could survive for years in the reservoirs, these would immediately spread again after the end of the treatment.

By antiretroviral therapy, amount of viruses in the blood can be lowered first
For these findings, the scientists had infected rhesus monkeys with the simian immunodeficiency virus (SI virus), a retrovirus, which is considered to be the virus of origin for the HI virus and, according to recent research, appears to have been found among monkeys for millennia. Although the virus was not yet detectable in the blood, some of the animals were given antiretroviral therapy as early as the third day, the other animals only seven, ten or 14 days after the infection. The treatment was conducted over six months, allowing the researchers to reduce the amount of virus in the blood in all monkeys below the detection limit of six RNA copies per milliliter of blood plasma.

Relapse sets in later treated monkeys later
But the „cure“ Did not last long, because after the treatment was stopped, the number of pathogens in all animals increased again. Conspicuous: The relapse in the monkeys treated from day 3 started a little later than in the others, which may be due to the researchers that the inactive viruses could survive in the mucosal tissue and in the lymphatic tissue: „These data show that the virus reservoir is rapidly established after intrarectal SIV infection by rhesus monkeys, even during the "Eclipse" phase and before the presence of viruses in the blood“, the researchers write in the journal „Nature“.„However, it remains unclear when and where the virus reservoir develops during the acute infection and to what extent it is susceptible to early antiretroviral therapy (ART).“, the scientists continue.

Important new challenges for strategies to combat HIV-1
This could possibly also the re-emergence of HI viruses in the so-called „Mississippi Baby“ be explained. In this case, an HIV-infected baby in the United States was initially healed as functionally cured after intensive early-onset therapy. But after two years without medication and in which no viruses could be detected in the girl's body, the pathogen had suddenly returned a few days ago. According to the scientists, the results could be considered as sobering in the fight against the HI virus - even if the SI and HI viruses differ significantly and the animals were also infected with a high dose. „This strikingly early generation of pathogen reservoirs represents important new challenges for the strategies to combat HIV-1“, the researchers continue. (No)