|
A counterintuitive way to fight a chronic infection linked with meningitis - by damping down the immune system - could have wider uses in tackling Aids and hepatitis. Scientists have found that a drug that traps white blood cells that fight disease can, paradoxically, lead to the clearance of a chronic infection by a virus linked with one form of meningitis. Their findings, published in the journal Nature, suggest a new strategy for fighting chronic viral infections that could apply to the treatment of important diseases such as hepatitis C and B, and also HIV/AIDS. The work, reported today in the journal Nature, comes as a surprise because disease-fighting white blood cells vanish from the blood usually signals a weakened immune system. But preventing white blood cells' circulation by trapping them in the lymph nodes can help mice get rid of a chronic viral infection, researchers at Yerkes National Primate Research and Emory Vaccine Centres have found.
The team's discoveries grew out of their study of two varieties of a virus that causes meningitis in mice, says senior author Dr John Altman, who did the work with Drs Mary Premenko-Lanier and Sarah Pruett, with students Nelson Moseley and Pablo Romagnoli. The clue to this unusual find came when they noted that mice which can can fight off infection by the lymphocytic choriomeningitis virus (LCMV) are vulnerable to chronic infection by one variant of the virus and work revealed that the reason was to do with how the less harmful strains led to white cells becoming trapped in the lymph nodes of infected animals. His team turned to an experimental drug called FTY720, also known as fingolimod, which prevents white blood cells from leaving lymph nodes. And, indeed, mice treated with the drug were able to get rid of the harmful strain. However, the reason that trapping white blood cells makes the body more effective at fighting infection is not known. Dr Altman says he and his co-workers are planning to test FTY720's effects with other viruses. As for when tests would begin, Dr Altman said "We try to be cautious and not excite too much premature enthusiasm among people suffering from diseases such as hepatitis C and HIV/AIDS." FTY720 has already been tested in human clinical trials for treating autoimmune diseases, when the body's immune system turns on itself, and preventing tissue transplant rejection because, by trapping white blood cells in lymph nodes, the drug keeps the cells away from the sites of disease. LCVM was among the first human pathogenic viruses to be isolated by medical researchers in the mid-1930s. It is one of about 20 members of the virus family Arenaviridae, each one of which in nature infects a separate rodent species that spreads the virus but causes minimal or no overt disease in the rodent host. Most human infections with LCMV result in a mild to moderate viral meningitis, but in immuno-suppressed patients such as those receiving kidney transplants it causes a severe disease that resembles a related arenavirus disease from Africa called Lassa fever. http://www.telegraph.co.uk
 |
News 
Subscribe to this comment's feed