Viral Russian Roulette
What do schizophrenia and multiple sclerosis have in common? A retrovirus.
Discover magazine reports (Douglas Fox, "The Insanity Virus," June 2010) that a virus that most of us carry in our DNA may be the underlying cause of many chronic, incurable conditions and diseases, including bipolar disorder, schizophrenia and multiple sclerosis.
Psychiatrist Fuller Torrey, director of the Stanley Medical Research Institute in Maryland (USA), and colleagues have uncovered evidence that a retrovirus, now dubbed HERV-W (human endogenous retrovirus W), may be at the root of a host of chronic, debilitating diseases. HERV-W appears to be common in our DNA, although most of us can rely on our immune systems to keep it in check. For some of us, however, the virus is able to switch on and raise an immune response that eventually becomes toxic, resulting years later in diseases as diverse as MS or bipolar disorder.
Until Torrey and his colleagues' discovery, many scientists had searched for a viral component to MS and other chronic diseases, and although they found people with these diseases had antibodies to a viral agent in their blood and brains, no actual live viral agent was ever found. Now we know why-it has been hiding in our DNA. Unlike other kinds of viruses, a retrovirus infiltrates cells and inserts itself into the DNA, allowing the cells to live. Our immune systems manufacture proteins that bind these infected strands of DNA, effectively rendering the retrovirus harmless. However, the theory is that repeated childhood infections by particular viruses, and the resulting immune system inflammation, weaken this defense, until eventually, in some of us, the HERV-W virus begins to do its insidious damage.
The root of the problem is a kind of viral Russian roulette that starts at birth (and perhaps even before) or in early childhood: The mother or newborn contracts one or more of certain common infections, such as influenza, herpes, or toxoplasma. As a result, the newborn's immune system goes on high alert, releasing many kinds of disease- and inflammation-fighting cells. The newborn's immune system can quickly become overloaded and turn toxic, leaving the child with a comprised immune system. Long-term immune system inflammation and repeated viral infections over the years appear to set up the conditions for the HERV-W retrovirus to switch on, attacking the body and causing damage that ultimately expresses itself as MS, bioploar disorder, schizophrenia, depending on the types of cells and tissues that are affected.
Other immune genes, called human leukocyte antigens, which help our bodies detect invading pathogens, are also implicated. Environmental stressors also may play a role in the cycle, helping to explain the seasonal cycle of symptoms in some of these diseases and the waxing and waning of symptoms in others.
Certain treatment approaches are showing promise in early clinical trials. For instance, one company in Geneva, Switzerland, has devised an antibody to neutralize certain of the implicated viral proteins. After injecting the antibody in rats with MS symptoms, researchers saw a "dramatic stop" to the process that causes demyelinating brain lesions. These lesions are a classic indicator of MS. It's too soon to tell when a new class of drugs or other clinical treatments will reach the general public, but this new evidence and the immune compromise theory that underlies it has ignited research into the role of HERV-W in several otherwise baffling and currently incurable diseases.
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