The Autoimmune Epidemic: Bodies Gone Haywire in a World Out of Balance--and the Cutting-Edge Science that Promises Hope (No Series) (21 page)

How vaccines spark autoimmune disease and how large a role they may play in setting the disease in motion in combination with other triggers is still an open question, however. Yet as researchers begin to delve more into this troubling correlation with newer lab techniques that allow them to trace antibodies back to the very thing that made them overproliferate in the first place, the answers they come up with may prove increasingly tricky for individual physicians, parents, and patients to grapple with.

Meanwhile, in a larger societal sense, whether vaccines pose a significant enough risk to question their widespread use remains, at best, a philosophical quandry, since nationalized immunization programs protect the masses against a number of devastating diseases and do it quite efficiently, whereas autoimmune disease due to vaccination has not been shown to afflict overwhelming numbers of children and adults. In any risk-benefit analysis, the numbers of lives saved from vaccines far outweigh the numbers of people who react by developing autoimmunity. Still, this is little comfort for the parent whose child goes in for his Haemophilus influenzae type b vaccine and ends up with a disease as devastating as childhood diabetes before the age of seven.

All this points to a more important mystery that has yet to be solved. Why don’t more people who experience common infections or who receive vaccines get sick? Why aren’t all 25 percent of people who have a genetic predisposition to autoimmunity falling ill as a result of molecular mimicry? Why does a viral hit cause the immune system to make such a monumental gaffe in some people and not others?

THE ROLE OF HEAVY METALS

It’s important to remember that there are multiple factors involved in the onset of autoimmune disease. Each of us has a different genetic susceptibility to autoimmunity, and we each also carry very different degrees of genetic ability to withstand the onslaughts of chronic toxic autogenic hits from the day-to-day environment in which we live. And that individual difference directly impacts how compromised our immune system becomes over time. The more compromised our system becomes, the more likely our immune cells are to become confused and overwhelmed, so that when we do meet infectious viruses or bacteria, mistakes can all the more easily happen.

To grasp how genetics, toxic agents, viruses, and vaccines become interlocking forces that can kick-start autoimmunity, we have to remember how environmental hits and chemicals can tax the immune system through long, slow, and continual environmental exposures—priming the pump, so to speak, so that the now proverbial barrel sloshes dangerously close to its brim and viruses can all the more easily “spill” the immune system over the brink.

Recent studies into how differently individuals process one particular autogen, the heavy metal mercury, bear this out all too perfectly. In the past decade, scientists in the field of autoimmune-disease research have become particularly concerned about mercury for two reasons—first, its increased ubiquity in our environment, and second, a stack of recent data proving that even low-level exposure to mercury, especially in people who are more genetically prone to develop autoimmunity, directly impairs the delicate balance of the immune system, playing a kingpin role in predisposing them to autoimmune disease.

Mercury, in one of its forms, thimerosal, is still used in some flu vaccines and some over-the-counter pharmaceuticals. Present until recently in virtually every vaccine children received throughout the 1990s, including hepatitis B, bacterial meningitis, diphtheria, whooping cough, and tetanus, thimerosal is now the subject of a well-known heated controversy questioning whether cumulative doses in childhood vaccines may play a role in autism and other developmental delays. While the thimerosal debate is best covered by authors focusing solely on investigating those claims, mercury in general, and mercury in vaccines in the form of thimerosal, are nevertheless pertinent to our discussion as to how an autogen can influence how fast or furiously an individual’s barrel fills to reach the onset of disease.

Our most significant exposure to mercury comes, as adults, from the air we breathe and the food we eat—especially from larger fish. Like all environmental toxins, mercury accumulates up the food chain. (The tiniest fish are consumed by bigger fish, which are eaten by large swordfish and tuna, so that by the time the tuna consumes his dinner, he’s packing in all the mercury ingested by the smaller creatures.)

How did so much mercury get into the oceans and lakes to be consumed by fish in the first place? Since the advent of the industrial age, the atmospheric burden of mercury in our environment—meaning the amount falling from the sky from waste from coal combustion, incineration, mining, coal-fired utilities, and industrial boilers—has tripled. In the United States, coal-fired power plants alone spew about fifty tons of mercury into the air each year. Dry particles of mercury travel effortlessly in effluent clouds across the American landscape—migrating from coal-burning power plants in the Midwest to points often thousands of miles away, where they literally rain out of the sky in what environmentalists commonly refer to as “mercury polluted rainstorms.” Once mercury particles shower to earth, they lace every acre, from forest floors to neighborhood parks to rippling ocean waves.

To measure how much mercury exists in our day-to-day environment, researchers tested mercury levels in fish, birds, and mammals across remote areas of New England and found that even animals far from industrialized cities carry disturbingly high amounts of mercury in their bodies, mercury that could be specifically traced back to power plants thousands of miles away in the Midwest. That’s telling to scientists, because it means even supposedly pristine air, water, and food sources—including those on seemingly distant mountaintops of New England—are already highly contaminated from mercury fallout.

Mercury finds its way into our bodies from other, more direct sources, of course, such as industrial waste releases and toxic spills. Today, the National Library of Medicine’s
TOXMAP
site lists a combination of 1,432 known current sites and 431 Superfund locales nationwide where mercury or mercury compounds have been released or leaked. All these external sources add to the burden of heavy metals we already carry in our bodies. According to the Centers for Disease Control, 12 percent of women of childbearing age now have mercury levels that exceed the Environmental Protection Agency’s safety standard. The 10 percent of women with the highest mercury levels tend to live in coastal areas, especially along the Atlantic coast, and carry body burdens of mercury at 5.9 parts per billion, way over the 3.5 parts per billion limit the EPA cites as a known health threat. Meanwhile, a 2007 New York City Health and Nutrition Examination Survey recently reported that a quarter of adult New Yorkers have elevated blood mercury levels. Similarly, in 2004, a study conducted jointly by the Environmental Quality Institute at the University of North Carolina at Asheville and Greenpeace analyzed women’s hair samples (one of several scientific means of testing for heavy metal exposure) and found that 21 percent of women of childbearing age have mercury levels higher than the EPA’s safety limit of 1 microgram of mercury per gram of hair.

This is no small thing: researchers know that mercury can cross the placenta and affect the developing brain of the fetus. Mercury, like lead, is a potent neurotoxin. EPA scientists estimate that one in six infants born in the United States is now at risk for developmental disorders because of exposure to mercury while in the mother’s womb. Mercury can accumulate in the umbilical-cord blood of pregnant women at a level that’s 1.7 times as great as the concentration in the mother’s blood itself. That means that a newborn’s mercury level might reach 5.8 parts per billion in a mother whose mercury concentration is just 3.5 parts per billion—at a particularly dangerous time in fetal brain development. Recently, researchers found that low levels of mercury can target critical stem cells in the brain that are essential to the growth and development of the central nervous system and cause them to prematurely shut down, especially when exposures happen during critical development periods like fetal growth and early childhood.

THE GENES-MERCURY DANCE

One of the major players in today’s cutting-edge research on how low-level exposures to mercury can directly stimulate autoimmunity or accelerate the disease is Kenneth Michael Pollard, PhD, associate professor in the Department of Molecular and Experimental Medicine at the Scripps Research Institute in La Jolla, California. For the past twenty years, Mike Pollard and his colleagues both at Scripps and at Linköping University in Linköping, Sweden, have been exploring how the interplay between genetics and mercury influences whether one will develop autoimmune disease—as well as how mercury stimulates autoimmune disease in some genetic groups more than others.

Pollard, a fifty-five-year-old native of Australia, is the author of sixty scientific papers, an international conference presenter, and has participated on six National Institutes of Health committees. He has made a career both in Australia and in California, investigating the way mercury influences the function of different sets of proteins in human body tissue and leads to autoimmune disease. Inside Pollard’s molecular laboratory at Scripps, the California sun beating down outside seems as remote as that on a tourist postcard; all one can hear is the hum of freezers that hold tissue samples and occasionally the sound of mice running through the sawdust of their cages. Pollard’s quest is to understand the effects of mercury on human biology, and on the autoimmune process in particular. As the average body burden of mercury that Americans carry increases by the year, Pollard’s mission “to prevent mercury exposure from leading to disease in the first place” has become all the more pressing.

Various types of mercury—elemental mercury, inorganic mercury, methyl mercury, and ethyl mercury (a by-product of thimerosal)—all affect people differently because they are metabolized by the body differently. Elemental mercury is the type that you find in dental amalgam. People who have fillings with dental amalgam can build up body burdens of mercury because, over time, mercury from their teeth leaches into the body and accumulates in the kidneys. Although a recent 2006 Food and Drug Administration report concluded that mercury dental fillings are safe, an expert panel for the FDA rejected that agency report only a week later. Panel members complained that the report excluded some important studies, making it impossible to reach a clear answer as to whether fillings are safe, especially for pregnant women and children. They concluded that far more study was required. Meanwhile, in the field of autoimmune-disease research, studies tie abnormal amounts of heavy metals such as mercury to scleroderma, with other research relating having a high number of dental fillings to one’s likelihood of developing scleroderma. One recent case-control study reported that severely affected scleorderma patients were more likely to have higher levels of mercury in their urine.

Methyl mercury, an organic mercury, is the form that’s commonly found in fish. Methyl mercury passes readily from the human gut to the bloodstream and into all organs and tissues. For reasons not yet completely understood, methyl mercury exposure does particular damage to the central nervous system. Once inside the body, some of that methyl mercury is converted into an inorganic form that can fasten on to and disable many of the cellular proteins and enzymes essential to cellular function. This inorganic form of mercury is the same type of mercury that Pollard is using in his experiments. Inorganic mercury is the major form of mercury that accumulates in the kidneys—and has been found to induce autoimmune disease in many different inbred strains of laboratory mice. Even low-dose mercury exposure increases the severity and prevalence of autoimmune myocarditis in mice.

“When you ingest fish that has mercury in it, that mercury is more highly reactive in the body than many people realize,” says Pollard, who is also the editor of a new book for scientists,
Autoantibodies and Autoimmunity,
a comprehensive look at the latest research on autoantibodies in autoimmune disease. Investigations by a number of researchers show that mercury reacts with proteins in the body by combining directly with body tissue. This interaction of mercury with the protein sequences that make up our body tissue changes the actual structure of these proteins. The result is a heavy-metal plus body-cell amalgam—an utterly new complex hybrid that is astonishingly part heavy metal, part body tissue. Not surprisingly, this half-human, half-heavy-metal complex, which sounds a bit like something out of a sci-fi movie, is wholly foreign to our bodies.

You might logically assume that the immune system now reacts against this new hybrid protein and, in the process of trying to destroy it, also destroys the organs and tissue of the body itself. But what Pollard has found in lab animals exposed to mercury is that the actual autoantibodies produced against the mouse’s own body tissue form not against these new hybrid proteins but directly against the mouse’s pure, unadulterated body tissue. Somehow, mercury produces such a potent response in the body that it not only creates these surprising hybrid proteins, it also forces the immune system, in a process not fully understood, to react against pure body tissue. But this damage does not necessarily happen in the same part of the body where mercury exposure first occurred. Pollard points out that “although we are exposing mice via injection under the skin, and getting inflammation there, the autoimmune response occurs in more distant tissues such as the kidney.” It’s almost as if the immune system is so traumatized by trying to figure out what to do with these different protein sequences—those from the mercury–body tissue hybrid and those that exist in the body’s own pure tissue—that immune cells moving through the body can no longer determine which is safe and which is harmful. They can attack the wrong target in the body anywhere.