Human Immune Systems May Be Pollution Victims

Deep in the Canadian Arctic, the native Inuit live on permafrost so thick they must rely upon the bounty of the icy blue sea. Like their ancestors a millennium ago, they hunt the whale, seal and trout they call “country food.”

Life seems unspoiled in the polar wilderness a thousand miles from the nearest industrial center. But in reality, these Arctic people carry in their bodies the world’s biggest loads of immune-suppressing pollutants--mirroring the poisons found in whale blubber.

Inuit mothers probably are passing damage to their infants through their wombs and breast milk. Born with depleted white blood cells, the children suffer excessive bouts of diseases, including a 20-fold increase in life-threatening meningitis compared to other Canadian children. Their immune systems are so dysfunctional that they sometimes fail to produce enough antibodies even to react to the usual childhood vaccines.

The plight of the Inuit illustrates the hidden danger that environmental pollutants seem to pose to the human body’s vital defenses for fighting off disease.

New scientific findings suggest that contaminated water, food and air seem to be suppressing people’s immune systems, lowering their resistance to viruses, bacteria and tumors they otherwise could have fended off.

Around the world, people routinely encounter industrial compounds and pesticides that deplete the immune cells of marine mammals and laboratory animals at fairly small doses. The most ubiquitous and persistent ones--polychlorinated biphenyls (PCBs), DDT and dioxin--are believed to be carried in the tissues of every living thing on Earth.

For most healthy people, a slight drop in immunity caused by the pollutants carried in their bodies merely could mean they catch the flu more often or stay sick a bit longer. But for vulnerable newborns or the chronically ill--especially those with the AIDS virus or other immune deficiencies--it could seriously compromise their health, immune experts say.

“We’re probably all--and I mean the whole doggone planet--immunosuppressed,” said Steve Holladay, an immunotoxicologist at Virginia-Maryland Regional College of Veterinary Medicine. “Simply, it means we’re not quite as healthy as we could or would be. Our risk of developing [diseases] is slightly higher.”

Also, in an unusual twist that only recently has captured the attention of experts, some chemicals, rather than suppressing the immune system, accelerate it--triggering an array of often-crippling and mysterious autoimmune disorders. Immune cells go haywire, attacking the body’s own healthy tissue in a false notion that they detected a foreign invader.

In recent years, lupus and other autoimmune diseases have increased internationally and seem to have popped up in extraordinary clusters in communities tainted with toxic chemicals--most notably the sleepy, sun-baked border town of Nogales, Ariz.

“To tell you the truth, it scares the hell out of me,” said Anna Acuna, one of many longtime Nogales residents afflicted with lupus. “It frightens me when I see young people diagnosed, it frightens me when I see mothers incapacitated. I think of us as being on the cutting edge of something that is happening all over the world.”

Suspicions about immune-damaging pollution are unproved, and the scientific techniques to test them have emerged in only recent years. Yet the theories are bolstered by a growing body of evidence from several hundred researchers, especially in Europe and Canada, who are examining animals in the wild, cells in laboratory tests and some human populations.

Gathered last year at an unprecedented environmental health summit, U.S. government, academic and industry scientists concluded that “the wide range of immune system impairments” that seem tied to pollution must be thoroughly investigated because the human race could be leaving itself biologically ill-equipped for survival.

Infectious diseases have surged worldwide, killing 16.5 million people each year. New viruses have emerged and old ones thought to be under control--such as tuberculosis--are flaring up again. No one knows what role immune-suppressing pollutants are playing, but health experts warn that the danger posed by a suppressed immune system has been demonstrated with the emergence of AIDS, where immune-deficient people are left defenseless to disease.

“On a population basis, even a rather modest immune suppression from pollution, in my view, has a contribution to the severity of a disease going on,” said Henk van Loveren, head immunobiologist at the Netherlands National Institute of Public Health and Environmental Protection, which has conducted pioneering research on immune suppression.

“People aren’t dropping dead,” he said. “But they may have an infection longer or get it faster, or maybe one person will die a bit earlier.”

Effect of Chemicals

Like soldiers on the front line, immune cells defend the body against a foreign invader such as a virus. But chemicals can block the cells from proliferating and mobilizing.

The immune system, like any good army, has multiple layers of defense. “Natural killer” cells are powerful, fast-moving warriors that mount the first attack against viruses and tumors. T cells clear an infection and order B cells to unleash antibodies, the ammunition against specific foreign agents.

Disarming of this immune infantry has been linked to environmental causes in various populations. Among the evidence:

* In the former Soviet Union, children in villages highly contaminated with pesticides are afflicted with two to five times more lung infections than those in less contaminated areas. Nearly 80% showed abnormal T cell counts or other immune deficiencies.

* Swedish fishermen who eat Baltic Sea fish containing PCBs and dioxin had reduced natural killer cells, and the more fish they ate, the fewer of the cells they had, a 1993 study showed.

* Children born to mothers who lived in dioxin-contaminated Times Beach, Mo., had a sixfold decrease in T cells compared to other children, a 1993 study showed. Adults, however, seemed normal and there was no evidence of increased disease.

* Sons and daughters of 2,000 people in Taiwan who ate rice oil accidentally tainted by PCBs in 1979 had a high rate of immune cell deficiency and three times more lung infections.

* One-third of Michigan farmers who consumed meat and milk from cows fed an immune-suppressing flame-retarding chemical in 1973 had unusually low T cell counts.

Ominous Damage

The animal kingdom, especially, is sending clear warning signals about the human danger. Europeans eat the same Baltic herring that left harbor seals defenseless to a massive viral dieoff. Canadians eat fish from the St. Lawrence River linked to T cell suppression and tumors in beluga whales. And eating Great Lakes fish apparently leaves birds with severely depressed immunity.

All animals, including humans, share the same basic immune system.

“We have to remember we live on the same planet as these animals,” said Sylvain De Guise, an immunotoxicologist studying Quebec’s beluga whales. “If we can demonstrate effects in a wildlife population, we raise concern about many other populations that may suffer more subtle effects, including humans.”

Experts suspect that the most severe damage begins before birth, since a fetus’ developing immune system is vulnerable to toxic chemicals consumed by its mother.

“If you ask me what the most sensitive organism is to these adverse effects, it’s the embryo,” said Linda Birnbaum, director of experimental toxicology at the U.S. Environmental Protection Agency’s Health Effects Research Laboratory.

There is no doubt that people who encounter extraordinarily large doses of industrial chemicals suffer severe immune deficiencies. Scientists, however, are undecided about whether the multilayered immune system is resilient enough to rebound from the long-term, low dose exposure to contamination typically found in the modern environment.

“What we’re trying to decide is . . . at what point [of immune suppression] do you worry about an increase in infectious diseases and tumors?” said Ralph Smialowicz, an EPA researcher who co-authored an immunotoxicology textbook.

As shown by AIDS patients, if immune cells are depleted by half, the human body succumbs to deadly infections. Damage from pollution, though, is nowhere near that severe.

Worldwide, people on average carry 1 part per million of PCBs in their fat. In comparison, seals suffer 35% depletion of immune cells when carrying 17 parts per million in their bodies. Terns in the Great Lakes had 30% fewer immune cells when the eggs they hatched from had 8 ppm.

A reasonable assumption, based on the animal data, is that most people have lost 5% of their disease-fighting ability due to PCBs in their bodies, said Michael Luster, head of immunology at the National Institute of Environmental Health Sciences and one of the nation’s foremost experts on the topic.

A 5% decline may sound minimal--a stressful day at the office could weaken immunity that much. But Luster said that, unlike transient stress, the damage from pollution can be permanent and effect billions of people.

“If the individual’s immune response is decreased by 5% in the large population,” he said, “and that is chronic, then over the years that would be a pretty large decrease that probably increases infectious disease.”

Lacking definitive proof connecting disease to pollution, some scientists remain dubious that the amount of suppression is substantial enough to cause human illness.

“Your immune system is being assaulted at all times during the day and night, but most of us go through life relatively healthy,” said Peter Thomas, an immunotoxicologist at IIT Laboratories, a Chicago research institute largely funded by the chemical industry.

“Look at HIV. You’ve really got to knock the hell out of the immune system to see effects, so why should we worry about the subtle effects from pollution?”

Most healthy adults can fend off viruses even with compromised immunity, but a fetus could suffer permanent damage to its thymus or bone marrow--the factories for immune cells--if its mother is exposed to contaminated food or water.

“Children are my greatest concern when it comes to those kinds of effects,” said Dr. Lynn Goldman, a pediatrician who is EPA’s assistant administrator for pesticide and toxics control. “Where we have observed health problems in humans, they have been found at the lowest contamination levels in children, particularly for prenatal exposure.”

Inuit infants have provided a living test tube for immunologists.

By air and by sea, the Canadian Arctic soaks up much of the hemisphere’s pollution. PCBs, used as insulators in electrical transformers, and the pesticide DDT used thousands of miles away, wind up there due to the northward flow of air and ocean currents. PCBs and DDT don’t break down or wash away, binding instead to sediments and building up in the fat of animals and humans via the food chain.

Due to their diet of contaminated sea animals and fish, Inuit women’s breast milk contains six times more PCBs than women in urban Quebec, according to Quebec government studies. Their babies have low B and T cell counts, which could explain their strikingly high rates of meningitis, bronchitis, pneumonia and other infections compared with other Canadians. One Inuit child out of every four has chronic hearing loss due to infections.

“In our studies, there was a marked increase in the incidence of infectious disease among breast-fed babies exposed to a high concentration of contaminants,” said Eric Dewailly, a Quebec Public Health Center researcher who coordinated the work.

Few Alternatives

Without seal, whale and fish, there are few alternatives for nourishment in a region where eggs cost $6 a dozen, a chicken brings $25 and fresh vegetables are a rare treat. Quebec health official Susan Bruneau said the Inuit would resort to processed foods that leave them prone to an even worse threat--heart disease.

Breast-feeding is still encouraged because its immunological benefits could outweigh its threats. “The benefits are well-known,” Bruneau said, “but the risks are potential.”

In the United States, the EPA banned PCBs and DDT two decades ago, but the agency does little to protect people from other immune-suppressing chemicals. Pesticides undergo a battery of tests on lab animals to predict health effects, but the tests are not sensitive enough to detect most changes in immune cells.

“With immune effects, we’re right at the cutting edge,” Goldman said. “There may be some opportunities in the future to add new tests to look for signs of immunotoxicity. But we need to know whether the animal data is predicting something meaningful to public health.”

Although all animals have the same basic immune systems, some species are more susceptible to pollution damage than others, perhaps due to different metabolism. And no one knows where humans fall in the spectrum of vulnerability.

“There appears to be a considerable difference in sensitivity. So do we protect the most vulnerable species or do we go for an average or do we go only for humans?” said Cornell University immunotoxicologist Rodney Dietert. “That’s one of the great dilemmas we face.”

Dioxin, for example, is the most toxic substance ever created by humans when it comes to laboratory rats and guinea pigs. But in people--such as Vietnam veterans exposed to Agent Orange or residents of Times Beach--results have been mixed about the impact on their immune systems.

“The public needs to understand,” said University of Wisconsin zoologist Warren Porter, “that we will never know the ramifications of the large-scale mixtures of all this stuff in our air and water.”

To unravel the mysteries of immune suppression and autoimmunity, experts look for a telltale symbiosis of pollution and sickness that is unlikely to be explained by mere coincidence.

On the Arizona side of Nogales, Anna Acuna lives in the shadow of Mexican factories and smoldering waste dumps. For years she would awake sobbing, convinced that her body--or maybe her mind--was crumbling. The joints in her legs and feet throbbed, and she was so fatigued that she struggled to simply climb out of bed and dress for work.

When finally diagnosed with the rare autoimmune disorder lupus, Acuna didn’t tell her friends, assuming she would never find anyone with the same peculiar and devastating disease. Years later, while lunching with three other women, Acuna stumbled upon her hometown’s best-kept secret.

“Out of the four women sitting there, three of us had lupus,” she said. “Friends started coming up to me and saying, ‘Anna, I had no idea. I have it, too.’ I don’t know why I did this, but I started writing their names down. And I ended up with a roster of 42 people in Nogales diagnosed with lupus.”

Arizona health officials suspect that an excessive rate of lupus and deadly multiple myeloma--two diseases involving faulty antibody-producing B cells--among longtime Nogales residents is linked to toxic chemicals in the air or water.

Medical researchers have proved that autoimmune disorders are triggered by accidental poisonings, medications and workplace use of chemicals. In the worst example, 20,000 Spaniards who consumed poisonous olive oil in 1981 suffered symptoms of scleroderma, a rare autoimmune disease in which the skin hardens. Most recovered, but more than 350 died.

Now, emerging research is exploring whether chronic exposure to lower-dose environmental chemicals, including some widely used industrial solvents, can trigger autoimmunity, especially in people with a genetic predisposition.

“We know medications can induce a syndrome similar to lupus, and those are chemicals. So why wouldn’t chemicals in the environment cause a lupus-like illness?” said Dr. Bridget Walsh, a University of Arizona rheumatologist who examined Acuna and about 100 other Nogales residents for a groundbreaking 1994 study.

In Tucson, a study commissioned by residents suing Hughes Aircraft reported an inordinate rate of lupus among 50,000 people who drank water highly contaminated with trichloroethylene, a degreasing solvent. The company, which paid $85 million to settle with 2,400 residents and faces several other class-action suits, hired a rheumatologist who countered that the study is seriously flawed.

Debate About Causes

Thousands of veterans of the Gulf War have complained of autoimmune-like joint pain. Silica is known to cause autoimmunity in quartz miners, leading experts to speculate that inhaling silica in desert sand might have triggered the effect in some soldiers.

“I’m not convinced by the studies to date, but I’m impressed by these observations, and they could be important clues,” said Dr. Evelyn Hess, a University of Cincinnati Medical Center expert in chemical-caused autoimmunity. “They should be followed up, since we’re dealing with disorders which we don’t know the cause.”

Clusters of disease are often an illusion. Many are suspected, few are proved. Nogales is one of the few.

In Nogales, a town of 20,000, 12 people between 1989 and 1993 were diagnosed with multiple myeloma, a bone marrow cancer, more than twice the rate expected in a town its size, according to the study by the University of Arizona and Arizona Department of Health Services.

Lupus was confirmed in 19 people and considered probable in seven more--four times the reported average and the highest rate ever found for the disease, which mostly strikes women and can inflame any joint or organ.

The list of those afflicted is believed to be much longer, since some illnesses were undiagnosed or latent, and residents who grew up in Nogales and moved were excluded.

“When you have two rare diseases in excess that are both B lymphocyte disorders, that suggests something is going on,” said Larry Clark, a University of Arizona epidemiologist who led the investigation. “We’re as close as anyone can get in showing that this looks like an environmental cluster in a high incidence area.”

The town, 95% Mexican American, is plagued with so many sources of pollution that no one has a clue which chemical--or more likely which combination--might be playing a role in the lupus and myeloma.

Separated from Mexico by a shabby wooden wall, Nogales is a residential enclave with no industry of its own to speak of. There are few signs of pollution on the Arizona side. No smokestacks. No festering dumps. No noxious odors.

But as the people of Nogales put it, pollution doesn’t carry a passport.

About 100 U.S.-owned electronics plants and other factories, called maquiladoras, line the Mexican side of Nogales and emit numerous toxic chemicals into the air. The concrete-lined Nogales Wash carries a nightmarish mix of raw sewage and toxics from Mexico. A Mexican dump caught fire on and off for decades before being moved farther from the border.

Autoimmune Response

The most persuasive evidence from the university study found that the closer people live to the pollution sources, the higher their auto-antibodies, a measurement of the severity of their immune cells’ attack on healthy tissues. Women living near the dump and the Nogales Wash had 10 times more auto-antibodies than those farther out in Nogales and in the town of Patagonia.

Margaret Chaboya, 45, was born and raised two blocks from the wash in a pleasant vanilla-colored stucco home with a triple-arched porch. “Never,” she said, “did I think there was anything harmful here.” A homemaker with luminous eyes and a radiant smile, she seemed healthy until she woke up nauseated one morning around Thanksgiving of 1994. Within two days, she was diagnosed with lupus so severe that 75% of her kidney function had been destroyed.

Despite chemotherapy, steroids and 13 other daily medications, Chaboya periodically suffers agonizing migraines and leg pains so severe that the weight of a bed sheet is sometimes unbearable.

“When you first get sick, who in the heck would blame the environment?” she said. “As Latinos, most of us think it’s God’s will or we’re being punished for something.”

It is possible, say some rheumatologists and the university epidemiologists, that the lupus in Nogales has more to do with genetics than the environment. Lupus occurs more often in Native Americans than Caucasians, and many Latinos have Native American roots.

“The bottom line is it’s my belief that there is no environmental cluster of lupus in Arizona or anywhere,” said Dr. Dan Wallace, chief of rheumatology at Cedars-Sinai Medical Center and a UCLA medical professor. Wallace was hired by Hughes Aircraft as an expert witness in the Tucson suit but is not involved in the Nogales research.

However, epidemiologist Clark said past generations of Latinos in Nogales apparently were unafflicted by lupus, and there is no genetic link that could explain the other disease, myeloma.

“It’s our generation that’s getting sick, not our mothers or our grandmothers,” said Acuna, 56, co-founder of Living Is For Everyone, a community group that convinced the state to conduct the health study. “The only thing that has changed is the maquiladoras. We all grew up in the ‘50s, and that’s when the maquiladoras came in.”

Arizona’s health department has compiled a long list of toxic compounds found in Nogales’ air. But no one knows which, if any, might be contributing to the diseases. The culprit could be something people were drinking and breathing years ago or that their mothers encountered before they were even born.

“I compare it to finding a needle in a haystack and a cow consumed the haystack and somebody ate the cow 20 years ago,” said Mike Foster, an Arizona hazardous materials inspector who patrols the border area.

With so many lingering questions about immune-altering pollution, and the human body’s defense mechanism at stake, researchers worry that the answers are too slow in coming.

“My god, something’s happening in this town,” Foster said. “I don’t know if we’ll ever find the link, but that doesn’t mean we shouldn’t look, and in the meantime, we should try to prevent this from happening.”

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The Immune System

Mammals, including humans, have developed a sensitive, elaborate and multi-layered network to protect themselves from foreign invaders such as viruses, bacteria and tumors:

Autoimmunity

The immune system can malfunction and become hyper-activated, triggering a condition in which immune cells attack the body’s healthy tissue as if it were a foreign agent. Many diseases can result, such as lupus. The most common symptom is joint pain.

Natural killer cells

These cells mount the first and most rapid defense against viruses and tumors. They recognize some tumor and virus cells without the need for specific antibodies.

T cells

These white blood cells play an essential role in clearing an infection. Some (called T-helper cells) communicate with other cells, such as B cells, to order an attack.

B cells

These white blood cells produce and secrete antibodies.

Antibodies

The proteins produced by B cells that attack specific foreign agents in bacteria, viruses, tumor cells.

Thymus

The small organ where stem cells mature to form T cells. Impairment of the thymus leads to low immune cell counts.

Bone marrow

The soft tissue in bones where stem cells are manufactured. T cells then pass through to the thymus to mature, while natural killer cells and B cells move straight to the blood.

Lymph nodes

These small structures, situated throughout the body, filter out foreign cells draining from body tissues.

Autoimmune disorders linked to chemical pollutants:

CHEMICAL / DISEASE

Cadmium: autoimmune kidney disease

Carbon tetrachloride: Goodpasture’s syndrome

Chlordane: lupus

Chromium: lupus

Hydrazine: lupus

Hydrocarbon solvents: Goodpasture’s syndrome

Mercury: autoimmune kidney disease

Paraquat: autoimmune kidney disease

Perchloroethylene: autoimmune kidney disease

PCBs: autoimmune thyroid disease

Silica: scleroderma

Trichloroethylene: lupus, scleroderma

Vinyl chloride: scleroderma

Source: Experimental Immunotoxicology

The Poisoned Pole

Although they live in one of the last, vast wild regions, the Inuit people of Arctic Canada are believed to be the most highly contaminated humans on Earch. The area where they live soaks up much of the world’s pollution due to northbound air and ocean currents. Because the Inuit rely on a diet of marine mammals and fish, their bodies collect extremely large amounts of PCBs, an immune-suppressing industrial pollutant. The women’s breask milk is more contaminated than is whale and seal blubber, and an infant could build up dangerous PCB levels in the blood after just a few months of breast-feeding. Inuit children suffer frequent meningitis, pneumonia, bronchitis and ear infections, which appear to be related to the immune damage caused by PCBs and other pollutants.

Arctic women’s milk fat: 1,052 parts per billion of PCBs

Polar bear fat: 7,002 ppb

Whale blubber: 1,002 ppb

Seal blubber: 527 ppb

Arctic fish: 152 ppb

Non-Arctic women’s milk fat (urban Quebac): 157 ppb

Source: Quebec Public Health Center