very moment of every day, our bodies are assaulted by toxins and viruses, bacteria and molds which are fully capable of killing us horribly. This is one important reason we have skin: to draw a line between our bodies and the outside world, through which almost nothing is allowed to pass. Of course, if we want to eat and breathe and see and defecate, our skin needs certain openings, which are protected by mucous membranes--a lesser but still important barrier. These can be penetrated, though, and new openings in the skin can be made accidentally, creating opportunities for these ghastly invaders to sneak inside.
There they find a microbial Eden: moist, climate-controlled, protected from damaging sunlight, and generously stocked with the machineries and raw materials of life. This is why animals, and especially mammals, have sophisticated, multilayered immune systems to detect, classify, neutralize and eliminate any and all foreign bodies, before they have a chance to set up camp. When the Ebola virus attacks, it generally overwhelms these defenses and starts replicating so rapidly and effectively that within days a majority of cells in the victim's internal organs and bloodstream have ruptured, their mass converted almost completely into clumps of new virus. Inside the skin, the body has literally turned to viral goo. This leads, not surprisingly, to the death of the host.
That's the deadliest virus in the world, though. It's important to remember how busy and effective and generally awesome our immune systems are, as demonstrated by the fact that this liquefaction doesn't happen to all of us, immediately, from pathogens as "harmless" as yogurt and the common cold. Pause a moment to reflect on that, because no system is perfect, and the immune system can unfortunately make us sick when it's overstressed or confused. Which is happening more and more these days, as we flee the rural areas of our natural environment in favor of cities.
Biological systems
can be revolting
Not that modern cities are all that dirty; in fact, with no parasitic worms, no significant fungi or soil bacteria, no heaps of manure, they may be too clean for our own good. Studies have shown a link between sterile environments and the incidence of immune-related disorders such as asthma and allergies. Our bodies expect a bitter conflict every day of their lives, and, like drunken mercenaries, they turn rowdy when they don't get one, attacking dandruff flakes and pollen grains and even food particles as though they were invading organisms. Damn yahoos.
This is annoying, inconvenient and sometimes dangerous, but an even darker side to the immune system surfaces when it mistakenly attacks the body's own tissues. This leads to a class of progressive, wasting illnesses called autoimmune disorders. Rheumatoid arthritis, a disease which erodes the protective membranes surrounding our joints, is one of the most common of these, afflicting about 1 percent of people in Western societies. A healthy joint is continuously repaired by the body, so that the normal wear and tear on it has no chance to accumulate. In an arthritic joint, though, these repairs are inhibited by inflammation, which gradually wears away the cartilage and even bone. This is incredibly painful and often disfiguring, and in the advanced stages of the disease the joints are often so swollen and misshapen that they refuse to operate at all. The immune system has gone berserk, literally crippling the body it's supposed to protect.
Traditional treatments for arthritis include pain killers for symptomatic relief and anti-inflammatory drugs to slow the erosion of the joint. These drugs are hard on the stomach, though, and can lead to ulcers and gastro-esophageal reflux disease--chronic severe heartburn. For many patients, it's simply a matter of picking which cross they'd rather bear. Steroids can soothe inflammation without chewing up the gut, but have other side effects in the body and brain which can be even more dangerous in the long run. This leaves only one final option: surgical repair of the joint, and ultimately its total replacement with a mechanical substitute. Real-life bionics don't make you superstrong, though. In fact, because they lack the self-repair mechanisms of living tissue, artificial joints are guaranteed to wear out at some point. And for the most part they're not available where patients need them most: in the intricate bone structure of the hands and feet.
Autoimmune diseases are caused by antibodies--special proteins designed to attach to specific foreign bodies or substances--to surround and imprison them until the kidneys can flush them out with other waste products. Antibodies are manufactured by a type of white blood cells called "B-lymphocytes," which are produced by stem cells in the bone marrow and programmed by the lymph nodes. But sometimes, mistakenly, B-cells will start generating antibodies which attach to collagen, or myelin, or some other material critical to the structure and functioning of the human body. By itself, this is relatively common and relatively harmless, but if an additional error is made, the immune response and resulting inflammation may lead to the endless reproduction of the erroneous antibody. The result is a vicious circle--what programmers would call an endless loop. Some researchers attribute this failure to a random genetic bit-hit, but certain autoimmune diseases also seem to run in families.
Doctors press human reset button
Frustrated with the limitations of tradition, doctors in the 1990s developed a radical new arthritis therapy: filtration of the entire bloodstream through a device called a "prosorba column." In a treatment resembling the dialysis used for kidney patients, the prosorba column filters unwanted substances--specifically the autoimmune antibodies--from the blood which passes through it. Even among longtime sufferers who've exhausted every other alternative, the success rate is around 50%, which, all things considered, is not too shabby. Unfortunately, as with dialysis, the results are temporary. To hold the disease at bay, regular treatments will be required for the remainder of the patient's life. Frustrated with that idea, researchers at University College in London have recently pioneered an even more radical approach. There are already drugs on the market which fight certain forms of cancer by targeting and destroying B-lymphocytes in the bloodstream. What these bold Brits did was inject high doses of these drugs into a group of arthritis patients, with the goal of killing off every last B-cell in their bodies.
It turns out that patients can live without B-cells for a few months. The antibodies already circling in the bloodstream provide protection against the body's various enemies, until the bone marrow produces a new batch of lymphocytes. And surprisingly enough, this new population retains all the stored immunities to actual pathogens, but in nine out of ten cases it does not include the genetic errors which led to the arthritis. In other words, with a single treatment 90% the patients were cured. Permanently. If you're a computer user--and what scifi.com reader isn't?--the obvious metaphor is the reset button you use to reboot a buggy Windows session. B-cell therapy may in fact be the biological reset button arthritis sufferers have dreamed of since the dawn of time.
And really, the news is even better than that: while rheumatoid arthritis can slowly cripple its victims, other autoimmune disorders, including multiple sclerosis and lupus, can kill. Sometimes quickly, always badly. But now, all of a sudden, there's hope: can B-cell therapy cure these diseases as well? It seems damned likely, although clinical trials won't be complete for a while yet. And it doesn't stop there. Autoimmune diseases occur more frequently among elderly, since they've had more time than younger people to accumulate genetic errors in their lymphocytes. This has led some people, myself included, to wonder how many of the symptoms of aging may in fact be caused by the accumulation of minor, undiagnosed autoimmunities. More than zero? I'll bet you a dollar.
In the future, routine medical maintenance may very well include visits to a "reset clinic" every decade or so, just to clean out the accumulated autoimmune garbage. Will we live forever as a result? Unfortunately not; aging stems from a variety of genetic and environmental causes which will not be so easily outsmarted. But we may live longer, and we'll certainly live happier, without ailments like rheumatoid arthritis coming between us and our health. Even for centenarians, it seems, life's pleasures await.
Wil McCarthy is a rocket guidance engineer, robot designer, science fiction author
and occasional aquanaut. He has contributed to three interplanetary spacecraft, five
communication and weather satellites, a line of landmine-clearing robots, and some
other "really cool stuff" he can't tell us about. His short fiction has graced the
pages of Analog, Asimov's, Science Fiction Age and other major publications, and his novel-length works include Aggressor Six, the New York Times notable Bloom, and The Collapsium.
