May 30, 2000 -- From the time she was 2 years old, Kathleen Arntsen suffered from a variety of health problems. "I was always thirsty," she says, "and even as a small child, I always had cold hands and feet." Arntsen also says that she was especially prone to infections, and "caught every childhood infection that there was. You name it, I got it."
Doctors couldn't find anything wrong with her. Her symptoms persisted and worsened by the time she went off to college, and she was labeled a hypochondriac because all tests kept coming back normal. But despite her problems, Arntsen kept up with school and was very athletic. "Then one morning, I just couldn't get out of bed. I ached all over," she remembers.
Even though the doctors still couldn't find any reason for her illness, Arntsen believed that there was something terribly wrong with her. Soon she was unable to lift her arms over her head, and she developed a rash on her face.
Finally, doctors found that she had lupus, a disease that affects millions of people worldwide. It causes the immune system to attack the body's own cells and causes multiple symptoms such as arthritis, sores on the skin, and kidney failure. And even though it's not primarily a hereditary disease, Arntsen's grandmother had died the year before, experiencing symptoms very similar to hers.
The majority of lupus patients are young women, like Arntsen, and the causes of the disease are still unclear, primarily because the condition is extremely complex and affects numerous systems of the body. However, a recent study indicates that researchers may be one step closer to uncovering the secret as to why lupus develops and perhaps one step closer to discovering an effective treatment or cure.
"The problem studying lupus is that lupus is a collection of multiple disorders with multiple [causes] ... what we clinically label as lupus is undoubtedly a whole slew of different disorders," says William Stohl, MD, PhD, who was not involved in the study. Stohl is an associate professor of medicine at the University of Southern California.
When cells in the body die, they break down into DNA, protein, and other debris, which needs to be cleared away in order for systems to function properly. The substance responsible for clearing away "cellular trash" is known as Dnase1, and German scientists have shown the first direct evidence that a deficiency in Dnase1 functioning may be one of the causes of lupus. This is because the "cellular trash" may cause the body to mount an immune response to it and to begin attacking its own cells.
The researchers found that Dnase1 levels were lower in people with lupus and in animal experiments, stopping the production of Dnase1 resulted in lupus-like symptoms.
But whether the lack of Dnase1 actually leads to disease, or simply makes the disease worse for those who already have it, is difficult for experts to agree upon.
It also is unknown what causes people to lack Dnase1. Several possibilities are under investigation, says study author Tarik MÃ¶rÃ¶y, PhD, a professor of cell biology at the Institut fÃ¼r Zellbiologie in Essen, Germany. "There may be a loss of the Dnase1 gene" which sparks production of the enzyme, he says. "Or we may inherit a Dnase1 gene that is less effective in producing the enzyme. Environmental factors that inhibit Dnase1 activity in the [blood] is also a possibility."
Whether or not treating lupus patients with Dnase1 will be effective still remains to be seen. Animal experiments have shown good results, but the outcome was less optimistic with actual lupus patients. The form of Dnase1 available leaves the body almost immediately, which makes it less effective for treatment.
MÃ¶rÃ¶y feels that Dnase1 might have a better effect if used early on in the disease or to prevent it rather than in patients with full-blown lupus.
But the study evidence is not definitive, and even if the scientists are correct, lupus is too complex a disease to have just one cause. "It's right now still in the stage of hypothesis and conjecture, which is based on suggestive evidence but I wouldn't go so far as to say its proven yet," Stohl says.
- Lupus is a complex disorder that affects multiple parts of the body when the immune system attacks the body's own cells.
- New research shows that levels of a substance, called Dnase1, responsible for cleaning up debris from dead cells, is lower among lupus patients, compared to others.
- It is not known yet whether treating patients with this Dnase1 can effectively fight or slow this disease.