WEDNESDAY, Dec. 1 (HealthDay News) -- The case of a man who
swallowed parasite eggs to treat his ulcerative colitis -- and
actually got better -- sheds light on how "worm therapy" might help
heal the gut, a new study suggests.
"Our findings in this case report suggest that infection with the eggs of the T. trichiura roundworm can alleviate the symptoms of
ulcerative colitis," said study leader P'ng Loke, an assistant
professor in the department of medical parasitology at NYU Langone
Medical Center. A human parasite,
Trichuris trichiura infects the large intestine.
The findings could also lead to new ways to treat the
debilitating disease, a form of inflammatory bowel disease (IBD)
currently treated with drugs that don't always work and can cause
serious side effects, said Loke.
The study findings are published in the Dec. 1 issue of
Science Translational Medicine.
Loke and his team followed a 35-year-old man with severe colitis
who tried worm (or "helminthic") therapy to avoid surgical removal
of his entire colon. He researched the therapy, flew to a doctor in
Thailand who had agreed to give him the eggs, and swallowed 1,500
The man contacted Loke after his self-treatment and "was
essentially symptom-free," Loke said. Intrigued, he and his
colleagues decided to follow the man's condition.
The study analyzed slides and samples of the man's blood and
colon tissue from 2003, before he swallowed the eggs, to 2009, a
few years after ingestion. During this period, he was virtually
symptom-free for almost three years. When his colitis flared in
2008, he swallowed another 2,000 eggs and got better again, said
Tissue taken during active colitis showed a large number of CD4+
T-cells, which are immune cells that produce the inflammatory
protein interleukin-17, the team found. However, tissue taken after
worm therapy, when his colitis was in remission, contained lots of
T-cells that make interleukin-22 (IL-22), a protein that promotes
Further, after worm therapy, the man's colon produced
significantly more mucus, said Loke, who noted that a lack of mucus
in the colon is linked with severe symptoms. "We think the worms
increase or restore mucus production in the colon," he said.
"Basically, the gut is trying to expel the worms. This increase in
mucus may play a role in relieving the symptoms."
"This is not the usual clinical trial, but you take your opportunities for unique observation where you can," said Dr. Gerald W. Dryden Jr., director of the clinical research division of gastroenterology, hepatology and nutrition at the University of Louisville, in Kentucky.
Before this study, IL-22 had not been associated with beneficial
effect in IBD, said Dryden. "While it doesn't determine
cause-and-effect, the study does seem to demonstrate an important,
previously unknown association between IL-22 and response to
helminthic therapy," he said.
Causing abdominal pain, diarrhea and other symptoms, colitis
affects about 700,000 Americans, according to the Crohn's and
Colitis Foundation of America. Scientists don't know what causes
the disease, but theorize that immune-system dysfunction plays a
Colitis is common in developed countries such as America --
where parasitic worm infections are rare -- and in Asia, Africa and
Latin America, where virtually the entire population is infected,
the study noted. Clinical trials with the pig whipworm
Trichuris suis have improved the symptoms of both ulcerative
colitis and Crohn's disease, and animal studies suggest that
various parasitic worms can suppress inflammation, the study
The study also suggests new, worm-based treatments for both
ulcerative colitis and IBD. Research might identify molecules
derived from worms that suppress inflammation, or pathways
activated by worms that can be targeted by more conventional
approaches, Loke said.
Right now, however, worm therapy is still not well-understood
and could potentially backfire, the study warned. "The problem is
that these worms themselves can cause harm and damage the gut,"
said Loke. "The individual in this study is lucky to have responded
so well, but for other people the worm infection may exacerbate
bowel inflammation." Studies that use the pig worm, which should
pose less risk to humans, are under way, he added.
For more about ulcerative colitis, head to the
U.S. National Digestive Diseases Information
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