Parasitic Worms Ease IBD
May Reduce Overactive Immune Response Behind Crohn's Disease, Ulcerative Colitis
IBD is believed to be among the "autoimmune" disorders that
includes lupus, multiple sclerosis, and psoriasis
and may result from an overactive immune response, in which cells that normally
attack invading disease and infection instead target healthy tissue. With IBD,
the immune system may overreact to normal intestinal bacteria, causing
inflammation and gradually eating away at the intestinal lining.
Summers says the worm eggs decrease this overactive immune
response, possibly by secreting a substance.
"We know that people with certain colonized worms in their
digestive tracts have a reduced immune response," he tells WebMD. "Therefore,
we're hopeful that this treatment may someday prove useful for other autoimmune
In fact, Crohn's and ulcerative colitis are often treated with
medications that suppress immune response (immunomodulators), such as AZA and
Mexate. Other IBD drug treatments include antibiotics, corticosteroids such as
Prednisone, or aminosalicylates such as Azulfidine and Dipentum.
More recently, some patients have been treated with "probiotics" -- bacteria given
specifically to retain remission that appear to work as well as
immune-suppressing drugs, says IBD expert Seymour Katz, MD, past president of
the American College of Gastroenterology and clinical professor of medicine at
New York University School of Medicine.
"So it's not that much of a galactic leap to say, 'Let's go one
step further and introduce these worms to change the immunologic response of
IBD patients," Katz tells WebMD. "This is certainly an intriguing concept that
has merit, but the data is still very premature. And knowing the litigious
nature of society, in addition to the fact that most people are repulsed by the
thought of being given worms, there's a lot of baggage that needs to be
Unlike other parasites that can cause infection, the pig
whipworm doesn't cause problems because it's not recognized by the human body
as a foreign invader, and only colonizes for a few weeks. The Iowa researchers
have also tested three other types of parasitic worms in studies of mice
induced with a form of colitis. All have been effective, says Summers.
"These worms have been around for 3 million years," he says.
"And one-third of the world's population is walking around with them in their
GI tracts today and apparently having no problems."